Define a figure of merit object
Cov <FOMObjectPath> FOMDefine {Satisfaction | InvalidData | Limits | Definition} <Parameters>
The Cov FOMDefine command enables you to specify the method by which the quality of coverage is measured for the figure of merit, and to define the satisfaction criteria that will be applied to the figure of merit.
A figure of merit enables you to evaluate the quality of coverage provided by the selected set of assets over the coverage area. For area calculations, <FOMObjectPath> is a figure of merit object. The Cov FOMDefine command is also available for calculating single-object coverage. For single-object coverage, <FOMObjectPath> can be a facility, place, target, vehicle (any type), sensor, receiver, transmitter or radar.
The next table describes the <Parameters> for the FOMDefine options, these <Parameters> are further defined in the following sections.
| Option | <Parameters> |
|---|---|
| Satisfaction | {Measure} [<Value>] |
| InvalidData | <Value> |
| Limits | {Options} |
| Definition | {FOMType} [<Parameters>] |
If Satisfaction is entered then valid values for {Measure} [<Value>] are:
If Satisfaction is set to On, the graphics follow the general behavior for satisfaction graphics. If Satisfaction is set to Off, static graphics are covered by at least one asset at some point during the coverage interval and Animation graphics are currently covered by at least one asset.
<Threshold> is the value that must be met if coverage is considered to be satisfied. Valid values for <Threshold> depend on the type of FOM. For example, for an Access Duration FOM the <Threshold> is entered in seconds.
The <Value> entered for InvalidData indicates when contouring is valid.
Set the limits used in computing Coverage statistics. Valid values for Limits {Options} are described in this table:
If entered, the Minimum and/or Maximum <Value> is entered in units appropriate to the FOM type. In general, Time values are entered in seconds, Angle values are entered in degrees, Angle Rate values are entered in degrees per second, Distance values are entered in Connect distance units, Velocity values are entered in Connect distance units per second.
| {Options} | Description |
|---|---|
| Use {On | Off} | If On, limits the FOM values to a user-defined range for computing statistics. Only the values within the specified Minimum and Maximum limits will contribute to the statistical parameters. |
| Exclude {On | Off} | If On, only FOM values that are outside of the specified Minimum and Maximum limits are used for computing statistics. |
| Minimum <Value> | Enter the minimum limit of the FOM values used for computing statistics. The Minimum <Value> must be less or equal to the Maximum <Value>. |
| Maximum <Value> | Enter the maximum limit of the FOM values used for computing statistics. The Maximum <Value> must be greater or equal to the Minimum <Value>. |
The following table describes valid values for Definition {FOMType} <Parameters>. Any or all <Parameters> can be entered on a command line.
| {FOMType} | <Parameters> | Description |
|---|---|---|
| AccessConstraint | Constraint <Name> | Enter the valid name for the constraint
to be measured.
Note: Constraint name must be entered before other parameters can be entered. |
| Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are:
Minimum, Maximum, Average, Sum, PercentBelow, and PercentAbove.
If {ComputeValue} is PercentBelow or PercentAbove then specify <PercentValue> which is between 0.0 and 100.0. |
|
| AcrossAssets {Value} | Enter the method for applying the constraint across assets. Valid values are: Minimum, Maximum, Average and Sum. | |
| TimeStep <Value> | TimeStep <Value> is entered in Connect time units. Valid values are 0.1 through 315576000.0 seconds. | |
| AccessDuration |
Compute {ComputeValue} [<PercentValue>] |
Valid values for {ComputeValue} are:
Minimum, Maximum, Average, Sum, StdDev, PercentAbove.
If {ComputeValue} is PercentAbove then specify <PercentValue> which is between 0.0 and 100.0. |
| AccessSeparation |
MinTime <Value> MaxTime <Value> |
<Value>, in both cases, is entered in Connect time units and must be greater than 0.0. |
| AgeOfData |
Compute {ComputeValue} [<PercentValue>] |
Valid values for {ComputeValue} are:
Minimum, Maximum, Average, PercentBelow, PercentBelowGapsOnly.
If {ComputeValue} is PercentBelow or PercentBelowGapsOnly then specify <PercentValue> which is between 0.0 and 100.0. |
| MinNumAssets <Value> | <Value> for MinNumAssets is an integer between 0 and 9999. | |
| CoverageTime |
Compute {ComputeValue} [<MinNumAssets>] |
Valid values for {ComputeValue} are
Percent, Total, PerDay, PercentPerDay, MinPercentPerDay,
MaxPercentPerDay, PercentPerDayStdDev, MinPerDay, MaxPerDay,
PerDayStdDev, PercentTimeAbove and TotalTimeAbove.
If {ComputeValue} is PercentTimeAbove or TotalTimeAbove then specify <MinNumAssets> which is an integer between 0 and 100. |
| DOP | Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are
Minimum, Maximum, Average, and PercentBelow.
If {ComputeValue} is PercentBelow then specify <PercentValue> which is between 0.0 and 100.0. |
| DOPType {DOPValue} | Valid values for {DOPValue} are GDOP, PDOP, HDOP, VDOP, EDOP, NDOP, PDOP_3, HDOP_3, VDOP_3, EDOP_3, NDOP_3 and TDOP. | |
| Method {MethodValue} [<BestNValue>] [{BestNMetric}] | Valid values for {MethodValue} are
OverDetermined, Best4, BestN, BestNMetric, BestNMetricAcc.
See table below for more information on setting the Method {MethodValue} options for DOP. |
|
| InvalidValueAction {Include | Ignore} | This setting controls the behavior of the computation of the static value of the figure of merit in cases where an insufficient number of assets are available to compute a navigation solution at one or more of the time samples used in the computation of the selected ComputeValue. A setting of Include specifies that such samples are assigned the value specified by the Invalid Data Indicator and included in the computation. A setting of Ignore specifies that such samples are ignored and not included in the computation. This latter case effectively computes the desired metric based only on times when a navigation solution can be computed. | |
| TimeStep <Value> | <Value> for TimeStep is entered in Connect time units and can be between 1.0 and 3600.0 seconds. | |
| NAsset |
Compute {ComputeValue} [<PercentValue>] |
Valid values for {ComputeValue} are
Minimum, Maximum, Average, PercentAbove and Unique.
If {ComputeValue} is PercentAbove then specify <PercentValue> which is between 0.0 and 100.0. |
| NavAccuracy | Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are
Minimum, Maximum, Average, and PercentBelow.
If {ComputeValue} is PercentBelow then specify <PercentValue> which is between 0.0 and 100.0. |
| NavType {NavValue} | Valid values for {NavValue} are GACC, PACC, HACC, VACC, EACC, NACC, PACC_3, HACC_3, VACC_3, EACC_3, NACC_3 and TACC. | |
| Method {MethodValue} [<BestNValue>] [{BestNMetric}] | Valid values for {MethodValue} are
OverDetermined, Best4, Best4Acc, BestN, BestNAcc, BestNMetric,
BestNMetricAcc.
See table below for more information on setting the Method {MethodValue} options for NavAccuracy. |
|
| InvalidValueAction {Include | Ignore} | This setting controls the behavior of the computation of the static value of the figure of merit in cases where an insufficient number of assets are available to compute a navigation solution at one or more of the time samples used in the computation of the selected ComputeValue. A setting of Include specifies that such samples are assigned the value specified by the Invalid Data Indicator and included in the computation. A setting of Ignore specifies that such samples are ignored and not included in the computation. This latter case effectively computes the desired metric based only on times when a navigation solution can be computed. | |
| TimeStep <Value> | <Value> for TimeStep is entered in Connect time units and can be between 1.0 and 3600.0 seconds. | |
| AssetUncertainty <TruncObjectPath> {AssetMethod} <Value> |
The Asset specified by <TruncObjectPath> must already be an assigned asset. Valid values for {AssetMethod} are Constant and ElevAngle. If {AssetMethod} is Constant, then <Value> is a number greater than 0. If {AssetMethod} is ElevAngle, then <Value> is a filename. |
|
| RcvrUncertainty <RcvrRange> | <RcvrRange> is a number greater than or equal to 0.0. | |
| NumberOfAccesses | Compute {ComputeValue} [<MinTime> <MaxTime>] | Valid values for {ComputeValue} are:
Total, MinPerDay, MaxPerDay, AvgPerDay, InSpan, and InSpanPerDay.
If {ComputeValue} is InSpan or InSpanPerDay then specify <MinTime> <MaxTime> which are entered in Connect time units and must be greater than 0.0. |
| NumberOfGaps | Compute {ComputeValue} [<MinTime> <MaxTime>] | Valid values for {ComputeValue} are
Total, MinPerDay, MaxPerDay, AvgPerDay, InSpan, and InSpanPerDay.
If {ComputeValue} is InSpan or InSpanPerDay then specify <MinTime> <MaxTime> which are entered in Connect time units and must be greater than 0.0. |
| ResponseTime | Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are
Minimum, Maximum, Average, PercentBelow, and PercentBelowGapsOnly.
If {ComputeValue} is PercentBelow or PercentBelowGapsOnly then specify <PercentValue>, which is between 0.0 and 100.0. |
| MinNumAssets <Value> | <Value> for MinNumAssets is an integer between 0 and 9999. | |
| RevisitTime | Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are
Minimum, Maximum, Average, StdDev, PercentBelow,
PercentBelowGapsOnly, and PercentNumBelow.
If {ComputeValue} is PercentBelow, PercentBelowGapsOnly or PercentNumBelow then specify <PercentValue> which is between 0.0 and 100.0. |
| {MinNumAssets <Value> | EndGaps <EndGapValue>} | <Value> for MinNumAssets is an
integer between 0 and 9999.
Valid values for <EndGapValue> are Ignore and Include. |
|
| ScalarCalculation | Scalar "<CalcScalarSpec>" | Specify the Scalar Calculation
component.
For details on the format of "<CalcScalarSpec>" see Component Specification Note: The Scalar "<CalcScalarSpec>" parameter is required. |
| Compute {ComputeValue} [<PercentValue>] | Valid values for {ComputeValue} are
Minimum, Maximum, Average, Sum, PercentBelow, and PercentAbove.
If {ComputeValue} is PercentBelow, or PercentAbove then specify <PercentValue> which is between 0.0 and 100.0. |
|
| TimeStep <Value> | <Value> for TimeStep is entered in Connect time units. | |
| UpdateAccesses {Yes | No} | Enable this option to update Accesses computed outside coverage for the case where the Scalar calculation component depends on access computations involving the grid object. | |
| Simple | N/A | Simple Coverage measures whether or not a point is accessible by any of the assigned assets. |
| SystemResponseTime | Compute {ComputeValue} | Valid values for {ComputeValue} are Minimum, Maximum and Average. |
| CommandStation {<InstPath> | NONE} | Provide an instance path for the
commanding object. This can be a single object or a constellation.
If commanding is not desired as part of the system response time
computation, specify NONE.
Constellation operators are not currently respected. |
|
| ReceiveStation {<InstPath> | NONE} | Provide an instance path for the
receiving object. This can be a single object or a constellation.
If downlink is not desired as part of the system response time
computation, specify NONE.
Constellation operators are not currently respected. |
|
| CommandPrepTime <Value> | <Value> for the amount of time required for command preparation is entered in Connect time units. | |
| CommandTime <Value> | <Value> for the amount of time required for transmission of the prepared command from the CommandStation to the assets is entered in Connect time units. | |
| PreCollectTime <Value> | <Value> for the amount of time required from receipt of commanding until a collection can be performed by the assets is entered in Connect time units. | |
| CollectionTime <Value> | <Value> for the amount of time required for data collection is entered in Connect time units. | |
| PostCollectTime <Value> | <Value> for the amount of time required asset collection until data can be transmitted to the ReceiveStation is entered in Connect time units. | |
| Downlink <Value> | <Value> for the amount of time required for transmission of the collected data from the assets to the ReceiveStation is entered in Connect time units. | |
| ForwardCrossLinks {On | Off} | Determines if a single cross-link between assets is allowed to be used to minimize the response time. | |
| TimeStep <Value> | <Value> for TimeStep is entered
in Connect time units.
TimeStep is used in the computation of Average System Response Time. Only used during the computation of satisfaction intervals for compute options other than Average. |
|
| TimeAverageGap | N/A | Time Average Gap measures the average length of the coverage gap found if the time line for grid points is sampled randomly. |
The following table describes the Method {MethodValue} options for the DOP {FOMType}.
| DOP {MethodValue} | Description |
|---|---|
| OverDetermined | Compute the DOP based on all of the currently available assets. |
| Best4 | Compute the DOP based on the set of four satellites that yields the minimum GDOP. |
| BestN <BestNValue> | Compute the DOP based on the
<BestNValue> which is the number of satellites.
<BestNValue> can be between 4 and 100; however if {DOPValue} is PDOP_3, HDOP_3, VDOP_3, EDOP_3 or NDOP_3 then <BestNValue> can be between 3 and 100. |
| BestNMetric <BestNValue> {BestNMetric} | Compute the DOP based on the number of
satellites and the specified metric used for determining 'best'.
Valid values for {BestNMetric} are GDOP, PDOP, HDOP, VDOP, EDOP, NDOP or TDOP <BestNValue> can be between 4 and 100; however if {DOPValue} is PDOP_3, HDOP_3, VDOP_3, EDOP_3 or NDOP_3 and {BestNMetric} is not GDOP or TDOP, then <BestNValue> can be between 3 and 100. |
| BestNMetricAcc <BestNValue> {BestNMetric} | Compute the DOP based on the number of
satellites and the specified metric used for determining 'best'.
Valid values for {BestNMetric} are GACC, PACC, HACC, VACC or TACC <BestNValue> can be between 4 and 100; however if {DOPValue} is PDOP_3, HDOP_3, VDOP_3, EDOP_3 or NDOP_3 and {BestNMetric} is not GACC or TACC, then <BestNValue> can be between 3 and 100. |
The following table describes the Method {MethodValue} options for the NavAccuracy {FOMType}.
| NavAccuracy {MethodValue} | Description |
|---|---|
| OverDetermined | Compute the navigation accuracy based on all of the currently available assets. |
| Best4 | Computes the navigation accuracy based on the set of four satellites that yields the minimum GDOP. |
| Best4Acc | Computes the navigation accuracy based on the set of the set of four satellites that yields the minimum geometric uncertainty. |
| BestN <BestNValue> | Computes the navigation accuracy based
on the specified number of satellites that yields the minimum GDOP.
<BestNValue> can be between 4 and 100; however if {NavValue} is PACC_3, HACC_3, VACC_3, EACC_3 or NACC_3 then <BestNValue> can be between 3 and 100. |
| BestNAcc <BestNValue> | Computes the navigation accuracy based
on the specified number of satellites that yields the minimum GDOP.
<BestNValue> can be between 4 and 100; however if {NavValue} is PACC_3, HACC_3, VACC_3, EACC_3 or NACC_3 then <BestNValue> can be between 3 and 100. |
| BestNMetric <BestNValue> {BestNMetric} | Compute the DOP based on the number of
satellites and the specified metric used for determining 'best'.
Valid values for {BestNMetric} are GDOP, PDOP, HDOP, VDOP, EDOP, NDOP or TDOP <BestNValue> can be between 4 and 100; however if {NavValue} is PACC_3, HACC_3, VACC_3, EACC_3 or NACC_3 and {BestNMetric} is not GDOP or TDOP, then <BestNValue> can be between 3 and 100. |
| BestNMetricAcc <BestNValue> {BestNMetric} | Compute the DOP based on the number of
satellites and the specified metric used for determining 'best'.
Valid values for {BestNMetric} are GACC, PACC, HACC, VACC, EACC, NACC or TACC <BestNValue> can be between 4 and 100; however if {NavValue} is PACC_3, HACC_3, VACC_3, EACC_3 or NACC_3 and {BestNMetric} is not GACC or TACC, then <BestNValue> can be between 3 and 100. |
To define the satisfaction criterion for a figure of merit so that the FOM value is less than or equal to 5:
Cov */CoverageDefinition/PolarIceCaps/FigureOfMerit/GPS FOMDefine Satisfaction AtMost 5.0
To define a measure of the vertical accuracy computed using the best selection of up to 8 assets. The dynamic value will be less than the reported static value 70% of the time based on sampling every 25 seconds:
Cov */CoverageDefinition/cd/FigureOfMerit/fm FOMDefine Definition NavAccuracy Compute PercentBelow 70.0 NavType VACC Method BestN 8 Timestep 25.0
To set the asset range uncertainty on the GPS11 satellite to a constant value of 12 meters:
Cov */CoverageDefinition/cd/FigureOfMerit/fm FOMDefine Definition NavAccuracy AssetUncertainty Satellite/GPS11 Constant 12
To set the receiver range uncertainty to 3 meters:
Cov */CoverageDefinition/cd/FigureOfMerit/fm FOMDefine Definition NavAccuracy RcvrUncertainty 3.0
To set the FOM to SystemResponseTime:
Cov */CoverageDefinition/CovDef/FigureOfMerit/SRT FOMDefine Definition SystemResponseTime Compute Maximum CommandStation */Facility/AWOTS_11_3m ReceiveStation */Facility/MGS_10m CommandPrepTime 0.0 CommandTime 0.0 PreCollectTime 0.0 CollectionTime 0.0 PostCollectTime 0.0 DownlinkTime 0.0 ForwardCrossLinks Off TimeStep 60.0
To set the FOM to Scalar Calculation type:
Cov */CoverageDefinition/CovUI/FigureOfMerit/FOM1 FOMDefine Definition ScalarCalculation Compute PercentBelow 70 Scalar "Satellite/SatCon Orbit.Cartesian.Y"
If activated, Connect returns an acknowledgement message.
This command belongs to the following group(s):
10.0.1
STK Programming Interface 11.0.1