May 20, 2015 • 40 mins
Radar is a cool technology. We explain how it works and what radar has in store in the future!
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Episode Transcript
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Speaker 1 (00:00):
Brought to you by Toyota. Let's go places. Welcome to
Forward Thinking. Hey, they're and welcome to Forward Thinking, the
podcast that looks at the future and says I was
seriously thinking about hiding the receiver when the switch broke
because it's old. I'm Jonathan Strickland and I'm Joe McCormick.
(00:23):
And today we're going to be talking about radar, right
and uh. And and just for our fans who are
my age or older, we're not talking about the popular
character from the movie and television series Mash unfortunately not.
Now we're talking about the actual technology radar, which is
(00:44):
nothing new. No, it's it's it's been around for quite
a few decades. But it's super cool. There's a lot
of different applications for it that are really interesting, and
apparently there are going to be some new applications for
it in the future. Yeah, and even if there is
a future, well, it's on my radar. Uh, it's gonna happen.
Might as well get it all the way early. The
(01:06):
neat thing is the way that the technology is is
changing over time. Like there it's being married with other technologies.
But we'll get into that, Okay, Well, let me. Let
me explore the layman's view of radar. What is radar
If you don't know, it has something to do with
a circular screen that has a line that sweeps around
(01:26):
it and goes you've mistaken ever sonar? Oh no, wait,
hold on, hold on. It has something to do with
like a little antenna that spins around really fast. Yeah,
that's that's closer, and there can be around around screen.
It's just the bloop is totally indicative of sonar ups
as opposed to radar. You could make a radar display.
(01:47):
Bloop could incredible. Future looking is one of the easiest
things to program. Look, I've I've I've studied screenplays, and
I realized that if you make it blue, you have
confused your audience. So but no. The other interesting thing
that we want to talk about before we actually get
into what radar is now it works is the fact
(02:08):
that it used to be an acronym and now it's
not anymore. It's one of those words like laser, laser
was like this wasn't it? Sure was? Yeah, so it
used to be. It used to stand for something and
won't stand. You could walk into them. The President of
the United States could walk into our room. Radar is
not gonna get up right, It's just like it's just
a lowercase word. You don't even capitalize it. What did
(02:29):
it originally stand for? Radio detection and ranging. That's what
the United States Navy referred to it and the r
A of radio were capitalized because it wasn't in the
day when they would just add extra random words and there,
and they didn't to make the really cool Yeah, they
didn't want and they didn't want to call it nar. Yeah,
so so turn on the dar. Yeah that did not
(02:52):
That did not fly. So they went with radar. But
today it's just radar. It's just a little lowercase word
radar because we we say it so much, you know.
I mean, boy, if I had a nickel for every
time I talked about radar in your average week. Well,
let's explain how radar actually works. It's actually a pretty
simple principle. Yeah, it's actually very similar to echolocation, right,
(03:17):
It's it's based on a very so and and in
fact sonar it's it's based on similar principles, except in
stuff of sound. We're talking about radio waves, which by
the way, don't work so well underwater, but they were
great above water. So, uh, Essentially, what you're doing is
you're sending out bursts of radio waves or microwaves, like
we're talking super short bursts, like microsecond long bursts. And
(03:39):
you do that often whatever direction you're looking at, and
if those waves encounter and object, some of them will
bounce back towards the source of the transmission. So you've
got to You've got transmitter and the receiver. You turn
on the transmitter, you send out a blast of radio waves,
you switch off the transmitter, you turn on the receiver,
(04:01):
and when those returning waves come back one, you know
that there's an object out there that the waves have encountered.
And too, you know how far away it is because
you can measure the time it took from when the
radio waves went out of the antenna to when the
echo came back in, and beyond that, you can actually
tell whether or not the object is moving towards you
(04:22):
or away from you using the Doppler shift, right, the
Doppler effect that we're all familiar with from hearing police sirens. Yeah,
so when you hear a police siren approaching you, it's
it's getting this high pitch noise. It gets higher and
higher and then after it passes you, you know that, yeah,
(04:42):
suddenly gets lower, right, And the reason it does that
the Doppler effect applies to all waves. It's not just
sound waves, it's also radio waves. And what's happening is
essentially those waves are being compressed ahead of the moving
object when it's coming towards you, so the frequen s
is increased. And when the frequency increases with sound, that
(05:03):
means the pitch goes up right, And when the object
passes by you, then the waves are being elongated. So
now the pitch has decreased, it's gone down. And if
you were standing right next to the to a stationary
police vehicle while it was having the siren go off,
it would sound in between those two well relatively speaking. Yeah.
And in fact, you can even observe this with visible light,
(05:25):
say like in astronomy, the disena moving away from us
faster and faster in the galaxy or in the universe
are going to be red shifted. Right. And in fact,
also this is really part of what sonic booms. You know,
why we have a sonic boom. If you're if you
have an object that's moving faster than the speed of
sound at whatever altitude you happen to be at. Because
(05:46):
sound speed depends upon the medium it's traveling through, and
with atmosphere, it could be affected by lots of stuff
like humidity, the air density, the temperature, all that kind
of thing. But anyway, if we're talking about something moving
faster than the speed of sound, all of those sound
waves get compressed so so flat that if you're in
(06:08):
front of that object and it's coming towards you, you're
not going to hear anything. You might, yeah, you might
say what's that before it gets past you, And once
it gets past you, then essentially all that sound is
unleashed and a catch us up, glorious boom of fury
and then and that's where the sonic boom comes in.
And actually the sonic boom rolls along as long as
(06:28):
the object continues to move faster than the speed of sound. Now,
with radio waves, we don't get the sonic boom because
we're talking about radio frequencies, we're not talking about acoustic waves.
But what we can see is that if the frequency
of the returning echo is greater than that what we
than the frequency we sent out, then we know the
object that we're looking at is moving toward us. If
(06:50):
the frequency is less than what we sent out, we
know the object is moving away from us. And by
sending out series of these signals, we can tell in
what direction and at what speed the object is moving exactly.
And because each of these verses like a microsecond in length, here,
you can you know, you can do this several times
a minute, you know, depending upon what your system is
looking for and uh and how you're focusing on that
(07:13):
particular section of sky. Usually yeah, and so if I
remember correctly, you'll probably be able to tell me mostly
radar is going to be operating in the microwave frequency
of the e M spectrum. That's that's largely what we
see today. A lot of radio radar works in the microwaves,
but it can't work in other other parts of the
(07:35):
electromagnetic spectrum. And I think originally a lot of it
was in radio. Yeah, right, so that would be yeah, yeah,
So if you imagine the the e M spectrum, like
you've got the longer wavelengths than visible light or microwaves,
and then even longer than that or what we usually
call radio waves. So yeah, and and the frequency would
be you know, the greater the frequency, the greater the
(07:57):
amount of information we can get back, which is why
you want to use higher frequencies if you can. But
we'll get into that later, which is part of why
we talked so much about microwaves in another episode. We
wait a minute, if you can get more information from
higher frequency, why don't we just use gamma rays. Well,
there are a lot of reasons why. One is that
we don't want a lot of incredible hulks running around. Yeah. Well, uh,
(08:22):
you know, honestly, obviously, gamma radiation would be inably dangerous,
even if we could generate it easily without pouring tons
of energy into whatever system we had created to make gama.
That was my guess. Is just that it's harder to
make and that it would also kill you. Yeah, the
two combined are really good reasons why we don't go
into it. Okay, Well, let's look back at the sort
(08:45):
of the early days of radar, the juvenilia of radar,
well back when radar was just a gleam in a
bunch of engineers eyes. The you gotta look at the
beginning of the twentieth century. So a lot of the
groundwork was laid in the nineteenth century, where you had
people discovering and experimenting with radio waves, but it wasn't
until the early twentieth century that we started seeing people
(09:06):
figure out, oh, we might be able to use this
in order to detect things. Uh. There was an engineer
in Christian hulls Meyer who invented a system that allowed
ships or trains to avoid collisions on foggy days. Uh.
The uh, the source I was reading, which was the
APS Physics website, referred to it as crude. In other words,
(09:27):
it was not a very refined system. Sure, but but
you can immediately see or not see. Is the case?
Maybe the benefit that radio waves have over electromagnetic light
waves well sorry, visible spectrum, sure waves on a foggy day,
because you can't see through fog, right, Yeah, you have
radio waves can bounce right through if light is going
(09:48):
to be reflected off the fog bank ahead of you,
it doesn't. You can't really count on that being an
effective signal to any other vehicles. So yeah, it was
certainly something that was useful. The U. S. Navy had
begun to a experiment with radar, although it wasn't called
that at the time, to search for ships. But actually
that research was largely overlooked in the United States, Like
(10:08):
it was a group of researchers within the Navy that
was doing a lot of this work, but because it
was viewed as experimental, it wasn't thought of as particularly
practical at that time. So it's kind of like they
were left to do their own thing, and no one
was really thinking it would ever come to anything. But
that's amazing because it seems so clear to us now
how useful something like radar is in warfare, Like you
(10:32):
can have real time updates about the position of enemy
vehicles in the moment, you know, as soon as they're
advancing on you. You can see them in long distances well,
especially things like aircraft, which would be particularly useful. And
in fact, over in the UK research was going on,
you know, in various places, but largely we have to
(10:52):
thank Sir Robert Watson What, who was actually a descendant,
a relative and distant relative of of the famous what
What did all the steam engines at any rate? Uh So,
Sir Robert Watson Watt began to work with radio waves
um as a means of detecting aircraft, but first had
(11:13):
been working in the Meteorological Office to develop systems to
detect lightning strikes because lightning can give off radio waves.
In fact, lightning strikes do give off radio waves, so
if you have a detector, then you can start to
detect thunderstorms, and that was considered to be very useful
the UH, the United Kingdom at the time, wasn't really
concerned with developing radio detection systems. But what happened was
(11:39):
there was a rumor going around that the Germans had
developed a death ray using radio waves, and so the
UK government came to Watson. Watton said, if that's a thing,
we're gonna need one of those. Can you even make
one of those for us? And so he started looking
into it, but very quickly he said, you know, there,
(12:00):
this doesn't seem feasible at all from everything I've learned.
That doesn't make sense. However, maybe we could focus on
radio detection instead of radio destruction. And he really began
to push for this means of using radio to bounce
waves off of objects so that you can detect them remotely,
and he got some support and it was very important
(12:23):
in the UK at the time because we're talking about
getting into World War two and the UK was heavily
involved and obviously the fears of Germans German aircraft coming
over and bombing England were warranted, so they the ability
to get people out of an area when they saw
(12:43):
when they saw craft coming huge absolutely necessary. Yeah. Funny
side note to this, This is actually sort of related
to the myth that carrots give you super eyesight. Did
you know this? I wrote a brain Stuff episode about this.
It's a fascinating little historical blip. So yeah, Apparently one
(13:05):
of the reasons that the British Royal Air Force was
pretty successful in repelling UH access air raids against the
British was that they had on board radar. So like
these these planes were equipped with you know, radar systems
that could tell them when enemy aircraft were approaching from
a very long distance. But of course they didn't want
(13:25):
to let onto anything like that, so part of their
misinformation campaign. Yeah, well, I think that's one theory. Other
people have different explanations for why they said this, but
for whatever reason, the British government said, you know, the
reason our pilots can see so well is because they
eat lots of vegetables rich in vitamin A like carrots.
So at the same time, of course they were trying
(13:48):
to get people to eat carrots because that was like
one of the you know, one of the foods, one
of the few foods that was plentiful in England at
the time, to and to grow victory gardens quote unquote
victory gardens that in which carrots were quite easy to grow. Right,
that's interesting, Yeah, oh well, you know, but so it
turns out it was a lie, you know, the pilots
(14:08):
suggesting that they just had super keen eye sight. At
the same time, vitamin A is very important for maintaining normal,
healthy eye sight. So so we eat your carrots, kid. Well. Meanwhile,
going back over to the United States, during the same time,
the Navy continued to develop radar and in fact named
it such, creating the first US radar and it was
(14:31):
called the x A F. It was installed on the
U s S New York battleship in nineteen thirty nine.
So obviously the earliest uses of radar were in military applications,
and that's not a huge surprise, I mean it was
that was where it was very much useful. But shortly thereafter,
once the war ended, we started to see radar get
used in lots of different applications, including a lot of
(14:53):
commercial ones, so air traffic control aboard aircraft itself, like
like you were saying jokes for commercial aircraft, not just um,
military aircraft also uh, commercial ships, UM and other means
as well. And and of course going back to what
Watson Watt was originally studying, we began using it for
(15:15):
weather detection, yeah, and forecasting. And this is uh, you know,
like Doppler radar. You hear it all the time, especially
here in Atlanta. Again they're so proud of their Doppler
radar UM, but yeah, it's Doppler radar. Is is using
the Doppler chef to detect moving weather patterns. And honestly,
what they're mostly looking at is precipitation. So you know,
(15:36):
the radar, the radio waves or microwaves will bounce back
from precipitation telling you, oh, well there's a front moving
in and we can keep track of it. We can
even map out the shape of it. And so when
you see the radar imagery that's based off the data
that's coming back from that, that uh the signals which
(15:57):
is pretty cool. Uh. The radar transmitters for Doppler radar
for weather are pretty powerful. They use food watts of
electricity when they're blasting out signals. I gotta be honest,
I have no idea how much that is. A regular
microwave oven is one thousand watts, So multiply a regular
(16:18):
microwave oven four fifty times and you get what. But however,
this particular radar technology isn't used, you know, It's not
like they turn it on and it's blasting out radio
waves for like hours at a time, right right, It's
it's more like defrost mode on your microwave where it
sends out kind of little blips and and then collects them.
(16:39):
All right, It's it's to get a composite. It's spending
most of its time listening rather than blasting. So it'll
send out a blast of radio waves in a very
short amount of time of fraction of a second, and
then it listens for a good long while for the
echoes to come back. So we're talking about um such
a short amount of time that the source I've read
said it transmits for about seven seconds in a typical hour.
(17:04):
So it sounds like if they just leave this thing on,
the army could have the death ray they wanted. Well,
they could at least drain the power grid nothing else. Uh,
I don't know that it would necessarily do anything else besides, um,
you know it could it could probably jam communications with
that many radio waves going out, but that'd be about it. Well.
(17:26):
I mean, we used to think about radar as this
kind of like high tech, expensive military technology, and it
used to be that. Yeah, but but now you see
it all over the place, right Yeah. Now it's actually
making its way into consumer technology. So I mean, you know,
it's not going to be in your smartphone, but it
might be in your car yet. Yeah. So autonomous cars
(17:48):
obviously need to have a lot of of sensors, right
in order to to note what is in their particular
neighborhood so that they know, you know, whether they can
merge over, change lanes, speed up, slow down, that kind
of thing, right, And you can use different kinds of
waves to do this. For example, one thing we've seen
employed a lot in autonomous cars is lidar, yeah, which
(18:08):
is you know, it's laser oriented as opposed to using
radio frequencies. But radar is also used. Uh. There are
lots of different systems where radar is used to maintain
a safe distance between the vehicle, the vehicle itself and
any vehicles around it. So you know, like the rule
of thomb being that if you're behind a vehicle, you
(18:29):
should be able to count to three uh when it
passes a landmark before you pass that landmark to Well,
these kind of systems will make sure you maintain that
safe distance at whatever operating speed the vehicle happens to
be at. So yeah, and I think you you talk,
you go into a little bit more detail about that
one in the video version, yeah, our radar episode, right, Yeah,
(18:51):
I specifically talk about dynamic cruise control, which is something
that's kind of a it's like a stepping stone between
the cars we have now and truly autonomous cars and
a lot of vehicles right now have dynamic cruise control UM.
And the basic principle is that you set the cruising
speed of your vehicle, but it also has this radar
system so it can maintain the proper distance between any
(19:12):
cars in front of it, and if it starts to
get past a certain threshold of safety, the system will
automatically apply the brakes to slow down your vehicle, but
you'll still be in cruise control so you don't have
to hit Yeah, you don't have to hit a break
or an accelerator to turn it off. You can just
let it keep going. And you know, if traffic starts
picking up, then obviously you would take it off of
cruise control, but otherwise you just let it go. I
(19:35):
think this is an interesting application of radar because if
you look back at the history of it, what it
was originally great for was seeing stuff that is very
far away. You know, it's sort of like extending our
vision beyond where we could where we can naturally ever
hope to sense with our puny, little human senses. But
now it's more about having cheap, controllable, short range options.
(19:59):
Oh sure, especially in that consumer space, right Uh, seeing
any kind of technology mature, we we tend to see
this kind of approach, this kind of a pathway. You know,
some technologies probably won't ever follow that pathway, just because
either they'll never get inexpensive enough or there's not a
practical consumer application for them. But this is one case
where there is a practical application, So that's pretty cool.
(20:22):
But there are other practical applications that are go a
little beyond being in your vehicle, yeah, less on the
consumer end. Other other cool stuff is happening in radar,
for example, radar in space. Fu um so starting background,
(20:45):
NASA in the e s A had teamed up and
began launching synthetic aperture radar devices into orbit. Are we
sure this isn't from portal? No? No, no, synthetic aperture. Yeah,
they're like synthetic aperture telescopes. It's a. It's a it's
a yeah. Yeah, it's totally think it's a really cool thing. Uh.
Synthetic aperture means that the radar equipment is on a
(21:06):
moving vehicle, which, to simplify the science ridiculously like almost criminally,
means that the aperture of the antenna can be as
long as the vehicle's flight path. And let me let
me explain that a little bit, because it makes absolutely
no sense the way I just said it. Okay, picture
a dish antenna, right, It's aperture is its diameter. Okay. Uh,
(21:27):
the greater the size of the dish, and that's the
greater the size of the aperture, the more data the
dish can take in. Uh, Thus the finer the resolution
of the final image that it creates. It's similar to
how film cameras work. You know, like if you've got
a wider lens aperture, more light can come in and
you can take a higher resolution photograph. Yeah, this is
one reason we can't say, resolve images of things that
(21:51):
are really, really really far away. We just can't build
telescopes with an aperture wide enough. Right. If you if
you could imagine like in you know, infinitely large aperture,
you could technically probably resolve almost anything out there. But
this is totally like the yes, now zoom in. No,
it doesn't always work like that. Zoom and enhanced zoom right,
(22:13):
zoom and enhanced. Yeah, yeah, we usually zoom in. But
it seems like it'd be impossible to build something that
had a physical aperture that big, right. And you know,
if you put an antenna on a vehicle like an
airplane or satellite, it means that you're limiting the physical
size of the antenna to what that craft can carry.
But by putting the vehicle in motion and including a
(22:33):
whole lot of processing capacity, the flight of the vehicle
can act like the total aperture of the antenna. Wow,
it's kind of crazy. Yeah, So it's like a virtue
I got Oh now I got the virtual aperture. Okay,
it's like it's like exactly what you called it earlier
on Synthetic said synthetic. UM and and this is really
(22:56):
cool physically just in terms of the pure science of it,
but it's all so awesomely practical. For example, it's used
currently to monitor situations like where to natural environments and
and damage done in disasters and illegal logging and stuff
like that. UH and researchers are also looking at ways
to bend it to even more different kinds of work,
(23:16):
like like structural monitoring of infrastructure that the tech can
detect movements of mere millimeters, so it can look for
problems in in places that no human person might go
out to for you know, however long it takes to
send someone out there. Yeah, I've actually seen this used
in UH in mapping features as well, in order to
(23:38):
do topographical mapping that kind of thing. Uh And in fact,
the image I saw was of Florida, and it was
amazing the amount of resolution there. UM Another really cool
thing that we're seeing, and it involves a space agency,
but not a space application. NASA and the Department of
Homeland Security partnered in an initiative called Finding Individuals for
(23:59):
Disaster and I'm urgency Response or Finder, and it's a
low powered microwave radar that looks it's it's used by
rescue workers who are looking for survivors in the wake
of a disaster, and recently it was used in the
wake of the massive earthquake in Nepal. So obviously there
was a huge tragedy and a lot of people went
(24:21):
to try and help and one of the groups had
this this low power microwave radar, and it can actually
detect survivors by detecting their heartbeats. They're using radar to
detect heartbeats through rubble, like up to thirty ft of
rubble or twenty feet of concrete or a hundred feet
of open space, and the fluctuations of the heartbeat or
(24:45):
the fluctuations of your chest just from breathing are enough
for the radar to pick up the difference, the differences
in that Doppler shift and tell the rescuers there's somebody
down there, which is pretty phenomenal. So you know, we've
covered radar looking at whether we looked at radar looking
at massive areas of the Earth and also just radar
(25:08):
looking for a single person in rubble, which is pretty
amazing to me. But so uh, these are all current
applications of radar. What about the future? Oh, I got it,
I got it, radar, home cooking appliances like a radar
Panini press radar. No, okay, never mind, Lauren, what's the
(25:32):
future of radar? Well, Joe, Uh, sorry, sorry to tell you,
there are no Panini presses that I'm personally aware of
in the works using radar. But uh, Modular radar is
a thing that of few research and development firms are
working on. See right now. Radar systems mostly have to
be custom designed for any given application. Um Now, I
(25:55):
will say a key feature of modern military radar at
any rate is the use of a ray of transmitters,
which allow the capacity to broadcast multiple beams that work
in tandem to cover a greater range um and also
help escape signal detection by other parties, which is pretty cool. So, so,
you know, if you're talking about extra bits that you
(26:16):
add to radar, you could say that an array is
sort of modular in a way, but that's not what
I'm talking about. So you mean just modular by like
adding parts like lots of little little bits that you
add together. Well see there. There are also definitely systems
for building your own um necessary power and type of
(26:36):
radar using interchangeable parts on a on a on a
base kind of unit um but as far as I
can tell, it wasn't until the two thousands that patents
began appearing for something closer to to like plug and
play modular radar, wherein each unit is the same and
can can interact with other units to adapt to particular
(26:59):
tax asks. So instead of having to commission a a new,
uh customized radar system for whatever application you have in mind,
you could go back to this basic modular approach and
build it from that, which I would imagine dramatically decreases
the cost. Yeah. Yeah, you can just order rather than
(27:21):
having to order an entire system, or even an entire
system that you can kind of customize, you can just
order a certain number of these units and they'll wind
up working together. That the Navy, via contract with Raytheon,
has been developing the scalable radar system that The building
blocks of these systems are called radar modular assemblies, and
(27:43):
each unit is a two foot square block that contains
everything it needs to function alone, but when grouped together
their power is multiplicative, which is so cool. Uh. This
is meant to replace the Spy one radar, which is
currently in use on naval ships UM, which supports air
defense and weather data collection and ballistic missile defense and
(28:06):
can help counter other forces search and track capacity. So
good stuff all, um, But nine of these modular suckers
could replace the Spy one, which is about twice as
large as as this array of modular things would be
being a twelve ft octagon. Just by one is a
(28:26):
twelve ft octagon? Is it is an octagon? Yes, because
apparently we are living in Battlestar Galactica, either that or
the UFC. You know, ray Theon really sounds like it
should be the name of a house and Game of
Thrones totally trying to figure out how to do that joke,
thank you, but I can't argue with that. But so,
(28:48):
so that's so that's nine of these modular units. If
you go up to thirty seven units, Raytheon says that
you can find a target half the size at twice
the range of a Spy one. And if you've got
sixty nine of the units, you could find a target
half the size at nearly four times the range um
or you know, if you wanted to, you could just
stick a single unit on a smaller vehicle. Uh. The
(29:11):
system is set for release in two sixteen, and as
of like today, which is May. Uh. Raython says that
the system has passed an internal and naval critical design review,
So it's moving forward, y'all. Radar is coming. I want
(29:34):
to hum so badly right now, tell us more, Laura,
I shall, I shall. Northrop Gremman, who was also in
competition for the Navy's contract on these modular units, seems
to be working on a vaguely similar system for the
Air Force UM and hey, you know, this sort of
thing would be also great for smaller, perhaps commercial applications
(29:55):
like running security on campuses and on streets and in shipyards,
a special using frequencies that can penetrate precipitation and stuff
like that. So all of this is thanks you know,
to technological advances in in both receiver and transmitter technology,
but also to lots of other tech that we've talked
about on the show before, like like modular robotic research
(30:17):
and semiconductor research and software and algorithmic improvements. So it's
how it's it's it's fascinating seeing all of these industries
coming together to create these relatively easy to use products
that can be used in so many ways. Yeah, I
think that's uh I I had no idea about this,
and this is interesting. That's another application of the sort
(30:37):
of like modular principle like we talked about in the
Modular Robotics episode. I like this idea of lots of
little minions that come together to become something greater. Okay, well,
you know, and some of the other stuff that we
need to talk about are some of the challenges that
come along with radar. And one of the big ones
is that you know, you've got a transmitter and risk
(31:00):
either your receiver is essentially a giant antenna that's trying
to pick up very faint signals. Sure, but the more
sensitive your receiver is, obviously the more junk it's gonna
pick up. That's that's a real issue, right, how do
you tell the stuff you want from all the junk
that you're getting as well? So in other words, like
you're trying to find out whether or not you know,
(31:23):
a stealth vehicle is flying overhead, but all you're picking
up is the Zoo Cruise radio show. Uh, you know
that's that's three miles down the road. Uh. That's obviously
for for the sake of levity, but really, I mean
there is this problem of how do you separate the
signal from the noise? And you know, depending upon the
application you're using, it may not be that big of
a deal. It may be pretty simple. But the more
(31:45):
refined you get, the more difficult it becomes to make
this separation. So let's say that you're using a microwave
UH radar system and you want to have a very
high resolution of the data that you're getting back. That's
actually pretty challenging. Uh. And there is a team of
(32:06):
researchers in Italy who have been trying to make it
easier using a photonics system. Now, photonics, if if you
break down the word, you you know that obviously it
has to do with light. It's some sort of optical system.
They're actually using lasers and photonic diodes in order to
generate radio frequencies. And the reason they're doing it is
because if you're using a like traditional radar system, you
(32:29):
typically begin with an analog signal. Then you have to
convert that analog signal into a digital signal, So use
a converter to convert it to digital, and then you
want to blast that out as your as your means
of trying to detect stuff. But you also want to
use a very high frequency if you can, because that's
where you're going to get the higher resolution data back.
(32:51):
But this approach is usually limited too, limited to around
two giga hurts and frequency. If you want to go
beyond that, you have to put that signal through what's
called an up converter. It's essentially boosting the signal. Yeah,
we can do that, and you can boost the signal
and send it out and when it comes back, now
you've got to read it, and you can't read it
and it's in that up converted format. You actually have
(33:14):
to run it through down conversion so that you can
read this signal. And the problem is every single step
in that process, from changing the analog to digital to
up conversion to down conversion can introduce more noise, meaning
that whatever you're getting back is getting harder and harder
to actually analyze. So the photonic system gets around that
(33:35):
by using this uh this optics system to generate those
radio frequencies, and the researchers say they can do a
much broader range of frequencies, including much higher frequencies than
any other system can make at the moment, and do
it in a much more stable way that they don't.
It's not got. It doesn't have this problem of introducing noise,
(33:56):
and they don't have to down convert the returning echoing
signal in order to analyze it because they're using the
same system to generate and receive the messages. They've even
said that you could switch this to a communications system
if you needed to, So not only would it become
a transmitter and receiver for radar, but it could become
(34:16):
a communications device where you could communicate with other stations. Um,
so pretty cool. They call it POE dear p h
O d I R and uh. They build a prototype
device and it worked, so they're now working on turning
it into more of a practical tool, because there's a
big difference between a prototype and something that would actually
(34:39):
work for anybody, of course, of course, yeah, but pretty yeah,
just everything today sounds like a Game of Thrones character
right that. Yeah, okay, so so what are some other
problems that we need to solve in in radar technology. Well,
a similar one to what we just mentioned is that
the returning echoes can be very, very faint, particularly if
(34:59):
we're looking at something that does not want to be found,
like a stealth plane. So you know stealth planes. The
reason why their stealth is not it's not that they're
hard to see. They're usually pretty easy to see when
they're on the ground. It's that they're hard to detect. Right.
Their surfaces are designed so that they disperse incoming radio
waves so that they don't reflect back to the the
(35:21):
point of origin. So it makes it much harder to
detect with a radar station. So now people are saying, well,
how can we detect it? You know, some of the
radio waves do get reflected back, but they're usually so faint.
There's so few of them that it is hard to
to say that's an actual hit versus a false positive
or noise random noise. So some researchers at the University
(35:46):
of York came up with a clever way of improving
the sensitivity of radar receivers using our old buddy quantum physics.
Oh Joe, I, since you have some uncertain to you
about physics. Okay, that was your third pun for the episode.
It was also the second time i've I've referred to
that joke, because I did that in the video episode two.
(36:08):
But anyway, although I don't know if they may have
cut that, the video episode hasn't got live yet, so
um at any rate. So the way that they're using
quantum physics is through entanglement, quantum entanglement, and we've talked
about that on this show before, but generally speaking, uh,
this gets this gets pretty complicated. We're gonna use the
(36:29):
super simplified way of saying it. Quantum entangled entanglement involves
coupling two particles or waves in such a way that
their states complement each other. So if we think of
it in photons, we usually talk about or or electrons.
Let's talk about electrons, you know, usually talk about electron spin.
So if one electron is spinning up, the other electron
is spinning down, and they are coupled this way, no
(36:51):
matter how far apart, you may move the two particles,
as long as you don't make the system collapse on itself,
in which case the the tanglement ends and they no
longer ares Yeah, they have nothing to do with each other.
So another way of putting it is that if you
know something about one of these particles, you know something
(37:11):
about the other one right at that moment in any rate. Yes,
So in this case they are coupling a microwave beam
with an optical beam. And the way this works is
the optical beam is more or less contained within the
radar system itself. There is some detection that goes with that,
but it gets way too complicated for me to understand,
let alone describe. So to simplify it, the optical beam
(37:33):
is contained within the system. The microwave beam is used
to beam out at wherever direction you're looking at. When
returning microwaves come back in, you can compare those echoes
against the optical beams. The optical beam acts like a reference,
and because the two were entangled, there's going to be
certain points where they correlate. If in fact, that is
(37:55):
the same microwave beam you beamed out in the first place,
and that would tell you, yes, there is in fact
something there, because these are the same beams you sent
out in the first place. And you could be sure
of that because the odds of these two different beams
matching up randomly are so astronomical as to be unthinkable.
(38:15):
So in other words, if you send it out and
you get a very faint reading, you might say, ah,
I think there's a stealth vehicle flying toward us based
upon this reading. And the only reason we can be
sure is because it the the qualities of this microwave
beam reflect the qualities of the optical beam that are
already in the system because they were a coupled together earlier,
(38:37):
which is pretty amazing stuff. It blew my mind when
I read into it, because, uh, you know, I didn't
even think about the possibility of entangling two very different things,
an optical beam and well, I mean, obviously they're both
electro magnetic radiation, but you don't really associate them together, right,
I mean, the only time I associate microwaves in light
(38:57):
or when I opened up the microwave door in the
little comes on. Otherwise it doesn't happen. It's a different
kind of entangled. Yes, as I have often been entangled
with microwaves, but that's more of a core issue. Yeah.
At any rate, I thought it was really cool to
see kind of this emerging technological development, and you know,
even this this system of radar, which you wouldn't really
(39:20):
necessarily think has evolved that much since it was first
uh you know, designed and engineered. You would figure, oh, well,
that's a very basic principle. I don't. I could see
where we could get better and better at detecting it,
but how do we go beyond that? It's pretty amazing,
I think, and when you get whenever you get to
the point where you're incorporating quantum mechanics, and it really
(39:41):
gets pretty uh heavy in my book. So at any rate,
this was really fun to talk about. It was an
interesting kind of thing that we didn't hadn't really considered before.
But if you guys out there in listener land have
suggestions for topics we should cover in the future, keep
sending those emails were We're accumulating them, we're addressing them,
(40:01):
we're uh doing more and more listener oriented episodes, and
we love hearing from you guys. Maybe you have a question,
maybe you have a suggestion I'd loved, or maybe even
you've worked with radar and you want to tell us
about your experiences. We'd love to hear from you. The
email address is FW thinking at how Stuff Works dot com,
or you can drop us a line on Facebook, Twitter,
or Google Plus. At Twitter and Google Plus, we are
(40:23):
FW thinking at Facebook. Just search fw thinking in the
search bar. Our Facebook page will pop up. Come like us,
please and leave us a message, and we'll talk to
you again really soon. For more on this topic in
the future of technology, I visit forward thinking dot Com,
(40:54):
brought to you by Toyota. Let's Go Places,
Brought to you by Toyota. Let's go places. Welcome to
Forward Thinking. Hey, they're and welcome to Forward Thinking, the
podcast that looks at the future and says I was
seriously thinking about hiding the receiver when the switch broke
because it's old. I'm Jonathan Strickland and I'm Joe McCormick.
(00:23):
And today we're going to be talking about radar, right
and uh. And and just for our fans who are
my age or older, we're not talking about the popular
character from the movie and television series Mash unfortunately not.
Now we're talking about the actual technology radar, which is
(00:44):
nothing new. No, it's it's it's been around for quite
a few decades. But it's super cool. There's a lot
of different applications for it that are really interesting, and
apparently there are going to be some new applications for
it in the future. Yeah, and even if there is
a future, well, it's on my radar. Uh, it's gonna happen.
Might as well get it all the way early. The
(01:06):
neat thing is the way that the technology is is
changing over time. Like there it's being married with other technologies.
But we'll get into that, Okay, Well, let me. Let
me explore the layman's view of radar. What is radar
If you don't know, it has something to do with
a circular screen that has a line that sweeps around
(01:26):
it and goes you've mistaken ever sonar? Oh no, wait,
hold on, hold on. It has something to do with
like a little antenna that spins around really fast. Yeah,
that's that's closer, and there can be around around screen.
It's just the bloop is totally indicative of sonar ups
as opposed to radar. You could make a radar display.
(01:47):
Bloop could incredible. Future looking is one of the easiest
things to program. Look, I've I've I've studied screenplays, and
I realized that if you make it blue, you have
confused your audience. So but no. The other interesting thing
that we want to talk about before we actually get
into what radar is now it works is the fact
(02:08):
that it used to be an acronym and now it's
not anymore. It's one of those words like laser, laser
was like this wasn't it? Sure was? Yeah, so it
used to be. It used to stand for something and
won't stand. You could walk into them. The President of
the United States could walk into our room. Radar is
not gonna get up right, It's just like it's just
a lowercase word. You don't even capitalize it. What did
(02:29):
it originally stand for? Radio detection and ranging. That's what
the United States Navy referred to it and the r
A of radio were capitalized because it wasn't in the
day when they would just add extra random words and there,
and they didn't to make the really cool Yeah, they
didn't want and they didn't want to call it nar. Yeah,
so so turn on the dar. Yeah that did not
(02:52):
That did not fly. So they went with radar. But
today it's just radar. It's just a little lowercase word
radar because we we say it so much, you know.
I mean, boy, if I had a nickel for every
time I talked about radar in your average week. Well,
let's explain how radar actually works. It's actually a pretty
simple principle. Yeah, it's actually very similar to echolocation, right,
(03:17):
It's it's based on a very so and and in
fact sonar it's it's based on similar principles, except in
stuff of sound. We're talking about radio waves, which by
the way, don't work so well underwater, but they were
great above water. So, uh, Essentially, what you're doing is
you're sending out bursts of radio waves or microwaves, like
we're talking super short bursts, like microsecond long bursts. And
(03:39):
you do that often whatever direction you're looking at, and
if those waves encounter and object, some of them will
bounce back towards the source of the transmission. So you've
got to You've got transmitter and the receiver. You turn
on the transmitter, you send out a blast of radio waves,
you switch off the transmitter, you turn on the receiver,
(04:01):
and when those returning waves come back one, you know
that there's an object out there that the waves have encountered.
And too, you know how far away it is because
you can measure the time it took from when the
radio waves went out of the antenna to when the
echo came back in, and beyond that, you can actually
tell whether or not the object is moving towards you
(04:22):
or away from you using the Doppler shift, right, the
Doppler effect that we're all familiar with from hearing police sirens. Yeah,
so when you hear a police siren approaching you, it's
it's getting this high pitch noise. It gets higher and
higher and then after it passes you, you know that, yeah,
(04:42):
suddenly gets lower, right, And the reason it does that
the Doppler effect applies to all waves. It's not just
sound waves, it's also radio waves. And what's happening is
essentially those waves are being compressed ahead of the moving
object when it's coming towards you, so the frequen s
is increased. And when the frequency increases with sound, that
(05:03):
means the pitch goes up right, And when the object
passes by you, then the waves are being elongated. So
now the pitch has decreased, it's gone down. And if
you were standing right next to the to a stationary
police vehicle while it was having the siren go off,
it would sound in between those two well relatively speaking. Yeah.
And in fact, you can even observe this with visible light,
(05:25):
say like in astronomy, the disena moving away from us
faster and faster in the galaxy or in the universe
are going to be red shifted. Right. And in fact,
also this is really part of what sonic booms. You know,
why we have a sonic boom. If you're if you
have an object that's moving faster than the speed of
sound at whatever altitude you happen to be at. Because
(05:46):
sound speed depends upon the medium it's traveling through, and
with atmosphere, it could be affected by lots of stuff
like humidity, the air density, the temperature, all that kind
of thing. But anyway, if we're talking about something moving
faster than the speed of sound, all of those sound
waves get compressed so so flat that if you're in
(06:08):
front of that object and it's coming towards you, you're
not going to hear anything. You might, yeah, you might
say what's that before it gets past you, And once
it gets past you, then essentially all that sound is
unleashed and a catch us up, glorious boom of fury
and then and that's where the sonic boom comes in.
And actually the sonic boom rolls along as long as
(06:28):
the object continues to move faster than the speed of sound. Now,
with radio waves, we don't get the sonic boom because
we're talking about radio frequencies, we're not talking about acoustic waves.
But what we can see is that if the frequency
of the returning echo is greater than that what we
than the frequency we sent out, then we know the
object that we're looking at is moving toward us. If
(06:50):
the frequency is less than what we sent out, we
know the object is moving away from us. And by
sending out series of these signals, we can tell in
what direction and at what speed the object is moving exactly.
And because each of these verses like a microsecond in length, here,
you can you know, you can do this several times
a minute, you know, depending upon what your system is
looking for and uh and how you're focusing on that
(07:13):
particular section of sky. Usually yeah, and so if I
remember correctly, you'll probably be able to tell me mostly
radar is going to be operating in the microwave frequency
of the e M spectrum. That's that's largely what we
see today. A lot of radio radar works in the microwaves,
but it can't work in other other parts of the
(07:35):
electromagnetic spectrum. And I think originally a lot of it
was in radio. Yeah, right, so that would be yeah, yeah,
So if you imagine the the e M spectrum, like
you've got the longer wavelengths than visible light or microwaves,
and then even longer than that or what we usually
call radio waves. So yeah, and and the frequency would
be you know, the greater the frequency, the greater the
(07:57):
amount of information we can get back, which is why
you want to use higher frequencies if you can. But
we'll get into that later, which is part of why
we talked so much about microwaves in another episode. We
wait a minute, if you can get more information from
higher frequency, why don't we just use gamma rays. Well,
there are a lot of reasons why. One is that
we don't want a lot of incredible hulks running around. Yeah. Well, uh,
(08:22):
you know, honestly, obviously, gamma radiation would be inably dangerous,
even if we could generate it easily without pouring tons
of energy into whatever system we had created to make gama.
That was my guess. Is just that it's harder to
make and that it would also kill you. Yeah, the
two combined are really good reasons why we don't go
into it. Okay, Well, let's look back at the sort
(08:45):
of the early days of radar, the juvenilia of radar,
well back when radar was just a gleam in a
bunch of engineers eyes. The you gotta look at the
beginning of the twentieth century. So a lot of the
groundwork was laid in the nineteenth century, where you had
people discovering and experimenting with radio waves, but it wasn't
until the early twentieth century that we started seeing people
(09:06):
figure out, oh, we might be able to use this
in order to detect things. Uh. There was an engineer
in Christian hulls Meyer who invented a system that allowed
ships or trains to avoid collisions on foggy days. Uh.
The uh, the source I was reading, which was the
APS Physics website, referred to it as crude. In other words,
(09:27):
it was not a very refined system. Sure, but but
you can immediately see or not see. Is the case?
Maybe the benefit that radio waves have over electromagnetic light
waves well sorry, visible spectrum, sure waves on a foggy day,
because you can't see through fog, right, Yeah, you have
radio waves can bounce right through if light is going
(09:48):
to be reflected off the fog bank ahead of you,
it doesn't. You can't really count on that being an
effective signal to any other vehicles. So yeah, it was
certainly something that was useful. The U. S. Navy had
begun to a experiment with radar, although it wasn't called
that at the time, to search for ships. But actually
that research was largely overlooked in the United States, Like
(10:08):
it was a group of researchers within the Navy that
was doing a lot of this work, but because it
was viewed as experimental, it wasn't thought of as particularly
practical at that time. So it's kind of like they
were left to do their own thing, and no one
was really thinking it would ever come to anything. But
that's amazing because it seems so clear to us now
how useful something like radar is in warfare, Like you
(10:32):
can have real time updates about the position of enemy
vehicles in the moment, you know, as soon as they're
advancing on you. You can see them in long distances well,
especially things like aircraft, which would be particularly useful. And
in fact, over in the UK research was going on,
you know, in various places, but largely we have to
(10:52):
thank Sir Robert Watson What, who was actually a descendant,
a relative and distant relative of of the famous what
What did all the steam engines at any rate? Uh So,
Sir Robert Watson Watt began to work with radio waves
um as a means of detecting aircraft, but first had
(11:13):
been working in the Meteorological Office to develop systems to
detect lightning strikes because lightning can give off radio waves.
In fact, lightning strikes do give off radio waves, so
if you have a detector, then you can start to
detect thunderstorms, and that was considered to be very useful
the UH, the United Kingdom at the time, wasn't really
concerned with developing radio detection systems. But what happened was
(11:39):
there was a rumor going around that the Germans had
developed a death ray using radio waves, and so the
UK government came to Watson. Watton said, if that's a thing,
we're gonna need one of those. Can you even make
one of those for us? And so he started looking
into it, but very quickly he said, you know, there,
(12:00):
this doesn't seem feasible at all from everything I've learned.
That doesn't make sense. However, maybe we could focus on
radio detection instead of radio destruction. And he really began
to push for this means of using radio to bounce
waves off of objects so that you can detect them remotely,
and he got some support and it was very important
(12:23):
in the UK at the time because we're talking about
getting into World War two and the UK was heavily
involved and obviously the fears of Germans German aircraft coming
over and bombing England were warranted, so they the ability
to get people out of an area when they saw
(12:43):
when they saw craft coming huge absolutely necessary. Yeah. Funny
side note to this, This is actually sort of related
to the myth that carrots give you super eyesight. Did
you know this? I wrote a brain Stuff episode about this.
It's a fascinating little historical blip. So yeah, Apparently one
(13:05):
of the reasons that the British Royal Air Force was
pretty successful in repelling UH access air raids against the
British was that they had on board radar. So like
these these planes were equipped with you know, radar systems
that could tell them when enemy aircraft were approaching from
a very long distance. But of course they didn't want
(13:25):
to let onto anything like that, so part of their
misinformation campaign. Yeah, well, I think that's one theory. Other
people have different explanations for why they said this, but
for whatever reason, the British government said, you know, the
reason our pilots can see so well is because they
eat lots of vegetables rich in vitamin A like carrots.
So at the same time, of course they were trying
(13:48):
to get people to eat carrots because that was like
one of the you know, one of the foods, one
of the few foods that was plentiful in England at
the time, to and to grow victory gardens quote unquote
victory gardens that in which carrots were quite easy to grow. Right,
that's interesting, Yeah, oh well, you know, but so it
turns out it was a lie, you know, the pilots
(14:08):
suggesting that they just had super keen eye sight. At
the same time, vitamin A is very important for maintaining normal,
healthy eye sight. So so we eat your carrots, kid. Well. Meanwhile,
going back over to the United States, during the same time,
the Navy continued to develop radar and in fact named
it such, creating the first US radar and it was
(14:31):
called the x A F. It was installed on the
U s S New York battleship in nineteen thirty nine.
So obviously the earliest uses of radar were in military applications,
and that's not a huge surprise, I mean it was
that was where it was very much useful. But shortly thereafter,
once the war ended, we started to see radar get
used in lots of different applications, including a lot of
(14:53):
commercial ones, so air traffic control aboard aircraft itself, like
like you were saying jokes for commercial aircraft, not just um,
military aircraft also uh, commercial ships, UM and other means
as well. And and of course going back to what
Watson Watt was originally studying, we began using it for
(15:15):
weather detection, yeah, and forecasting. And this is uh, you know,
like Doppler radar. You hear it all the time, especially
here in Atlanta. Again they're so proud of their Doppler
radar UM, but yeah, it's Doppler radar. Is is using
the Doppler chef to detect moving weather patterns. And honestly,
what they're mostly looking at is precipitation. So you know,
(15:36):
the radar, the radio waves or microwaves will bounce back
from precipitation telling you, oh, well there's a front moving
in and we can keep track of it. We can
even map out the shape of it. And so when
you see the radar imagery that's based off the data
that's coming back from that, that uh the signals which
(15:57):
is pretty cool. Uh. The radar transmitters for Doppler radar
for weather are pretty powerful. They use food watts of
electricity when they're blasting out signals. I gotta be honest,
I have no idea how much that is. A regular
microwave oven is one thousand watts, So multiply a regular
(16:18):
microwave oven four fifty times and you get what. But however,
this particular radar technology isn't used, you know, It's not
like they turn it on and it's blasting out radio
waves for like hours at a time, right right, It's
it's more like defrost mode on your microwave where it
sends out kind of little blips and and then collects them.
(16:39):
All right, It's it's to get a composite. It's spending
most of its time listening rather than blasting. So it'll
send out a blast of radio waves in a very
short amount of time of fraction of a second, and
then it listens for a good long while for the
echoes to come back. So we're talking about um such
a short amount of time that the source I've read
said it transmits for about seven seconds in a typical hour.
(17:04):
So it sounds like if they just leave this thing on,
the army could have the death ray they wanted. Well,
they could at least drain the power grid nothing else. Uh,
I don't know that it would necessarily do anything else besides, um,
you know it could it could probably jam communications with
that many radio waves going out, but that'd be about it. Well.
(17:26):
I mean, we used to think about radar as this
kind of like high tech, expensive military technology, and it
used to be that. Yeah, but but now you see
it all over the place, right Yeah. Now it's actually
making its way into consumer technology. So I mean, you know,
it's not going to be in your smartphone, but it
might be in your car yet. Yeah. So autonomous cars
(17:48):
obviously need to have a lot of of sensors, right
in order to to note what is in their particular
neighborhood so that they know, you know, whether they can
merge over, change lanes, speed up, slow down, that kind
of thing, right, And you can use different kinds of
waves to do this. For example, one thing we've seen
employed a lot in autonomous cars is lidar, yeah, which
(18:08):
is you know, it's laser oriented as opposed to using
radio frequencies. But radar is also used. Uh. There are
lots of different systems where radar is used to maintain
a safe distance between the vehicle, the vehicle itself and
any vehicles around it. So you know, like the rule
of thomb being that if you're behind a vehicle, you
(18:29):
should be able to count to three uh when it
passes a landmark before you pass that landmark to Well,
these kind of systems will make sure you maintain that
safe distance at whatever operating speed the vehicle happens to
be at. So yeah, and I think you you talk,
you go into a little bit more detail about that
one in the video version, yeah, our radar episode, right, Yeah,
(18:51):
I specifically talk about dynamic cruise control, which is something
that's kind of a it's like a stepping stone between
the cars we have now and truly autonomous cars and
a lot of vehicles right now have dynamic cruise control UM.
And the basic principle is that you set the cruising
speed of your vehicle, but it also has this radar
system so it can maintain the proper distance between any
(19:12):
cars in front of it, and if it starts to
get past a certain threshold of safety, the system will
automatically apply the brakes to slow down your vehicle, but
you'll still be in cruise control so you don't have
to hit Yeah, you don't have to hit a break
or an accelerator to turn it off. You can just
let it keep going. And you know, if traffic starts
picking up, then obviously you would take it off of
cruise control, but otherwise you just let it go. I
(19:35):
think this is an interesting application of radar because if
you look back at the history of it, what it
was originally great for was seeing stuff that is very
far away. You know, it's sort of like extending our
vision beyond where we could where we can naturally ever
hope to sense with our puny, little human senses. But
now it's more about having cheap, controllable, short range options.
(19:59):
Oh sure, especially in that consumer space, right Uh, seeing
any kind of technology mature, we we tend to see
this kind of approach, this kind of a pathway. You know,
some technologies probably won't ever follow that pathway, just because
either they'll never get inexpensive enough or there's not a
practical consumer application for them. But this is one case
where there is a practical application, So that's pretty cool.
(20:22):
But there are other practical applications that are go a
little beyond being in your vehicle, yeah, less on the
consumer end. Other other cool stuff is happening in radar,
for example, radar in space. Fu um so starting background,
(20:45):
NASA in the e s A had teamed up and
began launching synthetic aperture radar devices into orbit. Are we
sure this isn't from portal? No? No, no, synthetic aperture. Yeah,
they're like synthetic aperture telescopes. It's a. It's a it's
a yeah. Yeah, it's totally think it's a really cool thing. Uh.
Synthetic aperture means that the radar equipment is on a
(21:06):
moving vehicle, which, to simplify the science ridiculously like almost criminally,
means that the aperture of the antenna can be as
long as the vehicle's flight path. And let me let
me explain that a little bit, because it makes absolutely
no sense the way I just said it. Okay, picture
a dish antenna, right, It's aperture is its diameter. Okay. Uh,
(21:27):
the greater the size of the dish, and that's the
greater the size of the aperture, the more data the
dish can take in. Uh, Thus the finer the resolution
of the final image that it creates. It's similar to
how film cameras work. You know, like if you've got
a wider lens aperture, more light can come in and
you can take a higher resolution photograph. Yeah, this is
one reason we can't say, resolve images of things that
(21:51):
are really, really really far away. We just can't build
telescopes with an aperture wide enough. Right. If you if
you could imagine like in you know, infinitely large aperture,
you could technically probably resolve almost anything out there. But
this is totally like the yes, now zoom in. No,
it doesn't always work like that. Zoom and enhanced zoom right,
(22:13):
zoom and enhanced. Yeah, yeah, we usually zoom in. But
it seems like it'd be impossible to build something that
had a physical aperture that big, right. And you know,
if you put an antenna on a vehicle like an
airplane or satellite, it means that you're limiting the physical
size of the antenna to what that craft can carry.
But by putting the vehicle in motion and including a
(22:33):
whole lot of processing capacity, the flight of the vehicle
can act like the total aperture of the antenna. Wow,
it's kind of crazy. Yeah, So it's like a virtue
I got Oh now I got the virtual aperture. Okay,
it's like it's like exactly what you called it earlier
on Synthetic said synthetic. UM and and this is really
(22:56):
cool physically just in terms of the pure science of it,
but it's all so awesomely practical. For example, it's used
currently to monitor situations like where to natural environments and
and damage done in disasters and illegal logging and stuff
like that. UH and researchers are also looking at ways
to bend it to even more different kinds of work,
(23:16):
like like structural monitoring of infrastructure that the tech can
detect movements of mere millimeters, so it can look for
problems in in places that no human person might go
out to for you know, however long it takes to
send someone out there. Yeah, I've actually seen this used
in UH in mapping features as well, in order to
(23:38):
do topographical mapping that kind of thing. Uh And in fact,
the image I saw was of Florida, and it was
amazing the amount of resolution there. UM Another really cool
thing that we're seeing, and it involves a space agency,
but not a space application. NASA and the Department of
Homeland Security partnered in an initiative called Finding Individuals for
(23:59):
Disaster and I'm urgency Response or Finder, and it's a
low powered microwave radar that looks it's it's used by
rescue workers who are looking for survivors in the wake
of a disaster, and recently it was used in the
wake of the massive earthquake in Nepal. So obviously there
was a huge tragedy and a lot of people went
(24:21):
to try and help and one of the groups had
this this low power microwave radar, and it can actually
detect survivors by detecting their heartbeats. They're using radar to
detect heartbeats through rubble, like up to thirty ft of
rubble or twenty feet of concrete or a hundred feet
of open space, and the fluctuations of the heartbeat or
(24:45):
the fluctuations of your chest just from breathing are enough
for the radar to pick up the difference, the differences
in that Doppler shift and tell the rescuers there's somebody
down there, which is pretty phenomenal. So you know, we've
covered radar looking at whether we looked at radar looking
at massive areas of the Earth and also just radar
(25:08):
looking for a single person in rubble, which is pretty
amazing to me. But so uh, these are all current
applications of radar. What about the future? Oh, I got it,
I got it, radar, home cooking appliances like a radar
Panini press radar. No, okay, never mind, Lauren, what's the
(25:32):
future of radar? Well, Joe, Uh, sorry, sorry to tell you,
there are no Panini presses that I'm personally aware of
in the works using radar. But uh, Modular radar is
a thing that of few research and development firms are
working on. See right now. Radar systems mostly have to
be custom designed for any given application. Um Now, I
(25:55):
will say a key feature of modern military radar at
any rate is the use of a ray of transmitters,
which allow the capacity to broadcast multiple beams that work
in tandem to cover a greater range um and also
help escape signal detection by other parties, which is pretty cool. So, so,
you know, if you're talking about extra bits that you
(26:16):
add to radar, you could say that an array is
sort of modular in a way, but that's not what
I'm talking about. So you mean just modular by like
adding parts like lots of little little bits that you
add together. Well see there. There are also definitely systems
for building your own um necessary power and type of
(26:36):
radar using interchangeable parts on a on a on a
base kind of unit um but as far as I
can tell, it wasn't until the two thousands that patents
began appearing for something closer to to like plug and
play modular radar, wherein each unit is the same and
can can interact with other units to adapt to particular
(26:59):
tax asks. So instead of having to commission a a new,
uh customized radar system for whatever application you have in mind,
you could go back to this basic modular approach and
build it from that, which I would imagine dramatically decreases
the cost. Yeah. Yeah, you can just order rather than
(27:21):
having to order an entire system, or even an entire
system that you can kind of customize, you can just
order a certain number of these units and they'll wind
up working together. That the Navy, via contract with Raytheon,
has been developing the scalable radar system that The building
blocks of these systems are called radar modular assemblies, and
(27:43):
each unit is a two foot square block that contains
everything it needs to function alone, but when grouped together
their power is multiplicative, which is so cool. Uh. This
is meant to replace the Spy one radar, which is
currently in use on naval ships UM, which supports air
defense and weather data collection and ballistic missile defense and
(28:06):
can help counter other forces search and track capacity. So
good stuff all, um, But nine of these modular suckers
could replace the Spy one, which is about twice as
large as as this array of modular things would be
being a twelve ft octagon. Just by one is a
(28:26):
twelve ft octagon? Is it is an octagon? Yes, because
apparently we are living in Battlestar Galactica, either that or
the UFC. You know, ray Theon really sounds like it
should be the name of a house and Game of
Thrones totally trying to figure out how to do that joke,
thank you, but I can't argue with that. But so,
(28:48):
so that's so that's nine of these modular units. If
you go up to thirty seven units, Raytheon says that
you can find a target half the size at twice
the range of a Spy one. And if you've got
sixty nine of the units, you could find a target
half the size at nearly four times the range um
or you know, if you wanted to, you could just
stick a single unit on a smaller vehicle. Uh. The
(29:11):
system is set for release in two sixteen, and as
of like today, which is May. Uh. Raython says that
the system has passed an internal and naval critical design review,
So it's moving forward, y'all. Radar is coming. I want
(29:34):
to hum so badly right now, tell us more, Laura,
I shall, I shall. Northrop Gremman, who was also in
competition for the Navy's contract on these modular units, seems
to be working on a vaguely similar system for the
Air Force UM and hey, you know, this sort of
thing would be also great for smaller, perhaps commercial applications
(29:55):
like running security on campuses and on streets and in shipyards,
a special using frequencies that can penetrate precipitation and stuff
like that. So all of this is thanks you know,
to technological advances in in both receiver and transmitter technology,
but also to lots of other tech that we've talked
about on the show before, like like modular robotic research
(30:17):
and semiconductor research and software and algorithmic improvements. So it's
how it's it's it's fascinating seeing all of these industries
coming together to create these relatively easy to use products
that can be used in so many ways. Yeah, I
think that's uh I I had no idea about this,
and this is interesting. That's another application of the sort
(30:37):
of like modular principle like we talked about in the
Modular Robotics episode. I like this idea of lots of
little minions that come together to become something greater. Okay, well,
you know, and some of the other stuff that we
need to talk about are some of the challenges that
come along with radar. And one of the big ones
is that you know, you've got a transmitter and risk
(31:00):
either your receiver is essentially a giant antenna that's trying
to pick up very faint signals. Sure, but the more
sensitive your receiver is, obviously the more junk it's gonna
pick up. That's that's a real issue, right, how do
you tell the stuff you want from all the junk
that you're getting as well? So in other words, like
you're trying to find out whether or not you know,
(31:23):
a stealth vehicle is flying overhead, but all you're picking
up is the Zoo Cruise radio show. Uh, you know
that's that's three miles down the road. Uh. That's obviously
for for the sake of levity, but really, I mean
there is this problem of how do you separate the
signal from the noise? And you know, depending upon the
application you're using, it may not be that big of
a deal. It may be pretty simple. But the more
(31:45):
refined you get, the more difficult it becomes to make
this separation. So let's say that you're using a microwave
UH radar system and you want to have a very
high resolution of the data that you're getting back. That's
actually pretty challenging. Uh. And there is a team of
(32:06):
researchers in Italy who have been trying to make it
easier using a photonics system. Now, photonics, if if you
break down the word, you you know that obviously it
has to do with light. It's some sort of optical system.
They're actually using lasers and photonic diodes in order to
generate radio frequencies. And the reason they're doing it is
because if you're using a like traditional radar system, you
(32:29):
typically begin with an analog signal. Then you have to
convert that analog signal into a digital signal, So use
a converter to convert it to digital, and then you
want to blast that out as your as your means
of trying to detect stuff. But you also want to
use a very high frequency if you can, because that's
where you're going to get the higher resolution data back.
(32:51):
But this approach is usually limited too, limited to around
two giga hurts and frequency. If you want to go
beyond that, you have to put that signal through what's
called an up converter. It's essentially boosting the signal. Yeah,
we can do that, and you can boost the signal
and send it out and when it comes back, now
you've got to read it, and you can't read it
and it's in that up converted format. You actually have
(33:14):
to run it through down conversion so that you can
read this signal. And the problem is every single step
in that process, from changing the analog to digital to
up conversion to down conversion can introduce more noise, meaning
that whatever you're getting back is getting harder and harder
to actually analyze. So the photonic system gets around that
(33:35):
by using this uh this optics system to generate those
radio frequencies, and the researchers say they can do a
much broader range of frequencies, including much higher frequencies than
any other system can make at the moment, and do
it in a much more stable way that they don't.
It's not got. It doesn't have this problem of introducing noise,
(33:56):
and they don't have to down convert the returning echoing
signal in order to analyze it because they're using the
same system to generate and receive the messages. They've even
said that you could switch this to a communications system
if you needed to, So not only would it become
a transmitter and receiver for radar, but it could become
(34:16):
a communications device where you could communicate with other stations. Um,
so pretty cool. They call it POE dear p h
O d I R and uh. They build a prototype
device and it worked, so they're now working on turning
it into more of a practical tool, because there's a
big difference between a prototype and something that would actually
(34:39):
work for anybody, of course, of course, yeah, but pretty yeah,
just everything today sounds like a Game of Thrones character
right that. Yeah, okay, so so what are some other
problems that we need to solve in in radar technology. Well,
a similar one to what we just mentioned is that
the returning echoes can be very, very faint, particularly if
(34:59):
we're looking at something that does not want to be found,
like a stealth plane. So you know stealth planes. The
reason why their stealth is not it's not that they're
hard to see. They're usually pretty easy to see when
they're on the ground. It's that they're hard to detect. Right.
Their surfaces are designed so that they disperse incoming radio
waves so that they don't reflect back to the the
(35:21):
point of origin. So it makes it much harder to
detect with a radar station. So now people are saying, well,
how can we detect it? You know, some of the
radio waves do get reflected back, but they're usually so faint.
There's so few of them that it is hard to
to say that's an actual hit versus a false positive
or noise random noise. So some researchers at the University
(35:46):
of York came up with a clever way of improving
the sensitivity of radar receivers using our old buddy quantum physics.
Oh Joe, I, since you have some uncertain to you
about physics. Okay, that was your third pun for the episode.
It was also the second time i've I've referred to
that joke, because I did that in the video episode two.
(36:08):
But anyway, although I don't know if they may have
cut that, the video episode hasn't got live yet, so
um at any rate. So the way that they're using
quantum physics is through entanglement, quantum entanglement, and we've talked
about that on this show before, but generally speaking, uh,
this gets this gets pretty complicated. We're gonna use the
(36:29):
super simplified way of saying it. Quantum entangled entanglement involves
coupling two particles or waves in such a way that
their states complement each other. So if we think of
it in photons, we usually talk about or or electrons.
Let's talk about electrons, you know, usually talk about electron spin.
So if one electron is spinning up, the other electron
is spinning down, and they are coupled this way, no
(36:51):
matter how far apart, you may move the two particles,
as long as you don't make the system collapse on itself,
in which case the the tanglement ends and they no
longer ares Yeah, they have nothing to do with each other.
So another way of putting it is that if you
know something about one of these particles, you know something
(37:11):
about the other one right at that moment in any rate. Yes,
So in this case they are coupling a microwave beam
with an optical beam. And the way this works is
the optical beam is more or less contained within the
radar system itself. There is some detection that goes with that,
but it gets way too complicated for me to understand,
let alone describe. So to simplify it, the optical beam
(37:33):
is contained within the system. The microwave beam is used
to beam out at wherever direction you're looking at. When
returning microwaves come back in, you can compare those echoes
against the optical beams. The optical beam acts like a reference,
and because the two were entangled, there's going to be
certain points where they correlate. If in fact, that is
(37:55):
the same microwave beam you beamed out in the first place,
and that would tell you, yes, there is in fact
something there, because these are the same beams you sent
out in the first place. And you could be sure
of that because the odds of these two different beams
matching up randomly are so astronomical as to be unthinkable.
(38:15):
So in other words, if you send it out and
you get a very faint reading, you might say, ah,
I think there's a stealth vehicle flying toward us based
upon this reading. And the only reason we can be
sure is because it the the qualities of this microwave
beam reflect the qualities of the optical beam that are
already in the system because they were a coupled together earlier,
(38:37):
which is pretty amazing stuff. It blew my mind when
I read into it, because, uh, you know, I didn't
even think about the possibility of entangling two very different things,
an optical beam and well, I mean, obviously they're both
electro magnetic radiation, but you don't really associate them together, right,
I mean, the only time I associate microwaves in light
(38:57):
or when I opened up the microwave door in the
little comes on. Otherwise it doesn't happen. It's a different
kind of entangled. Yes, as I have often been entangled
with microwaves, but that's more of a core issue. Yeah.
At any rate, I thought it was really cool to
see kind of this emerging technological development, and you know,
even this this system of radar, which you wouldn't really
(39:20):
necessarily think has evolved that much since it was first
uh you know, designed and engineered. You would figure, oh, well,
that's a very basic principle. I don't. I could see
where we could get better and better at detecting it,
but how do we go beyond that? It's pretty amazing,
I think, and when you get whenever you get to
the point where you're incorporating quantum mechanics, and it really
(39:41):
gets pretty uh heavy in my book. So at any rate,
this was really fun to talk about. It was an
interesting kind of thing that we didn't hadn't really considered before.
But if you guys out there in listener land have
suggestions for topics we should cover in the future, keep
sending those emails were We're accumulating them, we're addressing them,
(40:01):
we're uh doing more and more listener oriented episodes, and
we love hearing from you guys. Maybe you have a question,
maybe you have a suggestion I'd loved, or maybe even
you've worked with radar and you want to tell us
about your experiences. We'd love to hear from you. The
email address is FW thinking at how Stuff Works dot com,
or you can drop us a line on Facebook, Twitter,
or Google Plus. At Twitter and Google Plus, we are
(40:23):
FW thinking at Facebook. Just search fw thinking in the
search bar. Our Facebook page will pop up. Come like us,
please and leave us a message, and we'll talk to
you again really soon. For more on this topic in
the future of technology, I visit forward thinking dot Com,
(40:54):
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