MainNavigation & tracking systemsZima2 USBL: User’s manual

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Zima2 USBL - Underwater acoustic tracking system
User’s manual

Zima2 USBL
User’s manual


1. Introducation

1.1. Purpose

The Zima2 underwater acoustic tracking system is designed to locate underwater objects equipped with Zima2-R responder beacons in real time.

Beacons-responders (hereinafter beacons) can be installed on:

The system allows you to determine:

1.2. Distinctive features

The navigation system Zima2 is an ultra-short-base navigation system (USBL), the principle of operation of which is based on the use of a phased antenna array to determine the horizontal angle of arrival of the signal and determine the distance to the beacon using the “request-response” method. The Zima2 system uses state-of-the-art digital broadband noise-resistant hydroacoustic communication technology, and the applied signal is specially Designed for difficult hydrological conditions, including those found in shallow waters.

1.3. System Composition

The system includes:

DF Antenna
Cable with integrated interface converter
Bat&Link Box
Bat&Link Box
Power supply and switching unit

2. Working with Zima2 USBL system

2.0. Before start

Specialized software 🐙 AzimuthSiute is required to work with the system.

Download the necessary software in advance. Installation is not required - just unzip the contents of the archive to a location convenient for you. Make sure all equipment is fully charged before heading out to the water and charge all devices if necessary.

Particular attention should be paid to power and switching units and responder beacons: in view of the fact that these devices have built-in power supplies based on LiFePO4, they have a very flat discharge characteristic and it is difficult to determine the degree of charge of the built-in source. Therefore, it is recommended to charge all devices no earlier than 1-2 days before use.

We use LiFePO4 based batteries because they are the most durable and withstand the maximum number of charge-discharge cycles compared to Li-ion and Li-Po batteries, and can also operate at low temperatures.

2.1. Preparing for work and equipment testing

2.1.1. DF Antenna mounting and setup


If you hold the antenna by the cable so that there is a rounded protrusion on the mounting groove on the left and a sharp protrusion on the right, then the zero direction of the antenna points forward and coincides with the molding seam. The zero direction is indicated by an arrow in the figure below.

DF antenna zero direction
The horizontal angle is measured clockwise from the zero direction of the antenna, the vertical axis is pointing down

The antenna determines the horizontal angle of signal arrival relative to its zero direction, the following requirements must be observed when mounting the antenna:

It is not recommended to install the antenna near large underwater objects: mooring walls, piers, breakwaters, large ships, massive supports and other water infrastructure facilities.

The antenna is connected to the power supply and switching unit using an extension cable with an integrated interface converter. There are two connectors on the cable: one for connecting to the power supply and switching unit, the other - underwater, for connecting the antenna.

Before submerging the antenna, make sure:

Water ingress into any connectors is completely unacceptable and will result in non-grant damage!

The extension cable must not have large free sags for the length of its immersion in water. It is recommended to fasten the cable to the rod with a rope or nylon ties.

Before connecting the antenna to the power and switching unit using an extension cable, make sure that the power supply is switched off!

The following sequence of actions is recommended when installing the antenna:

The dual channel power supply and switching unit (for connecting an external GNSS compass) requires additional steps:

Turning on the power supply and switching must be performed after launching the specialized software on the control PC. Software operation and setup are described below.

To clarify the names of the connectors on the power and switching unit panel, refer to the Bat&Link Box power and switching unit user’s manual.

2.1.2. Mounting of the responder beacon on the carrier

The responder beacon must be fastened only by special groove with a soft clamp in such a way as to exclude any uneven loading of the beacon body, excessive squeezing and shading/shielding of the beacon body. The figure below shows the basic requirements for mounting the acoustic part of the transponder beacon on the carrier:

Requirements for mounting the acoustic part of the transponder beacon on the carrier
* Shielding of the spatial hemisphere or parts of the antenna located above the mounting groove is not allowed; the pressure in the area under the fastening must be balanced with the external pressure*

The responder beacon should not be located near propulsion jets or directly in their path. The system requires a direct line of sight (through the water column) between the direction finding antenna and the responder beacon, so the beacon must be installed at the top of the carrier.

For autonomous responder beacon: The standalone beacon is turned on automatically when it falls into water (contacts for switching on from water are located on the battery pack). It should be remembered that immediately after switching on, the beacon determines atmospheric pressure for 5 seconds for more accurate depth measurement. Therefore, it is recommended to submerge the battery pack first and wait 5 seconds before submerging the responder itself.

For an integrated responder beacon: The integrated version of the responder beacon is switched on when power is supplied from an external system. Once turned on, the responder detects barometric pressure for 5 seconds for more accurate depth measurement. If the current value of the external pressure is more than 1200 mbar, then the beacon considers that it was switched on in the submerged position, and the atmospheric pressure calibration does not take place.

The operability of the beacon-responder can be easily checked by turning it on: after the power is turned on, after 2 seconds, a navigation signal is emitted once.

2.2. Working with the system

The system performs almost all the work automatically, the system needs to set:

Next, the system automatically polls responder beacons from the specified address range. Displays their position on the screen, and records the track in absolute coordinates, in the presence of an external GNSS compass.

During operation, the application writes log files, which can then be played back in the same time scale in which they were recorded.

2.2.1. Interface and functions of the AzimuthSuite application

The application 🐙 AzimuthSiute is designed to work under OS Windows starting from version 10 and higher with .NET Framework 4.8 installed. The application is portable and does not require installation. It is enough to unpack the archive to a place convenient for the operator. The application and all the libraries used by it are developed by LLC “Laboratory of Underwater Communications and Navigation” and are Open-Source.

The application communicates with the system devices according to the open NMEA-like protocol via the serial port. Application settings

The application uses two types of settings:

The appearance of the application settings editor window is shown in the figure below.

Settings editor
1 - List of used responder beacons, 2 - External GNSS compass usage option, 3 - External GNSS compass port speed, 4 - Antenna position offset from GNSS compass position in transverse direction, 5 - Antenna position offset from GNSS compass position Longitudinal direction, 6 - Angle correction (angle between GNSS compass zero and antenna zero), 7 - Output port usage option, 8 - Output port speed, 9 - Accept settings and cancel buttons, 10 - Reset settings to default values button, 11 - Maximum distance to responder beacons, 12 - Water salinity

The system supports sequential operation with up to 16 responder beacons. The operator can select the required beacon addresses in the 1 box by checking the corresponding checkboxes. Always check the boxes next to those addresses that will be used in the current work, otherwise the system will waste time polling beacons that are not in the water area.

Connection of an external GNSS compass is supported via serial port. To do this, check the 2 checkbox and specify the port speed. The port itself will be determined automatically by the system. If the compass is not installed coaxially with the antenna (not on the boom), you will need to set the position of the antenna relative to the position of the GNSS compass: the position of the GNSS compass is taken as the reference point of the Cartesian coordinate system and the lateral 4 and longitudinal 5 offsets are indicated antennas from this point (transverse in the direction of the port side - starboard side, longitudinal in the direction of the stern - bow). If the zero directions of the compass and the antenna do not match, you must specify the angular correction 6 - the angle between the zero directions of the compass and the antenna, counted from the zero direction of the compass clockwise.

The location of the DF antenna in relation to the anchor point is illustrated below:

Setting the location of the direction finding antenna relative to the anchor point and compass zero direction
Antenna offsets relative to the GNSS compass: lateral ΔX and longitudinal ΔY; angular mismatch of zero directions of compass and direction-finding antenna 𝛿

When working in sea water, specify the salinity using the 12 group of elements: either by entering a known value in the input field or using the built-in database of world ocean salinities by pressing the 🔎 button and indicating the current geographical coordinates .

When operating in inland fresh waters set the water salinity to 0.0 PSU. The salinity value is necessary for the system to more accurately determine the depth and speed of sound.

Maximum distance to the beacon is set in the 11 field and determines the maximum time interval for waiting for the beacon’s response. The value is set in the range from 500 to 5999 meters. The minimum applicable value for the current operating conditions should be specified, since this value directly determines the speed of the system and its idle time when the response of the responder beacon is missed.

If you want to transmit the computed geographic location of one of the responder beacons as standard NMEA (GGA, RMC) messages to another system, enable setting 7 and specify the name and speed of the port to which the application will transmit data. Since the port is used only for transmission, it cannot be determined automatically and its name must be specified.

When you press the OK button, the application will save the settings and prompt you to restart for the new settings to take effect. Main window

The view of the main window of the application is shown in the figure below.

View of the main application window
1 - Main toolbar, 2 - Map toolbar, 3 - Map field, 4 - Misc info text field, 5 - Log text field, 6 - Additional toolbar, 7 - Status bar, 8 - Responder beacon list toolbar , 9 - List of responder beacons, 10 - Switch panel of parameters displayed in the list of responder beacons
ID Description Units of measure Range
DPT Antenna immersion depth m 0 .. 300
WTM Water temperature reading °C -10 .. +40
PTC Antenna pitch ° -90 .. +90
ROL Antenna roll ° -90 .. +90
LAT Latitude according to external GNSS ° -90 .. 90
lon Longitude according to external GNSS ° -180 .. 180
SPD Speed according to external GNSS km/h (m/s) >= 0
CRS Course according to external GNSS ° 0 .. 360
HDN Azimuth according to external GNSS ° 0 .. 360
ID Description Units of measure Range
DST Distance to the beacon-responder from the position according to external GNSS data (slant range projection onto the water surface) m 0..5999
AZM Direction (course) to the transponder beacon ° 0 .. 360
DPT Depth of the responder beacon m 0 .. 300
RAZ Reverse direction (course) from the transponder beacon to the direction finding antenna ° 0 .. 360
ELV Vertical angle on transponder beacon ° 0 .. 90
MSR Parameter characterizing the quality of communication dB 14 .. 40
PTM Signal propagation time sec 0 .. 4
LAT Computed latitude ° -90 .. 90
lon Computed longitude ° -180 .. 180

The most important parameters here are AZM, DST and RAZ: by azimuth and distance, the operator can always understand where one or another responder beacon is located relative to him, and the RAZ parameter will allow perform the homing task. The display of various parameters is switched by the buttons on the panel (10). Configuring responder beacons

If work is being done with more than one responder beacon, it is imperative that their addresses are different. To set the address of the responder beacon, it must be connected to a PC. For autonomous execution of the responder beacon, it must be disconnected from the battery pack and connected via the supplied USB adapter.

For an integrated version, you must use the USB-UART converter according to the pinout:

ATTENTION! The voltage of the data lines of the response beacon is 0 .. 3.3 V! Use only converters with suitable levels to connect beacons to a PC.

Zima-R and Zima2-R wiring
Functions of wires of Zima-R and Zima2-R responder beacons

After connecting the beacon to the PC, launch the AzimuthSuite application and establish a connection by pressing the 🔌 LINK button (or the key combination Ctrl + L). The application will search for the port, the progress and result of the search is displayed in the status bar.

After the connection is successfully established, the menu item 🛠 UTILS🤖 DEVICEResponder settings… will become available. In the address setting dialog box that opens, the following functions are available:

Writing new settings to the non-volatile memory of the responder beacon takes from 1.5 to 3 seconds.

2.2.2. Working with the system

At this stage it is assumed that:

Beacons are recommended to be turned on in the surface position: within five seconds after power-up, atmospheric pressure is calibrated, which allows you to measure depth with greater absolute accuracy.

Since autonomous beacons turn on when the battery pack is immersed in water, it is recommended that the battery pack be immersed in water first, and the transponder beacon itself only after five seconds have passed.

It is desirable to turn on beacons in an integrated version before diving, if this is possible under current conditions.

To start the system, connect by pressing the 🔌 LINK button (or use the Ctrl + L key combination). The application will start searching for the connection port for the DF antenna and, if the corresponding setting is set, for the connection port for the external GNSS compass. Then turn on the Bat&Link Box power and switching unit. The connection status is displayed in the status bar at the bottom of the main application window. A green background below the corresponding text field indicates a successful connection.

It should be remembered that the application is designed to work with only one system device at a time: if both the direction finding antenna and one of the beacons are connected to the PC, then it is highly likely that the beacon will be the first to be detected when searching for the port. The search for the port of the direction finding station will not be performed in this case.

After the corresponding port (or ports) are detected, the system immediately proceeds to polling responder beacons, the addresses of which are specified in the settings. The work takes place in a fully automatic mode.

Make sure that the additional information text field is displayed (button 👽 on the map tools field is pressed) in the upper left corner of the map field. Immediately after connecting, the local parameters are displayed in the additional information field:

The map field is arranged as follows: the position of the vessel (DF antenna) is displayed in the middle. If an external GNSS receiver is not used, then the null direction of the antenna is assumed to point to the top of the screen. If an external GNSS compass is connected, the heading to the top of the screen is the same as Geographic North, and the vessel is displayed based on the current heading angle.

The position of the responder beacons is displayed in the form of circles with numbers, the circles are connected by lines with the center of the polar coordinate system - the position of the direction-finding antenna or the geolocation point, if an external GNSS compass is used.

The list of responder beacons REMOTES (to the right of the map field) displays the parameters of responder beacons known to the system. When a responder beacon response is missed (or if the responder beacon did not receive the interrogation signal), the string TMO: ⚑ is displayed in the parameter list of this responder beacon.

If an external GNSS receiver is used, the system calculates their absolute geographic coordinates and the application accumulates tracks of their own position and the calculated positions of the transponder beacons. Tracks are not saved automatically! To save tracks, use the menu item 🛠 UTILS🗺 TRACKS💾 Export… (or the key combination Ctrl + S). Saving in Google KML and CSV format is available.

The application allows you to emulate a GNSS receiver for one of the beacons in real time (if an external GNSS compass is used): the calculated coordinates can be transmitted as standard RMC and GGA messages via the serial port. The selection of the beacon address and the port name for emulation can be done while the system is running.

You should be aware of the factors that reduce the efficiency of the system, in particular:

2.3. Upon completion of work

3. Liability and Disclaimer

3.1. Terms of replacement and free warranty service

The manufacturer’s warranty covers only factory defects that appear during the operation of the device in accordance with this manual during the warranty period (2 years from the date of purchase).

The manufacturer guarantees free repair or replacement of faulty equipment from the delivery set that has failed due to a manufacturing defect.

The reasons for refusing free warranty service, free repair and replacement include:

3.2. Disclamer




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