ANTEX: PCV with azimuth, full freq range, ANTEX 2, SINEX metadata #533
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This is a useful function for parsing the formatted files, so move this from rinex.c into rktcmd.c and export it.
ourairquality
force-pushed
the
antex-freq-azi
branch
from
fa791ea
to
4db4aa9
Compare
Improve the ANTEX support. * Support PCV with azimuth. Was just NOAZI. Use linear interpolation between azimuth points, as well as the zenith. Satellite PCV still only supports NOAZI as that is most common, but all the support is there to extend this to vary with azimuth * Support ZEN1, ZEN2, DZEN, and DAZI. The PHV size is also now variable so the smallest size array is allocated. There was a fixed azimuth length of 19. It now correctly handles variations of these parameters. Require some more memory management, to free these. * Support the full range of frequencies, across systems. Was just GPS and NFREQ. The usage of the antmodel() etc functions needed to change. There were returning a NFREQ array with the offsets, but that did not work with multiple systems with different frequencies mapped to the frequency same indices - these functions are now single frequency functions. * Support PCO and PCV interpolation between frequency entries, with heuristics to avoid extrapolation of noisy data, and avoid interpolation across frequency bands (which may well be implemented with separate antenna elements e.g. stacked elements). * Add support for ANTEX 2 which avoids much redundancy. This required the PRN to SVN mapping in the SINEX satellite meta data. * Add minimal SINEX satellite meta data support, just for the PRN to SVN mappings. Adding the file-satmetafile option. * Support for the console apps. * Support for the qt apps, adding the satellite meta data file to the GUI. * Some windows app support, untested, and not yet the satellite meta data file for ANTEX 2 which needs adding to the GUI.
ourairquality
force-pushed
the
antex-freq-azi
branch
from
4db4aa9
to
6bf6d0b
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
The ANTEX support was limited, perhaps good for GPS frequencies L1 and L2, but beyond that it was limited, and using more signals across multiple systems it was problematic. If the PCO is missing or wrong for some signals then that makes the solution difficult or throws it off, often showing up as an error in the height first. While addressing those issues, also added support for PCV azimuth, and for ANTEX 2 which in turn needed some limited support for satellite meta data SINEX files.
This helps if not using matched antennas, and if using a competent base for RTK.
It assumes the antennas are horizontal and pointing north. There is no support in the code yet to consider the rover heading.
Added interpolation for the receiver PCO an PCV across frequencies. If a low end antenna has at least a GPS L1 and L2 calibration then that will be used for other signals in the same band. Even supplying the L1 and L2 PCO can help and this is often printed on the label.
Some antennas with an otherwise tight PCO can vary a lot over frequency in the lower frequency band, 10mm+, so interpolation will not always be great particularly in the lower frequency band.
The ANTEX 2 files are at https://files.igs.org/pub/station/general/atx_alternative/atx2/ and the meta data at https://files.igs.org/pub/station/general/ ANTEX 2 adds nothing over ANTEX 1 for the solution and should give the same solution, it was just a small thing to add support while look over this code. ANTEX 2 has less redundant information, almost half the file size. Some example options for ANTEX 2:
file-satmetafile =igs_satellite_metadata.snx
file-satantfile =igs20_sat.atx2
file-rcvantfile =igs20_rcv.atx2
The windows app GUI support is not done, that just means there is no file selection for the ANTEX 2 meta data file, it should otherwise work, and ANTEX 2 adds nothing to the solution.