Eli5 How sat natv in your car trasmits data?

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You don’t pay for it and there is no sim card but yet somehow you see your car icon move on a map?

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11 Answers

Anonymous 0 Comments

There’s no transmitter.

There’s a GPS receiver in your car infotainment unit or mobile phone which works out where you are by measuring the exact timing of radio signals from satellites. The infotainment unit or your phone has maps already downloades.

These are a free service provided by governments:

* GPS – U.S.A.
* Galileo – Europe
* Glonass – Russia
* BeiDou – China

Most built-in car units need you to buy new maps every year. Some dedicated units like Garmin and TomTom have free map updates, some don’t.

Anonymous 0 Comments

There’s no transmitter.

There’s a GPS receiver in your car infotainment unit or mobile phone which works out where you are by measuring the exact timing of radio signals from satellites. The infotainment unit or your phone has maps already downloades.

These are a free service provided by governments:

* GPS – U.S.A.
* Galileo – Europe
* Glonass – Russia
* BeiDou – China

Most built-in car units need you to buy new maps every year. Some dedicated units like Garmin and TomTom have free map updates, some don’t.

Anonymous 0 Comments

There’s no transmitter.

There’s a GPS receiver in your car infotainment unit or mobile phone which works out where you are by measuring the exact timing of radio signals from satellites. The infotainment unit or your phone has maps already downloades.

These are a free service provided by governments:

* GPS – U.S.A.
* Galileo – Europe
* Glonass – Russia
* BeiDou – China

Most built-in car units need you to buy new maps every year. Some dedicated units like Garmin and TomTom have free map updates, some don’t.

Anonymous 0 Comments

There’s usually a SSD card or DVD in your car somewhere that has all the map data. The GPS is receive only. You can buy new map data every year. You may get 1-2 free years of updates when you buy the car.

if you have XM radio (still receiver only), some GPS units can receive traffic/accident data.

Anonymous 0 Comments

There’s usually a SSD card or DVD in your car somewhere that has all the map data. The GPS is receive only. You can buy new map data every year. You may get 1-2 free years of updates when you buy the car.

if you have XM radio (still receiver only), some GPS units can receive traffic/accident data.

Anonymous 0 Comments

So the map itself is stored locally on your device. So it just needs to work out where to put you on that map. It receives signals from satellites, and uses that data to calculate where you are.

You’ve probably heard of something called triangulation. So basically, a satellite screams out saying “THE TIME IS 18:02:34.568 RIGHT NOW”. Your SatNav receives that signal and compares it with its own clock. Let’s use simple numbers to make the maths easier. Your SatNav receives the signal 1 second after it was sent. It knows that the signal travels at 1km per second, so therefore you must be 1KM from the satellite.

However, that alone doesn’t tell you where you are, because that satellite could be in any direction. So it does the same thing with multiple satellites, and eventually says “Well if I’m x distance from this satellite, y distance from this other satellite, and z distance from this other satellite, I must be here”. 3 is the minimum required for an accurate result, hence “triangulation”.

Anonymous 0 Comments

There’s usually a SSD card or DVD in your car somewhere that has all the map data. The GPS is receive only. You can buy new map data every year. You may get 1-2 free years of updates when you buy the car.

if you have XM radio (still receiver only), some GPS units can receive traffic/accident data.

Anonymous 0 Comments

So the map itself is stored locally on your device. So it just needs to work out where to put you on that map. It receives signals from satellites, and uses that data to calculate where you are.

You’ve probably heard of something called triangulation. So basically, a satellite screams out saying “THE TIME IS 18:02:34.568 RIGHT NOW”. Your SatNav receives that signal and compares it with its own clock. Let’s use simple numbers to make the maths easier. Your SatNav receives the signal 1 second after it was sent. It knows that the signal travels at 1km per second, so therefore you must be 1KM from the satellite.

However, that alone doesn’t tell you where you are, because that satellite could be in any direction. So it does the same thing with multiple satellites, and eventually says “Well if I’m x distance from this satellite, y distance from this other satellite, and z distance from this other satellite, I must be here”. 3 is the minimum required for an accurate result, hence “triangulation”.

Anonymous 0 Comments

So the map itself is stored locally on your device. So it just needs to work out where to put you on that map. It receives signals from satellites, and uses that data to calculate where you are.

You’ve probably heard of something called triangulation. So basically, a satellite screams out saying “THE TIME IS 18:02:34.568 RIGHT NOW”. Your SatNav receives that signal and compares it with its own clock. Let’s use simple numbers to make the maths easier. Your SatNav receives the signal 1 second after it was sent. It knows that the signal travels at 1km per second, so therefore you must be 1KM from the satellite.

However, that alone doesn’t tell you where you are, because that satellite could be in any direction. So it does the same thing with multiple satellites, and eventually says “Well if I’m x distance from this satellite, y distance from this other satellite, and z distance from this other satellite, I must be here”. 3 is the minimum required for an accurate result, hence “triangulation”.

Anonymous 0 Comments

GPS location service is free because it is a satelite broadcast signal and the satellites are government funded, however most cars nowaday DO have data capabilities for map/traffic/software download.

It’s called Internet-of-things connectivity. Your car nav computer actually has a 3G/4G/5G module built-in, with a sim card that has a special service plan activated. Car manufacturers made a deal with carriers to heavily discount these data plans with several restrictions:

* The data speed is heavily limited,
* Only connects to specific servers for nav/music,
* Low priorty in access requests,
* Sometimes nav computer IMEI and SIM ICCID/IMSI/data plan is paired and authorized service procedures starting from dealer/workshop is required to change pairing.

These rules prevents people from taking the SIM out of totalled cars and sell it as free internet forever cards. This doesn’t hurt the carrier’s business so they sold the data plans to car manufacturers VERY cheap. They are either paid upfront by including the cost in the price of the car, or the manufacturer pay a package deal annually as server/network costs to run their public web services.

Some manufacturers are cheaping out even this deal by saying these plans are only free for the first few years, usually lined up with car warranty. After it runs out, car owners have to pay for it monthly.