Acoustic Doppler flow velocity profiler small flow velocity field calibration system and method based on single-point flow velocity meter

Abstract

The invention mainly relates to an acoustic Doppler flow velocity profiler small flow velocity field calibration system and method based on a single-point flow velocity instrument, and aims to solve the problem of small flow velocity field calibration which is difficult to solve by the existing acoustic Doppler flow velocity profiler calibration mode. The system comprises a pulse interception hydrophone which is used for capturing the working state of an acoustic Doppler flow velocity profiler; the single-point flow velocity meter is used for measuring the flow velocity of a single water layer; the time sequence control module is used for ensuring that the single-point flow velocity meter and the acoustic Doppler flow velocity profiler carry out time-sharing measurement so as to avoid mutual interference between acoustic signals; and the unmanned aerial vehicle and the wireless LoRa data transmission module are used for communication between the upstream and downstream measurement equipment. After the single-point flow velocity meter and the acoustic Doppler flow velocity profiler complete flow velocity measurement, flow velocity data are sent to an upper computer, and the acoustic Doppler flow velocity profiler is calibrated by taking the measurement data of the high-precision single-point flow velocity meter as a reference.

Description

Technical Field

[0001] The invention mainly relates to a measurement calibration method, in particular to an acoustic Doppler flow profiler field calibration system based on a single-point flow meter, and belongs to the field of flow measurement. Background Art

[0002] Acoustic Doppler Current Profiler (ADCP) is a new type of hydroacoustic velocity measurement equipment that combines hydroacoustics, hydroacoustic physics, electronic technology, hydroacoustic transducers and other disciplines. As a new type of velocity measurement instrument, ADCP is widely cited in the field of velocity measurement due to its advantages such as high measurement accuracy, high efficiency, and low requirements for the measurement flow field during measurement. Although ADCP provides an efficient and high-precision flow measurement method, there may be process problems such as defects in the design and manufacture of the instrument, or uncontrollable factors such as different water temperatures, water flow instability, and different river channel forms during measurement, which will cause fluctuations in the final measurement results of ADCP. Therefore, it is very necessary to conduct regular calibration of ADCP.

[0003] At present, the calibration methods for ADCP at home and abroad can be roughly divided into two categories:

[0004] One is laboratory calibration, such as the water tank trailer method and the acoustic transponder method. The specific implementation method is to use lime powder and other particles to simulate scatterers in real waters in a laboratory pool environment, and fix the ADCP on a trailer moving at a certain speed to simulate the water flow rate. The calibration purpose is achieved by comparing the flow rate measured by ADCP with the trailer speed; or an acoustic transponder is arranged in the pool, and the ADCP is calibrated by emitting a frequency-biased acoustic pulse signal to the ADCP to simulate the acoustic signal of the sound wave in the real water after being reflected by the scatterer. The advantages of this type of laboratory calibration method are that the experimental conditions are controllable and the detection time is short, but because there is a measurement blind spot in ADCP flow measurement, there are certain requirements for the depth of the pool. At the same time, because the experimental conditions are all simulated, the calibration effect lacks a certain degree of authenticity.

[0005] The other is on-site calibration, such as the self-navigation test method. That is, the ADCP is fixed to the bottom of the ship, and sails back and forth within the specified route to offset the water flow rate. During the navigation, the ADCP measures the ship speed through bottom tracking, and the measured ship speed is statistically compared with the ship speed value measured by high-precision GPS to achieve calibration. Although this type of calibration method can be verified and calibrated in real waters, it also has high requirements for the measurement environment, and it is difficult to achieve small flow velocity calibration below 1m / s due to the ship speed and instrument accuracy.

[0006] So far, there is no ADCP low flow rate calibration solution in China. This has caused a lot of trouble for national metrology departments and users. Therefore, we propose an ADCP low flow rate on-site calibration system and method based on a single-point flow meter. Summary of the invention

[0007] In view of the shortcomings of the above-mentioned existing calibration methods, the present invention provides a low-flow rate on-site calibration system and method for an acoustic Doppler current profiler based on a single-point current meter, which adopts time-sharing measurement of the single-point current meter and the acoustic Doppler current profiler and wireless communication to realize the verification and calibration of the acoustic Doppler current profiler in a low-flow rate on-site environment.

[0008] The specific technical scheme of the method adopted by the present invention is as follows:

[0009] A low-flow field calibration system for an acoustic Doppler current profiler based on a single-point current meter includes a mother ship for deploying an acoustic Doppler current profiler. A pulse-listening hydrophone is arranged in front of the acoustic Doppler current profiler, and the acoustic Doppler current profiler and the pulse-listening hydrophone are connected to a hydrological cableway through a cable. The pulse-listening hydrophone is used to receive the working status of the acoustic Doppler current profiler in real time. A host computer, a timing control module, an upstream drone and a downstream drone are arranged next to the hydrological cableway; the host computer, the timing control module, the upstream drone and the downstream drone are connected to each other by cables. The upstream drone and the downstream drone are respectively equipped with wireless LoRa data transmission modules for remote communication. The wireless LoRa data transmission module is fixed to the upstream drone and the downstream drone respectively through a slide rail. The single-point current meter is connected to the downstream hydrological cableway through a cable and a fixed structure.

[0010] The present invention also discloses a low flow rate on-site calibration method of an acoustic Doppler flow profiler based on a single-point flow meter, comprising the following steps:

[0011] Step 1: First, fix the acoustic Doppler current profiler and the pulse listening hydrophone to the bottom of the mother ship through the adapter flange and travel to the upstream of the experimental river section with the mother ship. The cables connected to the acoustic Doppler current profiler and the pulse listening hydrophone are connected to the hydrological cableway.

[0012] Step 2: Deploy a single-point current meter to a designated water layer via a hydrological cableway downstream of the experimental river section, and put the single-point current meter into a standby state.

[0013] Step 3: The acoustic Doppler current profiler transmits an acoustic signal upstream to measure the flow velocity of the water layer. After the transmission is completed, the pulse listening hydrophone transmits the transmission completion signal to the timing control module; after analyzing the flow velocity data, the acoustic Doppler current profiler transmits the data to the host computer.

[0014] Step 4: The timing control module judges the signal transmitted by the pulse listening hydrophone. If the signal energy is higher than the specified energy threshold in three consecutive time windows, the timing control module sends a single-point flow meter working instruction to the wireless LoRa data transmission module carried by the upstream drone.

[0015] Step 5: The wireless LoRa data transmission module carried by the upstream UAV sends the instruction to the wireless LoRa data transmission module carried by the downstream UAV, and sends the work instruction to the single-point flow meter after protocol conversion.

[0016] Step six: the single-point flow meter ends the standby state and enters the working state, and measures the flow rate of the specified water layer through the transceiver and transducer. After the measurement, the water layer flow rate measurement data is transmitted back to the timing control module through the wireless LoRa data transmission module, and then sent to the host computer through the timing control module; after the transmission, the single-point flow meter ends the working state and enters the standby state.

[0017] Step 7: The host computer solves and analyzes the received acoustic Doppler current profiler velocity data and the single-point current meter velocity data, calibrates the acoustic Doppler current profiler velocity data through the single-point current meter velocity data, and sends the calibration result to the acoustic Doppler current profiler.

[0018] Step 8: The acoustic Doppler current profiler adjusts measurement parameters according to the calibration result to achieve low flow rate on-site calibration of the acoustic Doppler current profiler to be tested.

[0019] The biggest advantage of the present invention is that it fills the gap in the calibration method of acoustic Doppler current profiler in the field of calibration of acoustic Doppler current profiler in the field of low flow rate environment at home and abroad. It realizes the more convenient and efficient real-time field calibration of acoustic Doppler current profiler using single-point current meter, and provides a new idea for the calibration of acoustic Doppler current profiler. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the calibration system of the present invention.

[0021] Figure 2 It is a schematic diagram of a single-point flow meter of the present invention.

[0022] Figure 3 for Figure 2 Oblique view of .

[0023] Figure 4 The figure is a flow chart of the ADCP calibration method based on a single-point flow meter of the present invention.

[0024] Among them: 1. Host computer; 2. Hydrological cableway; 3. Timing control module; 4. Upstream UAV; 5. Downstream UAV; 6. Water flow direction; 7. Cable; 8. Acoustic Doppler current profiler; 9. Single-point current meter; 901. Lifting ring device; 902. Electronic compartment; 903. Battery compartment; 904. Tail wing; 905. Transceiver and transducer; 10. Pulse listening hydrophone; 11. Mother ship. DETAILED DESCRIPTION

[0025] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0026] like Figure 1-Figure 4 As shown, this system can be mainly divided into two parts: velocity collection equipment and control equipment. The velocity collection equipment includes a mother ship 11 for carrying and deploying an acoustic Doppler velocity profiler 8 and a pulse listening hydrophone 10, cables 7 and hydrographic cableways 2 for realizing the connection and data transmission between various devices, and a single-point velocity meter 9 for calibrating the velocity of a specific water layer measured by the acoustic Doppler velocity profiler 8. The control equipment includes a timing control module 3, which is used to ensure that the single-point velocity meter 9 and the acoustic Doppler velocity profiler 8 perform time-sharing measurements to prevent mutual interference between acoustic signals. The upstream drone 4 and the downstream drone 5 respectively carry wireless LoRa data transmission modules for long-distance communication between upstream and downstream. The host computer 1 is used to receive and store the velocity measurement data of the acoustic Doppler velocity profiler 8 and the single-point velocity meter 9 in real time.

[0027] like Figure 2-Figure 3 As shown, the single-point flow meter 9 includes a lifting ring device 901; an electronic compartment 902; a battery compartment 903; a tail wing 904; a transceiver and transducer 905; the lifting ring device 901 is connected to a fixing device in the middle of the single-point flow meter 9. The electronic compartment 902 is located at the front of the single-point flow meter 9, and is equipped with sensors such as temperature and pressure to monitor the current measurement environment. The battery compartment 903 is located at the rear of the single-point flow meter 9 and is connected to the electronic compartment 902 with a watertight cable inside. The tail wing 904 is located at the rear of the single-point flow meter 9 to ensure the integrity of the streamlined structure of the single-point flow meter. The transceiver and transducer 905 is embedded in the head of the single-point flow meter to measure the flow velocity of a specific water layer.

[0028] A method for field calibration of acoustic Doppler current profiler at low flow rate based on single-point current meter, such as Figure 4 As shown, the specific steps include:

[0029] Step 1: First, fix the acoustic Doppler current profiler 8 and the pulse listening hydrophone 10 to the bottom of the mother ship 11 through the adapter flange and travel to the upstream of the experimental river section together with the mother ship 11, and connect the cable 7 connected to the acoustic Doppler current profiler 8 and the pulse listening hydrophone 10 to the hydrological cableway 2.

[0030] Step 2: Deploy the single-point current meter 9 to the designated water layer through the hydrological cableway 2 downstream of the experimental river section, and ensure that the distance between the single-point current meter 9 and the acoustic Doppler current profiler 8 is kept above 2 km. After the deployment is completed, put the single-point current meter 9 into standby mode.

[0031] Step three: after receiving the working instruction from the host computer 1, the acoustic Doppler current profiler 8 transmits an acoustic pulse signal upstream to measure the flow velocity of the water layer. After the transmission is completed, the pulse listening hydrophone 10 transmits the transmission completion signal to the timing control module 3; after analyzing the flow velocity data, the acoustic Doppler current profiler 8 transmits the data to the host computer 1.

[0032] Step 4: The timing control module 3 judges the signal transmitted by the pulse listening hydrophone 10, amplifies the signal, filters it and detects its energy. If the signal energy is higher than the specified energy threshold in three consecutive time windows, the timing control module 3 sends the single-point current meter 9 working instruction to the wireless LoRa data transmission module carried by the upstream drone 4.

[0033] Step 5: The wireless LoRa data transmission module carried by the upstream UAV 4 sends the instruction to the wireless LoRa data transmission module carried by the downstream UAV 5, and sends the work instruction to the single-point flow meter 9 after protocol conversion.

[0034] Step six: After receiving the command, the single-point flow meter 9 ends the standby state and enters the working state, and measures the flow velocity of the specified water layer through the transceiver and transducer 905. After the measurement, the water layer flow velocity measurement data and the measurement environment information are transmitted back to the timing control module 3 through the wireless LoRa data transmission module, and then sent to the host computer 1 through the timing control module 3; after the transmission is completed, the single-point flow meter 9 ends the working state and enters the standby state.

[0035] Step 7: The host computer 1 solves and analyzes the received velocity data of the acoustic Doppler current profiler 8 and the velocity data of the single-point current meter 9 as well as the measurement environment parameters, and calibrates the velocity data of the acoustic Doppler current profiler 8 through the velocity data of the single-point current meter 9, and sends the calibration result to the acoustic Doppler current profiler 8.

[0036] Step 8: The acoustic Doppler current profiler 8 adjusts the measurement parameters according to the calibration result to achieve low flow rate on-site calibration of the acoustic Doppler current profiler to be tested.

[0037] A single-point flow meter is used to calibrate the acoustic Doppler flow profiler. The system is simple, the calibration time is short, and the calibration efficiency is high, filling the gap in the current field of flow measurement instrument calibration for the small flow rate on-site calibration of the acoustic Doppler flow profiler.

[0038] The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. The scope of the present invention is defined in the claims. Any form of modification may be made within the scope of protection of the present invention.

Claims

1. A low-velocity field calibration system for an acoustic Doppler flow profiler based on a single-point flow meter, characterized in that: A mother ship (11) is used to deploy an acoustic Doppler current profiler (8); a pulse listening hydrophone (10) is arranged in front of the acoustic Doppler current profiler (8), and the acoustic Doppler current profiler (8) and the pulse listening hydrophone (10) are connected to a hydrological cableway (2) via a cable (7); a host computer (1), a timing control module (3), an upstream unmanned aerial vehicle (4) and a downstream unmanned aerial vehicle (5) are arranged next to the hydrological cableway (2); wireless LoRa data transmission modules are respectively mounted on the upstream unmanned aerial vehicle (4) and the downstream unmanned aerial vehicle (5); the wireless LoRa data transmission modules are respectively fixed to the upstream unmanned aerial vehicle (4) and the downstream unmanned aerial vehicle (5) via slide rails; a single-point current meter (9) is connected to the hydrological cableway (2) via a cable (7).

2. The low-velocity field calibration system of an acoustic Doppler flow profiler based on a single-point flow meter according to claim 1, characterized in that: The hydrological cableways (2) are respectively arranged upstream and downstream of the experimental site, with two in total; the upstream hydrological cableway (2) is connected to a host computer (1), a timing control module (3) and an upstream unmanned aerial vehicle (4) via a cable (7); the downstream hydrological cableway (2) is connected to a downstream unmanned aerial vehicle (5) and a single-point current meter (9) via a cable (7).

3. The low-velocity field calibration system of an acoustic Doppler flow profiler based on a single-point flow meter according to claim 1, characterized in that: The single-point flow meter (9) comprises a lifting ring device (901), an electronic compartment (902), a battery compartment (903), a tail wing (904) and a transceiver and transducer (905); the electronic compartment (902) is located at the front section of the single-point flow meter (9), and the battery compartment (903) is arranged at the rear section of the single-point flow meter (9); the tail wing (904) is located at the rear of the single-point flow meter (9) and is connected to the battery compartment (903); the lifting ring device (901) is arranged above the connection between the electronic compartment (902) and the battery compartment (903); the transceiver and transducer (905) is embedded in the head of the single-point flow meter (9) and is connected to the electronic compartment (902) via a cable inside.

4. A method for calibrating an acoustic Doppler flow profiler at low flow rates based on a single-point flow meter, the flow calibration method specifically comprising the following steps: Step 1: The acoustic Doppler current profiler (8) and the pulse listening hydrophone (10) are fixed to the bottom of the mother ship (11) through the adapter flange and travel together with the mother ship (11) to the upstream of the experimental river section, and the cable (7) connected to the acoustic Doppler current profiler (8) and the pulse listening hydrophone (10) is connected to the hydrological cableway (2). Step 2: deploy a single-point current meter (9) to a designated water layer via a hydrological cableway (2) downstream of the experimental river section and put it into a standby state. Step 3: The acoustic Doppler current profiler (8) transmits an acoustic signal upstream to measure the flow velocity of the water layer. After the transmission is completed, the pulse listening hydrophone (10) transmits the transmission completion signal to the timing control module (3); after analyzing the flow velocity data, the acoustic Doppler current profiler (8) transmits the data to the host computer (1). Step 4: The timing control module (3) judges the signal transmitted by the pulse listening hydrophone (10). If the signal energy is higher than the specified energy threshold in three consecutive time windows, the timing control module (3) sends a single-point flow meter (9) working instruction to the wireless LoRa data transmission module carried by the upstream drone (4). Step 5: The wireless LoRa data transmission module carried by the upstream UAV (4) sends instructions to the wireless LoRa data transmission module carried by the downstream UAV (5), and sends the work instructions to the single-point flow meter (9) after protocol conversion. Step 6: The single-point flow meter (9) is released from the standby state and enters the working state, and the flow velocity of the designated water layer is measured through the transceiver and transducer (905). After the measurement, the water layer flow velocity measurement data is transmitted back to the timing control module (3) through the wireless LoRa data transmission module, and then sent to the host computer (1) through the timing control module (3); after the transmission is completed, the single-point flow meter (9) ends the working state and enters the standby state. Step 7: The host computer (1) calculates and analyzes the received velocity data of the acoustic Doppler current profiler (8) and the velocity data of the single-point current meter (9), calibrates the velocity data of the acoustic Doppler current profiler (8) using the velocity data of the single-point current meter (9), and sends the calibration result to the acoustic Doppler current profiler (8). Step 8: The acoustic Doppler flow profiler (8) adjusts the measurement parameters according to the calibration result, so as to realize the low flow rate on-site calibration of the acoustic Doppler flow profiler to be tested.

Images