Conditions for Antenna Calibration

The Geo++®-Method for Absolute Antenna Calibration operates the GNSS antenna to be calibrated on a robot and a second near-by reference station. The second GNSS system consisting of an antenna (normally a Leica Choke Ring with Radome) and a standard GNSS receiver is provided by Geo++® GmbH / GeoService® for the period of calibration.

Generally, standard cables, mount and GNSS receiver available at Geo++® GmbH / GeoService® GmbH are used with the antenna to be calibrated. The default interfacing at the GNSS antenna is a 5/8” thread.

A GNSS receiver must be made available by the customer, if the antenna cannot be operated with a standard GNSS receiver or if a particular GNSS receiver shall be used. Any special cables, cable connectors and/or mounts to be considered in the calibration must be provided by the customer. The robot used for the automated field calibration is limited with respect of antenna weight and dimensions. In case of having any doubts on the required equipment, this has to be clarified with technical staff beforehand.

Absolute Antenna Calibrations require the provision of the following equipment by the customer:

  • completely functioning GNSS antenna (to be calibrated)
  • any documentation on GNSS antenna (geometry, definition of geometric Antenna Reference Point ARP)
  • if applicable, antenna cable (10 meter) and/or connector to N adapter after query
  • if applicable, DIN adapter or 5/8” screw/interface for mounting antenna

The antenna calibration is no verification of antenna functioning or positioning performance, because only high elevation satellites are used and the antenna is tilted and rotated. Calibrations performed with no completely functioning antennas will be charged.

An appointment for the actual time period of calibrations is required and must be agreed upon with the technical staff. The period of time required for a single antenna calibration including handling and evaluation takes approximately 1 to 2 weeks. In case of several antennas within one order, handling is reduced and every additional calibration requires roughly one day. Nevertheless, due to the complexity of the system, fixed deadlines cannot be guaranteed. Please consider this for your disposition. It is absolutely necessary to contact Geo++® GmbH / GeoService® GmbH before sending any antenna.

The results will be delivered approx. 1 to 2 weeks after final measurements. The result of the antenna calibration is a type description, for each antenna a calibration protocol and absolute offsets as well as absolute elevation and azimuth dependent PCV in the Geo++® format. This format is directly readable for the current versions of the Geo++® software packages. In addition the results are provided in the international Antenna Exchange Format ANTEX. On the antenna housing, a label will be attached showing the calibration date and, if necessary, the orientation direction used in the calibration.

The calibration result can be used only exclusively for the processing of data that is observed with the calibrated antenna. The customer has to take care, that this condition is respected also if the calibration results are given to a third party. Geo++® keeps all rights at the calibration results. Changed or extented rights on the calibration results will only be granted through a written agreement. The calibration data is used for the analysis of antenna model series and where appropriate used in the computation of type means of the Geo++® GNPCVDB database.

The methods for antenna calibration are continuously advanced and optimised. The conditions shown above represent the state of the art at the time this text

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