Motorola 031431a manual Learning to Use Your Handset

Within the signal from each satellite there is a very accurate “time stamp” and information specifying exactly where in space each satellite is currently positioned.

Using this time stamp the AGPS unit can then calculate how long each received signal took to reach the handset and consequently exactly how far away each satellite is from the handset.

From these distances and the position of each satellite in space the AGPS unit can calculate the position of the handset.

To save your battery power the AGPS hardware is only turned on when a AGPS location fix is required by either a local application on your handset or by an application within the 3 network.

When the AGPS hardware is turned on it needs to search for the satellite signals which are available and evaluate the information contained in the signal before calculating the position. This process can take up to approximately 60 seconds. If the handset is currently connected to the 3 network then the AGPS will receive some assistance data which will reduce this time to less than approximately 20 seconds.

If the handset is being charged via the mains adapter or via the in- car adapter when location fixes are requested then the first will take the times detailed above but all subsequent ones will take less than approximately 5 seconds.

The accuracy of and the time taken to perform each AGPS position calculation is very dependent on both:

1The number of different satellite signals which can be received

2How strong each received satellite signal is.

The signal received on earth from AGPS satellites is very weak and are further weakened or even blocked completely by buildings or other objects.

So best AGPS performance in terms of accuracy and time required to do the calculation is achieved when the handset is outdoors with very little of the sky obstructed.

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