SIERA sonar measurement —
prove it with data.
SIERA is an acoustic measurement and calibration system that characterises the real performance of underwater sonar — hull-mounted, dipping, towed and sonobuoy systems — and measures platform acoustic signatures. It turns "we think it works" into measured, repeatable evidence.
A sonar is only as good as its last measurement.
Sonar performance drifts — with maintenance, with new processing, with the water itself — and a system that looks healthy on paper can be quietly degraded in practice. SIERA closes that gap. It presents a known, controllable acoustic target to a navy's sonars and ranges, so detection performance and platform signatures can be measured against a reference rather than assumed — and validated again whenever something changes.
Measure the systems your ASW capability rests on
SIERA characterises and calibrates underwater acoustic systems across the full family a navy fields — hull-mounted sonars, dipping sonars, variable-depth sonars and buoys — and measures far-field radiated noise (the acoustic signature) of platforms under controlled conditions.
The result is hard, repeatable data: not an opinion that a sensor works, but a measurement of exactly how well, where weaknesses surface in a trial rather than on operations.
One towed body, three acoustic roles
SIERA pairs a processing unit, a lightweight towed body and two electrical cable winches — and presents itself to the system under test in whichever role the trial needs.
Noise Maker
Generates a known, controllable acoustic source — the reference a passive sonar or signature measurement is taken against.
Repeater
Returns a controlled echo so active sonars can be characterised against a known, repeatable target return.
Responder
Replies to an interrogating system, letting active acoustic chains be tested end-to-end under controlled conditions.
Four subsets, one portable measurement chain
SIERA comprises four subsets: a processing and visualizing unit to drive the trial and capture results, a light towed body deployed from the trials vessel, two winches for towline storage, and two 250 m electrical cables with waterproof plugs (extensions available).
Because the towed body is light, the system can run from modest platforms rather than demanding a dedicated trials ship — and SIERA is equally relevant for operator training, putting realistic, measurable contacts in front of the team.
SIERA measurement system specifications
Indicative configuration — exact measurement envelope and instrumentation confirmed at quotation against your trials objectives.
- TypeSonar measurement & calibration system
- PurposeCharacterise & calibrate underwater acoustic systems
- Systems measuredHull-mounted, dipping, variable-depth sonars & buoys
- Acoustic modesNoise maker · repeater · responder
- Composition4 subsets: processing unit, towed body, 2 winches, 2× 250 m cables
- Acquisition / generation unit19-inch 6U enclosure (1U acquisition + 2 class-D amplifiers + 3U impedance matching)
- Towed body material316L stainless steel
- Towed body sensorsBrüel & Kjær 8106 hydrophone · Neptune Sonar D/11/BB transducer
- Towed body sizeL 2130 mm · shell Ø 150 mm · H 285 mm
- Towed body weight (air)33 kg
- Frequency band (emit / receive)200 Hz – 35 kHz
- Reception sensibility (sea state 0)up to 180 dB/µPa
- Emission level185 dB (3–20 kHz); 120–185 dB (200 Hz–3 kHz); 185–170 dB (20–35 kHz)
- ReferencedB/µPa @ 1 m
- PositioningGPS
- Signal processingReal-time or delayed
- Also relevant forOperator training
- Export statusITAR-free; EU / French export controls apply
- PillarRTsys Anti-Submarine Warfare
- OriginRTsys — Caudan (Brittany), France
Chosen by the Indian Navy
RTsys won a contract from Bharat Electronics Limited (BEL) for two SIERA systems to characterise and calibrate the Indian Navy's new-generation hull-mounted and variable-depth sonars (announced February 2021). Acoustic performance is invisible until it is measured — SIERA gives a navy a controllable reference and a portable measurement chain, so sonar systems and platform signatures are validated against data, on the navy's own schedule.
Check. Train. Analyze.
Anti-Submarine Warfare
The ASW overview — how the SIERA range and the SEMA target fit the Check-Train-Analyze doctrine.
See the ASW overview →
SEMA Training Target
A mobile or static target that recreates a submarine signature for ASW crew training and torpedo firings.
Explore SEMA →
Mine Counter-Measures
The other RTsys mission — a manned-and-unmanned MCM suite for EOD divers.
See the MCM suite →Part of a bigger mission
SepcoTech scopes and delivers this as one piece of a cross-supplier capability. See the missions it supports:
A safe pair of hands for defence at sea
Authorised Distributor
We represent RTsys directly — specification, supply and through-life support, coordinated from Denmark.
Naval & EOD Focus
A portfolio assembled for navies, coast guards and EOD units — not adapted from civilian kit.
One Point of Contact
Multi-supplier defence systems, integrated and quoted as a single package by one partner.
Backed Through Life
Training, spares and support for the full operational life of the system.
Speak directly with our defence specialist
Every enquiry is handled directly and in confidence — you will normally have a reply within one business day.
For spec sheets, capability documents, pricing or to arrange a briefing or demonstration — on this system or any platform in the SepcoTech defence portfolio — contact me directly:
- Spec sheets & technical datasheets on request
- Briefings & demonstrations for units & agencies
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