| Waves are an important element of ocean monitoring,and wave monitoring is of great significance to the understanding of the ocean and the development and utilization of its resources.At present,the most used wave monitoring is wave buoy,which can fully automate the observation and calculation of wave elements,but the instrument itself has long-term contact with seawater and is vulnerable to corrosion and impact.In this paper,a pulse laser wave monitoring system is developed to measure waves non-contactly and use multi-probe arrays to monitor complex wave elements,improve the accuracy of wave monitoring and reduce monitoring and maintenance costs.This paper draws on the successful application of laser ranging technology in various fields,and uses pulsed laser ranging technology,wave time series analysis technology and wireless communication technology to realize wave monitoring.The system model,device structure,hardware circuit and system software of the wave monitoring system are designed and developed,the trans-zero method is improved,and its usefulness is verified by simulation software,based on which the wave height and wave period are derived,and the mathematical calculation models of wave direction,wave speed and wavelength are derived based on the wave propagation characteristics using the spatial distance and angle between ranging probes and the time delay of wave propagation.The system mainly consists of a measurement device,a communicator and a host computer.The measurement device is mainly composed of STM32 as the main control unit,connected with three laser distance measurement modules.The laser range module consists of a laser transmitter circuit,a laser receiver circuit,a signal processing circuit and a timing circuit.The laser is reflected from the wave surface and accepted by the photodetector,and then the laser receiving pulse is obtained through signal processing such as amplification,filtering and moment identification,which is used to terminate the timer and thus obtain the laser flight time.The discrete sequence of wave change is obtained by laser ranging,and the wave change curve is obtained by fitting this sequence,analyzing the three-way wave change curve to find out the wave element data,and finally transmitting the monitoring data wirelessly to the communicator and the upper computer for storage and display through the ZigBee module.After experimental verification,the pulse laser ranging module developed in this paper can ensure the maximum measurement error within 0.03m in the range of 0.5～20m,which meets the ranging requirements of this system.The maximum error of the wave monitoring system prototype for wave height measurement is 8.57%(accounting for the observed value),the maximum error of the wave period is ±0.3s,and the maximum error of the wave direction measurement range is 0°～360°,which is 3° and can meet the needs of ocean wave monitoring. |
