Method and system for synchronously collecting terrain under river and lake surface water

The invention provides a method and a system for synchronously collecting terrain under river and lake surface water, the method is realized by adopting an unmanned aerial vehicle carrying a camera and a sonar ball, the sonar ball is connected with the unmanned aerial vehicle through a cable, and the method comprises the following steps: S1, formulating a collection task before taking off, comprising the steps of setting a flight height, a collection range, a starting point, camera aerial photography parameters and sonar parameters and planning a route, and the planned route comprises a coast surface water terrain synchronous collection route and a surface supplementary photography route; s2, the unmanned aerial vehicle flies to an initial point; s3, the sonar ball is placed on the water surface, the unmanned aerial vehicle sails according to the coast surface water terrain synchronous acquisition route, the camera performs coast surface terrain acquisition, and the sonar ball performs underwater terrain acqu