Horizontal attitude determination method based on underwater Snell window edge identification

Abstract

The invention relates to a horizontal attitude determination method based on underwater Snell window edge identification. A Snell window is an optical phenomenon during underwater air observation andcomprises space information. According to the method, the center of the Snell window in underwater air-to-air imaging is extracted through an image processing means to obtain the horizontal attitude of a carrier. The method comprises the following steps: firstly, performing noise filtering and binarization processing on an acquired image; introducing a lens model of the camera into a traditional Hough circle transformation algorithm, and extracting a Snell window and a center thereof from the binarized edge image; because the window center vector coincides with the zenith vector under the navigation coordinate system, calculating the horizontal attitude of the carrier finally by utilizing the relationship. According to the method, underwater optical information is fully utilized, full-autonomous horizontal attitude determination is realized, and the method can be used for initial alignment of underwater vehicles and correction of inertial navigation accumulative errors.

Description

technical field [0001] The invention relates to a horizontal attitude determination method based on underwater Snell window edge recognition. The method utilizes underwater imaging of the sky, and extracts the center of the Snell window in the image through an improved Hough transform to obtain the horizontal attitude of the carrier. It belongs to the field of underwater optical navigation. Background technique [0002] The ocean is rich in biological resources, mineral energy and space resources, and has great potential for development. Therefore, all countries regard the ocean as an important part of their development strategies. Underwater unmanned submersibles have played an irreplaceable role in the development of the ocean. In civilian use, it can be used for submarine topography detection, marine engineering construction, marine monitoring, marine rescue and salvage, etc., and in national defense, it can also be used for military tasks such as underwater surveillance...

AI Technical Summary

Problems solved by technology

However, these two navigation methods are not autonomous navigation. Among them, underwater acoustic positioning requires a preset underwater transponder, which is not applicable in the unfamiliar environment of the open sea; while the satellite navigation method can only receive satellites when the underwater vehicle floats to the water surface. The signal affects the continuity of the submersible's operation, especially in military applications, the two navigation methods seriously affect the concealment of the submersible

In Chinese patent CN109443379 A and Chinese patent CN 109141475A, the inertial navigation and Doppler odometer are combined to determine the initial attitude of the carrier. However, the Doppler odometer has certain requirements for the distance between the submersible and the seabed, and its output speed Information quality is greatly affected by seawater temperature, salinity, etc., so application scenarios and performance are limited

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