General Information | What's New? | Transition Issues and Limitations | Online Help Resources

ODTK 5.1 Release Notes

Including Changes through ODTK 5.1.1, ODTK 5.1.2, ODTK 5.1.3 and ODTK 5.1.4

These release notes contain information on system and disk space requirements for installing and running ODTK; information on new capabilities and features - including but not limited to Orbit Determination around the Moon and Sun - introduced in the current version of ODTK, including issues resolved from the prior version; transition information -- cautions, workarounds and operational tips -- to help maximize your successful use of the product; and a brief introduction to online help resources.

Unless otherwise indicated, the information presented below reflects the state of ODTK as of version 5.1. Changes introduced in ODTK 5.0, ODTK 5.0.1, ODTK 5.0.2 and ODTK 5.0.3 are described on a separate page.

General information

This section includes system requirements and background information on ODTK 5.1.

Working toward Vista compliance

AGI is actively working toward Vista compliance. Testing of AGI products on the Windows Vista platform is in progress. We will inform you when testing is completed and AGI products are Vista-compliant. Until then, this configuration should not be used for production purposes. While there are no known issues with ODTK on Vista at this time, there are several issues with STK. If you wish to experiment using ODTK and STK on the Vista platform, see the list of known Vista issues in the STK release notes.

System and disk space requirements

The following table sets out minimum and recommended system requirements for ODTK 5.1:

ODTK 5.1 System Requirements
Memory Disk Space Processor
Minimum 256 MB 1 GB 800 MHz
Recommended 512 MB 4 GB 2.0 GHz

An ODTK 5.1 installation requires 200-300 MB of disk space. Running a typical scenario, such as the Sapphire demo scenario that accompanies ODTK 5.1 (3 satellites, 5 trackers x 3 days), takes about 600MB disk space for simulator, filter and smother runs. During such a run the memory footprint of ODTK 5.1 is slightly over 110Mb.

Background

ODTK 5.1 is built upon the same verified astrodynamics functions and coordinate conversions as STK and its modules. ODTK 5.1 is a matched set of modules, designed to provide orbit determination and analysis support for the entire life-cycle of satellite tracking systems. All phases of systems design can be supported with simulated tracking data, Monte Carlo analyses, and covariance analyses. ODTK 5.1 can produce results for satellite orbit parameters by processing one satellite at a time or multiple satellites simultaneously. ODTK is a stand-alone product, not an add-on module to STK.

The main products in this suite are a tracking data simulator, a state-of-the-art optimal sequential filter and a matched optimal sequential smoother. The sequential filter is designed to provide capabilities in support of routine satellite operations, including orbit determination, ephemeris prediction, and bias and maneuver/thruster calibration. The sequential filter produces a realistic covariance for system performance analyses, tasking optimization, and calculation of the probability of collision (in conjunction with STK/CAT). The optimal smoother provides high accuracy post-fit ephemerides in support of mission data products.

Particular care has been taken to ensure that regression tests to ODTK 4.0 are satisfied, that ODTK 4 scenarios will load and run in ODTK 5.1, and that ODTK 4 restart files will initialize in ODTK 5.1.

What's New in ODTK 5.1?

The sections below describe the following new features and capabilities of ODTK:

Orbit determination around the Moon and Sun

The ability to perform OD for satellites in orbit about the Moon and Sun has been added. You can also transition from an Earth centric to Moon centric to Sun centric solution as your spacecraft moves through its trajectory. Satellite states can be input relative to the Moon or the Sun.

To support OD about central bodies other than the Earth, you can now specify the source of the planetary ephemeris (DE200, DE403, DE405, or DE418). Additionally, access of planetary ephemeris information has been updated to use the TDB time scale by default.

A new HTML tool - UpdateCentralBody.htm - is provided to allow the user to switch the satellite state and solution space between various central bodies.

Satellites now have a DynamicReports attribute that can be used to specify the central body and coordinate system to be used when diplaying data in a dynamic report. This attribute is only visible when the satellite's central body is not the Earth.

Custom Solar Radiation Pressure modeling using plugins

The ability to specify a custom solar radiation pressure model using a plugin script has been added. ODTK 5.0 could do this using a custom force model plugin, but now an explicit plugin point for reflection models has been created. The new plugin point also supports estimation of the parameter used as inputs to the plugin itself.

Support for the Deep Space Network (DSN) measurement models

The ability to process the following types of DSN tracking data in the Trk-2-34 format has been added: two way sequential range, two and three way total phase count. An example DSN tracking system is also provided with ODTK.

Modeling the effects of local station obscura in all ODTK processes

A new feature has been added allowing a local horizon mask to be used for a ground based facility. A new true/false attribute appears in the facility properties and if set to true will use an STK horizon mask file in the *.aem format.

Scripting updates

Users can now have their scripts write status messages to the MessageViewer window.

The JavaScript file extension ".js" has been added to the list of allowed script file extensions.

Percent has been added as a new unit dimension. It is used in maneuver uncertainty attributes such as Uncertainty.PercentMagnitudeSigma. Previously this was a unitless attribute.

Satellite object updates

The use of VOP integration is now user-controlled, as it is in STK.

Finite maneuvers now allow the user to specify specific propagation controls to be used druing that maneuver.

GPS attitude profiles have been added to regular satellites as well as the GPS constellation object.

Satellites have a new coordinate system "MeanOfDate" that can be used in the orbit state.

Add a retroreflector object to satellite

Satellites now support a retroreflector object for use when processing laser ranging measurements.

GPS Clock Steering has been added to the Smoother

GPS Clock Steering should improve Filter-Smoother clock consistency tests when it is used in the filter. This capability applies to the estimation of orbit and clock states for the GPS satellites.

Gooding IOD Improvements

A number of improvements have been made to the Gooding IOD method:

  • It can now use trajectory data embedded in the measurements themselves (typically B3 observations).
  • The limits on the range values have been expanded to 20 Earth Radii.
  • It will now allow for hyperbolic solutions. By default it will eliminate these unless you have set the appropriate flag to allow it.

Support for NGA GPS Monitor Station tracking data

We have added a new Tracking Data Provider, specifically designed to read the archived format for NGA GPS Monitor Station data, as provided by University of Texas Austin under contract to NGA.

Support for Navigation Tool Kit

ODTK has two new tools to support the creation of files for use in Navigation Tool Kit. The GeneratePSFFile.htm tool is used to generate Prediction Support Files (PSFs) and the GeneratePAFFile.htm tool is used to generate Performance Assessment Files. More information on these files can be found in the Navigation Tool Kit documentation.

PrioraNet tracking system

The old USN tracking system provided in ODTK 5 has been replaced with a PrioraNet tracking system based on data obtained from Universal Space Networks.

Version Changes in Tracking Data Interface

The following table shows changes in the tracking data interface between ODTK 5 and the current version:

ODTK 5  ODTK 6 
ODTK.Application ODTK.Application
ODTK5.Application ODTK6.Application
   
AgAttrAutomation5.AgAttrBuilder AgAttrAutomation6.AgAttrBuilder
   
AgMach10_5.AgODObsSet AgMach10_6.AgODObsSet
AgMach10_5.AgODObsSetCollection AgMach10_6.AgODObsSetCollection
AgMach10_5.AgODTrackingIDList AgMach10_6.AgODTrackingIDList
AgMach10_5.AgODRealList AgMach10_6.AgODRealList
AgMach10_5.OLEDBDataSource AgMach10_6.OLEDBDataSource
   
AgOdtkPlugin5.AgOdtkPluginSite AgOdtkPlugin6.AgOdtkPluginSite
   
IAgODProvideTrackingData5.AgODGenericObs IAgODProvideTrackingData6.AgODGenericObs
IAgODProvideTrackingData5.AgODProvideB3TrackingData IAgODProvideTrackingData6.AgODProvideB3TrackingData
IAgODProvideTrackingData5.AgODProvideCobTrackingData IAgODProvideTrackingData6.AgODProvideCobTrackingData
  IAgODProvideTrackingData6.AgODProvideDSNTrackingData
  IAgODProvideTrackingData6.AgODProvideEphemerisTrackingData
IAgODProvideTrackingData5.AgODProvideGenericTrackingData IAgODProvideTrackingData6.AgODProvideGenericTrackingData
IAgODProvideTrackingData5.AgODProvideGeoLocTrackingData IAgODProvideTrackingData6.AgODProvideGeoLocTrackingData
IAgODProvideTrackingData5.AgODProvideGeoscTrackingData IAgODProvideTrackingData6.AgODProvideGeoscTrackingData
IAgODProvideTrackingData5.AgODProvideGPSNavTrackingData IAgODProvideTrackingData6.AgODProvideGPSNavTrackingData
IAgODProvideTrackingData5.AgODProvideILRSTrackingData IAgODProvideTrackingData6.AgODProvideILRSTrackingData
IAgODProvideTrackingData5.AgODProvideLanceTrackingData IAgODProvideTrackingData6.AgODProvideLanceTrackingData
  IAgODProvideTrackingData6.AgODProvideMDPTrackingData
  IAgODProvideTrackingData6.AgODProvideOASYSTrackingData
IAgODProvideTrackingData5.AgODProvideRAWPRTrackingData IAgODProvideTrackingData6.AgODProvideRAWPRTrackingData
IAgODProvideTrackingData5.AgODProvideRINEXTrackingData IAgODProvideTrackingData6.AgODProvideRINEXTrackingData
IAgODProvideTrackingData5.AgODProvideUTDFTrackingData IAgODProvideTrackingData6.AgODProvideUTDFTrackingData
   
AgHtmlServer.AgHtmlServerInitOD50 AgHTMLServerODTK6.HTMLServer
   
HTML Utilities that are run inside ODTK and use HTML Server should instantiate it with:
   window.external.CreateObject("AGI HTML Server")

Capabilities Added and Issues Resolved From the Prior Release

The following table identifies limitations and issues that have been resolved in the current release, as well as new capabilities and improvements that have been added:

For convenience, this table includes all enhancements and resolved issues believed to be significant, including some that are discussed in more detail above.

New Capabilities and Resolved Issues
Tracking No. Description
03868 A new feature has been added allowing a local horizon mask to be used for a ground based facility. A new true/false attribute appears in the facility properties and if set to true will use an STK horizon mask file in the *.aem format.
06810 Integrator step size control has been added for finite maneuvers.
20553 An issue has been fixed where manipulation of the scenario to drop and add allowed measurement types can cause Data Product Lists to drop those measurement types and then fail when those data types are added back into the scenario.
22691 ODTK 5.1 script writers may now directly insert objects into the Filter TrackerList attribute, for example:

     ODTK.Scenario1.Filter1.TrackerList.insert(ODTK.Scenario1.TrackingSystem1.Facility1)

However names with hyphens, for example:

     set unused = ODTK.WizardScenario1.Filter1.TrackerList.insert(ODTK.WizardScenario1.Baseline.GUAM-A)

will not work due to scripting limitations.
23628 GHz has been added as an allowed frequency unit.
24796 A feature has been added that allows scripts to write status messages to the MessageViewer window.
25070 The satellite-altitude-too-low error message now includes the time when the threshold was tripped.
27008 The available precision for Date/Time fields has been extended to the nanosecond level, however we only maintain internal precision to the millisecond level at this time.
27363 The use of VOP integration is now user-controlled, as it is in STK.
27427 A problem has been fixed in which rough files displayed incorrect file size after being overwritten.
28674 Satellites now support a retroreflector object for use when processing laser ranging measurements.
30921 A fix was made to ignore trailing extraneous white space characters at the end of lines when reading the header section of STK ephemeris, attitude, and acceleration history files.
31093 Geometric data has been added to data providers for various measurement types. The measurement types affected are 1W Bistatic range, 2L GPS, TDRS 4L Range and 5L Doppler, BRTS 4L Range and 5L Doppler, RA & DEC, all GPS data types, NP Range, TDOA, FDOA, azimuth, elevation, range, and SB measurement types. The data added provides geometric range, azimuth, elevation, range rate, grazing altitude, and elevation constraint (from a horizon mask file), as appropriate. This change enables analysis of rejected residuals for local obscure and multi-path effects. A sample graph "Elevation vs Azimuth.gph" is included with the product install, where accepted or rejected data are indicated as a function of the geometric observing conditions for elevation and azimuth.

This enhancement required an update to the MeasurementHistory report table so any related report style should have the Verify Database operation performed on it. These new geometric and constraint values have been added at the end of the table to ensure existing reports will still work.
31097 We converted the units of the InstantManeuvers.Uncertainty.PercentMagnitudeSigma attribute from type Real to type Quantity with units of Percent (%). Older scenarios will have values converted upon load, and scripts that set this attribute need not be modified to continue working.
31155 A problem was fixed in which the simulator was sensitive to letter case when naming measurement files and created unnecessary duplicate files.
31329 Previously rough files were left in the invalid state if ODTK ran out of disk space or crashed during a filter run. Now they are left in a valid state by periodic saving of the state at the times of the restart records.
31550 GPS Clock Steering has been added to the Smoother. This should improve Filter-Smoother clock consistency tests when steering is used in the filter. This enhancement specifically affects scenarios where estimation of the orbit and clock states of the GPS satellites is being performed.
31891 An open issue exists when creating a PDF report under scripting control where the error message "IDispatch error 30084" is generated and the report is blank. That error message is generated by Crystal Reports and seems to occur only on specific computers and under specific conditions, probably due to memory content and layout. When this occurs we find that WORD reports are generated correctly under scripting and PDF reports will generate correctly manually. This issue cannot be fixed until we update to a newer version of Crystal Reports or convert to some other third party report software.
32113 The default initial orbit state for GPS satellites has been changed to be representative of a typical GPS orbit. In prior versions the initial orbit state resulted in a low Earth orbit.
32194 The attribute NewPositionVector has been added. NewPositionVector is a helper function that creates a three (3)-component input for use by the LambertSolution function.
32212 The capability has been added to change Solar Pressure models at a Restart time. If the estimation of any Solar Pressure parameter is either added or deleted or changed (i.e. changes to Gauss Markov statistics) at a Restart time then this is considered to be a model replacement. All the old Solar Pressure states are dropped and replaced by the new states which are initialized at the Restart time.

The Solar Presure parameters are now named SolarPressure.<name>. There are 2 impacts:
  • One impact is the way the state is listed in places like StateFileDumperTool.htm output. It used to be listed as "SolarPressure", now it will be listed as "SolarPressure.Scale".
  • The second impact is if you have written a custom script for a specific solar pressure parameter by name, that script may have to be rewritten to work with the new naming convention (SolarPressure.). An example might be changing Gauss Markov statistics for a solar pressure parameter at a Restart.
32216 ODTK now supports orbit determination for satellites in orbit about the moon and the sun in addition to Earth orbiting satellites. Support for satellites in heliocentric orbit is provided through the following DSN measurement types: two way sequential range, two and three way Doppler and two and three way total count phase. Support for satellites orbiting the moon is through the DSN measurement types and through normal two way range and two way Doppler.
32890 Dynamic Graphs for 2L GPS CA now show bias estimates (instead of zeros).
33023 New report styles were added to provide daily averages for biases in addition to the global averages provided by existing reports. These report styles are:
  • Daily Avg Sat Force Model Biases.rpt
  • Daily Avg Tracker Biases.rpt
  • Daily Avg Transponder Biases.rpt
33181 All smoother run files generated by ODTK 5.0.x with the SaveCrossCorrelation option set to false and having data points where state content change has occured will cause ODTK to crash in the reporting code that reads run files. Starting with ODTK 5.1 smoother run files are generated correctly. The older invalid run files generated by earlier versions cannot be read by ODTK 5.1 and have to be discarded.
33253 Gooding's angles-only IOD now recognizes and processes the locations of tracking satellites included in B3 type 8 or 9 observations of space-based trackers.
33435 A problem was fixed for the reporting of finite maneuvers that span multiple rough files where the state space was changed at one of the rough file boundaries.
33648 We have added a new Tracking Data Provider, specifically designed to read the archived format for NGA GPS monitor station data, as provided by University of Texas Austin under contract to NGA. The format document is available from AGI upon request as a PDF document (ATT9488648.pdf), as authored by Applied Research Laboratory, University of Texas at Austin.
33748 With the addition of the new SRP plug-in capability ODTK supports both COM Category registration and XML file registration. The COM Category registration will no longer be supported starting with ODTK 6.0 when we change GUIDs and User action is required to reregister plugins. We strongly recommend that new force model plugins be developed using the XML file registration method.
33829 A plugin interface to improve customization options for solar pressure modeling has been added. The solar pressure light reflection plugin point allows for custom solar pressure models to be included in the propagation of orbit trajectories and for the parameters associated with those plugins to be estimated during the orbit determination process.
33932 A new functional attribute named "GeneratePSFFile" was added to the application. This file takes a .filrun or .smtrun file as input and calculates RMS for the values in the PSF (Prediction Support File) using data at requested intervals. By default, data is sampled at 15 minutes. The new html utility GeneratePSFFile.htm allows the user to select the run file, time span and time step. This capability allows for the generation of input data for NTK via ODTK.
33933 We have added a new HTML utility, GeneratePAFFile.htm, to generate a GPS PAF (Performance Assessment File). The PAF file is generated from an ODTK .difrun file, and reports differences in GPS satellite position/velocity/clocks as compared to a reference. For instance, the GPS constellation from a filter run file could be differenced against an SP3 file or simulator run file.
34099 An issue with items in the data product list disappearing has been fixed.
34511 The sign of the ionospheric correction to Doppler measurement models has been corrected. The sign error in prior versions of ODTK affected the following measurement types: Two Way Doppler, TDRS 5L Doppler, TDRS 3L Doppler and TDRS BRTS 5L Doppler.
34524 The description of how ODTK interprets and uses the ionosphere and troposphere correction flags associated with observations in certain tracking data formats, such as GEOSC, has been updated for clarity. See the help page "Measurement Formats & Measurement Types in ODTK" or the page "Tracking Systems" for a more thorough discussion of how troposphere and ionosphere correction flags in tracking data are used.
34739 An issue with writing the restart record that caused the filter to fail to run has been fixed. This issue existed for cases where proper file permissions were not available on the restart directory.
34748 A new feature now allows the user to select the central body being used for the initial conditions and to select from a set of coordinate systems appropriate for that body.
34918 The simulation of GPS Phase has been changed so that the noise added to the measurement is independent and not accumulated. The default white noise sigmas in the measurement statistics table for GPS Phase derived measurements like DF, SD, DD have been updated to be consistent with the simulated measurements.
35345 The IntervalLength and IntervalOverlap attributes have been removed and are no longer supported as they are no longer needed for the smoother to work properly.
35381 If you specify a lag time of N minutes, and run the smoother from time t, the first possible ephemeris time will be written at t - N. For instance, if the lag is 15 minutes, and the smoother starts at 03:00, the first possible ephemeris time will be at 02:45. If there is no filter output at 02:45, then the next time processed, e.g. 02:44, will be the start of the ephemeris output. The filter output grid is formed from the measurement time grid, the process noise update interval, and maneuver times.
35388 Custom graph styles now allow point supression for a value of -777.7777 as the result of an arithmetic expression.

In this example,
if 'Minutes After Midnight' > 390 and 'Minutes After Midnight' < 395 or 'Pre Fit Residual' > 300 then
   result = -777.7777
else
   result = 'Pre Fit Residual'
end if
the pre-fit residual value will not be plotted if the time is in the range of 390 to 395 minutes or if the pre-fit residual value is greater than 300.
35420 A number of help documents on scripting in ODTK have been combined into a comprehensive scripting guide.
35681 The out-of-order measurement error message has been changed to include the date and time where the error occurred for easier troubleshooting.
35866 An issue with incorrectly reported pass start and stop times in the Measurement Summary Report has been corrected.
35999 The IRI2001 FORTRAN library was updated to fix a runtime error due to an array index out of bounds issue.
36393 Ground-based Ra/Dec measurements are now written correctly to the GEOSC tracking data format so they can be processed properly in STK/PODS.
36467 A problem in the IRI 2001 ionospheric model which could have resulted in the application crashing or the computation of incorrect total electron counts for cases where the analysis time period was beyond the span of the data file ig_rz.dat has been corrected.
36524 Angles-only IOD Range1Estimate and Range3Estimate can now accept values from 0 to 1.E20 er
36747 Geodetic elevation checks (min/max) are now used when considering ground-based GPS measurements. Prior versions of ODTK computed the elevation angle based on a spherical Earth assumption for the purpose of validating ground based GPS measurements.
36875 An issue with the ODTK SNGL license has been resolved. Previously the filter would allow tracker satellites tracking a target satellite only if the trackers used reference ephemerides and the tracker satellites' biases were not estimated. Now the tracker satellites' biases can be estimated under the ODTK SNGL license. Under this change the Filter attribute "SatelliteList" only contains the target satellite and not the tracker satellites.
36884 We now optionally write file summary information for Flux, EOP and planetary ephemeris files for each simulator, filter and smoother run. This information can be reported using the new report style Data File Summary.rpt.
36900 The capability to choose the source of planetary ephemeris has been added to the scenario properties. The capability to use TDB time when accessing the planetary ephemeris has also been added and is the default for new scenarios. When loading a scenario made prior to version 5.1, the UseTDB flag will be set to false.
36934 A new tracking data editing code has been created, using "OB" to indicate data edited because it falls outside the bounds specified in a facility AzElMask. The installed report styles have been changed to report this data as "Masked".
36952 ODTK now provides the DE200 planetary ephemeris file in the install.
37019 Proper handling of bad clock solutions in SP3 files has been added. In prior versions, navigation solutions including GPS satellites with bad clock solutions were corrupted. With the correction, the affected satellite is no longer used in the construction of the navigation solution.
37020 The ability to select an antenna correction model via the new attribute AntennaCorrectionType has been added to the facility class. Currently the options are limited to DSN antenna correction models which are all prefaced with DSN_. The antenna corrections currently only affect DSN sequential range modeling.
37073 The capability has been added to allow the user to provide a custom n-parameter Solar Radiation Parameter Light Reflectance model through a plugin. To support this plugin new static product styles have been added to report/graph results. These product styles will report and graph on all n-parameters in the model. Currently the Static Product Builder Data Limiting control does not include data limiting on solar pressure parameters. To limit the report and/or graph to one parameter, a custom report and/or graph style needs to be created for that parameter. Example custom report and graph styles have been added to help users create custom styles.
37323 An issue with the simulator, in which the application aborted when running a clock event, has been fixed.
37407 An issue in which hyperbolic orbits showed an OrbitClass of UNDEFINED has been fixed.
37417 GoodingAnglesOnly IOD has been changed to optionally allow for hyperbolic solutions.
37509 The StateFileDumperTool.htm utility has been updated to support non-Earth central bodies.
37576 ODTK now handles file conflicts gracefully when identical processes in two instances of ODTK are run concurrently, though results may be questionable.
37685 In the StateFileDumperTool.htm utility, results will change for some scenarios based on resolving differences between the gravitational parameter from the gravity file and the central body file. Previous behavior can be restored by setting the environment variable AGI_REVERT_GM to any value.
37700 NASA has changed the validity codes at the end of a UTDF data record. USN data now has "040404" (hex) as the last 3 bytes instead of "040F0F" (hex). For this version of ODTK we have stopped checking these bytes for validity, pending acquisition of an up-to-date ICD from NASA GSFC for all UTDF data sources.
37728 Min/Max elevation constraints are now applied to BRTS facilities; previously they were not applied.
37777 Both GPS and non-GPS satellites now present the same attitude profile options. GPS attitude profiles are now selectable for non-GPS satellites.
37837 A MathPlayer upgrade (version 2.1) caused equations in compiled help systems using the Microsoft HTML Help Viewer, such as the ODTK Help System, not to display properly. Attempting to open a page containing MathML-encoded equations caused the help system to terminate abnormally. Design Science has cured this deficiency in MathPlayer version 2.1a, which is installed automatically with ODTK 5.1 (replacing whatever version of MathPlayer is on the system).
37874 The default setting for the light time delay is now true for azimuth and elevation measurement models on new facilities.
37877 We have received updated PrioraNet station definitions for USN and have updated the tracking system definition to reflect these data, including nominal; values for sigmas. These values replace the ones shipped with ODTK 5.0.
37929 In Static Product Builder, SRP States report and graph were renamed to be SRP Plugin States.
37969 One cannot simultaneously process simulated and actual DSN tracking data using the same DSN facility. Actual DSN data are frequency ramped with the ramping information embedded in the TRK 2-34 file format, whereas simulated data (saved to the Generic Observation format) may assume a different ramping rate for the facility. A workaround is available, however. First, duplicate each DSN tracking facility with another facility and assign it a unique Tracking ID, then limit the simulator to using the duplicate facilities only. Both the simulated and actual data may then be processed simultaneously as coming from different facilities.
37990 The options for modeling gravity process noise have been expanded. Prior versions of the ODTK have used a gravity process noise model generated for the JGM2 gravity model. An improved model has been developed which now allows for inputs to be specified via the STK gravity file (.grv). It is now possible, therefore to have different gravity process noise applied for each gravity model. New versions of several gravity files (having _PN in their names) are shipped with ODTK 5.1 which contain process noise input data. For Earth orbiting satellites, the heritage JGM2 gravity process noise model will continue to be used when the gravity file does not contain process noise information. This will be the case for all scenarios created using prior versions of ODTK. For satellites orbiting other central bodies, the process noise information must be included in the gravity file for gravity process noise to be computed.
38025 ODTK was using an incorrect frequency when processing LA SD phase measurements. This has been corrected and the L1 frequency is now used.
38097 The ChangeCentralBodyTool.htm utility has been added to the installed utilities. This utility allows the initial conditions for a satellite to transformed to be relative to a different central body while retaining the position and velocity of the satellite relative to the solar system barycenter.
38101 The sign of the ionospheric correction to single frequency GPS Phase measurement models has been corrected.
38185 The simulator time step lower limit has changed from 1 sec to .001 sec.
38193 Albedo and thermal radiation pressure modeling are available for both the Earth and the Moon. The label "EarthRadiation" will be updated in a future maintenance release.
38211 An error in the computation of satellite attitude under certain conditions has been corrected. This error produced small changes in range type measurements for cases where an antenna offset from the center of mass was used.
38280 The BiStatic range model now checks the elevation constraints for both signal paths: from the transmit facility and from the tracking facility.
38382 The option to use approximately fixed steps in true anomaly during orbit integration when the eccentricity of the orbit is above a user defined threshold has been corrected for the cases where the integration method is selected to be either the RKF 7(8) or Bulirsch-Stoer. In prior versions, the step size was always selected as fixed in time.
38385 Both RunStk.htm and RunStkX.htm were changed to set the model size to zero and turn on the covariance ellipsoid whenever they are passing satellites to STK.
38390 The DE403 and DE418 ephemeris have been added to the ODTK 5.1 install.
38452 The GPSCatalog.txt file has been updated with the most current data.
38491 JavaScript can now be used to implement event handlers.
38532 A new plugin tracking data reader was added to read in azimuth, elevation, range, and Doppler measurements from data files formatted for use with TRACE. TRACE is an orbit determination tool developed by the Aerospace Corporation.

Transition matters and unresolved issues

This section presents transition issues of importance to the user, including operational tips and caveats to help smooth the path to successful use of ODTK, as well as a list of limitations and unresolved issues of which the user should be made aware.

Transition matters

It is suggested that you review the following list of cautions, workarounds and operational tips before using the current version of ODTK:

WSC Examples Change

ODTK TrackingDataProviders Windows Scripting Component (WSC) examples have been moved to a new location. If you have a custom Tracking Data Reader derived from a .wsc example, please note, that file "\ODTK\AppData\Scripts\MeasProviders\WindowsScriptComponents\CreatODDBObjects.txt" has been moved and renamed to "\PluginSamples\AGI.ODTK.ProgIDs.txt". The old file is still available in this release but we strongly suggest updating your code now.

Solar Pressure Model Parameter Naming

The Solar Pressure parameters are now named SolarPressure.<name>. There are 2 impacts:

  • One impact is the way the state is listed in places like StateFileDumperTool.htm output. It used to be listed as "SolarPressure", now it will be listed as "SolarPressure.Scale".
  • The second impact is if you have written a custom script for a specific solar pressure parameter by name, that script may have to be rewritten to work with the new naming convention (SolarPressure.). An example might be changing Gauss Markov statistics for a solar pressure parameter at a Restart.

Plugin Registration

ODTK v5.1 supports both COM Category registration and XML file registration. The COM Category registration will no longer be supported starting with ODTK 6.0 when we change GUIDs and User action is required to reregister plugins. We strongly recommend that new force model plugins be developed using the XML file registration method.

Retired Smoother Settings

The IntervalLength and IntervalOverlap attributes have been removed and are no longer supported as they are no longer needed for the smoother to work properly.

Gravity Process Noise Improvements

The options for modeling gravity process noise have been expanded. Prior versions of the ODTK have used a gravity process noise model generated for the JGM2 gravity model. An improved model has been developed which now allows for inputs to be specified via the STK gravity file (.grv). It is now possible, therefore to have different gravity process noise applied for each gravity model. New versions of several gravity files (having _PN in their names) are shipped with ODTK 5.1 which contain process noise input data. For Earth orbiting satellites, the heritage JGM2 gravity process noise model will continue to be used when the gravity file does not contain process noise information. This will be the case for all scenarios created using prior versions of ODTK. For satellites orbiting other central bodies, the process noise information must be included in the gravity file for gravity process noise to be computed.

Obsolete Attributes

The following attributes are now obsolete in ODTK 5.1.

  • Smother.ProcessControl.IntervalLength
  • Smother.ProcessControl.IntervalLength.Description
  • Smother.ProcessControl.IntervalOverlap
  • Smother.ProcessControl.IntervalOverlap.Description

Coordinate Frame Change

One of the choices for coordinate frame used during satellite ephemeris generation was "ECF". With the introduction of support for multiple central bodies, this has been renamed "Fixed".

  • ODTK 5.0: EphemerisGeneration.CoordFrame.Choices(0) = "ECF"
  • ODTK 5.1: EphemerisGeneration.CoordFrame.Choices(0) = "Fixed"

Unresolved issues affecting the current release

The user should be aware of the following limitations and unresolved issues affecting ODTK as of the date of this release.

Unresolved Issues
Tracking No. Description
00239 The filter cannot be single-stepped from the very beginning of the run. If you begin the run and then pause, you can single-step from that point. At the beginning of the run, however, the step forward button on the toolbar is grayed out.
04880 The X-axis labels on the histogram graph are not displayed symmetrically if the number of bins changes.
06610 When you have a SaveAs dialog open in ODTK, the part of the window that shows the contents of the current folder does not update. When you click the Create New button, it creates a folder but does not show it.
07071 Tracker satellites cannot share tracking IDs with GPS constellation PRN numbers. If a scenario contains both an optical tracker satellite and a GPS constellation, and the tracker satellite has a tracking ID between 1-36, the tracking ID will become ambiguous.
07402 Print preview of graphs does not function correctly.
07630 Setting the Display Product option to false on a graph data product is ignored when an Export option is chosen.
22691 ODTK 5.1 script writers may now directly insert objects into the Filter TrackerList attribute, for example:    ODTK.Scenario1.Filter1.TrackerList.insert(ODTK.Scenario1.TrackingSystem1.Facility1)
However names with hyphens, for example:
    set unused = ODTK.WizardScenario1.Filter1.TrackerList.insert(ODTK.WizardScenario1.Baseline.GUAM-A)
will not work due to scripting limitations.
23475 Users should not name objects using class names like Filter, Smoother, Simulator. Refer to the "VBA to VB.NET Migration" section of the ODTK Help.
26002 It is not possible to Export the HTML generated by the ViewScenario.htm utility to Microsoft Excel, even though the option is offered. This export feature is installed with the latest versions of Microsoft Office and appears on all web pages in IE.
26653 Due to a limitation with VBScript, an object with a name beginning with a digit should be accessed by an index or string lookup instead of directly. For instance, ODTK.Scenario(0).23DegIncSat will fail, while ODTK.Scenario(0).Satellite("23DegIncSat") will work.
29439 To avoid abnormal terminations that may occur when FLEXlm code is run with Windows Data Execution Prevention enabled, you need to change the DEP settings: Open the "System Properties", click on the "Advanced" tab and click on "Performance,... Settings..." button. This will bring up a dialog with three tabs. Click on the "DEP" tab and set the option to: "Turn on DEP for essential Windows programs and services only". You may need to restart the computer after that.
30517 The Plugins tab does not refresh the SupportsSave column. When you add a new plugin tracking data reader and click Apply, the column labeled SupportsSave is not refreshed. By default the value in this column is false, but after you add a new tracking data reader that supports save, then the value in this column should be true. The user must dismiss the panel and pull it back up to get the correct value.
31034 After a long predict, the covariance is quite large. A very large measurement update can drive the filter covariance negative. This issue is being addressed.
31636 If you add finite or instant maneuvers to the script or HTML page, or delete them, you must re-click the Satellite object. Otherwise the maneuver list dialog will display stale data.
31802 A GPS constellation object does not populate the PRNList until properties are applied. We suggest that when you first assign a source file to a GPS constellation, you press Apply before double-clicking on the PRNList to view its contents.
31917 The Static Product Builder does not update the Data Product List filename when it is loaded from a script. The workaround is to close and reopen the Static Product Builder or browse to the correct directory manually.
32139 State File To SP3 utility limits output to GPSSatellites named PRN01, PRN02, etc. This issue will be corrected in the next ODTK release.
36533 Since restart filenames are based on times which do not contain fractional seconds, do not attempt to write more than one restart record within a 1-sec time span. Otherwise a restart file correlated with a specific restart time may actually contain the restart state at a later restart time.

Changes introduced in ODTK 5.1.1

The following information applies to ODTK 5.1.1.

Capabilities added and issues resolved in ODTK 5.1.1

The following table identifies limitations and issues that have been resolved in the current release, as well as new capabilities and improvements that have been added:

New Capabilities and Resolved Issues in ODTK 5.1.1
Tracking No. Description
36784 The capability to simulate and process ground based X/Y angles has been added.
38026 The ability to process Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) measurements using a space based emitter and two ground receive stations has been added.
38858 Light time delay has been incorporated into the planetary obscuration check for satellites in orbit about central bodies other than the Earth. In version 5.1, measurements may have been ignored during a time period on the order of the light time delay on either side of the time interval when the obstruction occurred. In the case of a lunar orbiting satellite, this would be on the order of one second either side of the obstruction times.
38895 The computational efficiency of the albedo model has been significantly improved.
39174 A problem with the value of measurement bias uncertainty information written to the measurement history file as part of the filter output when running the filter in the simultaneous mode has been corrected. The problem resulted in bias sigma values being reported as zero. The error only affected the reporting of the bias sigma values and had no impact on the bias solution.
39361 The UTDF tracking data reader now has the option to only return those measurements that have the SRE autotrack flag set. The autotrack filter can be enabled from the Tools | Options | Plugin tab - select the UTDF reader and edit it's configuration. When the AutotrackFilter flag is set to true in the GUI, the reader will respect the SRE autotrack flag when determining if ground tracking data is valid or not. If the antenna is not in autotrack then the data will be ignored.
39425 ODTK 5.1 introduced a fix to prevent the rough file from being corrupted if the computer ran out of disk space. Unfortunately this resulted in filter run times that were approximately twice as long as in ODTK 5.0. The run time performance issue has been corrected.

For long filter runs, the rough file header will be saved every 30 seconds of wall clock time to keep the file intact in case writing of file is interrupted for any reason.
39426 The Ionosphere Measurement Corrections report was updated to add a column indicating the units for each measurement.
39511 A bug has been fixed which at times caused the ResidualsVersusReference utility to crash when the Reference Trajectory did not contain covariance data. Other symptoms included "not a number" being displayed in reports when calculating the measurement sigma.
39558 The UTDF tracking data reader set an invalid antenna ID of 0 when reading TDRSS tracking data that passed through the space-ground link antenna. It now sets the antenna ID to be 4 in this case.
39586 ODTK now reports back error messages when trying to read an invalid GPS ephemeris file and no longer crashes.
39877 The ability to produce graphs that used multiple run files was broken in ODTK 5.1. This has been corrected.
40032 Attempting to turn off Sun or Moon third body effects for a satellite via scripting by accessing these obsolete attributes will not work:

     sc.Satellite(0).ForceModel.Gravity.ThirdBodies.Sun = false sc.Satellite(0).ForceModel.Gravity.ThirdBodies.Moon = false

In both cases, these two commands turn on Sun & Moon effects. The proper way to remove these effects is to remove their entries from the Planets attribute, for instance:

     sc.Satellite(0).ForceModel.Gravity.ThirdBodies.Planets.erase "Moon"

Changes introduced in ODTK 5.1.2

The following information applies to ODTK 5.1.2.

What's new in ODTK 5.1.2

ODTK has received a Commodity Jurisdiction determination of EAR-99 from the US State Department. As such, it will no longer be treated as an ITAR product. With this version all references to ODTK being classified as an ITAR product have been removed.

Capabilities added and issues resolved in ODTK 5.1.2

The following table identifies limitations and issues that have been resolved in the current release, as well as new capabilities and improvements that have been added:

New Capabilities and Resolved Issues in ODTK 5.1.2
Tracking No. Description
40364 Errors in the custom gravity process noise implementation which resulted in incorrect process noise to be computed for satellites in orbits of moderate to high eccentricity or with an orbit radius greater than two planetary radii have been corrected. These errors only affected scenarios using the new custom gravity process noise implementation released with version 5.1 and required that the gravity (.grv) file specified for the scenario contain custom gravity process noise information. These gravity files, which were not part of releases prior to 5.1, have the character sequence "_PN" in the file name.
40623 An error in state construction related to estimated finite maneuvers has been corrected. The error resulted in an incorrect state index being used to retrieve finite maneuver states from the overall state estimate which in turn resulted in erroneous maneuver accelerations during the thrusting interval. This error only affected cases where: the filter or simulator was run in initial mode, multiple satellites were included in state space, at least one of the satellites contained a finite maneuver with estimation turned on and the initial conditions of that satellite were specified at a time different from the start time of the filter or smoother.

Changes introduced in ODTK 5.1.3

The following information applies to ODTK 5.1.3.

Capabilities added and issues resolved in ODTK 5.1.3

The following table identifies limitations and issues that have been resolved in the current release, as well as new capabilities and improvements that have been added:

New Capabilities and Resolved Issues in ODTK 5.1.3
Tracking No. Description
40614

The smoother was running extremely slowly when processing certain ODTK scenarios that produced denormal numbers. This problem was most evident on Pentium 4 processors. Additional code was added to set the floating point processor to use "Flush To Zero" mode. When a denormal number is found the processor sets the value to zero and continues. Regression testing has shown that this has NO impact on the actual results in ODTK.

For more information on denormal numbers and their behavior on Intel processors, please see the following links:

http://en.wikipedia.org/wiki/IEEE_754
http://softwarecommunity.intel.com/articles/eng/2100.htm
41133

A minor issue with the same GUID being used by both STK and ODTK has been resolved. This was causing the following error message to occur in STK at start up.

CoCreateInstance() of AgAsHpopPlugin8.AgAsHpopPluginSampleEngine returned HRESULT of 0x80040154
41511

A problem in the step size control algorithm used during the integration of orbits when using relative error based step control has been corrected. The fixed true anomaly predictive step algorithm was erroneously being used to provide the first guess at the integration step size. As a result of the error, integration of some orbits may have required additional computation time due to smaller than necessary step sizes being used. The accuracy of the resulting orbit was not adversely affected.
42046

The ability to account for motion of a tracking station as specified through a tracking data reader has been added. This capability provides an improvement in observation processing for ship based trackers. Support is provided for two way range, two way Doppler, azimuth, elevation, right ascension and declination observations.
42174

The capability to estimate facility position from ground based right ascension and declination measurements has been added.
42268

GenSimSchedule30 was updated to recognize sensors attached to facilities and use them when calculating access times.

Changes introduced in ODTK 5.1.4

The following information applies to ODTK 5.1.4.

Capabilities added and issues resolved in ODTK 5.1.4

The following table identifies limitations and issues that have been resolved in the current release, as well as new capabilities and improvements that have been added:

New Capabilities and Resolved Issues in ODTK 5.1.4
Tracking No. Description
43834

The two legged GPS pseudo-range measurement model has been modified to honor a transponder id set by the tracking data reader. This allows the proper association of observations with a particular relay transponder on a spacecraft which has multiple relay transponders attached.

The one way bi-static range measurement model has been corrected to properly estimate the bias associated with the relay transponder on the satellite of interest in the case where the transponder id is passed in from the tracking data reader and the satellite has multiple relay transponders attached. Cases where the satellite has only one relay transponder worked properly in prior versions and are not affected by this change.
44328

The True Equator Mean Equinox (TEME) of date reference frame has been added as an input option for satellite initial conditions and an output option for ephemerides predicted from a satellite initial state.
44329

Processing of direction cosine measurements such as those generated by the AF space surveillance fence has been added.
44907

The ability to import STK Satellite (.sa) and Facility (.f) files from STK via scripting has been added.
44914

A limitation in the space based measurement models for two way range, right ascension / declination and azimuth / elevation which prevented the use of these models for satellites orbiting bodies other than the Earth has been removed.
45250

An issue has been correct in which when the X angle values were less than zero the residuals were being calculated in the range -180 to 180 instead of 0 to 360, which is what the UTDF reader was providing.
45251

Added a GeomCheckFilter flag to the UTDF tracking data reader configuration options. When set to true it compares the transmit and receiver antenna geometry flags. If they don't match it will reject the measurements. By default this flag is true (backwards compatible with 5.1.3 and older versions of ODTK). If set to false then the reader will use the receive antenna geometry flag if the transmit geometry flag is set to zero.
45291

An error in the UTDF tracking data reader which would have resulted in the incorrect time tagging of measurements in the same year as and following a mid-year leap second has been corrected. The last mid-year leap second occurred on 1 Jul 1997 and no new mid-year leap seconds are currently projected.

45334

Transponders are now allowed under GPS Satellites

Online Help resources

The current version of ODTK is shipped with the following online help resources:

The ODTK Help System

The ODTK Help system appears in the Microsoft HTML Help Viewer, which uses components of the Microsoft Internet Explorer to display help topics and navigational tools. The latter are accessible from the following tabs:

  • Contents - Click on the book and page icons to find the topic of interest.
  • Index - Scroll down the list or begin typing the name of the index item in the textbox. When the item you are seeking appears in the list, double-click it or highlight it and click the Display button. If the item is found on more than one help page, a window listing the applicable pages will display.
  • Search - Type in the word or phrase for which you wish to search. To specify an exact phrase, enclose it in double quotes; otherwise, any page containing all of the words in the phrase (not necessarily contiguous) will be listed. After typing in the search term, either press the Enter key or click the List Topics button.
  • Favorites - This tab lets you bookmark help topics to which you might want to recur frequently. Clicking the Add button places the name of the currently displayed help topic in the list. To delete a topic from the list, select it and click the Remove button.

Context-Sensitive Help

F1 Help for OD Attributes

To display context-sensitive help for a property of an OD object, select it in the Object Properties window for the object and click the F1 key.

Help Buttons for Report and Graph Windows

Help buttons are available for the Static Product Builder, the Dynamic Product Selector, the Graph Designer and the Report Designer. Click these buttons for context sensitive help on the functionality in question.

Printable (PDF) documents

Several printable (PDF) documents accompany this version of ODTK, including a set of tutorials (Getting Started with ODTK), a scripting guide, and documents explaining the mathematical and scientific background of ODTK. To access these documents, go to the manuals page.