Assisted GNSS Technologies
Assisted GNSS for CellGuide Based Receivers
Improving performance of mobile receivers with assisted GNSS technologies
Assisted GNSS technologies enhance receiver performance for network connected as well as autonomous devices. Performance improvement results in faster time-to-first-fix (TTFF) and higher receiver sensitivity. Assisted GNSS is supported across CellGuide's GNSS receiver product range.
The GPSense GNSS positioning firmware supports all industry standard GNSS assistance including network assisted (SUPL), network long-term ephemeris and self-assisted long-term ephemeris.
Assisted GNSS Technologies
Network Assisted (SUPL)
The Secure User-Plane Location (SUPL) protocol is the standard network assistance method for cellular connected devices such as handsets and smart phones. SUPL v1.0 is used for GPS receivers and SUPL v2.0 adds support for additional GNSS.
Network Long-Term Ephemeris (LTE)
The long-term ephemeris method is used to enhance the validity of satellite orbit (ephemeris) data. While the basic broadcast ephemeris validity is up to 2 hours, LTE provides highly accurate satellite orbits are calculated on a server up to 7 days ahead. LTE data is sent to the mobile device using a network connection. The LTE file has a very small footprint of 2 kilobytes per week.
Self-Assisted Long-Term Ephemeris (SA-GPS)
Autonomous devices without a network connection cannot benefit from network connected assistance methods. SA-GPS is an ephemeris extension method that works on-board the mobile device without requiring a network connection. SA-GPS uses an ephemeris extension algorithm that has been optimized to run on mobile devices and requires a low amount of resources on the mobile device. SA-GPS enables orbit prediction up to 3 days ahead.