Byung Doo Kim

Brief paper: Adaptive IIR/FIR fusion filter and its application to the INS/GPS integrated system

Motivated by the complementary features of the IIR-type filter and the FIR-type filter, this paper proposes a robust IIR/FIR fusion filter and an INS/GPS integrated system designed with the fusion filter. In the fusion filter, an IIR-type filter (SPKF) and a FIR-type filter (MRHKF filter) are processed independently, and then the two filters are merged using the mixing probability calculated using the residuals and residual covariance information of the two filters. The merits of the SPKF and the MRHKF filter are integrated and the demerits of the filters are diminished through the filter fusion. Consequently, the proposed fusion filter shows robustness against model uncertainty, temporary disturbing noise, large initial estimation error, etc. The stability of the fusion filter is verified by showing the closeness of two filters in the mixing/redistribution process and the upper bound of the error covariance matrices. This fusion filter is applied to an INS/GPS integrated system. The performance of the INS/GPS integrated system designed using the fusion filter is verified through a simulation under various error environments and is experimentally confirmed.

Linear closed-form solution for wireless localisation with ultra-wideband/chirp spread spectrum signals based on difference of squared range measurements

In many practical applications of wireless localisation with ultra-wideband or chirp spread spectrum signals based on distance measurements, iterative least squares (ILS) method and direct solution (DS) method have been used. In these methods, some deployment conditions of reference nodes may cause problems such as: local minimum problem in the ILS method and red sea zone problem in the DS method. To overcome these problems, a linear closed-form solution based on difference of squared range measurements is presented in this study. The measurement used in this solution is the difference of squared range measurements instead of distance measurements. Also, it is shown that the proposed solution is equal to the range-difference measurements-based closed-form solution. Some Monte Carlo simulations were conducted to illustrate the proposed solution and demonstrate its performance. Through actual experiments, the validity of the proposed solution is confirmed.

Observability analysis of the INS/GPS navigation system on the measurements in land vehicle applications

In this paper, the observability of the INS/GPS navigation system for a land vehicle is analyzed on measurements and different dimension filters with respect to the measurements are designed. In the stationary case, it is shown that the horizontal accelerometer biases and vertical attitude errors and gyro biases are unobservable. An 8 th filter is designed based on the observability analysis. When GPS signal is available, a 15 th filter is used with position and velocity measurements. To estimate the INS errors even in the case that GPS signal is blocked a filter is designed in consideration of the non-holonomic constraints of a land vehicle. In this case, the horizontal position and velocity errors and vertical attitude error are unobservable. However, a 12 th filter including the velocity states is designed to estimate the accelerometer biases. Based on the results of the observability analysis and the different dimension filters, an efficient INS/GPS filter including the filters as sub-filters can be designed.