RejectFilter

General Mission Analysis Tool

RejectFilter

RejectFilter — Allows selection of data subsets for processing by the batch least squares estimator.

Description

Starting with release R2017A of GMAT, the RejectFilter resource replaces the StatisticsRejectFilter resource. The StatisticsRejectFilter resource is still available in this release but it is deprecated and will be removed in a future release.

The RejectFilter object is used to create criteria for the exclusion of subsets of the available data in the estimation process based on tracker, observed object, measurement type, or time. Instances of RejectFilter are specified for use on the DataFilters field of a TrackingFileSet or BatchEstimatorInv object.

GMAT implements two levels of data editing for estimation. First-level editing criteria are specified on the DataFilters field of the TrackingFileSet instance. At this level, the user may choose what data is admitted into the overall pool of observations provided to the estimator. Any data excluded at the tracking file set level will be immediately discarded and not available to the estimation process.

Second-level data editing is specified on the DataFilters field of the BatchEstimatorInv instance. At this level, the user may choose what data is used in the estimation state update. Residuals will be computed for any observations admitted through first-level editing, but any data excluded at the estimator level will be flagged as user edited, and will not affect the computation of the state correction. This allows the user to evaluate the quality of untrusted data against a solution computed using a trusted set of measurements.

A single reject filter may employ multiple selection criteria (for example simultaneous thinning by time and tracker). Multiple criteria on a single filter are considered in an AND sense. When multiple criteria are specified in a single filter, an observation must meet all specified criteria to be rejected. Multiple filters with different selection criteria may be specified on a single TrackingFileSet or BatchEstimatorInv. When multiple filters are specified, these act in an OR sense. Data meeting criteria for any of the specified filters will be rejected.

Fields

Field

Description

DataTypes

List of data types

Data Type	String Array
Allowed Values	A set of any supported GMAT measurement types, or 'All'
Access	set
Default Value	{All}
Units	N/A
Interfaces	script

EpochFormat

Allows user to select format of the epoch

Data Type	String
Allowed Values	UTCGregorian, UTCModJulian, TAIGregorian, TAIModJulian, TTGregorian, TTModJulian A1Gregorian, A1ModJulian, TDBGregorian, TDBModJulian
Access	set
Default Value	TAIModJulian
Units	N/A
Interfaces	script

FileNames

List of file names (a subset of the relevant TrackingFileSet's FileName field) containing the tracking data, to be excluded from processing. This field is only applicable when the RejectFilter is used on a TrackingFileSet.

Data Type	StringArray
Allowed Values	valid file name or 'All'
Access	set
Default Value	{All}
Units	N/A
Interfaces	script

FinalEpoch

Final epoch of desired data to process

Data Type	String
Allowed Values	any valid epoch
Access	set
Default Value	latest day defined in GMAT
Units	N/A
Interfaces	script

InitialEpoch

Initial epoch of desired data to process

Data Type	String
Allowed Values	any valid epoch
Access	set
Default Value	earliest day defined in GMAT
Units	N/A
Interfaces	script

ObservedObjects

List of user-created tracked objects (e.g., name of the Spacecraft resource being tracked)

Data Type	Object Array
Allowed Values	User defined observed object or 'All'
Access	set
Default Value	{All}
Units	N/A
Interfaces	script

RecordNumbers

A list of one or more single record numbers or spans of record numbers to reject. Observation record numbers are reported in the GMAT estimator output file. This field is only applicable when the RejectFilter is used on the estimator level.

Data Type	String array
Allowed Values	Integers or spans of integers (see examples)
Access	set
Default Value	{}
Units	N/A
Interfaces	script

Trackers

List of user-created trackers (e.g., name of the GroundStation resource being used)

Data Type	Object Array
Allowed Values	any valid user-created Tracker object (e.g., GroundStation) or 'All'
Access	set
Default Value	{All}
Units	N/A
Interfaces	script

Remarks

Some fields of RejectFilter are not applicable at either the first-level (tracking file set) or second-level (estimator) editing stages. The RecordNumbers field has no functionality when applied to a reject filter at the tracking file set level. The FileNames field has no functionality when applied to a reject filter at the estimator level.

Use of combinations of instances AcceptFilter and RejectFilter at both levels is permitted.

Examples

First-level (TrackingFileSet) Data Editing

The following examples illustrate use of a RejectFilter for first-level data editing. At this level, the RejectFilter instance should be assigned to the DataFilters field of a TrackingFileSet. In these examples, data meeting the criteria specified by the reject filter will be immediately discarded. All other data is admitted.

This example shows how to create a RejectFilter to reject all observations from station GDS.

Create GroundStation GDS;
Create RejectFilter rf;

rf.Trackers = {'GDS'};
 
Create TrackingFileSet estData;
 
estData.DataFilters = {rf};

BeginMissionSequence;

The next example will reject all DSN Doppler (i.e., DSN_TCP) tracking measurements from station GDS, and all tracking of any type from station CAN. All other tracking measurements will be accepted.

Create GroundStation GDS CAN;

Create RejectFilter rf1;
Create RejectFilter rf2;
 
rf1.Trackers  = {'GDS'}; 
rf1.DataTypes = {'DSN_TCP'};
rf2.Trackers  = {'CAN'};
 
Create TrackingFileSet estData;
 
estData.DataFilters = {rf1, rf2};

BeginMissionSequence;

Second-level (estimator) Data Editing

The following examples illustrate use of a RejectFilter for second-level data editing. At this level, the RejectFilter instance should be assigned to the DataFilters field of a BatchEstimatorInv. In these examples, data meeting the criteria specified by the reject filter will excluded from the estimation state update. Residuals will be computed for all available data (all data admitted at the first level), but data rejected at the estimator level will be flagged as user edited.

This example shows how to create a RejectFilter to reject specific observations by record number.

Create RejectFilter rf;

rf.RecordNumbers = {13, 25, 75-87};
 
Create BatchEstimatorInv bls;
 
bls.DataFilters = {rf};

BeginMissionSequence;

The next example shows how to simultaneously employ multiple reject filters. In this example:

MAD range data over the span 10 Jun 2012 02:56 to 13:59 is rejected
All CAN DSN_TCP data is rejected
All RangeRate data (from any station) is rejected

Create RejectFilter rf1 rf2 rf3;
Create GroundStation MAD CAN;

rf1.Trackers     = {'MAD'};
rf1.DataTypes    = {'Range'};
rf1.EpochFormat  = UTCGregorian;
rf1.InitialEpoch = '10 Jun 2012 02:56:00.000';
rf1.FinalEpoch   = '10 Jun 2012 13:59:00.000';

rf2.Trackers     = {'CAN'};
rf2.DataTypes    = {'DSN_TCP'};

rf3.DataTypes    = {'RangeRate'};

Create BatchEstimatorInv bls;

bls.DataFilters = {rf1, rf2, rf3};

BeginMissionSequence;

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