Application Name: GPS Finder
Description: Maps GPS satellite positions in the sky, and above a map of the Earth.
Publisher’s website: Cynoxure
Version/date reviewed: v.1.1.3 / 11-14-10
Phone/OS: Droid X / Android 2.2
Note: This app is also listed as CyGPSFinder, but the app’s name on the Android unit is GPS Finder.
Many GPS apps, like GPS Status and GPS Test, offer a map of GPS satellite positions in the sky; GPS Finder offers a similar map, but with some enhancements and additions.
The first time you run the app, it will likely tell you that the satellite orbit data is out of date, and recommend that you download updated data; it will also recommend the same procedure at future times. You should definitely do this, but the process will slow the app down significantly, and possibly even give you an “app not responding” error message; give it a minute or two to perform this process before using it.
Figure 1: The main “Ground Track” screen will show the position of all active GPS satellites plotted on a world map. You can tap and drag the map to scroll it, but only tap on an empty area to scroll it. Tapping on a satellite will select it (yellow ring), and display the satellite’s orbital path. The satellite closest to the central meridian of the display is highlighted with the larger red ring. Your current location is indicated by the black rings.
Figure 2: Select the “Sky Track” tab, and you’ll get a GPS satellite sky map similar to that in other GPS apps. The satellite you selected from the Ground Track Map will also be highlighted in this view, if it’s currently visible from your location. The bar at the bottom shows the time span when the satellite is visible from your location. If it’s currently visible, it will show a red bar indicating how much of the satellite’s visibility time has already elapsed. If the satellite isn’t currently visible, the bar will be entirely gray, and the time at left will indicate when it will next rise above the horizon. This doesn’t take into account blocking by your local terrain, or obstacles like buildings and trees.
Figure 3: You can’t tap another satellite in the “Sky Track” view to select it, as you could in “Ground Track”. However, you can select any satellite at any time using the “Select Satellite” function in the program menu.
Figure 4: In “Sat Finder” view, you can use your Android phone as a virtual “finderscope” to locate the position of a selected satellite in the sky. The arrow will point you towards the satellite’s position; tilt your Android unit until it shows up on the screen …
Figure 5: … in the virtual viewfinder crosshairs. Other satellite positions will be displayed if your view crosses their current location. Don’t expect to be able to see any sign of the satellite, even at night; at about 12,000 miles above the earth, it’s too far away to see with the naked eye.
Other issues: Apart from the slowdown when updating satellite orbit data, which resulted in an error message indicating that the app was non-responsive, no problems were encountered.
Final thoughts: Not sure how practically useful the app is, especially when other GPS apps show similar sky map data. But it certainly looks cool, and might be useful as an educational tool in showing people how GPS works.