Septentrio Demonstrates BeiDou+GPS+GLONASS Positioning

January 9, 2013  - By

Septentrio announced on January 7 that it has successfully implemented BeiDou support in the company’s high-precision receiver software, taking advantage of the recent official release of BeiDou’s Interface Control Document (ICD) to including the Chinese satellite navigation signals into its position-velocity-time (PVT) solution.

According to the Belgian GNSS receiver manufacturer, its engineers “are currently processing further data sets to finalize the implementation of full BeiDou support. Although the BeiDou constellation is still being deployed, the data analysis already shows promising results.”


Figure 1. Top: Computed height above reference point (m) for GPS-only, GPS+GLONASS and GPS+GLONASS+BeiDou vs. time of day (hour).

The top panel of Figure 1 compares the height from a stand-alone solution of GPS-only with a GPS+GLONASS solution and a third (in light blue) including BeiDou. “The value added by BeiDou is more than what was expected from a constellation that is still being deployed,” according to Septentrio business development manager Laurent Le Thuaut. “Although the solution is not aided by differential corrections, the position shows an increase in accuracy when sufficient BeiDou satellites are included.”

The bottom panel of Figure 1 shows that, even with the current BeiDou constellation (15 satellites total, of which five are geostationary over China, five in full mid-Earth orbit similar to GPS and GLONASS, and five in inclined geosynchronous orbit over Asia), the total number of satellites used over the European region reached 26 for a short moment.


Figure 2. L1 pseudorange residuals (m) for GPS (L1 C/A, top) and COMPASS (B1-I, bottom) vs. time of day (hour).

Figure 2 shows the L1 pseudorange residuals for all constellations individually. This comparison highlights the advantage of the GPS constellation, which builds on two decades of real-time orbit prediction. The BeiDou orbits are “quite accurate for a relatively young constellation, but show typical meter-level jumps when ephemerides are updated,” according to Septentrio.

Septentrio says that the new feature will soon become available on selected company platforms. Users of its multi-constellation receivers will then benefit from improvements in urban availability and signal integrity, thanks to the augmented signal coverage.

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