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Main ❯ Navigation & tracking systems ❯ Zima2 USBL: Data brief
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Zima 2 USBL Data brief |
General information
Zima 2 USBL is an underwater acoustic ultra-short baseline (USBL) navigation system designed to determine the location of underwater objects marked with acoustic responder-beacons Zima2-R using a direction-finding transceiver antenna Zima2-B.
System composition
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Zima2-B Direction-finding base station (with UART-RS422 extension cable) |
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Zima2-R Responder-beacons (one base station can work sequentially with a maximum of 16 responders) |
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Bat&Link Box Autonomous power supply and switching unit for the base station |
Tasks to be solved
- Determining the location of up to 16 underwater objects in the water area (tracking underwater objects)
- Determining the relative location (azimuth, distance, depth)
- Determining the absolute location (latitude, longitude, azimuth, distance, depth) when connected to an external GNSS and compass (or GNSS with compass function)
Distinctive features
- Compactness, long range and maximum ease of use make it possible to use the Zima2 system to work with various ROVs and AUVs, as well as with divers, in any combination
- The highly versatile beacons can be used either in a standalone version with a separate battery pack or integrated with the carrier for both power and data
- The system supports integration with external sources of navigation data: GNSS with compass function (connected to the host PC). In this case, the system determines the absolute geographic coordinates of underwater objects, allows saving the track of movement of underwater objects and has GPS emulation functions for one of the selected beacons for integration with third-party software (for example, Hypack, SAS.Planet, etc.)
- The ZIMA2-B antenna is mounted on a pole over the side of almost any vessel and connected to a 12 V / 3.5 A power source and to a host PC (Windows 10 or later) – in this minimum configuration, the system determines the position of the beacons (azimuth and distance) relative to the antenna. When a GNSS receiver with compass function (RMC, GGA, HDG) is connected to the host PC, the system determines the geographic coordinates of the beacons and can transmit them (RMC, GGA) to any serial port, thereby emulating a GNSS receiver for the selected responder-beacon;
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| Installation diagram of the Zima 2-B antenna The antenna is mounted on a rigid pole so that it is no closer than 2 meters to the surface of the water and no closer than 1.5 meters to the lowest point of the vessel. The antenna offsets relative to the position reference point and the angular offset between the antenna zero and the GNSS compass are set |
Interfacing schemes
Working in relative coordinates
To determine the relative location of the responder-beacons, the antenna is interfaced with a PC on which specialized open-source host software AzimuthSuite is installed. The antenna is connected to the PC via Bat&Link Box, which converts the interface to USB and powers the antenna.
In this case, the data and functions available to the user are:
- Azimuth (horizontal angle) to the responder-beacons in use;
- Distance to the responder-beacons
- Depths of the responder-beacons
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| Wiring diagram for working in relative coordinates |
Working in absolute coordinates
To determine the absolute location of the responder-beacons, the antenna is interfaced with a PC on which specialized host software AzimuthSuite is installed. The antenna is connected to the PC via Bat&Link Box, which converts the interface to USB and powers the antenna. Additionally, an external GNSS system with compass function, operating via the NMEA 0183 protocol (RMC and HDT sentences), is connected.
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| Wiring diagram for working in absolute coordinates |
In this case, the following data and functions are available to the user:
- Absolute geographic coordinates of the beacons and depth
- Azimuth (relative to north)
- Distance
- Recording a track of the movement of underwater objects with the possibility of subsequent saving in Google KML format.
Geometric limitations
Since the location of the Zima2-R responder-beacons is determined from the horizontal angle of arrival of the signal, the slant range and the depth difference, the antenna array of the Zima 2-B direction-finding station has the highest sensitivity in the angle range from 0° to 85° from the horizontal. The system accuracy may decrease when the responder-beacon is close to the nadir direction.
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| Geometric limitations of Zima 2-B 1 - Direction-finding antenna, 2 - upper hemisphere, 3 - working zone (0° .. 85°, 0 .. -85°), 4 - accuracy reduction zone (85° .. -85°) |