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Why The US Military Made GPS Free-To-Use

Why The US Military Made GPS Free-To-Use


Nearly every bit of data we use in our modern devices has a price tag associated with it, but there is one vital piece of technology that many of our devices depend on, that is free. It allows our phones to give us turn-by-turn directions, no matter where we are in the world, and it may one day even facilitate driverless cars. This, of course, is the Global Positioning System, or GPS, for short. This satellite constellation costs upwards of 12 billion dollars to build and launch, yet its service is available for free, worldwide. Well… not really for free. The US taxpayers paid for it, and continue to pay approximately 2 million dollars a day, to maintain and operate the system. But it wasn’t always available for use. These satellites were launched for use by the military to provide all divisions of the military with pinpoint accurate location information on their aircraft, ships, and even their individual soldiers, anywhere on the planet. The first Global Positioning satellite, the Navstar 1, was launched in February 22nd, 1978, aboard an Atlas rocket. Over the next 7 years, another ten GPS satellites were successfully launched into orbit. Only one of the twelve planned, Navstar 7, failed to launch. These Block I satellites validated the system’s capabilities and the lessons learned from the project were carried forward to the Block II satellites, which would complete the 24-satellite constellation, providing worldwide GPS coverage for the US military. A 24-satellite constellation ensures that at least 4 satellites have a direct line of sight with any point on the planet’s surface at all times. This ensures the GPS constellation can pinpoint your location anywhere on Earth through trilateration. We know exactly where the satellites will be at any time as a result of predictable orbits, and a ground station regularly checking in to make sure they are where we expect them to be. GPS satellites constantly broadcast a radio signal which the GPS receiver in your phone is constantly listening for. This signal tells your phone the satellite’s position, and what time it was sent at, thus allowing the receiver to calculate how far away it is from the satellite, as the radio signal travels at a known speed – the speed of light. Each satellite tells us we are within X kilometres, and thus we know we are somewhere on the circumference of a sphere with a radius equal to that distance. Getting this information from 4 satellites allows us to pinpoint exactly where we are on Earth by combining each sphere, and seeing where they intersect. Knowing the exact time is essential to making this system accurate. A divergence of 20 to 30 nanoseconds would make the distance measurements unacceptably inaccurate, so each satellite contains an atomic clock, the most accurate timekeeping device available, but, due to their size and cost, these cannot be used in phones so the GPS satellites also constantly update the phone’s time to ensure it is able to calculate the distance between itself and the satellite accurately. To keep this time measurement accurate, we even have to consider the effects of special relativity, because the receiver on the ground is moving slower than the satellite in orbit, which is travelling at 14,000 kilometres per hour. Special relativity predicts that the onboard atomic clock will experience time slower and thus fall behind the clocks on the ground by 7 microseconds a day. Furthermore, the satellites are orbiting at 20,000 kilometres above the surface of the planet, where the gravity of Earth has less effect on the curvature of spacetime. General relativity tells us that the clocks closer to the mass of Earth will fall behind the ones in orbit, so, if we calculate the time dilation due to gravity on the Earth’s surface, and then calculate the dilation at 20,000 kilometres from the planet’s surface, we can see that the clocks will diverge by 45 microseconds every day. Combining these effects, we have to make the clocks onboard each satellite to tick 38 microseconds faster than those on Earth. If this effect wasn’t taken into account, GPS calculations would lose 10 kilometres of accuracy each day making it completely useless, but, thanks to the efforts of those ingenious engineers and Einstein’s incredible discovery, we have a Global Positioning System on our smartphones with an accuracy within about 5 metres. But, as I said earlier, this system wasn’t always available to the average citizen; it was for military use only. To open this system up to the public would open a tool that could potentially be used against the US. After all, missiles used this system for navigation, too. The incentive to open its use for civilian use came in 1983 when a Soviet Su-15 shot down a Korean passenger jet that strayed from its intended route, into Soviet prohibited airspace. An error that could’ve been avoided had the new form of navigation been available. And so, on September 16th, 1983, president Ronald Reagan announced the Global Positioning System would be made available for civilian use, free of charge. But, there was a catch: the signal would be scrambled to decrease its accuracy to around 100 metres, making it useful, but not by today’s standards. This was intended to keep the US military’s tactical advantage, and prevent the system from being used for nefarious purposes. It wasn’t until 2000 that president Bill Clinton signed a bill to stop the scrambling and open accurate GPS to all civilians, including those outside of America. This was done in recognition of the huge economic benefits GPS could provide to companies in America. American armies have disrupted the signal in the past in areas like Iraq by blasting out radio waves that disrupt the radio waves incoming from the satellites, and this isn’t a difficult thing to do. In 2013, a truck driver in New Jersey wanted to mask his GPS location from his boss and used a small jammer, but inadvertently interrupted GPS navigation systems in Newark Airport every time he drove by. Beyond this simple jamming technique, which is easy to track, the US could simply choose to take away this privilege at any point, and cripple businesses across the world. So, countries around the world have been building their own GPS systems. Russia has its own 24-satellite constellation, and so does not depend on the US at all. A similar system will be available for China and Europe in 2020, while Japan has 2 satellites in orbit to increase GPS availability in its urban counties. These satellites’ orbits have been tailored to ensure that one is directly overhead at all times. Finally, India has 7 of its own satellites to cover India’s land area alone. This tool is probably one of the most underrated results of the space program. A simple radio signal that allows our farmers to operate driverless tractors to manage their land. Commercial fishing vessels use it to navigate, and find fishing locations. The aviation industry uses it for navigation, and collision avoidance. Even drones would not be possible without it, as anyone who has flown a DJI drone knows that you have to have a connection to at least 6 satellites to fly. Another technology that these drones have depended on to become so prevalent today, is computational simulations, and my friends at SimScale, who have kindly sponsored this video, are working to make engineering simulations available to everyone. The software I used for my thesis cost thousands of dollars to licence. Even the engineering firm I was working for previously was unwilling to pay to use it, but SimScale is available for free, if you don’t mind your results being available to the public to view, which brings me to the next fantastic part of SimScale. You can view thousands of simulations from the community, and learn alongside them. You can even take an existing community simulation, and adapt it for your use. They run workshops regularly to teach you how to design with their tools. One of my favourites was a recently-run workshop on drone design. I honestly can’t say how much I love this platform. If you are a hobbyist, an engineer, or a future engineer, I really recommend you sign up, and try your hand at engineering simulation. As always, thank you to my Patreon supporters for supporting this channel. Your pledges continue to allow me to improve the production quality of my videos, by making it possible for me to employ help with animation from Mike from MOBOX Graphics. If you wanna see more from Real Engineering or me, the links to my Twitter, Instagram, Facebook, and Patreon accounts are below.


Reader Comments

  1. ppl believing in satelites are believing in pseudoscience .
    a person who really believes he can see a satelite, which isnt bigger than a car according to the ppl who tell us they exist, with his naked eye and thousands of kilometers far away cant be taken serious.
    what we probably see in the sky (and that might be the reason why we even see something up there ) are high altitude baloons which are declared as "satelites", that kind of balloons are in use for decades and with the todays technology (i mean the technology which is not public and is certainly 20 years ahead ) they may have the posibilities to keep them at positions where they want them to fly.
    i mean there are ppl out there who believe that there is a tesla car with a muppet sitting in it , flying in an orbit around earth, thats hillarious and explains why this world is so fucked up despite the opportunity to use technology to learn and investigate something without the need to believe everything u get told by authorities and the media.

  2. We Indian too have our own navigation system called IRNSS (Indian Regional Navigation Satellite System) with 10 m accuracy (public) and 0.1 m accuracy (encrypted).

  3. Just FYI, in your video you said that drones wouldn't be possible without GPS but even if drones use it they do not absolutely depend on it. The navigation technology that drones really depend on is the accelerometer. The GPS as with other technologies, like the digital compass, the sonar and the vision-base navigation are there just to make more features available.

  4. 2:37 I had a phone once that lost track of what time it was because I was in the mountains with no service for so long and one day my phone got turned off and later when I turn it back on the time was wrong and even when I got service back it still didn't correct the time it stayed wrong permanently

  5. So you can put gps on radio antennas around the city town and have almost perfect position and not spend $2000000 dollars each day but the gov love spend your money…!

  6. Its not free. Instead they pay hundred thausand spy to mapping enemy location they use it free gps. Every human adding it address…routing street and naming every places easy for usa puting it on ther smart missile with lest money. Lol…

  7. Your videos are great and i juts cant stress enough on how much i love them.Keep the good work up and keep us educated.Much love from India.

  8. Wonder if all those foreign satellites are the reason behind the X 38? You wanna mess someone’s day up, good way to do it. Re-program satellites while in orbit? They ain’t saying but if I had to guess…

  9. My question is – why does it mess up big time in cities some times – I’ve had many experiences in San Francisco and Washington DC where it just gets lost – ie – it can’t “see” where I am going and gives me incorrect directions

  10. Fun fact, and you can FACT check it yourself, but iPhones are programmed with the most accurate time. There’s a video of NDT explaining why he owns an iPhone.

  11. I think the most important reason is that by making it public-available can pull down the cost of all GPS devices. Because the suppliers no longer have to make them exclusively for the military. Nowadays a GPS chip can cost just a few dollars.

  12. So if time can be relative, that also means the speed of light can change. Because if time goes faster then light will cover more distance per second?

  13. WHO INVENTED THE SPACE ENTERPRISE?
    The Vatican usee it's newly created Jesuits to publish Heliocentricism, where a stationary, unmovable Earth, as stated in their Bible scriptures was replaced by a spinning, orbiting, "Heavenly Sphere"; as taught in the major Universities, where Theory replaced Faith. From birth, you are indoctrinated to worship the man-made constructs of Heaven and Space.
    Vatican Jesuits invent the following:

    1543 – Theory Heliocentricism
    1582 – Heliocentric calendar (Pope Gregorian calendar)
    1651 – Theory Mapping Moon (Selenography)
    1763 – Theory Atomic Energy
    1809 – Theory Transmutation of Species
    1923 – Theory Missing Link (bones lost, molds prove find)
    1931 – Theory Big Bang (another ejaculation into the virgin source)

    Our history and science has been little more then a fictional story over the last 2000 years. It began, with obedience from the indoctrinated masses these illiterates who paid tithing for Faith based religion and war. Today, the indoctrinated masses are educated idiots who pay tax on their labor for Theory based science and war. This is the reality propagated across the face of the Earth.

    You defend one of these fictional stories:

    Theory – SPACE (Big Bang)
    ATOM, remove Electron create Explosion
    Evolution, requires you an APE like creature to consume flesh and blood

    Faith – HEAVEN (Holy Spirit)
    ADAM, remove Rib create Women
    Creationism, the HE God gave you the clean and unclean animals for food

  14. Thank you American tax payers. Also thank you for the military, since its basically protecting the entire west at this point.

  15. not a native english speaking have difficulties following the rocket fast narrations.
    _

  16. I just googled what the economic impact of GPS is, and it turns out the benefits account for about 0,3% of GDP every year. On average the US economy grows by about 2% a year, and 0,3% of that is made possible by GPS (along with other technologies of course). Over 15 years, an additional 0,3% in compounding GDP renders a 5% net increase in GDP. In other words we make 5% more money now than we otherwise would've, had we not had GPS. That's $3000 extra annually per person.

  17. I was told a long time ago by an engineer that worked with GPS that the only reason why GOS is free is because no one knew how to charge people for it.

    And you know what… I believe that statement is accurate.

  18. Multilateration rather than trilateration – and more than three or four satellites are used in solving for position and other motion parameters.

  19. It's free to use because it belongs to the tax payers. Just like the US army belongs to them too. No tax payers, no army.

  20. Maybe i missed something ,but if you combine the private and general relativity, you should aim the Atomic clock on board ticking 38 micro seconds slower not faster?

  21. THERE IS NO FREE LUNCH! 😠😠😠😠There is actually a huge pricetag! This GPS and these other "free" services are Big Brother's way of SPYING on us and keeping us under their thumb! 🖓

  22. So America just gave GPS to the world while the American taxpayer fits the 2 million dollar a day bill? I thought America and Americans were the cause of all the world's problems? Lmao.

  23. The thing about relativity is that they have not ruled out the fact that the sat is in orbit neutralizng Earth's gravitational field. They've gotten probes of different kinds moving much faster than 17000 MPH toward outlying planets etc but I have never reads single shred of the time dilation being greater at the greater velocities. Why?

  24. An engineer with a Scottish accent…who seems to kow what he is talking about….subscribed….call me old school….;-)
    Bet you have never used a slide rule…good for you…there is no longer any such thing as a Chinese account keeper who uses an abacus…..:-)

  25. The only selfless country in the world is united States.
    Others are building for personal use, US is making it for free for all mankind.
    God bless America

  26. Long story short to track us!
    Not only do they spy on citizens. They also torture some citizens.
    I have been a victim of SRA for 3 yrs this Aug. Abused with "no touch" torture and stazi type tactics.
    Mkultra/monarch/cointelpro/phoenix/artichoke programs are continued with 21st century tech. Take 3 min and visit biggerthansnowden.com whistleblower section. The people are called targeted indvduals or targeted citizens is a better description seeing how hundreds of thousands maybe more are being tortured.
    Former FBI chief ted gunderson signed a legal binding court affidavit exposing this genocide program. As well as satanist, child, sex and drug trafficking is being perpetrated by alphebet agencies. Edward Snowden has also spoke out about gangstalking.
    Radio frequency and psychotronic weaponry are used in todays modern mkultra 5.0 program. V2K (voice to skull), directed energy weapons, 24/7 surveillance, artificial telepathy (see Snowdens vid describing synthetic telepathy and gangstalking), etc.
    If that isnt enough horseshit then the perps throw in gangstalking/ organized stalking/ counterintelligence stalking. Perps following and intimidating, breaking into home, vandalising your stuff, drugging and raping you, killing you pet, spreading lies/ slander to brainwashed sheep to do felonys to you, ruin any relationships they can, and the list goes on nothing good. End game and best end for them is a TC kills themself. Perps get paid well to do this. TC get labeled schizophrenic or on drugs when they try to get help from police or healthcare providers.

  27. unless you're in a remote area, why not use radio signals from stationary ground based sources (cell/radio towers) to supplant/replace triangulation from satellite signals? especially in cities where urban canyons can have difficulty with GPS signal reception.

  28. GPS sucks where I live. It shows me 30miles away from my actual home. It will track me into my driveway, then suddenly it shows me in the wrong town.

  29. I got a free Garmin 1300 nuvi for 30 years company employment in 2011 and at the beginning it would leave a thin blue line on the map wherever I went; I could even retrace my trip with it but eventually the updates ( where I had been ) and the downloaded software updates took that away. Now with my smartphone, laptop and GPS the powers that be can keep an eye on me 24/7 LOL if they wanted to but that would only bore them to sleep.

  30. You did not give us the answer. it is simple, data means power and if you can know exact location 3 people then you can predict fourth people's location. that 4th people can be a politician or an enemy.

  31. I thought your phone communicated with land based towers and the towers communicated with the satellites.

  32. Special relativity is a hawx and GPS has nothing to do with it ,on the contrary gps is another proof that SR is wrong.

  33. Only reason is that they have something 1000x better military tech is 100years ahead of civilians tech

  34. How does the gps satellite update the gps’s clock when the distance is variable and the difference in the clock is what’s used to measure distance?

  35. If they tried to charge for gps use, theyd need to encrypt it or use some other identifying technology. This would make ir possible for russians to sniff out anything receiving enceypted gps signal and attack it would be a us military receiver

  36. Because America contributes to the prosperity of the world and share its knowledge although China takes advantage of the world and don't share anything

  37. Another reason the USA allowed use of the GPS was that countries like Australia and New Zealand were needed to operate the system ie Pine gap

  38. Question: So how many devices a gps satellite can serve? or does satellitea just sends constantly beam of signal toward earth so any no. of devices can receive it?

  39. Why Einstein made public his theory of relativity? After all without his idea the GPS would be impossible.

  40. Your content isn’t correctly aligned to your title. Therefore I’ve given it a negative thumbs down.

  41. Excellent video! I'm really glad this one over the relativity aspect of GPS satellites. That has always been one of the cooler engineering aspects of GPS satellites to me. It's not mine blowing or anyting but it's just really awesome our precision dictates the need to use it it

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