Ground Station Elevation Angle Feature
(last updated 2014 12 01)
The proposal is to add one new field to the GMAT GroundStation resource, MinElevationAngle, as
shown in the example below.
Create GroundStation GDS; %DSN Goldstone
GDS.CentralBody = Earth;
GDS.StateType = Cartesian;
GDS.HorizonReference = Ellipsoid;
GDS.Location1 = -2353621.251e-3;
GDS.Location2 = -4641341.542e-3;
GDS.Location3 = 3677052.370e-3;
GDS.Id = 'GDS';
GDS.AddHardware = {Transmitter1, Receiver1, Antenna1};
GDS.MinElevationAngle = 7;
Field
MinElevationAngle
Description
During simulation, this is the minimum elevation angle required in
order for data to be output. During estimation, this is the minimum
elevation angle required for data to be used to calculate an estimate.
Data Type
Allowed Values
Access
Default Value
Units
Interfaces
Real
[-90,90]
set get
0
degrees
script
NOTES:
1. Setting MinElevationAngle = -90 effectively turns “off” the obstruction.
We discuss how this new field is used in both Simulation and Estimation modes.
Simulation
If the local elevation angle from the GroundStation to the Spacecraft or other communication resource,
as appropriate, is greater than or equal to MinElevationAngle, GMAT will output data for that
measurement.
Estimation
1. For a given measurement, If the GroundStation to resource local elevation angle is less than
MinElevationAngle, then GMAT
a. will not use this measurement to calculate the state deviation vector estimate
b. will not use this measurement to calculate RMS statistics
c. will, in the statistical output report (SOR),
i. indicate the data was edited (not used for estimation). Note: GTDS puts an “E”
in one of the output columns to indicate that the measurement did not meet
the elevation angle constraint.
ii. show the value of the relevant computed elevation angle. Note: GTDS puts this
value in a different column.
iii. Show the O-C value for this measurement (even though it is not used to
calculate the state deviation vector estimate)