POSITION COMPENSATION SYSTEM

PROBLEM TO BE SOLVED: To appropriately remove bias errors from the result of geolocation. SOLUTION: Position coordinates measured by GPS are compensated by using a GPS velocity vector and an autonomous navigation sensor output, and locus data äQ(0), Q(1) through Q(M)} are formed out of the compensated position coordinates Pc(n) through Pc(n-K), obtained until the time t=K×T prior. Q(m) is the position coordinates of the point, traced back by a length of m×dL from the present point Q(0)=Pc(n), and Q(M)=Pc(n-K). Also coordinates X are determined by compensating the point Q(0) with the preceding bias error estimation value Y, and coordinates R(0) on the nearest road from the coordinates X are calculated. In addition, position coordinates R(1) through R(M) of the points on the road which are disposed at equal intervals of a length dL are determined, with the coordinates R(0) made of respective data point so as to form road section data äR(0) through R(M)}, and a weighted average of an error Δ(m)=Q(m)-R(m) for each point is estimated as the bias error. COPYRIGHT: (C)2009,JPO&INPIT