Options Dialog Box - PPK Settings Tab

To open the Options dialog box, click Options on the Post Process Kinematic dialog box and then select the PPK Settings tab.

Use the PPK Settings tab to review and specify what RINEX data information to use and how to process it.

Frequencies. Select the frequency data signals used in the GNSS solution, either L1, L1+L2, L1+L5, or L1+L2+L5.

Elevation Mask. Select the minimum acceptable elevation above the horizon that a satellite must be to avoid blockage of the signal (line-of-sight). Values range from 0° horizontal to 70° azimuth in 5° increments.

Interval. Select the interval time of observations, ether 1 second, 2 seconds, 5 seconds, 10 seconds, or 60 seconds.

The longer the interval diminishes data processing time by reducing the number of points used in that interval. Base units like CORS stations are typically at 5 second intervals, and a local base could be set to 2 seconds, or some other value closer to the rover receiver. It is important to note that processing uses the lowest common denominator of the unit time intervals.

Time Interpolation. Select the increment of time between base and rover units, either Linear or Closest Time.

Interpolation is the straight-line time between each unit. Closest time is where the rover point is processed by the time stamp closest to the base unit.

Elevation Model. Define the model to use that defines the height above an ellipsoidal model of the Earth to compute an orthometric height. Models delivered in the solution include: Ellipsoidal, NGS GEOID 12B, and NGS GEOID 18. Other models may be downloaded.

GEOID18 covers CONUS, Puerto Rico, and the U.S. Virgin Islands and supersedes GEOID12B in these regions. GEOID18 does NOT cover Alaska, Hawaii, Guam and the Commonwealth of the Northern Mariana Islands (CNMI) where users should continue to use GEOID12B.

To use EGM2008 (2.5' or 1') elevation models:

1. Download the appropriate file from the internet:
   • EGM2008 2.5' - Und_min2.5x2.5_egm2008_isw=82_WGS84_TideFree_SE.gz.
   • EGM2008 1' - Und_min1x1_egm2008_isw=82_WGS84_TideFree_SE.gz
2. Unzip the file and place it in the following folder: C:\ProgramData\Autodesk\C3D 2024\enu\Geoid Models.
3. Restart Civil 3D.

Satellite Systems. Select which satellite systems data files to incorporate into processing. When data is loaded, the RINEX files are scanned and active satellites are identified. If they are not previously selected, you will be prompted to select and add the data files if desired. The currently available satellite systems include:

• GPS (United States). The first space-based location system, launched by the USDOD in the 1970's and provides global coverage with 27 satellites.
• GLONASS (Russia). Provides global coverage with 24 satellites.
• Galileo (European Union). A civilian system operated by the European Global Navigation Satellite Systems Agency (GSA). Their first launch was in 2014 and plan to be fully operational in 2020 to provide global coverage.
• BeiDou (China). Regional service became operational in December 2012 and will consist of 35 satellites when fully operational to provide global coverage by the end of 2020.
• IRNSS (India). Provides regional service to India and the surrounding region with a constellation of 7 satellites (Indian Regional Navigation Satellite System).
• QZSS (Japan). Provides regional service to Japan and Asia-Oceania through a system of four satellites (Quasi-Zenith Satellite System).
• Exclude. Excludes satellites for positioning. Use the PRN numbers of the satellites to be excluded separated by spaces.
  • For GLONASS, Galileo, QZSS, BeiDou and SBAS, use Rnn, Enn, Jnn, Cnn and Snn, respectively (nn: satellite PRN or slot number).
  • If + is added to the head of the satellite ID, the satellite is included for positioning even if the satellite is unhealthy.