GnssProcessing
This program processes GNSS observations. It calculates the linearized observation equations, accumulates them into a system of normal equations and solves it.
The primary use cases of this program are:
- GNSS satellite orbit determination and station network analysis
- Kinematic orbit determination of LEO satellites
- GNSS precise point positioning (PPP)
The observation epochs are defined by timeSeries and only observations at these epochs (within a timeMargin) are considered.
To calculate observation equations from the tracks, the model parameters or unknown parameters need to be defined beforehand. These unknown parameters can be chosen arbitrarily by the user with an adequate list of defined parametrization. Some of the parametrization also include a priori models.
Lastly it is required to define the process flow of the gnssProcessing. This is accomplished with a list of processingSteps. Each step is processed consecutively. Some steps allow the selection of parameters, epochs, or the normal equation structure, which affects all subsequent steps. A minimal example consists of following steps:
- estimate: iterative float solution with outlier downeighting
- resolveAmbiguities: fix ambiguities to integer and remove them from the normals
- estimate: few iteration for final outlier downweighting
- writeResults: write the output files defined in parametrization
If the program is run on multiple processes the receivers (stations or LEO satellites) are distributed over the processes.
See also GnssSimulateReceiver.
| Name | Type | Annotation |
|---|---|---|
timeSeries | timeSeries | defines observation epochs |
timeMargin | double | [seconds] margin to consider two times identical |
transmitter | gnssTransmitterGenerator | constellation of GNSS satellites |
receiver | gnssReceiverGenerator | ground station network or LEO satellite |
earthRotation | earthRotation | apriori earth rotation |
parametrization | gnssParametrization | models and parameters |
processingStep | gnssProcessingStep | steps are processed consecutively |