Mini-Ranger 2 USBL – Underwater Target Tracking and Communications

Performance without the cost and complexity of a deep water USBL solution
Perfect for nearshore operations; UXO surveys, search and recovery, structure inspection
Portable and quick to mobilise; a great choice for small survey vessels, moored barges and unmanned vessels
995 m operating range; no need for an export license to use internationally
Add capability with bolt-on software feature packs; Extended Range and Marine Robotics
Works with a wide range of 6G transponders including RT 6 acoustic releases

Mini-Ranger 2. Tracking without the complexity

Mini-Ranger 2 is our mid-level USBL target tracking system that’s also able to support data harvesting from seabed-deployed equipment and instruments. The 995 m operating range is extendable to 4,000 m, and it can track up to 10 subsea targets at very fast update rates.

With a 995 m operating range, upgradeable to 4,000 m, Mini-Ranger 2 can track up to 10 underwater targets simultaneously, including divers, towed instruments, ROVs and AUVs. Opt for the Marine Robotics software pack and it will even communicate with these targets – enabling for example, data harvesting from seafloor instrument packages using an uncrewed surface vessel (USV). Expected system accuracy is 1.3% of slant range. Need higher precision or looking for a USBL that you can use as a dynamic positioning reference? Then take a look at our top performing USBL, Ranger 2 Standard.

Mini-Ranger 2 is a compact, easily installed system, so it’s the ideal choice for temporary installation on small survey vessels, as well as unmanned surface vessels (USVs). It’s built around the same market-leading 6G hardware and Wideband 2 digital acoustic technology you’ll find in our entire family of USBL systems – even the software is the same.

At the heart of the system is HPT 3000, a highly capable surface-deployed USBL transceiver which is optimised for performance in shallow water, high elevation and long lay back operating scenarios, as well data telemetry. It’s typically deployed over the side of a vessel on a simple pole arrangement or under the hull of a USV. If the system is going to be permanently installed, and one is available so, a through-hull deployment setup is a great option.

The HPT 3000 is connected to the system’s 1U-high Ethernet Serial Hub (ESH) and your PC running the Ranger 2 software application. Fit a transponder to each target you want to track and you’re ready to get your operation underway. Mini-Ranger 2 is simple to configure and easy to use, even if you have no prior experience of acoustic tracking technology.

A wide range of Sonardyne 6G transponders can be used with Mini-Ranger 2, allowing you to select the most appropriate model for each task. If you’re tracking divers, man-portable AUVs and micro-class ROVs, Nano is a popular choice. When tracking larger targets such as a towfish, a crane wire lowering a structure, or an observation-class ROV, WSM 6+ will meet your requirements. And if you’re looking for a combined tracking and acoustic release transponder, RT 6 is now available. It allows you to deploy, track and recover seafloor equipment, all using the instrument.



  • Powerful features for commercial users
  • Easy to transport, hardware comes in one box
  • Configurable for manned or unmanned vessel operations
  • Quick to mobilise, configure and uninstall
  • Shares common platform with other Sonardyne USBLs


  • MF frequency (19–34 kHz)
  • Sonardyne Wideband 2 digital acoustics for reliable performance in both shallow and deep environments
  • Supports Sonardyne Messaging Service for data exchange
  • Transceiver optimised for high elevation tracking


  • Up to 1.3% of slant range system accuracy
  • Up 10 targets tracked, simultaneously
  • 995 m tracking range; extendable to 4,000 m
  • 3 Hz position update rate


  • What’s in the box: HPT 3000, SIU, deck cables, software, manual
  • Warranty: 1 year return to Sonardyne service centre
  • ITAR Controlled: No
  • UK Export License: Not required for 995 m version. Required for extended range version

More about this product

Mini-Ranger 2 Specification and System sheet

Micro-Ranger 2 Mini-Ranger 2 Ranger 2
Where to use it: Inland, Inshore Where to use it: Nearshore Where to use it: Offshore
What to use it for: Tracking, Commanding and releasing RT 6 acoustic releases What to use it for: Tracking, Data harvesting, Commanding and releasing RT 6 acoustic releases What to use it for: Tracking, Commanding and releasing RT 6 acoustic releases
Operating platform: Dockside, RHIB, Small boat, Small USV Operating platform: Survey boat, Moored barge, USV, Small ship Operating platform: USV, Large ship
Typical installation: Temporary Typical installation: Temporary Typical installation: Permanent
Expected System Accuracy: Up to 5% of slant range Expected System Accuracy: Up to 1.3% of slant range Expected System Accuracy: Up to 0.04% of slant range
Maximum Range: Up to 995 m Maximum Range: Up to 4,000 m Maximum Range: Up to 11,000 m
Maximum Targets Tracked: Up to 10 in sequence Maximum Targets Tracked: Up to 10 simultaneously Maximum Targets Tracked: Up to 99
Maximum Update Rate: 3 Hz Maximum Update Rate: 3 Hz Maximum Update Rate: 1 Hz
Feature Expansion Packs: Yes Feature Expansion Packs: Yes Feature Expansion Packs: Yes



Software Version  
Mini-Ranger 2 V6.03.04 (Can only be installed on a PC running Windows® 10 OS and only supports Sonardyne 6G equipment)
V6.03.03 (Can only be installed on a PC running Windows® 10 OS and only supports Sonardyne 6G equipment)
V6.02.03 (Can only be installed on a PC running Windows® 7 OS and only supports Sonardyne 6G equipment)
V4.06.03 (Can only be installed on a PC running Windows® 7 OS and supports 5G and Sonardyne 6G equipment)


Technical Bulletins

Title Description
Important Security Features of the Marksman/Ranger2 Navigation Computer – No 11-003 The latest Windows XP Image (8026-051-A/B) on the Marksman / Ranger2 Navigation Computer has additional security features to minimise the risk of virus infections and system tampering. These include pre-installed antivirus software and a dual login feature. Note that this does not affect the NavPCs used for any other software products.
Marksman/Ranger 2 V3.01 CASIUS Processing Error – TB12-001 Marksman/Ranger 2 pitch/roll/heading measurements imported into CASIUS have an offset. When a .CAS file is saved by CASIUS, the resulting file contains the wrong pitch/roll/heading measurements. A fixed angular offset is added to the transceiver pitch/roll/heading corrections, leading to a shift in beacon positions, depending on water depth. A spin test would reveal the offset.



Title Description
Ranger 2 USBL Operator Training Course. Course details

This course provides the basic theory together with a thorough practical understanding of the operation of Sonardyne’s Ranger 2 Ultra-Short BaseLine (USBL) acoustic positioning system. Using both simulators and live in-water systems (Plymouth UK or Customer Vessel only) the course covers all aspects USBL positioning from system configuration through to tracking. Additional 0.5 Day practical CASIUS module available on request. This practical 2-day course is delivered at our in-water training facility in Plymouth, UK, at any of our regional offices (Aberdeen, UK; Singapore; Houston, USA; Rio Das Ostras, Brazil) or at customer site/vessel. Click here for planned course dates and booking information.

  General Training Information

Software Compatibility


To request a manual simply tick the box next to the manual you require and then press the Request Form button. You will then be able to request addition manuals for other products and your request will be emailed to our Customer Support Team who will reply to your enquiry. Alternatively please contact your local office who will be more than happy to help.

User Manual - Mini-Ranger 2
QSG - Mini-Ranger 2

  • Manuals Request


    How do USBLs work?

    Mini-Ranger 2 calculates the position of an underwater target by measuring the range (distance) and bearing (heading) from a vessel-mounted transceiver to an acoustic transponder fitted to the target; a technique known as Ultra-Short BaseLine (USBL) positioning. One of the main advantages of the USBL technique is that no other in-water acoustic equipment has to be deployed before underwater operations can commence. Only the targets being tracked need to be equipped with a transponder.

    The Sonardyne 6G and Wideband 2 technology inside all of our USBL systems offer precise acoustic ranging and hardware that is easier to set up and operate, even in the most challenging subsea operating environments. These features improve the efficiency of survey operations, reduce vessel delays and generate cost savings for owners.

    Can I get USBL position updates from my AUV with Mini-Ranger 2?

    A new feature in the latest release of Mini-Ranger 2 software allows an AUV fitted with an AvTrak 6 transceiver to receive USBL position updates on every navigation cycle. This can be used to provide high update rate USBL aiding to a navigation system – something that’s particularly important during descent when the vehicle’s navigation system has no Doppler Velocity bottom lock aiding, i.e. operating on free-inertial. In addition to receiving high update USBL position observation, the feature allows the AUV to pass status information into the AvTrak 6’s data buffer which is then retrieved automatically on the next navigation cycle and forwarded to the user’s topside mission control software. It is also possible for the mission control software to substitute bespoke commands such as requesting the AUV status, emergency abort, navigation status and snippets of observed data for QC. For details on how to update your software, email:

    How quickly can I start tracking beacons with Mini-Ranger 2?

    Quick Track allows you to instantly start tracking a beacon with no other information required other than the unit’s address. You’ll no longer have to manually add the beacon to your job and go through the process of acoustically acquiring the beacon’s configuration. Ranger 2 takes care of everything, leaving you to get on with your subsea operations. Quick Track is particularly useful for checking system performance.

    Can I perform a USBL verification in shallow water without a ROV to deploy or recover the beacon?

    Yes you can.
    You can deploy the beacon to the seabed using an arrangement similar to that below.
    USBL Verification
    The beacon, for example a WSM 6+, must be held vertical by a small float about 10 m above its transducer to prevent acoustic masking, with a (approximately) 1 m strop length from the beacon to a 20 kg clump weight (the strop length is important to reduce the possibility of the beacon hitting the weight and sustaining damage when it is lowered but not too long that the beacon ‘waves’ above it).
    A second 20 kg clump weight (approximately twice the water depth away) acts as the tether point for a larger location buoy which will be at the surface well clear of the vessel’s turning circle. The surface float’s strop should be long enough to compensate for tidal variations to prevent it from being pulled below the surface.

    Spin Test (DP Vessels):
    Track the transponder on the seabed with the vessel directly over the target. Set a way point for the transponder position and set the measure tool from the way point to the transponder or increase the trail history, ensure GNSS is being fed to the system.

    Slowly rotate the vessel over the top of the transponder, using the USBL pole as the centre of rotation whilst observing the snail trail on the Chart display for the mobile target.

    If the transponder trail history draws a doughnut shape greater than expected from the 1DRMS value, an error may be present in the pitch and roll installation corrections.

    Heading test:
    Track the transponder on the seabed with the vessel directly over the target and set a way point as the transponder position. Set the measure tool to measure from the way-point to the transponders reported position and ensure GNSS is being fed to the system. Sail away from the transponder in any direction at a constant speed.

    Watch the distance of the transponder from the way-point.

    If the mobile target moves perpendicular to the vessel heading there is a possible heading alignment error between the USBL transceiver and the gyro.

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