Preliminary Study On Altitude Determination Technique Based On Laser Doppler Velocimeter And Strapdown Inertial Navigation System

Considering the urgent requirement of the precious altitude for offhand fast mobile launch technique,which is a key technique for the weapon launch system,the altitude determination technique based on laser Doppler velocimeter(LDV)and strapdown inertial navigation system(SINS)is proposed in this paper.Researches made by this paper include 5 main parts:1)Precious calibration system design for LDV with expanded uncertainty of 0.03%.The calibration is carried out for self-developed reference-beam LDV,illustrating that the relative measurement precision of the LDV under calibration is 0.1%(1σ)in the velocity range from 0 to 200 km/h.2)Interference fringes detection for directional discrimination of LDV.The experimental results show that the interference fringes detection is viable to resolve directional ambiguity.Additionally,this technique ensures the small size and portability of LDV.3)Q factor improvement technique based on Electrically Tunable Lens(ETL).The experimental results show that the Q factor of the output signal by LDV is ten times of that without ETL,implying that the technique based on ETL is able to turn type I invalid signal,of which the Doppler signal is submerged by noise,into valid one,hence avoid signal loss.4)Differential detection method for anti-jamming.The results show that the power of the jamming signal is suppressed to be lower than that of the Doppler signal,thus type II invalid signal,of which the power of the jamming signal exceeds that of the Doppler signal,is changed to be valid and the velocity error is decreased.5)Vehicle tests for LDV/SINS integrated system.The maximum altitude difference of the test areas reaches 1391 m.Five-group-experiment results implies that the altitude error of LDV/SINS integrated system is no more than 8m,and the minimum relative altitude error is 0.26%.Additionally,the positioning errors of six tests are no more than0.2%.in conclusion,the developed LDV/SINS system is capable to provide highly accurate altitude and positioning parameters.