Hunting Operations (1978)
In 1978, Research and development on TNO-FEL’s HUNTOP mine-hunting computer simulation model was initiated. From the start, the HUNTOP model focused on the operational effectiveness in relation to the detection capabilities of a mine-hunting system. Although originally meant for research activities, the Huntop-model was installed as the basis for an on-board Real-Time Performance Indicator (RTPI) for mine hunting operations.
HUNTOP was capable of simulating and evaluating the operational effectiveness of the Royal Netherlands Navy Tri-partite minehunters of the Alkmaar Class, equipped with the (hull-mounted) detection sonar DUBM-21B. The main purpose of HUNTOP was to simulate the detection phase of a minehunting operation and express the achieved performance by means of operational effectiveness measures such as:
- characteristic detection width and characteristic detection probability (A/B),
- detection probability function (related to athwart distance from the ship),
- detection map giving the realised detection performance at each position in the operating area, or detailed – sonar and underwater acoustics related – detection performance measures such as reverberation level, target echo level, noise level, etc.
The entities modelled by the HUNTOP model are:
- minehunter, containing the following entities:
- sonar (type DUBM21-B);
- operation area, containing the following entities:
- water volume;
- bottom object (ground mines and other objects);
- calculation module:
- capable of calculating the required minehunting effectiveness measures.
The relation between the denoted entities is as follows:
- The sonar generates an acoustic signal (sonar ping).
- The water volume is responsible for the underwater acoustic sound propagation of the sonar signal including the calculation of effects such as ray-path bending, propagation loss, acoustic noise.
- The bottom objects reflect the propagated sonar signal in accordance with the applicable bottom object target strength function.
- The bottom reflects the propagated sonar signal in accordance with the bottom type at the applicable position(s) within the operation area.
- The water volume returns the propagated reflected sonar signal back to the sonar.
- The sonar applies its signal processing capabilities in order to filter and present echoes to the sonar operator.
- The sonar operator will process the sonar echoes and decide on the detection of minelike echoes according to predetermined operator curves.
During the simulation, the detection performance of the detection system as well as the detailed simulation data of the behaviour of the denoted entities such as contrast levels, reverberation levels, operator detection time, is logged.
The logged detection performance data will be used to calculate the detection performance figures to be used within minehunting planning and evaluation and tactical control:
- detection probability function (detection probability as a function of the athwart distance from the ship);
- characteristic detection width and probability (block function) to be used as input for presently available NATO planning and evaluation procedures;
- detection map providing information on the realised detection performance (provided as detection probability) related to all positions within the operation area (to be used for mission monitoring and evaluation purposes).
The other logged (detailed) simulation data could be used for detailed analysis or model validation purposes.
In addition to research applications of HUNTOP, the following HUNTOP applications were identified by the Royal Netherlands Navy to be used for operational purposes:
- Real-Time Performance Indicator: to be used for the on-board determination of the sonar performance and to advise on the optimal sonar settings;
- Sonar Analysis: to be used for the operational evaluation of (new) sonar systems;
- Analysis of Operational Tactics: to be used for the evaluation of mine-hunting tactics;
- Planning and Evaluation of Mine-hunting Exercises: to be used for planning (including planning of the minefield), monitoring and evaluation the results of a mine-hunting exercise;
- Validation of, and input for Trainers and Simulators: to be used for validating or providing input to mine-hunting modules of trainers/simulators;
- Analysis of the mine threat: to be used to assess the operational effectiveness of a mine-hunting system against a certain type of mine.
In the period 2000-2001, the Royal Netherlands Navy used the Sonar Performance Indicator (SPI) – Interim with the HUNTOP simulation model as the core.