SXBlue GPS Reference Manual
8
Figure 1-4 displays the static positioning error of e-Dif, while it is allowed to age for 14
consecutive cycles of 30 minutes. The top (red) line indicates the age of the differential
corrections. The SXBlue GPS computes a new set of corrections using e-Dif during the
calibration at the beginning of each hour. After the initialization, the age correspondingly
increases from zero until the next calibration.
The position excursion from the true position (the lines centered on the zero axis are
Northing (blue) and Easting (pink)) with increasing correction age is smooth from position to
position, but you can see that there is a slow drift to the position. The amount of drift will
depend on the rate of change of the environmental errors and how these change from the
models used inside the e-Dif software engine.
It’s up to you for how long you would like e-Dif to function before performing another
calibration. We recommend that you test this operating mode to determine the level of
performance that’s acceptable to you.
Figure 1-4 e-Dif Error Drift
To use e-Dif, an option must be purchased from Geneq. The SXBlue GPS system comes
pre-installed with e-Dif firmware and a simple key command is needed to enable the
application for use. Please contact Geneq for more information on this feature.
2.5 Post Processing
The SXBlue GPS receiver is able to output raw measurement data for post processing
applications. The raw measurement and ephemeris data are contained in the Bin 95 and 96
messages documented in chapter 9. Both messages must be logged in a binary file.
