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>
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectStations | platformSelector | |
outputfileTroposphere | filename | columns: MJD, ZHD, ZWD, dry north gradient, wet north gradient, dry east gradient, wet east gradient |
troposphere | troposphere | a 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
<satellite>:<parametrizationAcceleration>:*:*
,-
<satellite>:stochasticPulse.x::<time>
, -
<satellite>:stochasticPulse.y::<time>
, -
<satellite>:stochasticPulse.z::<time>
,
<satellite>:arc<no>.<parametrizationAcceleration>:*:*
,-
<satellite>:arc<no>.position0.x::
, -
<satellite>:arc<no>.position0.y::
, -
<satellite>:arc<no>.position0.z::
. -
<satellite>:arc<no>.velocity0.x::
, -
<satellite>:arc<no>.velocity0.y::
, -
<satellite>:arc<no>.velocity0.z::
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectSatellites | platformSelector | |
outputfileOrbit | filename | variable {satellite} available |
outputfileParameters | filename | variable {satellite} available |
inputfileVariational | filename | variable {satellite} available |
stochasticPulse | timeSeries | [mu/s] parametrization of stochastic pulses |
parametrizationAcceleration | parametrizationAcceleration | orbit force parameters |
ephemerides | ephemerides | |
integrationDegree | uint | integration of forces by polynomial approximation of degree n |
interpolationDegree | uint | for 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>:*:*
.
Name | Type | Annotation |
---|---|---|
name | string | used 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
<station>:position.x::
,-
<station>:position.y::
, -
<station>:position.z::
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectStations | platformSelector | |
outputfileGriddedPosition | filename | delta north east up for all stations |
outputfilePosition | filename | variable {station} available, full estimated coordinates (in TRF) |
nameConstraint | string | used for parameter selection |
selectNoNetStations | platformSelector | |
inputfileNoNetPositions | filename | variable {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 | double | stations > huber*sigma0 are downweighted in no-net constraint |
huberPower | double | stations > 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
earth:polarMotion.xp:<temporal>:<interval>
,-
earth:polarMotion.yp:<temporal>:<interval>
, -
earth:UT1:<temporal>:<interval>
, -
earth:nutation.X:<temporal>:<interval>
, -
earth:nutation.>:<temporal>:<interval>
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
outputfileEOP | filename | EOP time series (mjd, xp, yp, sp, dUT1, LOD, X, Y, S) |
estimatePole | parametrizationTemporal | xp, yp [mas] |
estimateUT1 | parametrizationTemporal | rotation angle [ms] |
estimateNutation | parametrizationTemporal | dX, 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.
Name | Type | Annotation |
---|---|---|
selectStations | platformSelector | |
inputfileRangeBias | filename | variable {station} available |
RangeBiasStation
Estimates a constant station range bias in $[m]$ for selectStations.
The parameter names are <station>:rangeBias::
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectStations | platformSelector | |
outputfileRangeBias | filename | variable {station} available |
RangeBiasSatelliteApriori
A priori satellite range bias value for selectSatellites.
Name | Type | Annotation |
---|---|---|
selectSatellites | platformSelector | |
inputfileRangeBias | filename | variable {satellite} available |
RangeBiasSatellite
Estimates a constant satellite range bias in $[m]$ for selectSatellites.
The parameter names a <satellite>:rangeBias::
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectSatellites | platformSelector | |
outputfileRangeBias | filename | variable {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 RodrÃguez (see SlrComModel2RangeBiasStationSatellite) and additionally for biases from the ILRS Data Handling File converted with SlrSinexDataHandling2Files.
Name | Type | Annotation |
---|---|---|
selectStations | platformSelector | |
selectSatellites | platformSelector | |
inputfileRangeBias | filename | variable {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::
.
Name | Type | Annotation |
---|---|---|
name | string | used for parameter selection |
selectStations | platformSelector | |
selectSatellites | platformSelector | |
outputfileRangeBias | filename | variable {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.
Name | Type | Annotation |
---|---|---|
selectStations | platformSelector | |
inputfileTimeBias | filename | variable {station} available |
TimeBias
Estimates a temporal changing time bias in $[ms]$ for selectStations.
The parameter names are <station>:timeBias:<temporal>:<interval>
.
Name | Type | Annotation |
---|---|---|
name | string | used 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.
Name | Type | Annotation |
---|---|---|
name | string | |
parameters | parameterSelector | parameter to constrain |
sigma | double | sigma of the constraint (same unit as parameter) |
bias | double | constrain all selected parameters towards this value |
relativeToApriori | boolean | constrain 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.
Name | Type | Annotation |
---|---|---|
parametrization | slrParametrization |