Primary Research On Miniaturized Laser Gyro SINS/GNSS Integrated Navigation System

Strap-down Inertial Navigation System(SINS)is one kind of autonomous navigation system whose errors accumulate with time.Compared with SINS,Global Navigation Satellite System(GNSS)has many advantages,such as high precision and all weather operations,but also easy to be interfered.The SINS /GNSS integrated navigation system can overcome the defects of the two systems and has broad application prospect.According to the demands of Institute of Acoustics of Chinese Academy of Sciences(IACAS)for Marine Exploration Project and other engineering applications,a miniaturized laser gyro SINS and SINS/GNSS integrated navigation system are researched.Calibration methods,temperature related error compensation,numerical simulation and actual navigation experiments are carried out in the paper.The main work including:(1)Current situation and development of miniaturized laser gyro,miniaturized laser gyro SINS and SINS/GNSS integrated navigation system at home and abroad are introduced.Error equations and navigation equations of SINS are presented.(2)The scale factors,biases and misalignment angles of laser gyros and accelerometers are calibrated for miniaturized laser gyro SINS.(3)Cubic polynomial and quartic polynomial with or without the term dT/dt(Temperature change rate with time)are used to fit the bias curves of laser gyros and accelerometers,thus the biases of laser gyros and accelerometers are improved.(4)Three alignment methods including analytical alignment,inertial frame alignment and Kalman filtering alignment are analyzed.Actual navigation experiments for miniaturized laser gyro SINS are carried out,and the results show that the azimuth error angle is 0.4?,horizontal error angle is 2? after 12 h of navigation,which meets the demands of IACAS for Marine Exploration Project.(5)Based on numerical simulation and actual navigation experiments,the loosely coupled laser gyro SINS/GNSS integrated navigation system has been studied preliminarily.Results show that the SINS/GNSS integrated navigation system has higher accuracy and stability than SINS.