I need to check the accuracy of GPS... but when i use location.getAccuracy then it doesn not return me any value... Does it take time..If it takes time then how long does it takes?
In android devices, mainly you can have two sources by which you can get position info : GPS_PROVIDER and NETWORK_PROVIDER
GPS_PROVIDER uses your GPS chipset to get a position fix. This has a greater accuracy.
NETWORK_PROVIDER uses the information from cell-tower to triangulate your location. Hence its accuracy is not as quite good.
You can get your accuracy info from Location.getAccuracy() or from NMEA data.
Does it take time..If it takes time then how long does it takes
Once you've started getting fixes it won't take much time. Time to first fix can be 30 seconds to 15 minutes. It depends on your GPS chipset, terrain conditions, cold/warm start etc.
To choose the best provider read this article
Related
In application I need to get geo position of phone every x minutes (for now it's 5min and 50m), in such a way that phone doesn't discharge during day. The accuracy of position must be at least 40m. By now I have listeners for gps and network. The problem lies in the fact that the data I can receive sometimes is totally wrong (depends on phone) - new position can be even 200m from my real position and with 40m accuracy; next point can be the same but in opposite direction. For my app it's fatally.
So the question is next: Is there any way to get more accuracy data but not very often?
Update 1: to show the problem in action:
(The phone is lying in the fixed position)
To get more accurate location make sure you're using the ACCESS_FINE_LOCATION permission in your manifest. To prevent higher battery usage, you can use setInterval and setFastestInterval on your LocationRequest object. Longer intervals mean less battery usage by your app.
You should not be accessing the gps and network directly, you should be using LocationManager and using ACCURACY_FINE in your Criteria. This will help conserve battery life, and avoid issues with phones where the gps may have been disabled. There's more detail on that here.
As far as the accuracy of your location, you can use Location's getAccuracy method to get Android's estimate of how accurate a measurement is. If it doesn't fit your criteria, discard it and poll again.
I'm not sure which location providers I should use:
20 seconds is the maximum time I can manage without location.
The accuracy is less important for me, I can manage with accuracy of 500m.
Take a look at the location manager class. It will give you the information about location. And because you need an accuracy of 500m , I would suggest you to use gps, as networks(assuming you mean cellular) will have a lesser accuracy.
I'm using Fused Location Provider library in android. It is working perfectly fine. But I've an issue with it, it returns location updates in 5 sec minimum.
I've tried every thing like setting minimum updates time to 1 millisecond, and distance to 0.01 meter and Priority to PRIORITY_HIGH_ACCURACY
My code :
locationrequest.setInterval(1); // 1 milliseconds
locationrequest.setSmallestDisplacement(0.01f); // 0.01 meters locationrequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
But no use, still minimum time between two successive location updates is 5 seconds.
My Questions is : Is there any way to decrease location updates time to 5 milliSeconds ?
-> I need location updates for only 10 minutes, So no issue with the high battery consumption.
-> I need any way (possible): Is there any external hardware available, which connects via Bluetooth and send location updates upto that level ?
Edits:
Let me ask you a different question :
What can be the minimum possible time for location updates and how to achieve that ?
Let's say i want to track a car, which is moving with the speed of 400 KM/h, means 5 meter in about 50ms. So can you suggest any better way to track this car ?
The precision and accuracy of location-sensing hardware (GPS, AGPS, etc.) means that getting updates more frequently than every few seconds isn't likely to provide meaningful results. In fact, technology like the Fused Location Provider is likely to prioritize getting more accurate results rather than providing results every few hundred milliseconds.
In addition to that, the battery drain from getting updates multiple times a second is likely to be very significant.
All that said. The way to get every update that your location-sensing hardware is receiving is to set the location update interval and minimum displacement to zero, and to prioritize accuracy.
locationrequest.setInterval(0); // No delay.
// locationrequest.setSmallestDisplacement(0); // This is the default.
locationrequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
Note that this will give you every update, but depending on the hardware limitations, and potentially the Fused Location Provider implementation, there's no guarantee this will be any faster than the 5s frequency you've found so far.
I am developing an app, where I need (GPS) coordinates every couple of seconds, unfortunately the GPS uses a lot of battery.
Is it possible to get a good estimated position (including altitude) based on the last GPS position(s) and motion sensors from an Android smartphone, for let's say 1 minute?
What algorithms would I need to look into?
This does not work with GPS.
The GPS chip has to track the sattelites all the time, so it makes no difference for battery consumption if you get once a minute or once a second.
Things changes when you only need a position evry 5 minutes, then it could make sense to stop location service, and restart again. (but even that is only a vague estimation).
Finally you have to measure which intervall really saves battery.
bye the way: i can record 8 hours of gps with one fix per second, on iphone 4
In my android application i need to GetSpeed from GPS
But the onLocationChanged() is called only every second even if set distance distance/time to 0 in requestLocationUpdates
How can i get the GPS Speed with higher frequency ? I don't need position, only speed
Is it possible to call GetSpeed outside onLocationChanged()?
Thank You very much
onLocationChanged is slow because it takes some time to fire get a first gps fix from the hardware. The speed estimate is a property of gps fixes. Hence speed changes along with with the location. You can try getLastKnownLocation() wich provides the last fix immediately. Use location.getTime() to decide if the last location is fresh enough.
GPS technology does not measure speed. It is merely a way to get accurate position. The speed value is based on position calculation.
That's why you can't get better frequency for speed values: the information is not there. Only (very short time) after a location update can there be any speed update.