Abstract: An LADCP and combined inertial navigation system combined observation system and method. The system includes an LADCP, combined inertial navigation system host, data processing unit, wireless transmission module, voltage-resistant wireless antenna, battery cabin, first and second GNSS antennae and an instrument support. The data processing unit is connected to the LADCP and the system host through serial ports to obtain ocean current profile measurement data, a GNSS position, GNSS orientation data, three-axis acceleration data, a three-axis gyroscope angular velocity, a roll angle, a pitch angle and a course angular rate. Real-time high-precision correction is performed on a three-dimensional flow velocity of an ocean current profile observed by the LADCP based on the orientation data, roll angle, pitch angle and the course angular rate. Accordingly, measurement precision of flow velocity and flow direction by the LADCP is improved, and working costs to carry out profile flow observation are reduced.

Abstract: An ocean current measurement method, includes: acquiring three-dimensional coordinates measured by four GNSS (Global Navigation Satellite System) positioning modules on the surface drifting buoy and attitude data of the surface drifting buoy measured by an attitude sensor; correcting the three-dimensional coordinates measured by the four GNSS positioning modules based on the attitude data; optimizing the corrected three-dimensional coordinates of the four GNSS positioning modules according to the mounting positions; converting the optimized three-dimensional coordinates of the four GNSS positioning modules into latitude and longitude coordinates; and calculating coordinates of the surface drifting buoy, an instantaneous flow velocity and flow direction of ocean current and sea surface elevation through the latitude and longitude coordinates of the four GNSS positioning modules.