Marine Magnetics

Easytrak USBL Systems

Applied Acoustics Easytrak Ultra-Short Baseline (USBL) systems provide accurate, real-time positioning of underwater targets such as ROVs, AUVs, divers, towfish, side-scan sonars, magnetometers and subsea construction equipment. An Easytrak system uses a vessel-mounted multi-element acoustic transceiver to communicate with a beacon installed on the underwater target. The system determines the target’s range and bearing, compensates for vessel heading and motion, and combines this information with GNSS data to produce a geographically referenced subsea position. The Easytrak range extends from the compact and cost-effective Vesta to the survey-grade Pyxis INS + USBL. Commercial, long-range, multi-target and military-grade configurations are available for shallow-water surveys, offshore construction, UXO operations, subsea inspection, diver tracking and autonomous vehicle positioning.

Product Range

Easytrak Vesta USBL – Model EZT-2666

Vesta is the most compact and economical Easytrak system. It is intended for small-vehicle operations, diver tracking and nearshore surveys requiring simple mobilisation and reliable positioning at ranges up to approximately 1,000 m. Vesta supports eight transponder targets, Sigma 3 digital signalling, digital depth telemetry, internal GNSS and external heading input. Its customisable interface, waypoint logging and industry-standard outputs make it suitable for integration with survey and navigation software.

Typical applications:

Underwater survey and inspection
Diver and small ROV tracking
Cable and pipeline route surveys
Nearshore construction and salvage
Marine archaeology

Easytrak Nexus 2 Lite – Model EZT-2696

Nexus 2 Lite is a high-performance, cost-effective USBL system using bidirectional Sigma 2 spread-spectrum acoustics. It provides full hemispherical coverage and can simultaneously track up to ten subsea targets. The compact desktop console connects to a user-supplied laptop or computer through USB. Optional EasyCal 2 calibration and geographically referenced chart-overlay software can be added according to the project requirements.

Typical applications:

Hydrographic and geotechnical surveys
ROV and towfish positioning
Subsea construction
Cable and pipeline route surveys
Nearshore inspection and salvage

Easytrak Nexus 2 Max – Model EZT-2698

Nexus 2 Max is the latest generation of the advanced Nexus digital USBL platform. It can simultaneously position up to 16 subsea targets and offers directional and omnidirectional transceiver options with maximum operating ranges up to 4,000 m. The system incorporates UDP sensor inputs and outputs, NTP time synchronisation, data interpolation, RS-232/RS-422/RS-485 connectivity, four responder outputs and remote-control capability. These features simplify integration with modern survey vessels and autonomous platforms. When used with Applied Acoustics 1100 Series beacons, Nexus 2 Max supports Multi-Fire common interrogation and MiQ acoustic data telemetry.

Typical applications:

UXO survey positioning
Multiple magnetometer or towfish tracking
Long-layback towing operations
ROV and AUV positioning
Diver tracking and reporting
Offshore construction and inspection
Launch and recovery operations

Pyxis INS + USBL – Model EZT-3690

Pyxis combines Applied Acoustics Sigma 2 USBL technology with an integrated SBG Systems Navsight Apogee inertial navigation system. The tightly coupled, factory-calibrated arrangement eliminates the requirement for a conventional USBL calibration after installation. Pyxis provides survey-grade subsea positioning, independent INS outputs, GNSS time synchronisation, data and event logging, data replay and optional post-processing. Directional and omnidirectional transceivers provide operating ranges up to 4,000 m and acoustic positioning performance down to 0.12% of slant range.

Typical applications:

Precision UXO survey positioning
Very shallow-water tracking
Long-range and long-layback tracking
ROV and AUV operations
Horizontal target tracking
Offshore construction
Rapid mobilisation between vessels

Easytrak Nexus 2 – Model EZT-2691

The military-grade Easytrak Nexus 2 is designed for accurate positioning of multiple dynamic subsea targets in demanding naval and defence environments. It incorporates bidirectional Sigma 2 acoustics, 16-target tracking, Multi-Fire operation, geographical navigation overlays and EasyCal 2 calibration. Directional and hemispherical transceiver configurations are available, with maximum operating ranges up to 4,000 m. The system has been tested against relevant military electromagnetic, environmental, vibration and shock standards.

Typical applications:

Mine-countermeasure operations
Under-hull inspection
Military diver tracking
Naval ROV and AUV positioning
Tactical subsea inspection
Multiple underwater asset tracking

MIPS 2 – Models EZT-2785 and EZT-2786

MIPS 2 is a compact, ruggedised USBL transceiver developed for integration into crewed and autonomous naval platforms. It incorporates heading, pitch, roll, pressure and temperature sensing within a single deployable unit. The EZT-2785 provides a directional acoustic footprint and higher positioning accuracy, while the EZT-2786 provides full hemispherical coverage. High-speed RS-422 communication allows integration with third-party command, navigation and mission systems.

Typical applications:

Mine-countermeasure operations
Under-hull inspection
Diver tracking
Naval ROV and AUV tracking
Autonomous vessel integration
Original equipment manufacturer integration

Full Specifications

System Comparison

Specification	Vesta	Nexus 2 Lite	Nexus 2 Max	Pyxis INS + USBL	Nexus 2 Military	MIPS 2
Model	EZT-2666	EZT-2696	EZT-2698	EZT-3690	EZT-2691	EZT-2785/2786
Maximum targets	8 transponders	10	16	16	16	10
Maximum range	Approx. 1,000 m	995 m	Up to 4,000 m	Up to 4,000 m	Up to 4,000 m	Up to 3,000 m
Best acoustic accuracy	3% of slant range	0.45% of slant range	0.12% of slant range	0.12% of slant range	0.12% of slant range	0.10% of slant range
Range resolution	0.10 m	0.01 m	0.01 m	0.01 m	0.01 m	0.01 m
Frequency band	18–32 kHz	18–32 kHz	18–32 kHz	18–32 kHz	18–32 kHz	18–32 kHz
Maximum acoustic coverage	180°	180°	180°	180°	180°	180°
Acoustic protocols	Sigma 1, Sigma 3, Tone, HPR400	Sigma 2 and legacy Tone	Sigma 1, 2, 3, Tone, V-NAV, HPR400	Sigma 1, 2, Tone, V-NAV, HPR400	Sigma 1, 2, 3, Tone, V-NAV, HPR400	Sigma 1, 2, 3, Tone, V-NAV, HPR400
Multi-Fire	No	Yes	Yes	Yes	Yes	Configuration-dependent
Integrated GNSS	Yes	External	External	Integrated INS/GNSS	External	External/OEM
Integrated INS	No	No	No	Yes	No	Integrated AHRS
Chart overlay	No	Optional	Included	Included	Included	Host-system dependent
Military configuration	No	No	No	No	Yes	Yes

Maximum range and export availability depend on the selected transceiver and applicable UK export-control requirements.

Vesta EZT-2666 Specifications

Parameter	Specification
Transceiver	ETM-904C
Position accuracy	2.0° RMS; 3% of slant range
Range resolution	0.10 m
Frequency	18–32 kHz
Beam pattern	180°
Transmitter level	186 dB re 1 µPa at 1 m
Integrated heading accuracy	0.5° RMS
Integrated pitch and roll	Better than ±1.0° RMS
Targets	8 transponders or 1 responder
Update interval	1–10 seconds, selectable per target
Console dimensions	260 × 90 × 250 mm
Console weight	Approximately 2.6 kg
Console supply	18–24 V DC, 60 W
AC adapter input	90–230 V AC, 47–63 Hz
Communications	Ethernet, USB and 2 × RS-232
Data output	RS-232 or UDP
Internal GNSS accuracy	Better than 2 m 2DRMS with SBAS
Transceiver dimensions	291 × 78.5 mm
Transceiver weight	Less than 4 kg
Standard cable	20 m
Operating temperature	−10°C to +40°C
Storage temperature	−20°C to +50°C

Official Vesta datasheet

Nexus 2 Lite EZT-2696 Specifications

Parameter	Specification
Transceiver	EZT-2686N
Position accuracy	0.45% of slant range with external sensors
Maximum range	995 m
Range resolution	0.01 m
Frequency	18–32 kHz
Beam pattern	180°, hemispherical
Transmitter level	Typically 192 dB re 1 µPa at 1 m
Targets	Up to 10
Interrogation rate	Greater than 2 Hz
Integrated heading accuracy	0.5° RMS
Integrated pitch and roll	±0.20° RMS
Console dimensions	252 × 260 × 54 mm
Console weight	1 kg
Console supply	48 V DC
AC adapter input	90–230 V AC, 47–63 Hz
Serial interfaces	4 × RS-232
Calibration	Optional EasyCal 2
Chart overlay	Optional GeoTIFF and DXF
Transceiver material	316 stainless steel
Transceiver dimensions	152 mm diameter × 432 mm
Weight in air/water	16 kg/11 kg
Depth rating	30 m
Standard cable	30 m
Cable options	20–100 m
Operating temperature	−10°C to +40°C
Storage temperature	−20°C to +50°C

Official Nexus 2 Lite datasheet

Nexus 2 Max EZT-2698 Specifications

Parameter	EZT-2782 transceiver	EZT-2780 transceiver
Acoustic precision	0.14° DRMS	0.07° DRMS
Acoustic accuracy	0.25% of slant range	0.12% of slant range
Beam pattern	180°	170° calibrated
Maximum unrestricted range	2,000 m	4,000 m
Non-export-controlled range	995 m	995 m
Transmitter level	192 dB re 1 µPa at 1 m	195 dB re 1 µPa at 1 m
Weight in air/water	16 kg/11 kg	20 kg/15 kg

General parameter	Specification
Targets	Up to 16
Range resolution	0.01 m
Frequency	18–32 kHz
Refresh rate	0.5 seconds
Transceiver depth rating	30 m
Transceiver material	316 stainless steel
Standard cable	50 m
Maximum cable	150 m
Console dimensions	482 × 88 × 345 mm, 19-inch 2U
Console weight	6.15 kg
Console supply	90–250 V AC, maximum 250 VA
Computer	Embedded Windows 10, 64 GB SSD
Serial interfaces	4 × RS-232/RS-485 inputs; 2 × RS-232 outputs
Ethernet	1 × 1 Gbps RJ45
USB	6 ports
Responder outputs	4 × BNC
Timing	GNSS time and NTP synchronisation
Network data	UDP input and output
Chart formats	GeoTIFF and DXF
Operating temperature	−10°C to +40°C
Storage temperature	−20°C to +50°C

Official Nexus 2 Max datasheet

Pyxis EZT-3690 Specifications

Parameter	EZT-3782 transceiver	EZT-3780 transceiver
Acoustic accuracy	0.25% of slant range	0.12% of slant range
Acoustic repeatability	0.12° DRMS	0.07° DRMS
Maximum unrestricted range	2,000 m	4,000 m
Non-export-controlled range	995 m	995 m
Beam pattern	180°	170°
Weight	15.5 kg	20 kg

General parameter	Specification
Targets	Up to 16
Range resolution	0.01 m
Frequency	18–32 kHz
Interrogation rate	Greater than 2 Hz
Multi-Fire	Up to 10 common-interrogate beacons
Transceiver depth rating	30 m
Standard cable	50 m
Cable options	30–100 m
INS roll and pitch accuracy	0.008° RMS RTK; 0.005° RMS PPK
INS heading accuracy	0.04° with 2 m baseline; 0.025° with 4 m baseline
RTK/PPK position accuracy	0.01 m horizontal; 0.02 m vertical
Real-time heave	5 cm or 5% of swell
Delayed heave	2 cm or 2% of swell
Timestamp accuracy	Better than 200 ns
PTP/PPS accuracy	Better than 1 µs
Dead-reckoning drift	1 ppm
Console dimensions	483 × 133 × 348 mm, 19-inch 3U
Console weight	7.5 kg
Console supply	90–250 V AC
Ethernet	2 × 1 Gbps
USB	6 ports
Responder outputs	4 × BNC
Operating temperature	−10°C to +40°C
Storage temperature	−20°C to +50°C

Official Pyxis datasheet

MIPS 2 Specifications

Parameter	EZT-2785	EZT-2786
Configuration	Directional	Hemispherical
Position accuracy	0.10% of slant range	0.25% of slant range
Acoustic repeatability	0.07° DRMS	0.13° DRMS
Maximum range	3,000 m	2,000 m
Range-limited option	995 m	—
Beam pattern	150° calibrated	180°
Range resolution	0.01 m	0.01 m
Frequency	18–32 kHz	18–32 kHz
Transmitter level	195 dB re 1 µPa at 1 m	195 dB re 1 µPa at 1 m
Targets	10	10

General parameter	Specification
Communications	RS-422, 115,200 baud
Power requirement	48 V DC, 0.5 A average
Operating temperature in water	−4°C to +32°C
Operating temperature in air	−20°C to +44°C
Storage temperature	−20°C to +44°C
Humidity	5–95%, non-condensing
Maximum interface cable	100 m
Cable safe working load	25 kg
Military EMC	MIL-STD-461D
Environmental testing	DEF STAN 00-35
Export status	UK export-controlled

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