Changes between Version 8 and Version 9 of Processing/Applanix

Timestamp:

Sep 19, 2007, 1:10:37 PM (17 years ago)

Author:

mggr

Comment:

--

Processing/Applanix

@@ -34 +34 @@
 == 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:
 {{{
@@ -58 +60 @@
 
 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 http://gps.ordnancesurvey.co.uk/etrs89geo_natgrid.asp
- 1. Click the pretty pink 'ETRS89 xyz' button
- 1. Enter the coordinates from the `APPROX POSITION` field in the .07o file
- 1. Convert to National Grid
- 1. In POSGPS, enter these grid coordinates (using Grid: British Grid)
-
-WRONG!  need to convert, not transform. saving for tonight
+ 1. Go to http://www.ordnancesurvey.co.uk/oswebsite/gps/information/coordinatesystemsinfo/gpsspreadsheet.html and get the coordinate conversion spreadsheet
+ 1. 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
+ 1. Check the constants are set for WGS-84
+ 1. 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)
 
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