Simulator Outputs

This gives you the option to reset the Scenario Measurement Files list upon successful conclusion of the simulator run.

If set to true (the default):

• The simulator measurement file(s) will be added to the scenario measurement file list (if not already included).
• The simulator measurement file(s) enable flag will be set to true in the scenario measurement file list.
• The enable flags for any other measurement files in the scenario list will be set to false.

If set to false:

• No change will be made to the scenario file list.

When true, the simulator will produce separate files for each pass for observations. A pass is a series of tracking measurements for a tracking strand, which consists of a tracker, a primary object, and potentially additional objects. The primary object is nominally the satellite being tracked. The precise method for defining the tracking strand is controlled by the setting Measurements.PassDetectionCriterion. A pass terminates when the gap between successive measurements exceeds the MinPassDelta property given in the primary object properties. The simulator uses Measurements.Filename as a proxy for the name(s) of the output files.

Let the Measurements.Filename="<Basename>.<ext>"

Then the simulator will name the output files based on the Measurements.PassDetectionCriterion attribute setting. If you select TrackingStrand for this attribute, then the files will have names in the form:
<Basename>_<modified tracking strand>_<start time>_<end time>.<ext>
Where:
<modified tracking strand> is the full tracking strand, where the primary object name has been replaced with the primary object tracking ID.
<start time> is the UTC time of first observation in the pass.
<end time> is the UTC time of the last observation in the pass.
The time in the output is in the form yymmdd_hhmmss.

For example:
Let Measurements.Filename = "\user\Documents\STK_ODTK 13\Tracking Data\Scen1.gobs"

Then the following would be a possible output file for range/Doppler measurements:
\user\Documents\STK_ODTK 13\TrackingData\Scen1_TrkSys1.FacA_1001_2016_0922_150700_2016_0922_160000.gobs
<------Basename------> <modified tracking strand> <------start time------> <------end time------><ext>

A possible output file for 4L Range/5L Doppler measurements would be:

\user\Documents\STK_ODTK 13\TrackingData\Scen1_TrkSys1.FacA_Relay_1001_2016_0922_150700_2016_0922_160000.gobs
<------Basename------> <modified tracking strand> <------start time------> <------end time------><ext>

If you set the criterion to TrackerAndPrimary or TrackerAndSatellite, then the files will have names in the following form:

<Basename>_<tracker name>_<primary/sat object id>_<start time>_<end time>.<ext>

Where:

<tracker name> is the unique alphanumeric name of the tracker.

<primary/sat object id> is the tracking ID of the primary or satellite object.

<start time> is the UTC time of first observation in the pass.
<end time> is the UTC time of the last observation in the pass.
The time in the output is in the form yymmdd_hhmmss.

For example:
Let Measurements.Filename = "\user\Documents\STK_ODTK 13\Tracking Data\Scen1.gobs "

Then the following would be a possible output file for range/Doppler measurements:
\user\Documents\STK_ODTK 13\TrackingData\Scen1_TrkSys1.FacA_1001_2016_0922_150700_2016_0922_160000.gobs
<------Basename------> <tracker> <id> <------start time------> <------end time------><ext>

In this case, the measurement file name for 4L Range/5L Doppler would be the same as the file name for Range/Doppler since the relay satellite designation is not present in the file name.

The ODTK application uses certain criteria to detect new passes. In addition to honoring the MeasurementProcessing.MinPassDelta setting on satellite objects, the software initiates new passes when it detects a change in the current set of objects involved in the generation of measurements. To determine the elements of the tracking strand for the ODTK software to monitor for change, choose from the following options for the PassDetectionCriterion attribute as they are available:

• Based on Scenario: The ODTK software will follow the scenario-level setting Scenario.Measurements.PassDetectionCriterion, which will be one of the options below. Based on Scenario is obviously not available in the scenario properties selection for PassSelectionCriterion.
• TrackingStrand: A change in any object in the entire tracking strand will trigger the detection of a new pass.
• TrackerAndPrimary: A change in the tracking object or the primary object, typically the target satellite, will trigger the detection of a new pass. The ODTK application maintains this method for the sake of backward compatibility of the simulator file-by-pass capability. This may result in a combining of measurements for complicated tracking strands with simple measurements, such as those involving relay satellites.
• TrackerAndSatellite: A change in the tracking object or the target satellite object will trigger the detection of a new pass. The ODTK application maintains this behavior for backward compatibility sake for the View Measurements operation. This may result in a combining of measurements for complicated tracking strands with simple measurements, such as those involving relay satellites.

The TrackingStrand option is likely preferred in most cases, but the TrackerAndPrimary option may be preferred when generating GNSS measurements from a space-based receiver. The primary object in this case is the receiver. Selecting the TrackerAndPrimary option will result in the ODTK software placing all of the measurements from that GNSS receiver into the same pass, while both the TrackingStrand and TrackerAndSatellite options would result in the software identifying individual passes for each GNSS satellite that is tracked.

In addition to affecting how the ODTK software detects pass boundaries, this setting also affects how the software names pass-based observation files. See the description for Measurements.OutputByPass.

Configure the STKEphemeris attribute to output the truth ephemeris for each satellite, written to the Ephemeris directory as

Where ext is one of the following:

• e - when using STK Ephemeris formt
• oem - when using CCSDS 502 format

The SP3Ephemeris parameter is used to optionally reformat the output ephemeris and clock data into an SP3 (https://files.igs.org/pub/data/format/sp3_docu.txt) file. The simulator generates one file for each Constellation object for which ephemeris and clocks were estimated.

You can generate the SP3 data over on of the following choices:

1. The process interval only
2. The predict interval only
3. The process and predict interval

Data over the process interval requires that STKEphemeris be available over the process interval and that clock data be added to the process run file.

Data over the predict interval requires that the STKEphemeris be generated over the predict interval.

The granularity for the STKEphemeris may be different than the SP3 ephemeris.

The output file name is in the form:

<GNSS Name>_<Process Type>_yyymmdd_hhmmss.sp3

where

<Process_Type> = “Truth”| “Filter| “Smoother”

yyymmdd_hhmmss refers to the start time of the SP3 file in Scenario.Units.DateFormat system.

Example filename is: