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

ODTK 6.2.0 Release Notes

These release notes contain information on system and disk space requirements for installing and running ODTK; information on new capabilities and features 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 6.2.0.

General information

This section includes system requirements and background information on ODTK 6.2.0.

System and disk space requirements

The following table sets out minimum and recommended system requirements for ODTK 6.2.0:

An ODTK 6.2.0 installation requires 200-300 MB of disk space. Running a typical scenario, such as the Sapphire demo scenario that accompanies ODTK 6.2.0 (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 6.2.0 is slightly over 110Mb.

Compatibility with Windows Server 2005 and 2008

Windows Server 2008 installations must have the Desktop Experience option turned on before running the ODTK install. This option is available from the Windows Control Panel.

Microsoft recommends running services under a specific user account and does not recommend running under the SYSTEM account unless absolutely necessary.

If you run ODTK under the Local System (SYSTEM) account on a 64-bit system you will need to create a C:\Windows\SysWOW64\config\systemprofile\Documents folder and verify that the C:\Windows\System32\config\systemprofile\Documents folder properly links to it and that both have appropriate permissions.

If you plan to run multiple instances of ODTK on the server you will need to ensure that the system is configured to reserve enough Desktop Heap Memory for each session. See blogs.technet.com for a discussion of the settings in HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\SubSystems

We recommend reserving ~256k of Desktop Heap for each instance of ODTK running on the system.

Background

ODTK 6.2.0 is built upon the same verified astrodynamics functions and coordinate conversions as STK and its modules. ODTK 6.2.0 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 6.2.0 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 5 are satisfied, that ODTK 5 scenarios will load and run in ODTK 6.2.0, and that ODTK 5 restart files will initialize in ODTK 6.2.0.

What's New in ODTK 6.2.0?

ODTK 6.2.0 is a maintenance release containing enhancements of interest to the space situational awareness community and tracking of unknown objects.

• General
• Satellite Updates
• Least Squares
• Filter
• Simulator
• Measurement Models
• GPS Receivers
• Static Product Builder
• Default Parameters

General

• The Jacchia-Bowman 2008 atmospheric density model is now supported. Users should note that this model requires additional space weather indices beyond the usual flux data supplied by AGI.
• STK binary ephemeris format is supported for both input and output. This reduces the size of the ephemeris files. Note that this format is only supported in STK 10 or later releases.
• The GGM03C gravity model has been added.
• An application level attribute ODTK.AppVersion was added to allow scripting clients to identify the ODTK version that they are connecting to.
• Ephemeris files produced by the filter and smoother now use a nice clean ScenarioEpoch time as the reference. While it doesn’t change the overall ephemeris results, it’s easier to read and interpret the time tags when looking at a file by hand.

Satellite updates

The Satellite object has been enhanced to allow the following:

• The solar radiation pressure (SRP) model terminology has been updated to use C_R rather than C_P to refer to the solar radiation pressure coefficient. This makes ODTK consistent with standard terminology used elsewhere in the industry and academia. Backwards compatibility code is in place to allow loading your existing scenarios and scripts. The standard report and graph styles shipped with ODTK have been updated appropriately. Users should review any custom styles they may have and update them. Please refer to the transition steps below for more details.
• The drag and solar radiation pressure estimation options have been expanded to allow additive or relative terms to be estimated for each. Previously the SRP parameter (C_R) that was estimated was additive and the drag parameter (β) was relative.  The SRP model also allows estimation of CrA/m. This is useful in cases where the satellite being tracked has an unknown area and mass.
• Drag modeling may be included in the variational equations.
• The integrator settings support a separate configuration for prediction (after the filter, smoother, or least squares runs). The standard integrator choices may be used, along with the addition of a new Gauss-Jackson integration method.

Least Squares

The Least Squares object has been enhanced to allow the following:

• The user may now choose to use an a-priori covariance during the estimation. This allows you to constrain the state during the estimation process.
• There is a new option to transfer the position and velocity covariance to the satellite when transferring the state. Because the least squares covariance is often optimistic (e.g. too small), you may optionally provide a multiplier for the position and velocity that will be used to inflate them when transferred.

Filter

The Filter object has been enhanced to allow the following:

• A new option to compute global corrections to the Jacchia 1970 and Jacchia-Bowman 2008 atmospheric density models has been added. Updates may be computed via three formulations: as corrections to the nighttime minimum exospheric temperature, T_C , and the inflection point temperature at 125 km altitude, T_X , as correction to the global exospheric temperature T∞, or as direct relative corrections to the density, Δρ/ρ. Computed corrections can also be applied during orbit determination for satellites not used during the determination of the temperature corrections.
• A new option for the Filter and Simulator to detect and use updated object settings for estimated stochastic parameters in restart mode. This new option provides an alternative to using the StochasticModelUpdates lists on the Filter or Simulator object to specify updates to stochastic model settings or nominal parameter values.
• A new option to allow an external file containing sensor biases to be used during estimation rather than estimating the biases directly.

Simulator

The Simulator object has been enhanced to add new options to the interval files used with the custom tracking intervals. These include options for specifying the tracker via a tracking strand and adding a tracking granularity delta time.

Measurement Models

Trackers supporting optical measurements such as right ascension and declination (or their space-based equivalents) now support a TEME of Zero hour and TEME of Jan 0 as optical frame options.

GPS Receivers

Ground-based GPS receivers can now specify their antenna offsets in the Height, East, North convention as used in SINEX files from the IGS.

Static Product Builder

Ephemeris files can now be used as inputs for report and graph styles that use position and velocity information.

Default parameters

The default parameters for several objects in ODTK have been updated to better represent operationally relevant values. The changes only affect new objects that are created in your scenario. Any existing objects that are loaded as part of a saved scenario will continue to have the same values as before. Users with scripts controlling ODTK should review their scripts to see if the script was relying on the previous default values. If so, you should update your script to either explicitly set the properties to the desired value or confirm that the new values have no impact.

On the satellite object:

	ForceModel.Gravity.ThirdBodies.UseInVariationalEquations = true
	ForceModel.Drag.UseInVariationalEquations = true
	ForceModel.SolarPressure.SunPosMethod = Apparent
	ForceModel.SolarPressure.UseInVariationalEquations = true
	PropagatorControls.IntegrationMethod = RKF 7(8)
	PropagatorControls.StepSize.StepControlMethod = Relative Error

These changes provide a better default force model and integrator configuration.

On the Filter and Smoother objects:

	Output.DataArchive.SaveCrossCorrelations = false

These changes reduce the size of the files contained in the filrun and smtrun folders produced by the filter and smoother.

On the Smoother object:

	ProcessControl.StateTransitionMode = Linear

This change defaults the fixed interval smoother to use the Linear transition mode (vs. the Nonlinear). Testing at AGI has shown the Linear mode to produce slightly more accurate results in the period immediately preceding a tracking data pass.

Version Changes in Tracking Data Interface

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

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.

...
  SetLocale(1033)
  ...
  set fac = ODTK.Scenario(0).TrackingSystem("TrackingSystem1").Facility("Facility1")
  set Lat = fac.GeodeticLocation.Latitude.GetIn("deg")
  MsgBox "Lat = " + cstr(Lat)
...

Transition 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:

Updating custom Report and Graph styles for ODTK 6

The database tables from the various *.*run files (*.filrun, *.smtrun, etc.) used by the Static Product Builder have been updated to reflect the changes in the naming of the solar radiation pressure parameter from Cp to Cr. Additional columns have been added to support the new additive and relative options for the solar radiation pressure and drag parameters. Users that have created their own custom report and graph styles in earlier versions of ODTK will need to update them to work with ODTK 6.2.0. Use the procedure below to update your reports. Graphs do not have an equivalent procedure, however you should test each custom graph to ensure that it continues to function as desired. If not, edit the graph style and update it appropriately.

Changes in Database Table Contents

From release to release, the contents of database tables used in the definition of report and graph styles may change, usually through the addition of new elements to the record definitions. These changes can impact the content of custom report styles created by the user. Before attempting to use a report style generated with a version prior to ODTK 6.2.0, a Verify Database operation should be performed and a new copy of the report style should be saved to a new directory. Overwriting the old style will cause that style to work incorrectly with the prior version of ODTK. The Verify Database operation is performed by highlighting the report style in the Static Product Builder, clicking on the Edit button then right clicking on the Database Fields and selecting Verify Database. After the verification completes, save the style.

Scripting Guide Updates

Please see the ODTK Scripting Guide for changes to scripting interfaces and additional scripting examples.

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.

Online Help resources

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

• ODTK Help System
• Context Sensitive (F1) Help
• Printable (PDF) Tutorials and Technical Documents

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 text box. 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 refer to 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.