水下地形辅助导航新方法仿真

水下地形辅助导航是水下运载体导航定位技术研究的关键技术之一。传统的水下地形辅助导航采用回声测深仪,导航定位精度低,有时甚至失效。本文将多波束测深引入水下地形辅助导航,将水深映射为灰度值,利用快速傅立叶变换将输入灰度图从空间域变换为频率域。先采用相位相关技术进行粗匹配,再采用图像Hu不变矩特征进行精匹配,实现导航定位。对基于不同实验获取的实测海底地形图、惯性导航数据、DGPS数据以及多波束实测数据进行了实验室仿真。仿真结果表明,新方法可以极大地提高水下地形导航定位精度,使INS误差降低到原误差的15%以内,尤其是在INS初始误差较大时(小于3 km)导航定位精度改进更好。

A new method for underwater terrain-aided navigation

Underwater terrain-aided navigation(UTAN)is an important technology to the underwater vehicle.Traditionally,as the echo sounder is deployed in UTAN,the navigation and positioning accuracy is very low.In this paper,the multi-beam sounding has been introduced into UTAN,the water depth is mapped into grayscale value,the input image is transformed based on FFT from spatial domain to frequency domain.The Fourier phase correlation technique is used to estimate the candidate translations in order to decrease searching space.The Hu invariable moments are then applied to obtain the best matching from candidate translations obtained from phase correlation.Based on different experiments to obtain the measured seabed topography,navigation data and multi-beam sounding data measured,the experimental results show the proposed method can acquire higher accuracy of the navigation and positioning for UTAN,the errors of INS have been reduced to about 10% of the its original ones,especially in the case of the large original errors(less than 3 km)for INS the accuracy is improved obviously.