PreprocessingSst

This program processes satellite-to-satellite-tracking (SST) and kinematic orbit observations in a GRACE like configuration. Three different observation groups are considered separately: SST and POD1/POD2 for the two satellites. This program works similar to PreprocessingPod, see there for details. Here only deviations in the settings are explained.

Precise orbit data (POD) often contains systematic errors in addition to stochastic noise. In this case the variance component estimation fails and assigns too much weight to the POD data. Therefore an additional downweightPod factor can be applied to the standard deviation of POD for the next least squares adjustment in the iteration. This factor should also applied as sigma in observation for computation of the final solution e.g. with NormalsSolverVCE.

Short time variations of the gravity field can be co-estimated together with the static/monthly mean gravity field. The short time parameters must also be set in observation:parametrizationGravity and can then be selected by estimateShortTimeVariations:parameterSelection. If these parameters are not time variable, for example when a range of static parameters is selected, they are set up as constant for each time interval defined in inputfileArcList. The parameters are constrained by an estimateShortTimeVariations:autoregressiveModelSequence. The weight of the constrain equations in terms of the standard deviation can be estimated by means of Variance Component Estimation (VCE) if estimateShortTimeVariations:estimateSigma is set. The mathematical background of this co-estimation can be found in:

Kvas, A., Mayer-Gürr, T. GRACE gravity field recovery with background model uncertainties. J Geod 93, 2543–2552 (2019). https://doi.org/10.1007/s00190-019-01314-1.

Name	Type	Annotation
outputfileSolution	filename	estimated parameter vector (static part only)
outputfileSigmax	filename	standard deviations of the parameters (sqrt of the diagonal of the inverse normal equation)
outputfileParameterName	filename	estimated signal parameters (index is appended)
estimateArcSigmas	sequence
outputfileSigmasPerArcSst	filename	accuracies of each arc (SST)
outputfileSigmasPerArcPod1	filename	accuracies of each arc (POD1)
outputfileSigmasPerArcPod2	filename	accuracies of each arc (POD2)
estimateEpochSigmas	sequence
outputfileSigmasPerEpochSst	filename	accuracies of each epoch (SST)
outputfileSigmasPerEpochPod1	filename	accuracies of each epoch (POD1)
outputfileSigmasPerEpochPod2	filename	accuracies of each epoch (POD2)
estimateCovarianceFunctions	sequence
outputfileCovarianceFunctionSst	filename	covariance function
outputfileCovarianceFunctionPod1	filename	covariance functions for along, cross, radial direction
outputfileCovarianceFunctionPod2	filename	covariance functions for along, cross, radial direction
estimateSstArcCovarianceSigmas	sequence
outputfileSigmasCovarianceMatrixArc	filename	one variance factor per matrix
computeResiduals	sequence
outputfileSstResiduals	filename
outputfilePod1Residuals	filename
outputfilePod2Residuals	filename
observation	choice	obervation equations (Sst)
sstIntegral	sequence	integral approach
inputfileSatelliteModel1	filename	satellite macro model
inputfileSatelliteModel2	filename	satellite macro model
rightHandSide	sstRightSide	input for the reduced observation vector
sstType	choice
range
rangeRate
rangeAcceleration
none
inputfileOrbit1	filename	used to evaluate the observation equations, not used as observations
inputfileOrbit2	filename	used to evaluate the observation equations, not used as observations
inputfileStarCamera1	filename
inputfileStarCamera2	filename
earthRotation	earthRotation
ephemerides	ephemerides
gradientfield	gravityfield	low order field to estimate the change of the gravity by position adjustement
parametrizationGravity	parametrizationGravity	gravity field parametrization
parametrizationAcceleration1	parametrizationAcceleration	orbit1 force parameters
parametrizationAcceleration2	parametrizationAcceleration	orbit2 force parameters
parametrizationSst	parametrizationSatelliteTracking	satellite tracking parameter
keepSatelliteStates	boolean	set boundary values of each arc global
integrationDegree	uint	integration of forces by polynomial approximation of degree n
interpolationDegree	uint	orbit interpolation by polynomial approximation of degree n
sstVariational	sequence	variational equations
rightHandSide	sequence	input for observation vectors
inputfileSatelliteTracking	filename	ranging observations and corrections
inputfileOrbit1	filename	kinematic positions of satellite A as observations
inputfileOrbit2	filename	kinematic positions of satellite B as observations
sstType	choice
range
rangeRate
none
inputfileVariational1	filename	approximate position and integrated state matrix
inputfileVariational2	filename	approximate position and integrated state matrix
ephemerides	ephemerides
parametrizationGravity	parametrizationGravity	gravity field parametrization
parametrizationAcceleration1	parametrizationAcceleration	orbit1 force parameters
parametrizationAcceleration2	parametrizationAcceleration	orbit2 force parameters
parametrizationSst	parametrizationSatelliteTracking	satellite tracking parameter
integrationDegree	uint	integration of forces by polynomial approximation of degree n
interpolationDegree	uint	orbit interpolation by polynomial approximation of degree n
covarianceSst	sequence
sigma	double	apriori factor of covariance function
inputfileSigmasPerArc	filename	apriori different accuaries for each arc (multiplicated with sigma)
inputfileSigmasPerEpoch	filename	apriori different accuaries for each epoch
inputfileCovarianceFunction	filename	approximate covariances in time
inputfileCovarianceMatrixArc	filename	Must be given per sst arc with correct dimensions.
inputfileSigmasCovarianceMatrixArc	filename	Vector with one sigma for each
sampling	double	[seconds] sampling of the covariance function
covariancePod1	sequence
sigma	double	apriori factor of covariance function
inputfileSigmasPerArc	filename	apriori different accuaries for each arc (multiplicated with sigma)
inputfileSigmasPerEpoch	filename	apriori different accuaries for each epoch
inputfileCovarianceFunction	filename	approximate covariances in time
inputfileCovariancePodEpoch	filename	3x3 epoch covariances
sampling	double	[seconds] sampling of the covariance function
covariancePod2	sequence
sigma	double	apriori factor of covariance function
inputfileSigmasPerArc	filename	apriori different accuaries for each arc (multiplicated with sigma)
inputfileSigmasPerEpoch	filename	apriori different accuaries for each epoch
inputfileCovarianceFunction	filename	approximate covariances in time
inputfileCovariancePodEpoch	filename	3x3 epoch covariances
sampling	double	[seconds] sampling of the covariance function
estimateShortTimeVariations	sequence	co-estimate short time gravity field variations
estimateSigma	boolean	estimate standard deviation via VCE
autoregressiveModelSequence	autoregressiveModelSequence	AR model sequence for constraining short time gravity variations
parameterSelection	parameterSelector	parameters describing the short time gravity field
downweightPod	double	downweight factor for POD
inputfileArcList	filename	list to correspond points of time to arc numbers
iterationCount	uint	(maximum) number of iterations for the estimation of calibration parameter and error PSD
variableNameIterations	string	All output fileNames in preprocessing iteration are expanded with this variable prior to writing to disk
defaultBlockSize	uint	block size of static normal equation blocks

This program is parallelized.