A set of counter-balanced dither mechanism for Ring Laser Gyroscope (RLG) has been designed to reduce the influence of lock-in of RLG. Designed dither frequency is 344.16Hz. By Finite Element Methodology (FEM) calculation, it js proved that the mechanism mode is reasonable and the strength requirements of the mechanism's material are satisfied. The error between the actual dither frequency, 316Hz, and the designed is less than 8.2%. In 30 minutes, the stability of dither frequency and amplitude (RMS value) are less than 0.05% and 5% respectively. The horizontal direction of the mechanism is much easier to be influenced by base vibration than the vertical one, but the readout signal is still good for application.

An inertia navigation system (INS) must be regulated with aided information for its long-time precision navigation. In the paper, the local geographic information entropy as an aided information is used to correct the INS error. The minimum variance matching algorithm is designed and simulated with MATLAB. As a result, geo-information is hardly interfered by the “outer world” as an aided navigation model autonomously or semi-autonomously.

GpsOne, which fuses GPS and wireless base station positioning signals, is a hybrid wireless assisted GPS technology proposed by Qualcomm Inc. It provides positioning service through wireless communication networks. Compared with GPS, gpsOne is more suitable for vehicle navigation due to its wider workable regions (urban, rural and even underground areas), higher positioning accuracy, lower price and no cold start. However, single gpsOne cannot be used for vehicle navigation due to its large positioning error (more than 100m) when GPS signals cannot be received completely. Therefore, gpsOne should be assisted with other positioning modes to promote the reliability, redundancy and fault-tolerance of vehicle navigation system.

Proper selection of dither amplitude and frequency of RLG influences the effect of dither bias directly. In order to reduce lock-in of RLG effectively, the width of dynamic lock-in is obtained by deducing the basic input-output equation of RLG in the article. Corresponding optimization model is based on the purpose of reducing the influence of dynamic lock in. The result of the optimization shows that it is necessary to enlarge dither depth to reduce the nonlinear influence. When dither depth is large enough, there is no evident effect on the reduction of dynamic lock-in by enlarging it further. However, dynamic lock-in may be reduced to zero by modulating dither depth locally with very small value according to the result of optimization. Some constructive conclusions are obtained in the end of the article.

coarse and the accurate. The coarse matching rules include mean absolute difference (MAD) and mean square difference (MSD) which is usually applied in terrain contour matching (TERCOM). The accurate matching is the ICCP optimization. Simulation results show that the updated ICCP matches application conditions very well and it is convergent with very high precision. Especially, when INS precision is not high, the updated ICCP matching process is more stable and its precision is higher than TERCOM’s.