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Any decent navigation apps that also display current Speed?

Aside from cars, motorcycles tend to have a speedo that is farther off. On mine, it is 10%, a lot of Suzukis are similar. So if the speed limit is 55 and I want to do 59mph, I have to take 5.9 (or round up to 6 to make it easier) and add it to 59 to get a speed of 65mph. I have to go 65mph on my speedo to actually be going 59. It requires constant calculation.

Simply fix? Use a GPS unit. Just because YOU can see a need for a function, doesn't mean there isn't one for a LOT of other people.
 
Johny_G said:
Hi there!

I am working on app that actually shows current speed over Google Navigation. For now, there is only threshold system of speeding alerts, but I am working on better solution. If you are interested, please visit these forums with Android Market link:

[APP] gMapsSpeed | Speed info and speeding alerts for Google Navigation - xda-developers

Best regards,
Jan Gruncl
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Looks nice, I'll keep my eyes on it and if you get a database of speed limits it would be an amazing app!
 
chawski said:
speedometers on cars are generally off by +/- 2-3mph. that doesnt sound like much but in a state that 9 over is a zero point ticket, 2-3 mph could be worth a few hundred dollars.
As long as the GPS is properly working, it will ALWAYS be more accurate than the speedo on the car
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This is extremely false. A properly calibrated speedometer from a car that is relatively new will always be more accurate.

For a GPS to determine speed, it must send the signal to the sat, the sat then sends a signal back down. Then the phone has to render it. This of course, if you aren't in a rainstorm or tunnel or something.

GPS's are usually at least 5 meters accurate. So that means if you are going 60 MPH, they could be 5-15 miles per hour off if they were not working properly.
 
Saltine713 said:
For a GPS to determine speed, it must send the signal to the sat, the sat then sends a signal back down. Then the phone has to render it.
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That's not quite how GPS works. The satelites all have finly tuned and calibrated atomic clocks on them, and they send out a timecode signal that the GPS receiver reads. And the receiver also has it's time set via an "almanac" it receives. Then the receiver takes the time it has, and compares the signals it's getting from the sats. Since the sats will be different distances from the receiver, it can calculate how far away that sat is be the difference in the timecode the sat sends and the time the receiver knows it is, and the more sats it can see, the better the resolution. The receiver never sends out a signal to the sats, it only receives from the sats.
 
I don't know how you in the states have it with GPS resolution, but where I live it is extremely accurate. As I understand it, it updates several times per second, that should be enough for very accurate speed calculations!
A friend of mine is working in the Uav industry, and they have used the navigator in smartphones to actually guide UAV:s with so much precision that they could auto-land on a road.
Try that with bad calc's......
 
Graffen said:
I don't know how you in the states have it with GPS resolution, but where I live it is extremely accurate. As I understand it, it updates several times per second, that should be enough for very accurate speed calculations!
A friend of mine is working in the Uav industry, and they have used the navigator in smartphones to actually guide UAV:s with so much precision that they could auto-land on a road.
Try that with bad calc's......
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Actually, gps works great and is very accurate here in the US
 
GPS receivers these days work really well these days so even tiny, fairly cheap ones are really accurate, so if the phone manufacturer integrates it properly it should work really well. That's true pretty much anywhere on earth, except maybe polar regions, as long as the phone has a good "view" of the sky.
Hrethgir said:
That's not quite how GPS works. The satelites all have finly tuned and calibrated atomic clocks on them, and they send out a timecode signal that the GPS receiver reads. And the receiver also has it's time set via an "almanac" it receives. Then the receiver takes the time it has, and compares the signals it's getting from the sats. Since the sats will be different distances from the receiver, it can calculate how far away that sat is be the difference in the timecode the sat sends and the time the receiver knows it is, and the more sats it can see, the better the resolution. The receiver never sends out a signal to the sats, it only receives from the sats.
Click to expand...
That's a decent basic description but ignores one important aspect for this thread: the receiver doesn't just use the time delays from each sat's given location, but also frequency shift (doppler effect) from each sat's given velocity. So the receiver's solution is a postion vector (lat, lon, alt) plus a velocity vector.

So each GPS "track" includes a speed and direction, and that's what most apps use. It's often very accurate, again unless your phone can't see the sky well, or it's just got a bad design.

A vehicle spedometer should also be really accurate, but of course they don't have a US Air Force spending lots of money and effort keeping it calibrated, so after a few years they can start to drift. If you are putting one in, make sure it's set for the diameter of your tire :)
 
I wonder if an app like Webkey (that can control/view your phone from a PC), would keep up with the speed reading. Could track/watch from a PC what the GPS was doing if it was on in the car.

Lots of apps show speed these day (GPS Essentials, Car Home, Car Dashboard)
 
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