KONGSBERG HiPAP System Operation and Maintenance Guide

Sinking depth: During operation, lower the transducer to at least 2 meters below the bottom of the ship, but avoid the risk of bottoming out. Shallow water operations can partially retract.

Gate valve maintenance: The hull unit is equipped with manual or hydraulic gate valves, which can replace the transducer without entering the dock. Check the seals and lubrication once a year.

Cable path: The transducer cable (multi-core shielded) to the transceiver unit should be avoided from being laid parallel to high-power cables (such as frequency converter output), with a minimum spacing of 0.5 meters.

3.2 External Sensor Interface

HiPAP must be connected to the following external sensors to achieve nominal accuracy:

Sensor type affects recommended devices

The heading directly affects the horizontal azimuth angle, and the error increases with the horizontal offset of the fiber optic compass (accuracy<0.1 °)

Motion Reference Unit (MRU) compensates for ship roll/pitch, and the accuracy directly affects the final positioning error. Kongsberg MRU 5 (accuracy 0.03 °)

Sound velocity profiler (SVP) calibrates sound ray bending (refraction) errors using a projection or CTD probe, in real-time or input profile files

GNSS (GPS/DGPS) converts underwater coordinates to absolute geographic coordinate differential GPS with an update rate of ≥ 1Hz

The Golden Rule: Do not use low precision MRUs with HiPAP systems. The total position error is the sum of HiPAP's own error and sensor error. Spending tens of thousands of dollars to purchase HiPAP with a cheap attitude sensor is not worth the loss.

3.3 Networked deployment of APOS operating system

APOS runs in a Windows environment and supports multiple operating stations. Configuration points:

Main station: Connect the fiber optic transceiver unit to control all functions.

Slave station: communicates with the master station through Ethernet, can view data in real time, and can take over the master control at any time (with no quantity limit).

Data output: Output standard NMEA or proprietary statements (such as $PSXN, 20) to DP systems and survey software (such as EIVA, QINSy) through serial ports (RS-232/422) or UDP Ethernet.

Deep analysis of SSBL and LBL positioning modes

4.1 SSBL (Ultra Short Baseline) Mode

Principle: The shipborne transducer measures the horizontal angle, vertical angle, and slant distance of the responder, and calculates the relative position through trigonometric geometry. Due to the linear amplification of angle error with distance, the accuracy of SSBL is inversely proportional to the operating distance.

Applicable scenarios:

Within a water depth of 500 meters, rapid deployment is required without laying an underwater array.

Track a single moving target (such as ROV, towed fish).

Acoustic reference for dynamic positioning (DP) system.

Optimization techniques:

The use of a narrow beam (HiPAP 501's 10 ° beam) can significantly suppress angle errors.

Enable Cymbal protocol to achieve a 30% accuracy improvement.

Real time input of sound velocity profile and correction of sound line curvature.

4.2 LBL (Long Baseline) Mode

Principle: Set up an array of three or more responders on the seabed, and calculate the position of the ship relative to the array by measuring the slant distance between the ship and each responder. The accuracy of LBL is almost independent of water depth, and only depends on the geometric accuracy of the formation and ranging error.

Applicable scenarios:

High precision positioning requirements for deep water (>1000 meters).

Installation of underwater structures (such as templates, Christmas trees, BOP).

Multi User Localization (MULBL): Multiple ships or ROVs share the same underwater array.

HiPAP's LBL features include:

Fast LBL responder positioning: Automatically measure all baseline distances within the array.

Accurate measurement mode: used for precise measurement before installation of underwater facilities, with a relative accuracy of centimeter level.

Geographical LBL calibration: Use GPS to calibrate the absolute coordinates of the underwater array.

4.3 Mixed use strategy

In actual deepwater operations, a combination of "LBL array for ship positioning+SSBL for ROV positioning" is often used. HiPAP allows for no mode switching of the responder, and the same cSIDE responder can simultaneously respond to LBL ranging and SSBL interrogation, greatly improving operational efficiency.

Key points of APOS operation and configuration

5.1 Initial Setup Wizard

After the first use or reinstallation, the following calibration must be performed:

Automatic transducer alignment calibration: Select a known position water surface responder (such as hanging on the side of the ship), and automatically calculate the installation angle (yaw, pitch, roll) of the transducer relative to the ship reference point through the APOS menu "Calibration ->Transformer Alignment". This process needs to be carried out under calm sea conditions.

Sound Velocity Profile Input: On the "Sound Velocity" page, you can manually input the depth sound velocity table or receive CTD profile data in real-time through the serial port. The system will correct the curvature of the radiation in real-time based on this.