KONGSBERG HiPAP System Operation and Maintenance Guide

KONGSBERG HiPAP Underwater Acoustic Positioning System: Complete Manual for Selection, Configuration, and On site Troubleshooting

Accurate underwater positioning is the cornerstone for ensuring safety and efficiency in deep-sea exploration, dynamic positioning drilling, underwater robot (ROV) navigation, and subsea pipeline laying operations. The ultra short baseline (SSBL/USBL) system has become the mainstream in the industry due to its simplicity of only requiring a single transducer on board and an underwater responder. However, the bending of sound rays, multipath interference, changes in ship posture, and noise pollution in deep water environments can all lead to a sharp amplification of positioning errors.

Kongsberg Maritime's HiPAP (High Precision Acoustic Positioning) series is globally recognized as the benchmark for high-performance underwater positioning. From the flagship model HiPAP 501 (241 element spherical transducer) to the portable HiPAP 351P, and then to the ultra deep water HiPAP 101 (working depth of 6500 meters), this family covers various application scenarios from shallow water to full sea depth. This article is based on the technical specifications of the HiPAP system, combined with practical engineering experience, to systematically explain the installation specifications of transducers and deck units, the configuration of APOS operating system, the selection principles of SSBL/LBL positioning modes, the advantages of Cymbal broadband protocol, and the most commonly encountered fault diagnosis and troubleshooting methods on site. Whether you are a DP operator, acoustic positioning engineer, or ROV navigator, this article will be an essential technical reference for you to carry with you.

HiPAP System Architecture and Core Technologies

2.1 System Composition Modules

A complete HiPAP system includes the following core components:

Transformer: Installed at the bottom of a ship or a telescopic hull unit, it is responsible for transmitting acoustic interrogation signals and receiving replies from responders. The number of array elements varies from tens to 241 depending on the model.

Transceiver Unit: Installed near the hull unit, it contains a digital transmitter, preamplifier, and beamforming electronic components, and communicates with the operation station through optical fibers.

Operator Unit: An industrial computer running APOS (Acoustic Positioning Operating System) software, equipped with a color display, keyboard, and trackball. Support multiple workstations, one primary and multiple backup.

Hull Unit: A lifting mechanism with gate valves that can extend the transducer several meters out of the bottom of the ship, avoiding the bubble layer near the waterline and propeller disturbance of the water flow. Ensure safe use within a speed of 10 knots.

Transponder/responder: Installed on underwater targets. The traditional MPT/SPT series uses FSK modulation, while the new cNNE series supports Cymbal broadband protocol and over 100 channels.

2.2 Beamforming principle of transducer

The core difference between HiPAP and ordinary USBL systems is full digital beamforming. Each transducer element is independently connected to the DSP, which measures the phase and amplitude of the incident signal to accurately calculate the horizontal and vertical angles of the responder. All models adopt automatic focusing narrow transmission/reception beam technology, and the beam direction is dynamically directed towards the target responder by the tracking algorithm. The advantages brought by narrow beam:

The signal-to-noise ratio (S/N) has significantly improved, enhancing the accuracy of angle measurement and maximum operating range.

Suppress acoustic reflections (multipath interference) and environmental noise from other directions.

For HiPAP 501, the receiving beamwidth is only 10 °, achieving an angle measurement accuracy of 0.03 ° level.

2.3 Cymbal Protocol - Broadband Direct Sequence Spread Spectrum

The second generation HiPAP 501/451/351/101 introduced the Cymbal acoustic protocol and adopted direct sequence spread spectrum (DSSS) technology. Compared to traditional narrowband CW pulses, Cymbal has the following revolutionary improvements:

Angle accuracy improved by 30% (in SSBL mode)

The ranging accuracy reaches 0.02 meters (up to 0.01 meters between cNNE responders)

Significant increase in operating distance

Enhanced multi-path suppression capability

Support Multiplaying to improve location update rate

Automatically adjust the transmission power of the responder to extend battery life

High speed telemetry data rate (up to 8 kbit/s), interleaved transmission of data and positioning signals

Add 50 independent responder channels (based on the original 56 channels)

No mode switching: The responder can dynamically switch between SSBL and LBL

Installation and Integration Specification

3.1 Installation points of transducers and ship units

Installation location: Keep as far away as possible from the bow thruster, side thruster, propeller, and bilge drain. It is best to install telescopic hull units through moonpools or flat areas in the middle of the hull.