Version 10 (modified by mggr, 12 years ago) (diff)


To check on the right coordinates of OS active stations, see the link below

Base station data not 1 second resolution? Resample (interpolate using posgps). While this doesn't improve the data, it apparently makes it more evenly applied (no internal interpolation?). Unverified.

Short notes on processing

  1. Understand what you're doing!
  2. Create new project, aim at <data dir>/applanix. Name should be "YYYYJJJ.ppc". Both filename kernels should be "YYYYJJJ".
  3. Hit "Extract"
    1. Kernel should be "YYYYJJJ".
    2. Read through output for errors - key things to look for are data gaps (if large, you may have to split the processing)
  4. Hit "POSGPS"
    1. Convert input files to GPB (File -> Convert -> Raw GPS to GPB)
    2. Plane applanix
      1. Set receiver type to autodetect
      2. Point at the applanix/Extract directory (check this!) and 'Auto add all' (this should add a NovAtel OEM3 file)
      3. Select the Novatel file, click options and Make all epochs Kinematic (this is because the Novatel is the sensor on the plane, which is definitely kinematic!)
      4. Run the conversion (check output for errors)
    3. Base stations (repeat for all base stations)
      1. Set receiver type to autodetect
      2. Point at the base station directory, probably Rinex, and 'Auto add all' (this should add a file, probably Rinex for the UK)
      3. Run the conversion (check output for errors, some health warnings are ok)
    4. File -> Add Remote File, select the gpb file in the applanix/Extract directory, defaults fine
    5. (for all base stations - note: multiple base stations may need other stuff done)
      1. File -> Add Master File(s), select the gpb file in the basestation directory
      2. (if you have gaps, it may offer to resample for you - not sure if we need to do this or not)
      3. The basestation data will come with extra info specifying the precise location and antenna type.
      4. Fill in the antenna type (use advanced method) if you have the info, otherwise set the height appropriately
      5. The base station location will come in a particular datum/coordinate system - you must correctly convert this to a form that POSGPS knows about.
      6. For UK base stations, see the instructions below for this conversion.

UK Rinex base stations

For the UK Rinex stations, the position is provided as Earth-centered Cartesian coordinates (XYZ) in the ETRS89 datum (directly compatible with WGS-84, just more exacting). As they're compatible, these coordinates just need to be converted to WGS-84 lat/longs for POSGPS. If we were coming from or going to a different datum/coordinate system (e.g. OS National Grid), we would need to do a coordinate transformation rather than conversion - this is complicated!

For the O/S UK GPS network (Rinex format files), the .07o file has a header like this:

     2.1            OBSERVATION DATA    G (GPS)             RINEX VERSION / TYPE
GPServer 2.50 2620  Rinex Merge         11-May-07 08:03:46  PGM / RUN BY / DATE
NEOT                                                        MARKER NAME
                                                            MARKER NUMBER
National GPS Network Ordnance Survey                        OBSERVER / AGENCY
0036227             LEICA SR530         4.20                REC # / TYPE / VERS
     0                                                      RCV CLOCK OFFS APPL
102098              LEIAT504        LEIS                    ANT # / TYPE
  3918702.4172    -7624.0107  5015612.3424                  APPROX POSITION XYZ
        0.0000        0.0000        0.0000                  ANTENNA: DELTA H/E/N
     1     1     0                                          WAVELENGTH FACT L1/2
     5    C1    P2    L1    L2    D1                        # / TYPES OF OBSERV
     1.000                                                  INTERVAL
  2007     5    10     9     0    0.0000000     GPS         TIME OF FIRST OBS
APPROX POSITION XYZ replaced by precise ETRS89 values       COMMENT
                                                            END OF HEADER

Note the ANT # / TYPE line and the ANTENNA: DELTA H/E/N for antenna details.

The APPROX POSITION XYZ is the precise ETRS89 X,Y,Z location (see COMMENT sections to confirm this it says it's precise). This must be converted to a WGS-84 lat/long:

  1. Go to and get the coordinate conversion spreadsheet (or see attachment)
  2. Enter the coordinates from the APPROX POSITION field in the .07o file into the XYZ fields on the Enter Coords here sheet, clearing the other fields
  3. Check the constants are set for WGS-84
  4. Take the lat/long/ellipsoidal height from the XYZ to lat,long,H sheet and enter into POSGPS (you may want to save these as a favourite too)

Todo: add in detailed notes from Applanix training course

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