This very important section introduces to you the Antenna
Management component in GNSS Spider. It covers how to import and update antenna information and how to ensure that antenna
information is properly applied in all GNSS Spider components after being updated.
Note: From GPS Spider V2.2 onwards only ABSOLUTE antenna calibration data must be used in GNSS Spider. It is the network operators’ responsibility to ensure that user-defined antenna
information in the GNSS Spider Antenna Management is consistently updated to meet this requirement!
Leica Default antennas
All antenna calibration data that is provided by default within the Antenna Management component of GNSS Spider for the default Leica antenna types contain ABSOLUTE antenna phase centre offsets and PCV.
The Leica default ABSOLUTE antenna calibration values are so-called “Type-Mean” calibrations that are based on a minimum of five –
typically more – individual antenna calibrations executed and supplied by Geo++® GmbH.
Note: When updating from earlier version of GPS Spider the
previously used RELATIVE calibration values will be updated to these new ABSOLUTE calibration values. The GNSS Spider software set- up will automatically perform this update to the GNSS Spider antenna database.
User-Defined Antennas
When using a mixture of different antenna brands and models in the reference station network, (as some are not available in GNSS Spider as Leica Geosystems default type antenna), then it is the network operators responsibility to provide the required ABSOLUTE antenna calibration information. These can then be added as user-defined antennas to the GNSS Spider Antenna Management database. Please refer to the GNSS Spider on-line help documentation to learn how to manually add or import antenna calibration data.
To obtain antenna calibration data for non-Leica Geosystems equipment the following options are recommended:
(a) Use individual absolute antenna calibration data for each antenna in the network. Such individual antenna calibration service is supplied e.g. by Geo++® GmbH.
(b) Use Geo++® GmbH type-mean absolute antenna calibration data for each non-Leica Geosystems antenna in the network. Type mean calibration data for non-Leica Geosystems default antenna can be obtained directly from Geo++® GmbH.
(c) Use IGS published absolute antenna calibration models for all antennae in the network.
For latest updates of the igs05_xxxx.atx file please refer to the IGS server under:
http://igscb.jpl.nasa.gov/igscb/station/general/
(d) Use NGS published absolute antenna calibration models for all antennae in the network.
For latest updates of this data please look on the NGS antenna calibration home page under:
http://www.ngs.noaa.gov/ANTCAL/images/ant_info.abs
Note: Although theoretically absolute antenna calibration data is not correlated with a specific reference antenna model and thus all such calibration data should be well compatible, we recommend avoiding mixing calibration data from different sources, to prevent
inconsistencies due to any remaining biases.
Using above mentioned options (a) or (b) as source for calibration data of non-Leica type antenna should be well compatible to the GNSS Spider default antenna calibrations.
Further it is strongly recommended to verify all reference station coordinates whenever changing the applied antenna calibration data.
Updating or Modifying User-Defined Antenna Calibration Data
Unlike GNSS Spider default antenna types, all user-defined antenna information can be modified or updated by the network operator. The following two options within the GNSS Spider Antenna Management are available:
1. Manually modify antenna settings using the Antenna properties dialog.
This is only possible if the antenna is not assigned to any site. Assigned (used) antennas are indicated by the exclamation mark symbol “ ”.
2. Import new antenna information from an antenna file.
During the import any new antenna contained in the file will be added. For each existing antenna you will be prompted to confirm overwrite of the antenna information. This function also allows overwriting data for antennas that are currently assigned to a site! Please remember again that it is not recommended to mix antenna calibration data from different sources.
Note: Updating antenna calibration information for any antenna that is assigned to an active site requires all GNSS Spider Positioning, Post- Processing and Real-Time products, as well as SpiderNET network processing that are using this site to be reinitialized. This is required in order to ensure the updated information is correctly applied. Please refer to the following section for recommended steps ensuring all GNSS Spider products are being properly reinitialized.
Recommend- ed procedure to update antenna information in GNSS Spider
The following steps are the recommended procedure to update the antenna data e.g. from relative calibration to absolute calibration.
Step Action
1 Ensure that all users of your reference station services are informed in advance about the system maintenance. Advice them about the maintenance period and that GNSS Spider services might temporarily not be available and must not be used during this period, until further
notification.
2 Directly before starting the update, make sure that no RT- users are connected and Positioning/Post-Processing services are not in use.
3 Import the new user-defined antenna information from a file, e.g. ANTEX format file and confirm to overwrite existing antenna information for each antenna that shall be
4 Now all active RT-Products on both, the Site Server and Network Server, Positioning and Post-Processing products, as well as SpiderNET network processing that are using sites for which antenna information has been updated,
must be re-initialized.
To re-initialize the products they have to be de-activated and then activated again, and SpiderNET network
processing has to be either reset or stopped and started. Note that the multiple-select function will help to make this fast and simple.
Note: Alternatively it is also possible to use the GNSS Spider Server Control Manager (see section: GNSS Spider Server control above.) to stop and start the GNSS Spider Site and Network Servers. This will also re-initialize all services and processes using antenna calibration information.
5 Ensure that all GNSS Spider services are now properly configured and running.
6 Verify that Real-Time, Positioning and Post-Processing Services are providing the expected data and accuracy. Field tests for RTK are recommended.
7 Notify all users of your reference station network products about all configuration changes they are concerned with, e.g. that from GPS Spider V2.2.0 onwards RT-Product services use either Null Antenna or ABSOLUTE antenna calibrations (depends on your individual configuration). Note: When upgrading from any earlier version of GPS Spider (V2.1 or earlier) to GNSS Spider, the above steps are required for all user- defined antenna types with RELATIVE calibration, to be updated to ABSOLUTE calibration values.
Antenna Management onboard the GR10, GNSS1200 and GPS500 receivers
When using GNSS Spider to configure a GR10, GNSS1200 or GPS500 receiver for internal data logging or direct RTK output from the receiver, please take additional notice of the following:
■ Receivers cannot reduce RTK corrections to the “Null Antenna”. Receiver generated RTK corrections will always be based on the antenna type and its related calibration values that are loaded onto the receiver.
■ For a Leica default antenna that is assigned to a site and uploaded to the receiver, by name recognition the receiver will select the appropriate Leica default antenna from its onboard database. The Leica default antennas that are pre-installed with the receiver firmware still contain RELATIVE calibration values. Therefore transmitted RTK data will be based on these RELATIVE calibration values!
■ For a new user-defined antenna that is assigned to a site and uploaded to the receiver it will be added to the receivers onboard database with its ABSOLUTE calibration values, if a user-defined antenna with the same name does not yet exist in the receiver onboard antenna database.
■ For an existing user-defined antenna that does already exist in the receiver onboard antenna database with the same name the onboard loaded calibration values will not be overwritten with the ones defined in GNSS Spider. The already onboard loaded antenna with its associated calibration values will be used.
■ Receiver onboard antenna type and calibration data is logged into the Leica binary MDB raw data files.
■ Receiver onboard antenna type and calibration data is further used to compute the reference station coordinates that are transmitted for RTK using RTCM V2.1 format. Thus a rover that receives RTCM V2.1 must use exactly the same antenna calibration information as is used on the reference receiver. Newer RTCM versions and other RTK formats only or additionally transmit the coordinates of the ARP or ground marker, so that the rover must not necessarily apply exactly the same antenna calibration values, but only has to use the correct antenna types. The calibration values used on the rover for its locally attached antenna and the received reference station antenna must however be consistent (same source and same calibration type relative or absolute).