Trackdyne Documentation
Main ❯ Navigation & tracking systems ❯ VigilArc USBL: Compatibility information sheet for positioning and heading systems
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VigilArc USBL Compatibility requirements for GNSS |
Compatibility requirements for heading and position determination systems
1. General information
Converting VigilArc USBL responder-beacon measurements from local polar coordinates to geographic coordinates requires the geographic position and heading of the VigilArc Array antenna. The host system must combine these data with the antenna measurements.
Two options are possible:
- The data on the geographic position and orientation of the antenna are generated using a GNSS compass. This option is the most preferable
- The data on the geographic position of the antenna are generated by a GNSS receiver, and the data on its orientation relative to the cardinal directions are generated using a magnetic compass
2. Protocol requirements
For integration with a host computer, navigation data sources can use serial ports or RS-232/422/485 to USB interface converters. Check the electrical interface of each device before connecting it.
The following NMEA 0183 sentences provide the required data:
- HDG - Heading from a magnetic compass
- HDT - True heading from a GNSS compass
- RMC - Geographic position from a GNSS receiver
Use either RMC + HDT from a GNSS compass or RMC + HDG from a GNSS receiver and magnetic compass. The host system must interpret the heading reference correctly when calculating geographic coordinates.
3. Accuracy and update rate requirements
The accuracy of the GNSS receiver must be no worse than 2.5 m (2DRMS), and the update rate of the geographic position data must be at least 1 update per second.
Recommended accuracy of the orientation readings relative to the cardinal directions: 1° (DRMS), at an update rate of 5 Hz.
Navigation data sources with lower accuracy may be used, but keep in mind that the error, especially in determining the angular orientation, is ultimately carried over to the calculated position of the responder-beacons: the errors in determining the angle of arrival of the signal of the responder-beacon and in determining the antenna orientation relative to the cardinal directions using a magnetic or GNSS compass are summed.