The optimal integrated GPS/INS

Based on a C/A code, single frequency, six-channel GPS receiver and a medium-precision strapdown inertial navigation system, three different state equations (state numbers 18, 15, 9 respectively) and three different observation equations are examined in detail in the paper and numerical simulations are also carried out. For given typical precision of GPS and INS for a given initial hypothesis, simulation results indicate that position-and-velocity observation perform the best if state equations are given. On the other hand, the 15-state-equation behaves best on comprehensive evaluation if observation equations are given. Also, the authors investigate the influence correction rate and initial conditions could have on performance of the integrated system and some preliminary laws of HkΓk-1Qk-1Γk^φ-1Hk^φ varying with Qk-1 are presented