GNPCV2PDF

The GNPCV2PDF service allows to visualize ANTEX files. You can upload any ANTEX file and you will receive a pdf-file with the PCV graphics by e-mail.

The GNPCV2PDF service was initially developed to check fo so-called GLONASS spikes in ANTEX files.

GLONASS spikes were introduced by a flaw in a conversion tool used for re-formatting from the Geo++ ANT format to the international ANTEX format. Unintentionally spikes in the GLONASS PCV were generated in the resulting ANTEX files.The effect was not detected, because analysis and controls are mainly using the Geo++ ANT format and are not based on ANTEX.

Affected are

  • only GLONASS PCV
  • only PCV in an ANTEX file
  • only some ANTEX files
  • only ANTEX files over a limited time period
  • only ANTEX files generated before November 2011

PCV given in the Geo++ ANT format and the result from the absolute GNSS antenna calibration are correct. The correct PCV value of a GLONASS spike onĀ  L1 and/or L2 is always 0.00 mm. The abbreviation for the GLONASS system is within ANTEX “R”, which causes the frequencies to be named also as “R01″ and “R02″.

Investigations of the impact on geodetic GNSS applications revealed so far no significant effect for positioning tasks. Obviously, the size of the isolated GLONASS spikes is not big enough to cause systematic effects, even for short-time applications (like RTK positioning).

An example is given in the following graphic, which shows the two so-called spikes on the GLONASS L2 (R02) frequency for an elevation of 15 deg, azimuth of 305 deg and 330 deg. The plot shows the pure azimuth-dependent PCV (AZI PCV), i.e. the elevation dependent PCV part (NOAZI line in ANTEX file) is substracted. Therefore the neighbouring PCV are not zero. PCV are continuous and do not have discontinuities, which is also a reason to use spherical harmonics to model and describe PCV.

LEIAR25_R4______LEIT_10271001_GLO_R02_AZI_PCV

The easiest way to check for spikes is a plot of the GLONASS PCV. A GLONASS spike can be recognized bestĀ  in the ionosphere-free linear combination (effects from the original R01 and R02 PCV are amplified by a factor of 3) and in the pure azimuthal PCV (main part of elevation-dependent PCV removed).

Geo++ enabled an upload facility to provide plots from an uploaded ANTEX input file to provide an analysis tool to customers. In case you have affected Geo++ ANTEX files, please send the file to gnpcvservice@geopp.de. Geo++ will support all inquiries to remedy the spikes and provide a neat ANTEX file.

Link to GNPCV2PDF to visualize PCV from an ANTEX file.

GNPCV2PDF_start-button

We apologize for any inconvenience.

gnpcv2pdf

Print Friendly