Adaptive Power Saving Strategy for GPS Intelligent Terminal

Focusing on the demand of positioning and power saving management for GPS intelligent terminals, taking police usage for example, a satellite searching strategy is developed to resolve the GPS´s TTFF (time to first fix) problem. The strategy includes two types: user working time based strategy and GPS working characteristic based strategy. In further, the active states of the mobile terminal is collected by the gravity sensor to improve the TTFF strategy. A test with DOPOD P660 PDAs shows that under the adaptive TTFF strategy, PDAs´ operating time can be extended to eleven hours and forty five minutes, about three times the strategy not used, which could satisfy the needs of the police usages.