Get an idea of the number of satellites, signal, elevation, bearing, almanac, ephemeris and accuracy
The visible satellites appear as small circles with a unique ID number. A small yellow arc represents the signal strength available from the satellite. The satellite color changes depending upon availability of data. If Ephemeris data is available it is Green else if Almanac data is available it is Orange otherwise it is Red
The central solid circle color will change depending upon mode of operation. Stopped – Grey, Running – Orange, Green – Location Fix Available
When the satellite is close to center then it is overhead. When the satellite is at periphery of circle then it is at horizon
Almanac is longterm and imprecise satellite data which is typically invalidated every few months.
Ephemeris is shortterm and precise satellite data which is typically invalidated by the GPS engine in a couple of hours. The GPS engine requires at least 4 satellites to get a fix. With precise ephemeris data the accuracy and time to fix improves.
More satellites with valid ephemeris the better the accuracy.
If you use an app which uses GPS like Maps then you will find that the moment you close the app it takes some time to get GPS fix back. This app helps keeps the GPS alive so that the delay in regaining GPS will be minimum
When an app using GPS is launched there is a delay before the location is available. This delay is because the GPS engine requires the latest satellite data to get the position fix. So while the GPS engine downloads the latest satellite data no position fixes are possible. The solution to this problem is to keep the GPS Engine updated or Alive so that it is always in an updated state
The GPS is a very power hungry process. If the GPS is running continuously then it will quickly drain the battery. So this app gives a low power and high power mode option to the user. High power mode keeps the GPS locked ON continuously and not recommended for extended periods. The Low power mode is a reasonable compromise and only wakes up the device from time to time to refresh satellite data
The Notification controls in the status bar get enabled once the Start button is clicked. The notification control can be stopped or disabled altogether. As a safety feature the notification will autostop after the set runtime.