SlrParametrization

This class defines the models and parameters of the linearized observation equations for normal points (see SlrProcessing) \[\label{slrParametrizationType:model} \M l - \M f(\M x_0) = \left.\frac{\partial \M f(\M x)}{\partial \M x}\right|_{\M x_0} \Delta\M x + \M\epsilon, \]where the left side is the observation vector minus the effects computed from the a priori models. After each least squares adjustment (see SlrProcessing:processingStep:estimate) the a priori parameters are updated \[\label{slrParametrizationType:update} \M x_0 := \M x_0 + \Delta\hat{\M x}. \]The vector $\M x_0$ can be written with SlrProcessing:processingStep:writeAprioriSolution. Any outputfiles defined in the parametrizations are written with SlrProcessing:processingStep:writeResults.

Each parametrization (and possible constraint equations) has a name which enables activating/deactivating the estimation of subsets of $\Delta\M x$ with SlrProcessing:processingStep:selectParametrizations. The a priori model $\M f(\M x_0)$ is unaffected and is always reduced.

The model for the one way range observations between station $s$ and reflector $r$ can be described as \[\label{slrParametrizationType:slrFullModel} \begin{split} f_s^r(\M x) &= \frac{1}{2}\left(\left\lVert \M r^r(t_{bounce})-\M r_s(t_{trans}) \right\rVert + \left\lVert \M r_s(t_{recv})-\M r^r(t_{bounce}) \right\rVert\right) \\ &+ \text{troposphere}(t,\M r_{ss}^r) + \text{bias}^r + \text{bias}_s + \text{bias}_s^r + \text{other}(\ldots) + \epsilon_r^s \end{split} \] See also SlrProcessing.

Troposphere

A priori tropospheric correction is handled by a troposphere model (e.g. Mendes and Pavlis). Additional parameters in $[m]$ for zenith delay can be set up via troposphereEstimation. These parameters can be soft-constrained using parametrization:constraints to avoid an unsolvable system of normal equations in case of data gaps.

The parameter names are <station>:troposphere:<temporal>:<interval>.

NameTypeAnnotation
name
stringused for parameter selection
selectStations
platformSelector
outputfileTroposphere
filenamecolumns: MJD, ZHD, ZWD, dry north gradient, wet north gradient, dry east gradient, wet east gradient
troposphere
tropospherea priori troposphere model
troposphereEstimation
parametrizationTemporal[m] parametrization of zenith delays

DynamicOrbits

The estimation of (reduced) dynamic orbits is formulated as variational equations. It is based on inputfileVariational calculated with PreprocessingVariationalEquation. Necessary integrations are performed by integrating a moving interpolation polynomial of degree integrationDegree. The parametrizationAcceleration must include at least those parameters that were estimated in PreprocessingVariationalEquationOrbitFit. Additional stochasticPulse parameters can be set up to reduce orbit mismodeling.

The parameters and parameter names are divided into global

and arc related parameters

NameTypeAnnotation
name
stringused for parameter selection
selectSatellites
platformSelector
outputfileOrbit
filenamevariable {satellite} available
outputfileParameters
filenamevariable {satellite} available
inputfileVariational
filenamevariable {satellite} available
stochasticPulse
timeSeries[mu/s] parametrization of stochastic pulses
parametrizationAcceleration
parametrizationAccelerationorbit force parameters
ephemerides
ephemerides
integrationDegree
uintintegration of forces by polynomial approximation of degree n
interpolationDegree
uintfor orbit interpolation and velocity calculation

GravityField

Estimates a (time depending) gravity field together with at least one parametrization:dynamicOrbits. The parametrization of the gravity field can be set with parametrization.

The parameter names are gravityfield:<parametrization>:*:*.

NameTypeAnnotation
name
stringused for parameter selection
parametrization
parametrizationGravity

StaticPositions

Estimates a static position for all selectReceivers in the terrestrial frame.

No-net constraints can be applied for a subset of stations, selectNoNetReceivers, with a standard deviation of noNetTranslationSigma and noNetRotationSigma and noNetScaleSigma and noNetScaleSigma. If the template inputfileNoNetPositions is provided the constraints are applied relatively to these positions. Only stations with an existing position file are considered. Without inputfileNoNetPositions the constraints are applied towards the apriori values from SlrProcessing:station. As a single corrupted station position can disturb the no-net conditions, the rotation/translation parameters are estimated in a robust least squares adjustment beforehand. The computed weight matrix is used to downweight corrupted stations in the constraint equations.

In case you want to align to an ITRF/ILRS reference frame, precise coordinates can be generated with Sinex2StationPositions.

The parameter names are

NameTypeAnnotation
name
stringused for parameter selection
selectStations
platformSelector
outputfileGriddedPosition
filenamedelta north east up for all stations
outputfilePosition
filenamevariable {station} available, full estimated coordinates (in TRF)
nameConstraint
stringused for parameter selection
selectNoNetStations
platformSelector
inputfileNoNetPositions
filenamevariable {station} available, precise coordinates used for no-net constraints (in TRF)
noNetTranslationSigma
double(0 = unconstrained) sigma [m] for no-net translation constraint on station coordinates
noNetRotationSigma
double(0 = unconstrained) sigma [m] at Earth's surface for no-net rotation constraint on station coordinates
noNetScaleSigma
double(0 = unconstrained) sigma [m] for no-net scale constraint on station coordinates
huber
doublestations > huber*sigma0 are downweighted in no-net constraint
huberPower
doublestations > huber: sigma=(e/huber)^huberPower*sigma0

EarthRotation

Earth rotation parameters (ERPs) can be estimated by defining estimatePole ($x_p$, $y_p$) and estimateUT1 ($dUT1, LOD$).

Estimating length of day (LOD) with the sign according to IGS conventions requires a negative value in parametrizationTemporal:trend:timeStep.

Constraints on the defined parameters can be added via parametrization:constraints. An example would be to set up estimateUT1:constant so the $dUT1$ parameter is included in the normal equation system . Since $dUT1$ cannot be determined by SLR, a hard constraint to its a priori value can then be added.

The parameter names are

NameTypeAnnotation
name
stringused for parameter selection
outputfileEOP
filenameEOP time series (mjd, xp, yp, sp, dUT1, LOD, X, Y, S)
estimatePole
parametrizationTemporalxp, yp [mas]
estimateUT1
parametrizationTemporalrotation angle [ms]
estimateNutation
parametrizationTemporaldX, dY [mas]

RangeBiasStationApriori

A priori station range bias value for all selectStations. The ILRS provides the mean range biases ILRS Data Handling File, but these have been determined using the passive satellites LAGEOS and Etalon and are therefore only suitable for passive satellites and not for active ones. Use SlrSinexDataHandling2Files to convert the range biases from ILRS Data Handling File to instrument file.

NameTypeAnnotation
selectStations
platformSelector
inputfileRangeBias
filenamevariable {station} available

RangeBiasStation

Estimates a constant station range bias in $[m]$ for selectStations.

The parameter names are <station>:rangeBias::.

NameTypeAnnotation
name
stringused for parameter selection
selectStations
platformSelector
outputfileRangeBias
filenamevariable {station} available

RangeBiasSatelliteApriori

A priori satellite range bias value for selectSatellites.

NameTypeAnnotation
selectSatellites
platformSelector
inputfileRangeBias
filenamevariable {satellite} available

RangeBiasSatellite

Estimates a constant satellite range bias in $[m]$ for selectSatellites.

The parameter names a <satellite>:rangeBias::.

NameTypeAnnotation
name
stringused for parameter selection
selectSatellites
platformSelector
outputfileRangeBias
filenamevariable {satellite} available

RangeBiasStationSatelliteApriori

A priori station-satellite range bias value between all selectStations - selectSatellites pairs.

For standard ILRS processing this class should be setup twice. Once for the model from José Rodríguez (see SlrComModel2RangeBiasStationSatellite) and additionally for biases from the ILRS Data Handling File converted with SlrSinexDataHandling2Files.

NameTypeAnnotation
selectStations
platformSelector
selectSatellites
platformSelector
inputfileRangeBias
filenamevariable {station} and {satellite} available

RangeBiasStationSatellite

Estimates the station-satellite range bias in $[m]$ between all selectStations - selectSatellites pairs.

The parameter names are <station>.<satellite>:rangeBias::.

NameTypeAnnotation
name
stringused for parameter selection
selectStations
platformSelector
selectSatellites
platformSelector
outputfileRangeBias
filenamevariable {station} and {satellite} available

TimeBiasApriori

A priori time bias value for all selectStations. The ILRS provides the mean time biases ILRS Data Handling File, but these have been determined using the passive satellites LAGEOS and Etalon and are therefore only suitable for passive satellites and not for active ones. Use SlrSinexDataHandling2Files to convert the time biases from ILRS Data Handling File to instrument file.

NameTypeAnnotation
selectStations
platformSelector
inputfileTimeBias
filenamevariable {station} available

TimeBias

Estimates a temporal changing time bias in $[ms]$ for selectStations.

The parameter names are <station>:timeBias:<temporal>:<interval>.

NameTypeAnnotation
name
stringused for parameter selection
selectStations
platformSelector
estimateTimeBias
parametrizationTemporal[ms]

Constraints

Add a pseudo observation equation (constraint) for each selected parameters \[ b-x_0 = 1 \cdot dx + \epsilon, \]where $b$ is the bias and $x_0$ is the a priori value of the parameter if relativeToApriori is not set. The standard deviation sigma is used to weight the observation equations.

NameTypeAnnotation
name
string
parameters
parameterSelectorparameter to constrain
sigma
doublesigma of the constraint (same unit as parameter)
bias
doubleconstrain all selected parameters towards this value
relativeToApriori
booleanconstrain only dx and not full x=dx+x0

Group

Groups a set of parameters. This class can be used to structure complex parametrizations and has no further effect itself.

NameTypeAnnotation
parametrization
slrParametrization