We bought a GPS Logger 2.4 kit for tracking applications. We are using mode 1 (sleep) at a 10 minute interval so that we can track a subject for as long as a week. But we found the GPS does not timeout when the subject when to somewhere where there is no GPS signal. This will keep the GPS working and comsuming over 100mA, and drain the battery quickly. So we modified the firmware a little and added a timeout to it.
The problem now is, we can’t determine what value should be assigned to the timeout. A cold start can take as long as several minutes, while a hot fix takes less than 20 seconds. If the subject went to a no signal area for a long time (e.g., over 10 hours), we cannot determine when the GPS went out of the area, so we cannot determine when to try a cold start, while keep doing a five minute timeout try will drain the battery very quickly, using a 30 second timeout will make it impossible to do cold start even when the user move out of the area.
Have anybody encountered this problem? Any idea to solve it?
Thank you.