| 主权项 |
1. A method of location estimation using distributed message passing of heterogeneous observation data accompanied with a data-fusion scheme, the method comprising:
obtaining values of location (x1,k, x2,k) of a moving terminal (MT) from observed values of currently received radio signals transmitted from base stations of a digital television system, a wireless local area network (WLAN), or a wireless personal area network (WPAN) which are land-based signals at a current time (time k); and obtaining values of speed (s1,k, s2,k) of a moving terminal (MT) from observed values of the acceleration and an error propagation law at a current time (time k), and where predicting values of location and speed of said MT at a next sampling time (time k+1) using a calculation formula[x~s~]=[x1,k+1x2,k+1x.1,k+1x.2,k+1]=[x1,k+1x2,k+1s1,k+1s2,k+1]=[10Δk0010Δk00100001][x1,kx2,kx.1,kx.2,k]+[u1,ku2,ku3,ku4,k]to obtain the predicted values of location and speed of said MT at said next sampling time (time k+1) are (x1,k+1,x2,k+1) and ({dot over (x)}1,k+1,{dot over (x)}2,k+1)=(s1,k+1,s2,k+1)), respectively; and where (u1,k, u2,k) and (u3,k, u4,k) are predicted errors of location and speed of said MT at said current time, respectively; and Δk is selected from a group consisting of a sampling time and a time-difference between said current time and said next sampling time
when said MT moves to a location at said next sampling time (time k+1), combing said observed values of location at time k with said obtained values of speed at time k to obtain the predicted values in the form of means and variances at said next sampling time (time k+1); and obtaining the observed values in the form of means and variances of location and speed of said MT at said next sampling time (time k+1), receptively, and, then, based on the predicted values in the form of means and variances of location and speed and the observed values in the form of means and variances of location and speed, giving different fusion weights to extract more accurate estimated values in the form of means and variances of location and speed by using a heterogeneous data fusion algorithm at said next sampling time (time k+1); and based on features of said error propagation law and an inherent nature of distributed message passing in a factor graph (FG) scheme, said heterogeneous data fusion algorithm gives different weights to fuse values of location and speed passed between variable nodes (VNs) and factor nodes (FNs) according to reliability information between said values of location and speed. |
