Hello,
I’m using RINEX files from Leica receiver and antenna.
Antenna has a vertical offset related to the frequencies L1 or L2. In the RINEX file we can read :
LEIAX1203+GNSS ANT # / TYPE
2725382.8235 3463537.1973 -4595151.6764 APPROX POSITION XYZ
1.2440 0.0000 0.0000 ANTENNA: DELTA H/E/N
L1PhaOff: 0.0585 L2PhaOff: 0.0555 COMMENT
This is a comment so it is not read by software. I wonder if these offset should be given in RTKLIB parameters or if they are already included in the observables. In RTKLIB there is no option to give a different offset for each frequency. You could only give one vertical offset. This is not an issue as they are very close (3 mm).
Hi, I’ve got the solution.
Phase vertical offset is not a simple vertical correction like antenna height. It should be applied to satellite distances.
RTKPOST allow this kind of correction. They are included in two antenna data files : igs08.atx and ngs_abs.pcv (under “data” directory in RTKLIB installation folder). You should declare them in Files tab in Options window. Then you have to select your base and rover antennas in “Antenna Type” scrolling list, and write antennas physical heights in Delta U (usually found in RINEX header).
If your antenna is not listed, download the latest files from NOAA or IGS : https://www.ngs.noaa.gov/ANTCAL/LoadFile?file=ngs08.atx https://www.ngs.noaa.gov/ANTCAL/LoadFile?file=ant_info.003
The latter one should be renamed and replace data/ngs_abs.pcv
Using these data significantly improved vertical accuracy : for a known point, I had got a 6 cm accuracy without antenna data, and 2 cm with it.
Regards
Pierre
Are these antenna files included in the Emlid RTKLIB distribution? With data for the Emlid Reach Antenna?
I cannot seem to find any “data directory”. It seems there is no way of inserting the APC (antenna phase center) to ARP (antenna reference point) distance in RTKPOST other than referring to files under Options > Files.
No, but you can find it under RTKlib http://www.rtklib.com/ and look for latest beta with complete fileset
or add it your self from https://www.ngs.noaa.gov/ANTCAL/
But, no data is available for Reach units yet. So you dont need to look for any calibration file for Reach now.
Not sure if or when its going to be.
Ones you add the antenna calibration file (in the same folder you har RTKpost), it will appaer in the dropdown list as mentioned by @zipang
