Navigation Processing with POSPac

This is a work in progress by wja for the new systems for the 2021 campaign

Create new project

• Project>New default project

Import flight nav data from posatt/applanix/raw/ directory

• Project>import
• Select all the default.??? files
• "Rover Antenna Specification"
  • Manufacturer: Applanix:
  • Type: "Unknown External (Unless known!)
• Check log form inport that there are no Errors: Reports > Message Logs
  • View the "IMU Data Continuity Checking" log. If there are errors about missing data, this could have been from before the plane's take off. Try skipping the first (or more) nav files but check that the flightlines and see if this error goes away. Make sure the inported nav data covers the flight lines.

Basestations

• Import external basestation (i.e one collected by the ops team):
  • Project > Import.
    • This should only accept RINEX format data, if it is not RINEX (e.g Trimble format *.T02) then you can try using the Tools > Convert to RINEX in POSPac.

• Import OS basestations with Project "Find Base Stations"
  • I have experienced "File not found" appearing when I try and download and import basestations. So I have been downloading OS basestations myself and importing them with Project > Import

• OS basestations can be accessed vis ftp:
  • This is an example of downloading all OS basestation data from the St. Neots (SNEO) basestation for day 201 of 2021 to the current local directory:

lftp ftp://rinex.ordnancesurvey.co.uk/gps/rinex
cd 2021/201
mirror --include-glob=sneo* ./

• These RINEX files can then be imported with Project > Import.
• If imported basestation data doesn't include ephemeris data, this also needs downloading (OS basestation RINEX data only includes the *.o file, which is just the GNSS measurements rather than the meteorological and ephemeris files).
  • Project > Find Base Stations > Select None > Tick all Precise Ephemeris and Broadcast Ephemeris rows, click "Download and Import" to download, then click "Download and Import" again to import.

If four basestations are available:

• Project > SmartBase Quality Check
• If the quality is good, then it will prompt you to continue to the Applanix SmartBase (ASB) stage which will run when 'Continue' is clicked.

GNSS-Inertial Processor:

• If using multiple basestations, use GNSS Mode: IN-Fusion Smartbase
• In GNSS-Inertial Processor > Properties > GNSS-Intertial Processor > Lever Arms and Mounting Angles, add the appropriate lever arms.

Generate QC report:

• Reports > QC Report >

Export SBET nav file:

• Export SBET: Custom Smoothed BET