What is SBAS+?

Answer

Here is a reply about SBAS+ from Trimble.

SBAS+ is an enhancement to regular SBAS operation. The goal of SBAS+ is to use as much SBAS correction information as possible and as many satellites as possible to help improve yield and accuracy when positioning in SBAS mode on Floodlight™-enabled Geo 7X handhelds.  SBAS+ enables the following:

• Uses autonomous (de-weighted) satellites in an SBAS+ position. Non-GPS, uncorrected satellites are used and contribute to the position solution. The autonomous satellites are de-weighted appropriately so that they add to the quality of the position without reducing the accuracy. As more satellites drop out of the position solution (for example in tougher GNSS conditions), the autonomous satellites have relatively more impact on the position.

• Use the SBAS ionospheric model whenever possible, even for satellites without an SBAS pseudorange correction term. One component of normal SBAS corrections is a regional model of ionospheric conditions. By modeling the ionosphere this impact of this error source can be mitigated. With SBAS+ the ionosphere model is also applied to non-SBAS corrected satellites (i.e. Galileo, BeiDou & GLONASS).

• Use SBAS corrected satellites in an autonomous position. If we don’t have at least 4 SBAS-corrected satellites, (or something else prevents us from a full SBAS+ position), the position solution will be autonomous. However, we can still use the individually corrected satellites in the autonomous position—increasing the quality of autonomous position results.