A-GPS Server Software
eRide’s Assisted GPS (A-GPS) Server Software is designed to easily enable any Carrier or Location Based Services operator the ability to offer the additional performance benefits of A-GPS to their users.
eRide’s High Sensitivity GPS receivers can decode Satellite Navigational Data at signal strength levels down to –146 dBm, generally several dB lower than competitive GPS Receivers on the market.
In a hot or warm start condition, where the GPS receiver has some knowledge of time, satellite ephemeris or almanac and position, this operational limit for acquisition and tracking can drop down to as low as –161 dBm for eRide High Sensitivity GPS Receivers. Using eRide A-GPS Server aiding techniques, TTFF and solution quality are greatly enhanced for any state the GPS receiver is in, including enabling cold starts below the –146 dBm Navigation data decode threshold.
Upon the request for aiding data, the A-GPS Server provides the following information to the user:
- Time Accurate to 1 second plus Data Link Latency
- Accurate Compact Satellite Models for 4 hours
- Long Term Satellite Models (LTSM) for up to 7 days
- DGPS Corrections with satellite models for 30 seconds and 15 minutes (optional)
- Advanced position aiding with previous information
- Ionospheric parameters
- Information regarding satellite health
- World Altitude Model Altitude aiding
A-GPS aiding data needs to be acquired on start up only and every 4 hours thereafter depending on signal quality. The Compact Satellite Model is applicable for 4 hours so even if lock is lost on all satellites or the GPS receiver is turned off, if it is re-started within 4 hours it is not necessary to request the A-GPS data again. Also, the Long Term Satellite Model can be valid for up to 7 days, ensuring successful acquisition and operation without connection to the A-GPS Server for as long as the LTSM is valid.
eRide offers multiple models for operation and support of the A-GPS Server Software and GPS Reference Stations. Currently eRide operates a 24/7 A-GPS Server and Global Reference Network of GPS Reference Stations that provides both A-GPS data and Long Term Satellite Models. A-GPS can be provided using the eRide Server or a user can establish their own Server and network of Reference Stations or some combination can be configured to meet varying needs and requirements. For example, a customer wanting to offer a Location Based Service can establish their own Server that provides eRide A-GPS data as well as maps, LBS databases, etc and obtain the A-GPS data from either the eRide A-GPS Server or establish their own A-GPS Server and network of Reference Stations.
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