Without A-GPS, a GPS receiver needs to locate at least four satellites in direct line-of-sight and then download their location data. This process takes 30 seconds under optimal signal conditions and can take much longer in adverse conditions such as in a car already in movement.
u-blox offers two A-GPS services: AssistNow Offline and AssistNow Online. The Offline service provides assistance data that is valid for up to 14 days. In contrast, AssistNow Online downloads new assistance data packets at every device start-up. These much smaller data packets are downloaded straight to the GPS receiver, making AssistNow Online ideal for applications without Flash memories such as mobile phones.
AssistNow was previously sold as an additional service to the u-blox chipsets. This announcement is just another sign of the growing competition between GPS semiconductors vendors. Despite a fast growing demand fo GPS chipsets there is a strong competition going on with small players such as u-blox, u-nav, NemeriX facing bigger players such as Global Locate and SiRF and semiconductor giants such as STMicro, Texas Instruments and CSR.