As I continue in my quest to gauge and apply the utility of my GPS enabled phone, there are a couple of apps and programs I’ve come across that I believe are worthy of mention. They are, of course, free.
The first is a program provided by Trimble, which allows one to schedule their GPS-contingent outings based upon a foreknowledge of probable satellite availability. The program is Trimble Planning Software. Based upon a user specified location, and date/time window, the software will return a range of information pertaining to the satellites that can be expected to be ‘visible’ in the sky above.
The program’s knowledge of satellite availability at particular locations/dates/times is accomplished by data files, known as GPS Almanacs, that are fed into the program. Such files are available online through various resources. One such resource is the US Coast Guard’s Navigation Center.
With respect to the information the program returns to the user, they include
It should be noted that this program does not take into consideration issues such as physical obstructions that may impede satellite availability. Otherwise, knowing the above, users can plan for the most opportune time to schedule their outings. Of the above information which the program provides, the bottom line gauge would likely be the DOP plot. Very simply, Dilution of Precision gauges just how good/reliable measurement information will be. The lower the DOP, the better. Here’s a brief article on DOP.
The second application I came across is one for Android phones, developed by EclipSim, and known as GPS Status and Toolbox. This app does almost exactly what Trimble’s software does, but only in real-time, and with no ability to forecast future satellite availability. Note that it even has a DOP readout. I’ll likely be using this app to gauge and compare to the field readings I hope to do soon.