Software

Currently, the software is separated into two main projects: C++ and MATLAB. The C++ project handles at the moment conversion of obs, nav, clk and sp3 files to json files. The MATLAB project uses the json file to run the (precise) GNSS algorithms.

Single Point Positioning (SPP)

Implementation can be found here: Analysis/+SPP

The latest version uses a least squares approach to solve the SPP problem.

The following states are estimated:

\[\begin{split}\begin{pmatrix} x_\text{ECEF__m} \\ y_\text{ECEF__m} \\ z_\text{ECEF__m} \\ \text{rx_clock_offset__m} \\ \text{zenith_tropo_delay__m} \end{pmatrix}\end{split}\]

Precise Point Positioning (PPP)

Implementation can be found here: Analysis/+PPP

The latest version uses a least squares approach to solve the PPP problem. Precise satellite ephemerides data aswell as precise clock data are used to calculate the PPP position of the receiver. For this, sp3 and clk files are used. The sp3 file contains the precise satellite ephemerides data, while the clk file contains the precise clock data. The obs file is used to calculate the pseudorange and carrier phase measurements. The OpenRTK.exe needs to be used with flags obs, sp3 and clk to generate the json file. The json file is then used to run the PPP algorithm.

The following states are estimated:

\[\begin{split}\begin{pmatrix} x_\text{ECEF__m} \\ y_\text{ECEF__m} \\ z_\text{ECEF__m} \\ \text{rx_clock_offset__m} \\ \text{zenith_wet_delay__m} \\ \text{ambiguities} \\ \end{pmatrix}\end{split}\]

Ambiguities for all satellites in ionosphere-free-combination are estimated.