GNSS receiver performance monitoring

Project Description

The aim of this project is differential verification of short-term and seasonal changes of calibration constants of GPS receivers, including variation due to changes of delays of different parts of equipment. The base method is collection and analysis of measurement data taken from pairs of GPS receivers working with the same local reference timescale, so the data taken from pairs of GPS receivers working with different local reference timescales/clocks, but with supplementary results of direct measurements between the used as a reference timescales/clocks, are accepted.

Theoretically, the difference between GPS receivers in such pairs should be constant, but practically, this difference can vary due to individual sensitivity on external temperature of the equipment, different type of antennas and different type of receivers and software. It is assumed that the data will be collected and analysed for the period of at least one year of permanent observations. The analysis will be performed for GPS C/A code mainly, so with measurement data in CGGTTS format. The involved GPS receivers do not have to be calibrated because the subject of investigations is only the changes with respect to the other one in the pair.

Progress Report 2022-03-30

In 2019,the TC-TF EURAMET community has performed a revision of this project in the context of:

  • a complexity of interpretation and necessity of usage details of the local technical information known only a related laboratory
  • a recommendation CCTF/17-05 on the utilization and monitoring of redundant time transfer equipment in the timing laboratories contributing to UTC, which recommends monitoring their CCDs and the internal characteristics of their laboratory reference signals

It was decided to change the formula of this project and to update the role of participating TF labs. Since then, each participant initiates and performs the internal analysis individually. The selected more interesting results are presented and discussed during TC-TF EURAMET annual meetings. The chosen new special cases shall be added to the compendium of the project, together with all recognized until now the existing special cases (explained and not explained). The compendium will be created as a growing set of attachments to this project, published in EURAMET webpage. The coordinator supports the individual participants and collect “special” cases

The following institutes are now participating in this project:
INRIM (Italy), DMDM (Serbia), SMD (Belgium), ILNAS (Luxembourg), IMBiH (Bosnia and Herzegovina), AOS SRC PAS (Poland) and NIT (Poland)