GPS - General question

[sbi]

Does the GPS in a smart phone use data, or is it like any other GPS (connected to the satellite)?

 

[sbi]

The GPS doesn't use any data. A GPS uses a tiny bit to get your location. The program you're using is what uses data.

OK, I am confused.
If the GPS gets the data from the satellite, what data is needed by the program?
Just like a standard GPS that is not connected to a cell phone or data package, the program is within the device and it gets the 'update' from the satellite, so does a cell phone gps program is installed on the phone, isn't it?

 

[John Redcorn]

Almost all phones (surely all androids) have assisted gps where as the gps is starting up it downloads data from the internet or your carrier using your data connection to get an "ephemeris" basically a list of all the gps satellites and their approximate position in the sky that day. It helps the gps lock on lots quicker.

If you have data disabled (or you're using your old phone with no sim or wifi connection) it can't download this ephemeris and it will have to find the sats on its own and it takes a lot longer.

Try it out, download gps status, turn off your data and wifi, from gps status clear the agps data then see how long it takes to lock on.

This is all related to getting your position in the form of latitude, longitude, altitude, thre little numbers that's it. Actually showing that position on a map is completely separate, not done by satellites at all. The actual maps that show are not coming from the satellites on any device, maps come from google on your android or iphone over your data connection or if you're using a standalone garmin or tom tom gps it has a whole country's or continent's worth of maps saved inside on flash mem.

 

[cdl]

Almost all phones (surely all androids) have assisted gps where as the gps is starting up it downloads data from the internet or your carrier using your data connection to get an "ephemeris" basically a list of all the gps satellites and their approximate position in the sky that day. It helps the gps lock on lots quicker.

If you have data disabled (or you're using your old phone with no sim or wifi connection) it can't download this ephemeris and it will have to find the sats on its own and it takes a lot longer.[...]

For example, the TomTom Go Live 1000 GPS has an embedded sim it uses to access google places and for "satellite quick fix", i.e. to find the satellite signal quicker

 

[sbi]

OK, so if I get it correctly, Data (as in my data plan) is used initially to fixate my location on the map and with the satellites and then the rest, during navigation, uses data from the GPS only?

The bottom line is, how much of my data (plan) is being used on GPS navigation?

 

[cdl]

OK, so if I get it correctly, Data (as in my data plan) is used initially to fixate my location on the map and with the satellites and then the rest, during navigation, uses data from the GPS only?

The bottom line is, how much of my data (plan) is being used on GPS navigation?

I have never verified myself, but according to most material I found, only a few KBs. With google you might find more precise information.

 

[Tslide91]

OK, so if I get it correctly, Data (as in my data plan) is used initially to fixate my location on the map and with the satellites and then the rest, during navigation, uses data from the GPS only?

The bottom line is, how much of my data (plan) is being used on GPS navigation?

GPS satellites only give your phone it's location.

What the "a" in "aGPS" means is "assisted," like posted earlier. What that means is the phone uses data to download the map and directions packets. It doesn't use much data at all.

So. When you fire up Maps, before the GPS even comes into play, the phone downloads the info it needs. Then it connects to the GPS satellites to get location. GPS doesn't use any data. However, aGPS uses a little bit of data.

It all happens simultaneously, I just put that in a step-type-scenario to make it a little more clear.

 

[sbi]

GPS satellites only give your phone it's location.

What the "a" in "aGPS" means is "assisted," like posted earlier. What that means is the phone uses data to download the map and directions packets. It doesn't use much data at all.

So. When you fire up Maps, before the GPS even comes into play, the phone downloads the info it needs. Then it connects to the GPS satellites to get location. GPS doesn't use any data. However, aGPS uses a little bit of data.

It all happens simultaneously, I just put that in a step-type-scenario to make it a little more clear.

Right, I understand that the GPS itself doesn't use any data, however, is the usage of data (by the 'a' in the gps) continuous or is it only initially, as you mentioned, and then the rest of the navigation comes only from the gps?
Sorry if I dig into this, I am just trying to understand who's the major player here. For example - is the software in the device, through a continuous download of data (kb or mb, it doesn't matter), the one doing the navigation (after the initial fix by the satellite), or is it the satellite - AGPS - that does the navigation after the initial download of the map?! Kind of confusing.

 

[daveybaby]

Getting your location via GPS doesnt use any data. It's entirely passive, you just receive signals from the satellite. If you turn off all data then GPS will still work just fine. The satellite (actually multiple satellites) doesnt plan your route, all it does it give you your current location. Well actually all it does is tell you the time, your phone calculates where you are by triangulating based on the time delay from several satellites (the bigger the delay, the further away the satellite is, and we know where all the satellites are, so if you know how far away several satellites are you can work out your location).

But displaying your exact location on a blank map isnt much use. Downloading map information (e.g. google maps) from the internet to display that location on does use data. Planning a route using google nav does use data (not a huge amount though). The satellite doesnt give you a route, all it does it tell you where you are, the software in the phone works out where that is on the route.

However, you can pre-cache areas in google maps, so if you know where youre going ahead of time you can download that area, and then you can see where you are on a map when youre out & about. You cant do this with google navigation though, you need a connection to google's servers in order to plan the route.

Also: if you use dedicated satnav app with built in maps (e.g. copilot live) then all of the maps are stored on your SD card, and the route is planned and tracked by your phone, so in that situation you dont need any data connection at all.

 

[sbi]

@daveybaby - Thanks!

Now the question is - is there any GPS app for Android that can be stored on the SD card, like iGO8 for example? I use iGO8 on my standard GPS unit.

 

[cdl]

@daveybaby - Thanks!

Now the question is - is there any GPS app for Android that can be stored on the SD card, like iGO8 for example? I use iGO8 on my standard GPS unit.

copilot live premium is pretty good: http://www.copilotlive.com/

www.66.com sounds promising, especially because it is based on the TomTom maps. It would be great if it had iqroutes and HD traffic, as well, because that's what sets TomTom apart from its competitors, imho. HD traffic basically provides real-time updates to the traffic situation based on the data it receives from all the TomTom units in the area. More details here:
TomTom, portable GPS car navigation systems - HD Traffic

PS I know HD traffic is great in Europe, and way better than the Garmin traffic updates. I have no clue what the coverage is elsewhere.

 

[daveybaby]

There are quite a few - but you do have to pay for them (cos that map data aint cheap).

I've got copilot live installed for the UK and it's pretty good. There's a US version too, dunno how good it is cos i dont live there . I hear navigon is good but its very expensive.

There have been quite a few threads around discussing the best satnav app over the years, best bet is to have a look around in the android applications forum.

 

[cdl]

There are quite a few - but you do have to pay for them (cos that map data aint cheap).

I've got copilot live installed for the UK and it's pretty good. There's a US version too, dunno how good it is cos i dont live there . I hear navigon is good but its very expensive.

There have been quite a few threads around discussing the best satnav app over the years, best bet is to have a look around in the android applications forum.

I agree copilot live premium seems pretty good. Bear in mind when searching for reviews and comments that the premium version is pretty recent, and quite different; most comments are likely to refer to the old vesion.

I especially like the possibility to choose among 3 routes, an option most satnavs don't give you. Unfortunately the traffic updates are almost useless compared to TomTom; but then TomTom has its share of problems because it rushed to the market half-baked, incomplete devices full of glitches and bugs, not all of which are entirely solved. Don't take my word for it, check their forums.
Probably the most relevant issue for the Android community is that the latest TomTom devices won't work with most Androids because most Androids (shame on google) don't support bluetooth rsap (remote sim): the TomTom keeps trying to access the phone book contacts, causing the bluetooth connection to keep dropping and becoming effectively useless. There's no option to stop the TomTom from trying to access the phone book and act just like a normal loudspeaker - something most older models pulled off perfectly. The few Androids which support this tend to be HTC or Samsung.

 

[John Redcorn]

Right, I understand that the GPS itself doesn't use any data, however, is the usage of data (by the 'a' in the gps) continuous or is it only initially, as you mentioned, and then the rest of the navigation comes only from the gps?

The agps data is only downloaded initially and then only updated/re-downloaded every 2 or 3 days.

The rest of the location info lat/long/alt comes only from gps. If you choose to translate those 3 numbers into a moving map then that uses your internet connection unless you've bought some offline nav app.

 

[sbi]

Thank you all.