Method using side-scan sonar to measure tonnage of ship

Abstract

The invention relates to a method using a side-scan sonar to measure the tonnage of a ship. The method comprises the following steps: when a photoelectric sensor detects that ship passing signals exist, a tow fish arranged under water is started; the tow fish scans the side of a measured water area to acquire an underwater acoustic image of an underwater part of the ship; the sailing speed and the passing time of the ship are simultaneously measured, and the length of a ship body is calculated according to the product of the ship speed and the passing time; an underwater acoustic image of a measured area is acquired by a computer connected with the tow fish; then image processing is conducted on the underwater acoustic image of the measured area, so as to extract an acoustic shielding shadow of the measured ship; the draft depth of the ship body and the width of the ship body below a water line are acquired according to a combination of a projection relationship and measured environmental parameters; the total tonnage of the ship is calculated according to the length of the ship body, the draft depth, the width of the ship body below the water line, and a square model coefficient of the ship marked on a ship-borne certificate; and the difference between the total tonnage and the net tonnage of the ship marked on the ship-borne certificate equals to the actual-load tonnage of the ship.

Description

technical field [0001] The invention relates to a method for measuring ship tonnage by side-scanning sonar. Background technique [0002] According to the "Rules for the Implementation of the Waterway Management Regulations of the People's Republic of China" (2009) and the "Measures for the Collection and Use of Ship Passing Gate Fees in Jiangsu Province" (1997), when a ship passes the lock, it should be paid to the shipping administration department according to the actual tonnage of the ship. Corresponding ship lock fee. At present, most ship locks in China determine the tonnage of a ship mainly based on the navigation certificate, supplemented by manual measurement, that is, the actual tonnage of the ship is estimated based on the gross tonnage of the ship's certificate, the load line of the hull and the actual draft. load tonnage. There are following problems in this way: [0003] 1. The phenomenon of overloading and overloading in the water transportation industry ha...

AI Technical Summary

Problems solved by technology

[0003] 1. The phenomenon of overloading and overloading in the water transportation industry has been repeatedly prohibited, which can easily lead to safety accidents at ship locks and endanger the safety of waterways and waterway facilities;

[0004] 2. Criminals corrupted and bought surveyors, colluding with them, arbitrarily falsely reporting the actual tonnage of ships, evading the fees that should be paid, resulting in a large loss of state fees and rampant corruption;

[0005] 3. Unscrupulous ship owners can reduce costs by overloading and evading fees, so that the legally paying ship owners lose their competitive advantage in the market and disrupt the normal order of the water transport market

However, the methods proposed in the literature are more theoretical and lack practicality and reliability considerations. There are mainly the following problems:

The non-directional sound waves emitted at the same sound frequency will be reflected between the hull wall and the channel wall and cause severe reverberation, making it difficult for the sonar probe to work normally;

[0008] 2. The system is difficult to work stably for a long time

The impact of water flow, erosion of salt, sedimentation of silt and activities of aquatic organisms in the water environment will seriously affect the reliability and endurance of a large number of sonar probes

The sonar probes are installed underwater, and maintenance and maintenance are more difficult. When a certain number of sonar probes fail, it will lead to major errors in measurement or system failure;

[0009] 3. Poor anti-interference ability

If there are large changes in the hydrological environment, and obstacles such as floating objects, eddies, or fish schools appear in the water body, there will be more wild points in the distance data collected by the sonar sensor, and the measurement results are prone to large deviations;

[0010] 4. The system architecture is huge and complex, and the response time is long

Each measurement needs to wait for the data sent back by each probe to perform corresponding calculations. There are many subsequent algorithm steps, the amount of calculation is relatively large, and the response time of the system is relatively long.

Images