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ODTK 6.4.x Feature List Continues to Grow!

By: Jim Woodburn
The just released ODTK 6.4.3 adds even more incredible features to the popular ODTK 6.4 family of releases, which includes 6.4.1 and 6.4.2 in addition to the substantial 6.4 minor version release. The ODTK 6.4.x series of releases include the following features.

ODTK 6.4 Expanded GNSS Capabilities

With ODTK 6.4, we provided a major upgrade to GNSS processing capabilities. Support for GNSS Constellations Multiple GNSS constellation objects can now exist in an ODTK scenario. This allows ODTK users to simulate and process data from multiple GNSS sources simultaneously. Accordingly, the GPS-related-objects GPS Constellation, GPS Receiver, and GPS Satellite have been named to GNSS Constellation, GNSS Receiver, and GNSS Satellite, respectively to reflect the more generic nature of multiple GNSS constellations. A System Time offset is included to support analyses in multi-GNSS environments. Similar to GPS, other GNSS systems can have their own realization of a system time which is defined by the collection of clocks within the GNSS. The System Time Offset, associated with the GNSS constellation, defines the time offset between a particular GNSS system and “the reference” GNSS system with a clock state (phase, frequency, and aging) that can be just an input, or an a priori input and then estimated. System time offsets can also be simulated. Full support for all PRNs used in each of the constellations is provided. To support multiple GNSS receivers, the PRN numbers are offset by a Base number so displayed PRN is Base plus PRN. A separately-licensed ODTK feature enables you to estimate the orbits and clocks within GNSS constellations. For more information, contact your AGI sales representative.

GNSS Catalog Files Updated

The various GNSS constellation catalog files are continually updated to reflect the latest launches and constellation changes, which can also be obtained online via the Data Update Utility. Other catalog file enhancements:
  • The ability to estimate an antenna offset when processing NAVSOL measurements.
  • The NAVSOL tracking data format now enables you to specify component based measurement sigmas. This is useful navigation solution uncertainties by component are available from your GNSS receiver.

New Measurement Types, Signal Types and Frequencies

Support of additional GNSS constellations has resulted in an explosion in the number of GNSS measurement types, signals and frequencies supported.

RINEX Support Upgrades

We now support the RINEX 2.12 (QZSS extensions) and 3.0.2 format observation files. The way ODTK associates TrackerIDs with RINEX MARKER NUMBER records has changed when the RINEX MARKER NUMBER record contains an IERS DOMES number. The prior behavior is that ODTK read the MARKER NUMBER record until a non-numeric value is encountered. This limited DOMES numbers to associate with five-digit TrackerIDs, because the sixth character is usually an "S" or "M" followed by three more digits. The new behavior converts the sixth character to a zero, allowing association with the nine-digit TrackerIDs by default. This change allows co-located receivers having unique DOMES numbers to also have unique TrackingID associations by default.

HTML Utilities

To make your job easier, we created two new HTML utilities for use with RINEX files.
  • CreateReceiverSite that quickly builds a ground based GNSS receiver and attached antenna based on the data from a RINEX file.
  • RINEXClockToSimrun.html reads a RINEX file and converts the clock information in it to a .simrun file. This is useful for analyzing the clock statistics using the Allan Variance or Hadamard Variance output styles.

SP3 Support

Our SP3 interface software has been updated to recognize the QZS (QZSS), GAL (Galileo), and GLO (GLONASS) time system indicators and support the range of PRNs used by each of the constellations listed above. ODTK can now generate an SP3 file for each constellation based on the estimated orbit and clock states. In addition, the simulator, filter, and smoother now have the option to generate SP3 files during the actual processing interval and/or a prediction interval. This is useful when estimating GNSS constellations.

Navigation Solutions

The generation of single frequency navigation solutions (via the HTML utility GenerateNavSolutions or a direct call to the ODTK GenerateNavSolutions function) now include ionosphere corrections and the group delay. For ground receivers, GenerateNavSolutions now includes troposphere corrections.

Attitude Profiles

The QZSS and Galileo standard attitude profiles are now supported.

General Enhancements

In addition to the major enhancements in the area of multiple GNSS processing, we have provided a number of other capability and usability improvements.

Reporting and Graphing Usability Improvements

 

  • The Static Product Builder now includes a drag and drop capability and standard hot key support for copying (Ctrl-C) and pasting (Ctrl-V) products in the product list.
  • Additional report and graph styles that calculate the Allan and Hadamard variance for clocks used in the scenario.
  • Accumulated and average delta-V parameters were added to the Finite Maneuver Summary table, which are useful when trying to figure out how much delta-V was applied during a finite maneuver.
  • BeiDou, Galileo, GLONASS, and QZSS can be reported and graphed   (and can be updated using the Data Update Utility).
  • New report and graph styles are provided that display an ellipse in the local horizontal plane representing the uncertainty in a facility location estimate.

New Measurement Types

The ability to construct and process Differenced One Way Doppler (DOWD) measurements has been added. DOWD measurements are constructed by differencing two simultaneous one way Doppler (3L Doppler) measurements taken from a single user satellite through two TDRS satellites. See GNSS measurement types.

Tracking Instruments

Satellites have a new sub-object called TrackingInstrument. The TrackingInstrument is used to host measurement models that were previously to be held by the satellite object itself (e.g., space-based right ascension and declination, ephemeris position and velocity, etc.). ODTK users may now model multiple sensors of the same type on a single satellite where each sensor has its own specific body frame offset from the center of mass and measurement model configuration. Updated Data
  • ODTK is now using the JPL DE430 ephemeris for the central body locations instead of the DE421 ephemeris.
  • Support for the Mars MGM2011 gravity field including a process noise model has been added.

Filter Enhancements

  • New backwards (in time) running filter that enables you to sequentially process measurements backwards in time from your initial state.
  • New edited measurement flags that identify measurements which have been explicitly rejected based on operator settings, as Force Reject (FR). Measurements rejected because an object in the measurement strand does not support that measurement type will be marked as Invalid Object (IO).
  • New “IgnoreButReport” option in the CustomDataEditing and ResidualEditing fields for observations that you don’t want the filter and least squares objects to process, but you still want to see these measurements in the estimation output.

Initial Orbit Determination

The Herrick-Gibbs method now supports the combination of direction cosine and range measurements.

More Information

For more information, see ODTK Product page and the ODTK help.  
Posted: 4/18/2016 3:26:57 PM


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