[Touch 3G General] ronp76:
Re: GPS not turning on

Most PDA GPS's do not turn on automatically by themselves unless instructed or invoked by a software application. I have not looked carefully at my Jade clone's SIRF's specifications but most GPS under ideal situations can take as little as 42 seconds when warmed up to get four satellites to lock on to. Four satellites are necessary in most sytems are necessary for 3D satellite navigation (satnav or GPS).

What are ideal situations? Glad you asked. Basically, one of the most critical needs for a GPS is accurate time. This is the first item that must be sync'ed by satellites. To use a gross example, let's say your clock is off 60 minutes. In a car that could equate to roughly 60 miles. Satellites need accurate time because when they begin to sync, they will compute what satellites are available to sync with your GPS. Just like the sun, moon and stars are only in the sky at moving intervals of time, only a fixed amount of satellites are overhead at any given time.

Once your GPS begins to sync, ephemeris data (which satellites and the times they are overhead) is transmitted to your GPS. When combined with accurate time, the resolution of where your receiving GPS becomes easier.

The next critical issue is where does your GPS think it is. If the GPS was last turned on at the factory (testing), then it will store that location as its last known position. Guess what? If you're in Paris, France and your GPS was made in Malaysia, your last known position known now as initial positon to the satellites will tell them based upon time to use satellites in the Asian area to compute your satnav position. A GPS without a good initial position will make it difficult for satellites to accurately determine your location which could now takes a minimum of four minutes as long as ten minutes and maybe even hours.

Finally, where is your GPS physically located? In ideal conditions, it is outside with clear sky overhead in a stationary location. It's easier to shoot a sitting duck; a moving target or a GPS on the go complicates all the issues of time, location and signal acquisiton.

To help you, I recommend you download a small cab file that be used in your Today screen. It is aptly called "GPS Toggle". In essence, like a mechanic warming up your car prior to you driving it on a cold day, this plug-in "warms up" your GPS for you prior to needing it.

There is one thing you need to do to help your GPS - it is best for WM to manage it (a recommended feature from Microsoft). Go to the Settings tab, External GPS (why it is called that on my Settings tab is beyond me). Then click through the screens to have WM manage the GPS. On one tab you will asked to choose a Port from which all your programs will access data. You need to use an unused Port. I recommend Port 9 but that is up to you.

The reason for doing this is if WM manages the data, it will keep the GPS on and provide the resolved info to all applications. If the programs managed the GPS, they could selectively turn on and off the GPS and also block each other from using the GPS. You don't want that to happen. That is why MS recommends WM manage the data.

GPS toggle, when installed on your Today screen, will have an ON/OFF switch. When you turn it on, it will on the same line tell you how many satellites it has found and when it has sync'ed with them. When you see that four satellites are in the green (meaning your GPS is found ready for 3D satnav), then you can use satnav program of your choice.

The GPS uses battery power and supposedly is a big drain on smartphones. You want to turn it off and on only as necessary. Hope this helps (it's sticky stuff good info)!

GPS Toggle download link: http://www.freewarepocketpc.net/ppc-download-gps-toggle.html