Underwater Geopositioning Systems
Sovation, a newly born French company, is glad to announce the arrival on the market of STAR-RTK Underwater geopositioning systems.
The product's development started early in 2025. Subsystems sea trials are ongoing.
Demonstrations planned: Q1-2026
Deliveries: Q2-2026
Quick setup from any ship of opportunity
1 km² survey area
Track multiple vehicles simultaneously
Metric accuracy (WGS-84)
For ship's hull inspections
A complete underwater positioning solution
3 to 4 pingers moored 1 km apart around the survey area. They transmit pings every second in the 30-40 kHz range.
Equipped with a GNSS-RTK receiver to accurately measure exact pingers' transmission times and relay information by radio to the tracking station.
Hydrophone + electronics mounted onboard each ROV/AUV to measure the time of arrival (TOA) of each ping. Data is relayed via umbilical to the surface control station.
Laptop & GNSS-RTK RF transmitter that computes ROV position every second, displays the track on a digital chart, and records/exports positions.
Illustration of a full STAR-RTK deployment: reference buoys, seabed pingers, surface vessel and tethered ROV tracked in real time.
A STAR system consists of 3-4 pingers, 1 reference buoy with GNSS-RTK receiver, 1 acoustic signal receiver for ROV/AUV, and a tracking laptop. The pingers are moored around the survey area, transmitting pings every second. The reference buoy measures transmission times, and the acoustic receiver on the ROV measures arrival times to calculate precise positioning.
STAR uses two GNSS RTK "Rover" receivers - one aboard the deployment boat and one in the reference buoy. Fed with RTCM corrections via NTRIP protocol, they deliver centimeter-level accuracy (WGS84). The reference buoy acts like an RTK "Base Station," underwater transmitters behave like fixed GNSS satellites, and the hydrophone is the receiving antenna.
Traditional systems use Interrogation/Response cycles. STAR is a "One Way Travel Time" (OWTT) system, similar to GNSS, where waves propagate from transmitters to mobile devices, allowing unlimited simultaneous mobile device tracking.
High-end USBL systems integrate gyro-laser inertial platforms for accurate WGS-84 positioning but are expensive. Lower-end USBL systems use magnetic heading sensors requiring calibration and additional equipment for WGS-84 coordinates. STAR-RTK offers the accuracy of premium USBL systems without the high cost.
STAR systems use GNSS RTK receivers offering centimetric accuracy. Time of arrival is measured with 10⁻⁴ second precision (15 cm when measuring ranges). The main error source is the offset between pinger mooring coordinates and actual seabed locations, which can be reduced to tenths of centimeters through calibration. Overall expected accuracy is submetric.
STAR-RTK provides: (1) Geopositioning for mapping purposes, (2) Navigation and Guidance to optimize vehicle routes and reduce mission time/overlap, and (3) Supervision for real-time monitoring of expensive underwater vehicles.
The entire STAR-RTK system weighs less than 10 kilograms and can be easily carried in a car. Installation is immediate once equipment is on board, requiring no calibration, allowing missions to start without delay.
Yes. For hostile environments, STAR components can be deployed by AUVs guided by INU+Doppler navigation. The reference buoy becomes a seabed-laid station broadcasting RTK corrections via low data rate, broadband acoustic signals to all underwater vehicles.
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