How GPS Works | STUFF YOU SHOULD KNOW

welcome to stuff you should know a. production of iHeart. [Music]. Radio hey and welcome to the podcast I'm. Josh and there's Chuck and Jerry's here. too Jerry's at a cabin in the woods even. uh and this is stuff you should know. podcasting from the future that's right. uh and we are going to take a couple of. minutes here the the head of the show.

to uh pay tribute to how stuw works.com. founder Marshall brain who passed away. uh last November at the age of. 63 yeah he is the guy who started it all. and it's really hard to um understate. the impact that that guy had on our. lives yeah 100% um just about Marshall. he was uh an electrical engineer had a. Bachelor of Science he was a longtime. professor in State and in 1998 he.

founded as a hobby house upworks.com. because he wanted to uh he had a very. pure goal which was to to make uh. complex things understandable and. relatable to Everyday People and that is. you know that's what we still do we were. hired as writers there MH um I never met. Marshall personally I think I saw him. come through the office a couple of. times early on but I never had the. pleasure of actually sitting down with a. guy uh I'm met him a couple of times he.

was a good guy um he uh he I think some. of his first articles I think the first. one might have been like how air. conditioning works yeah uh remember. Scooby-Doo we did an episode on. Scooby-Doo based on one of his articles. was that Marshall yeah totally oh. interesting but yeah he he was a very. good guy and without him I can tell you. I would not be. podcasting um and if I were it probably. wouldn't be a very good podcast cuz you. and I would have never met uh you and I.

would have never met like the the fact. that Marshall came along and founded how. stuff works set my destiny in a lot of. ways so I'm really grateful to him for. that yeah for both of us uh he was also. a an author uh one of his books is. called the Doomsday Book colon uh the. science behind Humanity's greatest. threats something that Josh has. particular interest in yeah for sure um. yeah he's a transhumanist down with Nick. Bostrom and all the all those guys yeah.

uh so Marshall was also a TV host um he. eventually was um the director of NC. State's engineering opportunities. program which helped Mentor aspiring. inventors and Marshall was survived by. his wife Leanne his four kids uh David. Arena Johnny and Ian and their dog. summer and it was just really sad to. hear the news CU like like you said. Marshall if it wasn't for him we. wouldn't be here now and we we'd like to. think we're still carrying on his. tradition of making complex things.

accessible I like to think that too yeah. so here's to you Marshall rest in peace. um and as tribute we chose an article. one of the few ones that we hadn't. recorded that that Marshall wrote. originally on GPS and this is like bread. and butter Marshall brain stuff there's. engineering there's science yeah there's. some more engineering uhhuh there's. figuring things out with circles and. diameters and stuff like that like. straight up Marshall stuff yeah classic.

Marshall classic how stuff works and um. even though our show is kind of grown. and morphed it's fun to go back and do. these every now and then yeah for sure. so let's get started shall we all right. GPS tells you where you are the end. there you go that's that's word for word. Marshall's article yeah it's actually uh. sounds intimidating but it's really not. at all uh it's a pretty simple process. uh believe it or not yeah surprisingly.

um but what it is overall GPS uh is a um. as Marshall wrote a space-based radio. navigation system uh that uh te. technically GPS is the one that the US. government owns if you live in another. country it's not called GPS it's called. a what a gnss yeah Global navigation. satellite system is the generic term and. GPS is become like the kleenex of global. navigation satellite systems like it's. the proprietary eponym yeah exactly but.

you know that's what the system is that. tells you where you are uh when you take. out your little smartphone and say where. in the world am I or how in the world do. I get somewhere if you want to get. somewhere they got to know where you are. at that moment and that's why you can do. that. 247 yeah and GPS is owned and operated. by the American government um and it's. paid for by the American taxpayers but. it's used worldwide um I think out of. eight point something billion people on.

the planet today six billion of them use. GPS every day so it's America's gift I. think is what I'm trying to say because. if anything that's what America is known. for is like creating things and giving. it away to the rest of the world for. free yeah well we'll see what happens. with that uh you never know but right. now that's the the current situation um. the they do this with uh satellites uh. at least 24 usually there's more than 30.

and if wherever you are on on Earth uh. if you had you know super super long. Vision you could look up and see four of. these bad boys uh with your eyeballs. because you got to have those four to. tell you where you are for sure. technically you just need three but. let's not get into that right now okay. so those satellites they're up a medium. earth orbit about 11,000 mil above Earth. they C Circle it constantly they're not.

geostationary so they circle the Earth. and they rise and set I guess every 12. hours so twice a day um they're like the. tides basically and the GPS satellites. are just one component there's three. components there's a satellite component. there's the control component which is. on the ground uh the space force runs. GPS so they're constantly tracking. monitoring telling satellites what to do. like really bossing them around and then. the third component is you the person.

using GPS or more technically your. receiver that you're is telling you. where you are in the world yeah that's. the important part because I've tried. I've gone out there without a phone and. just shouted up where am I nothing. happens get a. phone uh the kind of one of the cool. things about GPS is this was kind of. roughly figured out a long time before. we even had satellites there was a. doctor Dr Ivan gettting who was a. physicist an American who basically said.

hey you know what you could find out. someone's 3D coordinates uh if you use. radio signals and just calculated the. time it takes for those signals from. different sources to reach a single. point on Earth right and that's GPS. basically yeah and the people around. getting especially his greatest critics. were like oh yeah yeah how you going to. do that there's nothing up in space you. jerk how are you going to do it exactly. and he said just wait and they sat. around and they waited um I don't know.

how long they waited for a while and. they finally went home and then a couple. years after that the Soviets came to the. rescue and a certain weird way they. launched Sputnik and in America in the. United States it was not a happy time. they called it the Sputnik crisis. because basically at the time we thought. the Soviets were just like some. Backwater backwards country and all of a. sudden they were the first ones to. launch a satellite into space and it. took us by surprise but Dr getting's.

theory was able to be put into use. because American scientists figured out. that you could track Sputnik because. it's radio signals um I don't know quite. how to put it let's say they engaged in. the Doppler effect they dabbled in. Doppler so that when the satellite was. moving away from you the frequency that. reached you here on Earth was different. than the frequency when the satellite. was moving toward you or when the. satellite was just stationed above you.

so they figured out that you can track. satellites based on these radio signals. and that gave the initial rise to GPS. which is you need to track the. satellites to know where they are. because that is an essential piece of. information for GPS and that kind of led. to people saying like Okay let's let's. get getting's idea off the ground. literally yeah literally off the ground. and into space uh Sputnik was October 57. and couple of years later we said oh. yeah we'll see your Sputnik and we'll.

raise it five satellites or I guess. raise it for for a total of five. satellites sure all Aces that's right. and this was. 1960 I'm sorry in 1967 they had really. precise clocks on board these satellites. and then just five years six years after. that in 73 uh navstar was formed and. that is the system the program that you. know that is GPS basically and then we. said all right now it's just going to. take us about 20 years to figure all.

this out yeah 1995 the whole thing was. finally operational they just kept. shooting up satellites and tinkering. with it and get it going and um I wish. we would have kept the name navstar I. think it's a little cooler than GPS but. I don't know maybe it sounds a little. more hostile or assertive so GPS is. probably okay you want to talk about. assertive what about space force space. force is I don't know what space force. is the the the name it sounds like a. movie it does like a Mel Brooks movie it.

does um but but so we called it GPS uh. and there were two versions that they. released at the same time one was L1 uh. that bandwidth was used for civilian. purposes everything from um well just if. you were in the military let's say you. used L1 if you were in the military you. used L2 it's much more precise out of. the gate but the entire reason that this. went from what I think was originally a. military project in intended just for.

use by the military um to one where. everybody who had a GPS receiver could. use it for free um was actually based on. a tragedy that occurred in 19 I think 83. with Korean Airlines flight. 07 yeah that was uh a flight intended to. go from New York to seou uh to get there. they were flying over Alaska and still. today we don't really know why but at. veed off course about 200 miles into. Soviet airspace uh there was not a great.

area of Soviet airspace to be near. because it was uh near some secret. military installations and so they. scrambled a couple of fighter jets. Soviets did uh migs I reckon and they. tried to contact the plane could not get. in touch and then downed the plane with. a missile and killed everybody uh 269. people uh I remember this I was 12 oh. yeah and yeah I mean you know of course. I didn't understand something like that. fully at 12 but I remember it being you.

know all across the news um well having. been raised in the United States and. being 12 in 1983 during the Cold War oh. bet you were so mad at the rusky commies. for doing that oh man oh man it was. there was probably a song on FM radio. that you know encapsulated this oh I'm. I'm sure like that a DJ made you know. not a real song right right there were. so many it used to be such a thing yeah. it was weirdly it was a thing but I'll. bet it was e it was Survivor that sang.

the song yeah probably um what I don't. fully get now what I do get is that uh. you know airplanes and Air airlines have. GPS on their airplanes so they don't do. this now but why did that like broaden. it to the public at large like couldn't. they have just said all right it's for. the military and for the. FAA I don't know maybe they just thought. that there were other potential. tragedies that they couldn't foresee. that could be got I I don't know I don't.

know if if there's one thing that I'm. not it's in Ronald Reagan's head. right I just don't know uh so we have. one GPS system which is kind of a. problem uh we don't have a backup yet. which you know we'll talk a little bit. about that more later but uh there is. more than one GPS because it's not like. uh China and Russia are like hey we'll. just you know use your GPS when we want. to bomb something thing when we want to.

shoot a missile at you yeah exactly so. China and Russia and the EU all have. their own GPS and I think they all have. backups even and we don't right it it. just takes too many floppies to back up. our GPS so we're just going without. right now yeah uh you want to take a. break yeah let's take a break I think. it's a fantastic setup okay and when we. come back we're going to really Wing It. by trying to explain how GPS works. [Music]. [Applause].

[Music]. [Applause]. [Music]. all right so if you want to U geolocate. something or somebody um you're going to. need you're on Earth you know you can.

just use longitude and latitude and. that'll that'll do a pretty good job. sure uh GPS is like hey what if you want. to find out where you are relative to. sea level we can do that and you can't. longitude and latitude yeah uh and GPS. does that with microwaves they they. decided not to use radio waves for. reasons we'll talk about but they use. microwaves sent down to earth they do. and so these microwaves I've seen both. Chuck I've seen that they're constantly. beaming Transmissions like basically. uninterrupted from the satellites or.

that they do it like on a repeating. pattern regardless however this. information arrives it contains a few. really important pieces of information. and one thing we should point out. apparently there's a misunderstanding. that a lot of people think when you open. up like your location services or. whatever on your phone your GPS antenna. ping satellites that's not the case it. passively listens for GPS the four GPS. satellites broadcast.

constantly or intermittently um and it. picks them up right and so the. information it gets is the time this is. a really important component and we've. talked before about atomic clocks and. just how ridiculously precise they are. and on um a GPS satellite there's. multiple atomic clocks that are keeping. time together and to make sure that they. stay. synchronized um and then the satellite. sends its own location apparently they. figure out their location using.

Celestial landmarks like quazars so the. satellite knows where it is at all times. so it can tell you or your GPS receiver. and then there's a satellite ID that. says I'm me and that is good enough. that's right uh and that is in the form. of a pseudo random code um and one of. the cool Parts about that is it uh it's. going to tell you like yeah it's coming. from this satellite here's my pseudo. random code but it also uh uses a a. slightly differently altered.

frequency um so the frequencies don't. Jam one another so all these satellites. because the frequencies are just. slightly varied can all talk to each. other because you don't want satellites. up there jamming each other no but they. can also talk to you too virtually at. the same time if not at the same time. because don't forget you're getting. information from four different. satellites to figure out where you are. so you don't want to get one from one. wait a couple minutes get one from the. other you want them all to be coming in. basically at the same time and by by.

slightly altering their frequencies they. can all. arrive right and this is one final bit. of uh keykey information here all these. satellites great they're beaming. microwaves down fine if you if if we. didn't know how fast those microwaves. traveled then none of that would do us. any good we have to know exactly how. fast that stuff travels in order to. measure a distance uh and in this case. we know that electromatic waves.

microwaves travel at speed of light. 186282 m per second right so now they. have all the basic information I think. this is why you were saying at the. outset this is actually kind of a simple. um setup GPS is um if you take so if. that satellite sends you an information. piece of like a signal and it says I. sent this exactly at 1:45 p.m. um and it. arrives at 1:45 p.m. in 1 second and you.

know that microwaves travel at the speed. of light you can use that information to. calculate the distance between you and. the satellite okay when you know that. the satellite is located here in space. and then you figure out your distance. from the satellite you start to have. your first piece of information about. where you are because now you know where. you are relative to one satellite that's. not enough information to tell you where. you are on Earth Earth but it's a really.

good start that's right uh and you might. be thinking like yeah but what about um. stuff getting in the way uh like if if. this stuff is supposed to be exact then. you know what about a tall building or. what about um you know weather and space. like that can throw all this off right. guys and that's true but they have a. very uh pretty brilliant workaround for. that uh one method is called. differential GPS and they have these um. antenna on Earth that are that are. locked in they're stationary they're not.

going anywhere uh we know exactly where. they are uh they're called known points. for that reason and since we know. exactly where those are they're. receiving these Transmissions from GPS. and so they can calculate whether or not. the location is off and that you know if. if this thing is locked in place but the. calculation coming from the GPS is off. by a little bit hey it must have gone. through some thick Shrubbery or bounced. off a building or something something. but either way we're locked in place so.

we know exactly what that should be and. thus we'll know what that discrepancy is. and we can account for that right so. once that that known Point has that. discrepancy it sends that out that. information out to all the GPS receivers. in the area so they can use it to adjust. their own GPS um readings that they're. getting from those satellites that were. slightly off but they didn't have any. way to remedy it now they do because the. gnome point is like satellite B is off.

by like 10 NS don't tell it but I just. wanted to let you know yeah and Hey. listen I won't tell everybody I'll just. adjust it on my end and they'll never. know that you screwed up right and also. there's something in your teeth. right oh it's. kale gross kale is so gross you don't. like kale I can't I have to choke it. down and gross is the wrong word it's. just too harsh yeah yeah too much kale.

like a salad with only kale or like uh. God forbid you eat a bag of kale chips. like you would die you wouldn't be able. to breathe any longer it's too much at. once yes oh boy uh all right so now we. get to trilateration take it away friend. Oh no you're the trilateration expert. between us let's tell everybody what. happened well first of all let me. explain that trilateration is not the. same as triang ation because uh we're.

not talking about ankles we're talking. about distance MH and somewhere in there. is the key of where I was screwing up. because you had sent me this in a very. elegant sort of simpl to explain way hey. this is this is Marshall Okay allaha. Marshall brain uh it was explained about. you know like a VIN diagram three. circles overlapping and then the point. where they overlap is where you are. we'll explain that more thoroughly but I. was just drawing three random circles. and I'm like three random circles don't. always intersect at a point right like. they might overlap in an area and so the.

center of that area maybe is what we're. talking about but then I realize you. can't just draw three random circles and. expect them to have a tangent point. because they don't always right uh in. the case of GPS I guess it's just a very. exact measurement from one place to. another and in that case they will. intersect right okay okay so I think you. should also tell everybody when you sent. me a picture of your three circles with. the the like the part where they they. overlap they all overlap uh you would.

put a point in there and wrote bingo. with an exclamation point you're like. case closed I thought I really figured. out something here I think you may have. discovered something else that we're not. aware of yet so I don't think us just. put it to this no I think like you might. have just invented like a new way of. calculating things no I'm sure there's a. name for it and some science person's. going to say oh Chuck that's just blank. oh I wish they would cuz I don't know. either but I like hats off to you.

because man I can't tell you how many. circles I guess you probably Drew just. trying to get this to work and I don't. blame you I was smart and was like. there's Madness there I'm just going to. try to understand this as best I can I'm. not going to try it myself I got a. freaking Compass at one point cuz you. were like it's cuz the circles are. willy-nilly and I was like okay I'll. draw them. perfect okay so well let's talk about. trilateration because in in theory I. guess it's it's it's very simple and the.

way that um that Marshall described it. was let's say you're lost you're in the. United States M and you ask somebody. where you are and that person says you. are 625 miles from Boise Idaho and you. say thanks a lot that doesn't tell me. much right you actually push them down. as they're walking away yeah but uh. after after you um get away uh you're. chased by the police but you make it. down an alley and hide behind some. garbage cans as they pass by you have. good idea you go buy a map and you.

spread out your map uh maybe you buy a. compass as well all a Chuck and you draw. a a circle around Boise Idaho using. Boise as the center point that uh is 625. miles in diameter or at least represents. that by scale right yeah and you're like. okay I am somewhere on this circle that. has a diameter of 625 miles around Boise. kind of helpful it's a little bit narrow. down but I need more information so you.

go find somebody else and you say hey do. you know where I. am yeah is this where I could come in. yeah I was hoping hey well I'm not going. to tell you that but how about this. you're 690 miles from Minneapolis okay. so that's great at least they didn't. repeat the Boise thing right because if. they said that you'd just be like man. that didn't help at all but now you know. where you you are from Minneapolis and. you can do the same thing with. Minneapolis using that as the center. point of a circle youw draw one a circle. with a radius of 690 Mi around.

Minneapolis now you're really close. because what you'll find is the circle. around Boise and the circle around. Minneapolis they overlap right yeah you. get a little football in the middle yeah. like a VIN diagram M and if you look at. a VIN diagram where those two circles. overlap there's two points where they. intersect right they where they cross. each other those lines cross each other. and because you are 625 mi from Boise.

and 6 um 90 M from Indiapolis. the you are somewhere where those two. circles overlap with those two points. one of those is right the other is off. by hundreds of biles so you still need. to narrow it down right so you're like. is there one more wiseacre in this town. who will tell me by not telling me where. I am where I am right and so you go into. this final the only other gas station in. town and you say guys uh someone told me.

I was 625 from Boise didn't help much. someone else said 690 from Minneapolis. please just tell me where I am they said. oh oh you're 65 miles from Tucson pal. did you just trash the place at this. point yeah you just lay waste you find. the nearest broom and you just start. knocking everything off the. shelves my collector. beerstein all right so now you got three. circles though and this is where I got. super tripped up cuz I was like oh cool. let me draw this out and I drew it out. and I was like these don't intersect at.

a common point right uh but if you're. using exact GPS calculations distance. from a. satellite uh or in this case points on a. map um then that's that's you you know. exactly where you are because it's going. to intersect at at only one place at. three points yeah all three circles were. will overlap with one another so they. intersect at two different points each. circle inter intersects with the other. at two points but all three of them will. only intersect at one single point and.

you have just. trilateral your position you now you. know where you are and Marshall said. this is Denver by the way that's where. you are is Denver because I think if we. hadn't have included that some people. would have been really upset yeah but. you knew you're in Denver because you. can't catch your breath and it smells. like wheed everywhere that's right and. now you have to figure out what to do. even though you're dead yeah and. liberals and conservatives are smashed. together and everyone's like what kind. of state is this it is it's crazy like. that isn't it yeah I love Colorado I.

think it's interesting that way it's. it's like all of the shows we've done in. Denver it's like a wedding like split. down the middle the people on one half. of the room all have guns out the other. half are all playing hacky sack right. it's an interesting place and one guy. goes hey you ever triy to shoot a hacky. sack in. midair watch this it's kind of fun right. okay so um that's trilateration that's. 2D trilateration because what you've. done is found your if you were a flat.

point and the Earth was flat which it's. not um that's all we would need to do. but the Earth is a sphere it's round and. so what GPS uses is 3D trilateration. which rather than flat circles it uses. spheres and when the three or four. usually because you use four satellites. where those spheres all intersect the. one point that's where you are because. now you not only know where you are. longitude L latitudinally you also know.

where you are at. altitudinally my friend I hate to break. it to you but you did the old Josh Clark. insert and extrac consonant thing. trilateral. isation it's trilateration I know and. I've been wanting to say trilateral. isation for so long well you weren't. even saying get off my chest you were. saying. trilateral okay all right so now has. three ways so trilateration. trilateration that sounds made up like.

space force I know all right. trilateration isation yeah El. station so that's it that's how you. figure well I should say that's how your. GPS receiver figures that out it has it. knows where those three or four. satellites are because they tell it. where they are uh it figures out the. distance between you the in your. receiver uh for each of those four and. it tells it oh here's where I am because. here's where all those that information.

intersects right and I think you. mentioned the Spheres while I was. obsessing about the extra L right yes I. did okay great and there's a really. pretty image out there I can't remember. what website I found it on but if you. search like how GPS. trilateration uhhuh Works um it it will. come up I'm sure but it shows like the. four spheres created by the satellites. and they're all in four different. primary colors and it's so pretty I saw. I understand that there are three. primary colors but whatever the fourth.

one is it's basically a primary color as. far as I'm concerned. okay uh should we take our second break. yeah I think so Chuck we we earned it. with that. trilateration trilateration explanation. explanation we'll be right back. [Music]. [Applause]. [Music]. [Applause].

[Music]. uh okay Chuck so there's one other thing. kind of like a little sidebar I felt. like we should talk about um if you've. ever um tried to figure out where you. are and your phone's like turn on Wi-Fi. and we'll get a better reading I never. understood that until you explained it.

so what it's trying to do is it's. prompting you to turn on your Wi-Fi. based positioning system and what that. is based essentially on the same thing. that Dr gettting was getting at which is. um you can use information from. different sources to and comparing those. sources to figuring out where you are. and so rather than using satellite. information this uses the it bases it on. the own strengths of different Wi-Fi.

network Towers antenna and so depending. on how strong one signal is compared to. where you are uh in addition to. comparing it to another signal and. another signal another signal it's like. oh you're you're in Denver right uh you. don't know how dumb I am I I don't think. you're dumb I know you're not dumb but. let's hear what you have to say I say. this out loud at the risk of losing. listeners that might be new listeners. are like I can't listen to this guy oh. this is really dumb up until to.

yesterday uh whenever my phone or my car. or something said you know turn on your. Wi-Fi to improve accuracy of your. location I was like I'm not near near my. house what is this thing asking me to do. I'm not I'm not near my Wi-Fi you. weren't like you're not the boss of me. no I I was just uh that's pretty dumb I. don't no it's not Wi-Fi is everywhere it. doesn't have to be your house Wi-Fi so. yes that's one way it does it and it. does it in your house too but that's. because your router is a big blabber.

mouth and tells everybody where you are. so it's like they don't know I'm not. near my house why is it asking me to. turn on my Wii is so stupid Oh Boy uh. all right so speaking of the opposite of. stupid your smartphone um how accurate. are those things uh when GPS first. started they said and this was again. like 95 is they said uh it's going to be. accurate to within 100 m 95% of the time.

which at the time was like hey that's. not bad at all like that gets me in the. in the neighborhood of where I want to. be uh they've gotten much much better um. now they say 2 m within 2 meters of 6.6. feet but it's really closer than that. they did some measuring in 2021 and the. global average uh across all users was. about just a little more than 2 feet mhm. and you know again that that depends on. a lot of things if it's got buildings in. the way um space weather atmospheric.

conditions uh apparently like a really. dense like jungle canopy or thick. Shrubbery can uh actually degrade the. accuracy of that signal yeah you got a. hickory tree well Ts for you because GPS. isn't going to work is that a thick tree. thick canopy yeah I would yeah I think. so I mean it's a known shade tree no a. oh it's a uh it's a it's a. kst that's right put it on the list if. it could could broadcast information it. would also be a known Point yeah exactly.

um so there's a there's an a couple of. other things that can mess with your GPS. signal coming from the satellite because. remember I said that they navigate. celestially well if the Earth position. itself relative to the satellite. satellite can know where it is but um if. the Earth shifts a little bit like the. the magnetic core sloshes around just. enough that the Earth kind of wobbles a. little bit or if the sea currents are. particularly strong it can like slow the.

rotation of the earth those things I. mean just the tiniest tiniest changes. can alter the accuracy of the signal. that it gets but that's just the signal. that they're like we're going to get you. within six feet um they don't guarantee. your receiver and your receiver. typically adds a little bit of um. inaccuracy I think 5 m is usually what. you what you're going to get from like. your average dumb uh GPS receiver yeah.

and I get I mean it's amazing we're here. because if you're like GPS to just say. this is good if you're if you're five. feet away from the restaurant or your. friend and you don't see them that's on. you yeah just look up yeah so we're. getting better though you know no no. it's getting I mean I imagine they're. going to have it I think uh March. 24 uh if you're an ideal if it's clear. skies you're out in the middle of the. the desert or something they can they. can be as accurate as 30 cm which is.

five ablea batteries end to end right. we're going to get even better than that. though Chuck because right now there's. some really good GPS antenna that are. starting to pop up in smartphones and. those those are uh dual band dual dual. band dual frequency receivers one of. those two and that uses the L1 the. standard civilian um GPS band that has. been around since the beginning but has.

gotten better over time and it also uses. the new whizbang L5 and this is like the. next generation of GPS it's not. widespread enough yet there's not enough. satellites out there that are L5 for an. antenna to just rely on that but when. you put L1 and L5 together it gets. pretty good um the thing is is you might. ask yourself. like why why would you need to get like. within centim of the restaurant that. you're going to it doesn't make.

sense well some people use GPS for more. than just finding the restaurant that. they're going to yeah that's right and. uh your parents and grandparents might. be using their garment still so just uh. have patience with them I think that. Garmin was actually one of the original. GPS devices yeah and it's still being. used in certain cars and certain. people's families are those things even. supported any longer I don't know man. it's pretty funny though it's like. looking at a at a MySpace web page or.

something when you look at it how bet it. is uh but yes I took a soft task you. were talking about other things that. this is used for um a lot uh we talked. about Landing airplanes that's pretty. important um accuracy is pretty. important maybe not down to the. centimeter but um if you want to track. soil moisture you can do that via GPS if. you want to measure the size of a. glacier and whether it's shrinking or. moving you can do that very very. accurately mhm uh and not just sort of. ballpark things anymore um migration.

patterns uh if you want to see where. that that school of Wales is headed uh. and and how they know when they get. there and how far they are from where. they started you can do that with great. accuracy yeah also um things use it to. basically stay in position like modern. agricultural equipment like Harvesters. they go in a straight line by themselves. thanks to really precise GPS same with. self-driving cars oh sure yeah uh and.

then like apparently it's just grown so. ubiquitous and so reliable that. contractors use it like a like digital. blueprints will have GPS coordinates for. like a nail or an electrical outlet or. something like that so you can know. exactly where that thing's going to go. which I mean that's got to cut down on. construction costs and time dramatically. yeah I thought the uh the thing on. tunneling was kind of cool I never. really thought about that but if you're. tunneling through two sides of a.

mountain uh to ideally meet in the. middle and have a a one long tunnel. that's not one tunnel with a little. zigzag in the middle because they were. off by a little bit you can do that down. to the centimeter you know or 30. centimeters rather yeah a tunnel that. goes through a mountain with like a hair. pin turn in the middle of it that sounds. great and if you put all this stuff. together all these different uses for. GPS which again the American taxpayers. give to the world for free uh it. generated I think in.

202294 billion dollar worth of stuff. right all of that yeah receivers that. were sold all the tunnels that were. drilled correctly like all that stuff. came to generate $94 billion and in the. next five years it's expected to hit. almost 300 billion so it's a big deal. like we rely on GPS a lot and so because. we rely on something this much and. because like you said we don't have a. backup of GPS in particular um it can be.

pretty. um delicate I guess you could say to put. it delicately um because it can get. screwed up pretty bad pretty easily and. in fact on a very local level you or I. could go screw up somebody's GPS for fun. anytime we wanted yeah that was a little. disconcerting to learn I thought like oh. well surely this thing has just some. weird robust uh government. Shield that cannot be hacked right yeah.

and that's not true uh in fact the. military I mean it's it's part of. military just regular operations to jam. GPS uh for another country uh their. planes and drones or to spoof it is when. you send it uh you know jam it and make. it non-operable but you you're like o. here's some fake coordinates that you're. going to think are real right yeah like. they do that all the time countries do. that to us all the time uh but like you. said any that's got 300 bucks can get a. softwar defined radio and figure out how.

to use it and jam somebody's GPS and so. your neighbors walking around wondering. where that restaurant is I know they're. like a. Fridays right I wanted to go to. bans um yeah so you were talking about. spoofing apparently Iran in 2019 Just. for kicks um spoofed uh a British um. cargo ships GPS and told that it was in. international waters when really they. had drifted into Iranian Waters so Iran.

was like oh you're our ship now and. you're our crew now and they held the. whole thing for 10 weeks just by being. jerks apparently I can't figure out what. the point would have been for that other. than to. flex yeah that is a little odd I'm sure. somebody knows or maybe it was a flex. yeah and the kids still say that right. they Flex oh you're asking the wrong guy. okay well let's say they do I mean Ruby. says things I don't understand and I. just don't even ask um I know I know uh. my niece Mila was schooling us on slang.

and I'm like there's no context for that. it doesn't make any sense yeah I I I'm. trying to think of one example I know. I'm going to get wrong no cap no. something like skibbidy. oh oh skibby toilet yes and I understand. yes it's a web video or whatever but the. the the videos itself make no sense. whatsoever too yeah hey you know all we. did in the 80s was shorten awesome to a.

and un a that was our big contribution. that was as sophisticated as we got I. don't know about the skippity stuff yeah. and I don't mean to complain I mean each. generation like Builds on the last comes. up with its own stuff I'm happy about. that I just don't understand it and I. well that's the point I think you know I. think you're right actually and I'm kind. of hurt by that yeah it's it's you know. kids and teens come up with their own. language so adults don't know what the. heck we're talking about and they can. laugh behind backs yeah we did the same. thing I didn't we said that's very Unos.

and my our parents were like what are. they saying I can't make heads or tails. of. that uh Airlines can get jammed U there. was a study that found intentional. jamming of Airlines was a problem uh in. three regions only three uh more than. 70,000 flights were jammed between. February and August of. 2022 and um that you know once you jam. it up you can't reset it like that plane. lands and then the unjamming happens.

yeah you have to turn the whole thing. off and reset everything you can't just. reset the GPS antenna and they need to. work out all that stuff don't you think. they definitely do but something about. those flights being jammed those are. civilian flights being jammed by Bad. actors and sometimes governments and. militaries so what you're trying to do. essentially is to crash a Plane full of. people like that's your shot it's not. like a really um dedicated shot at it. but that's pretty much the goal of doing.

that to an. airliner yeah and you have no idea how. much I put my hand over my mouth when. you said Bad actors and I almost shouted. out a few names of actors who are you. GNA name no I can't because you know you. never know people might listen to this. I'm I'm wear I'm sensitive to hurting. people's feelings now here in my 50s I. think that's great man well text me some. names then I will okay uh there's. another thing that that um spoofing I. believe mhm I think they use spoofing.

for it um is to cheat at games like. Pokémon go yeah where you can um fake. where your own GPS coordinates are to. say like oh I'm at the um I don't know. Pikachu's layer or something like that. so give me the egg that Pikachu is. guarding which I can turn into like some. ski ball tickets and get a. comb or a skib. toilet I hope that doesn't mean. something dirty right. it it means nothing from what mil's told.

me like it's just basically a thing you. say okay I hope I'm not outing Mila is. uncool though well I'm just glad that. you have uh someone in your life that's. that's down with that kind of stuff. because uh it's pretty vital these days. I don't know if it's vital that I know. that skibby toilet exists but maybe not. that but goity toilet has its own. Wikipedia entry oh I believe it have you. seen the videos though that it's based. on no but I see a screenshot now and. they're mesmerizing it doesn't it.

doesn't pull me in you should watch a. second or two of it you don't need to. watch much you get the gist of it really. quick but it's like like your you'll. find that your mouth is open not in awe. but just because like you're glazed over. right right uh so like you said the. United States is not unaware of the. vulnerability that was what I was saying. it was a in a delicate position it's. vulnerable it's a very vulnerable system. um in you know like globally and also.

locally so they are taking steps to. update it and that is going to come in. the form of adding more and more L5. satellites right but for. now if you want to be a little shocked. taking into consideration how dependent. we are on GPS the average age of a GPS. specifically the United States's global. positioning system satellites is 13. years yeah that is really old for a.

satellite But Chuck tell them how old. the oldest satellite in the. constellation of GPS satellites is uh. that would be 27 years. old is that right yeah yes that thing. has. [Laughter]. sarcopenia oh I guess that's it for GPS. huh yeah this was more fun than I. thought uh and you know I'm glad we had. some fun and had some laughs because. that feels like a a lighter tribute for.

Marshall than uh something else for sure. hope hopefully we made you proud. Marshall and thanks again for everything. uh and since we said thanks to Marshall. brain then I think it's time for. listener. mail uh I'm going to call this forget. rice how about some peace and love hey. guys big fan of the show I love. listening when training for marathons. and love the recent Marathon episodes. uh while listening to the history of. refrigeration the rice method for.

managing a musculoskeletal injury was. mentioned did you know guys that in 2020. the medical world threw out the rice. method and transitioned to peace and. love H I don't even remember mentioning. that let alone knowing that did but I. think I probably did um so for peace and. love we have. protection uh avoid activities that. cause pain for two to three days. elevation. uh the a is avoid anti-inflammatories. because apparently that reduces healing.

and you should avoid ice too I have. heard that that anti-inflammatories are. actually not very good for you I I just. I never take those anyway cuz I don't. really need to but yeah lucky some. people really need them I know I'm I'm. sure uh where was I a so down to C. compression e. education uh which is avoid unnecessary. passive treatments your body will heal. so I guess educate yourself they were. like we really need an e here yeah.

basically uh and then we and is not. spelled out but love is uh load let your. pain be your guide. optimism condition your brain uh. vascularization painfree. cardio uh and exercise restore Mobility. through active approach um and Sarah. says this is a lot I hope people can. learn to avoid ice and. anti-inflammatories for opal recovery. but it's having a hard time catching on. uh and that is I can imagine why that is.

from Sarah uh PT bird nerd hollingworth. and she's a bird nerd and loves our bird. episodes that's awesome thanks Sarah way. to spread the good word I know there's a. lot of good advice and information in. there but it's just going to take months. of digesting that information to try to. figure out those acronyms yeah uh if you. want to be like Sarah and put something. on our radar that we weren't aware of. before we love that kind of thing uh you. can send it to to us via email like. Sarah did to stuff podcast at.

iheartradio.com. [Music]. stuff you should know is a production of. iHeart radio for more podcasts ihart. radio visit the iHeart Radio app Apple. podcasts or wherever you listen to your. favorite shows. [Music].