SECOND ORDER COMPLEMENTARY GLOBAL POSITIONING SYSTEM/INERTIAL NAVIGATION SYSTEM BLENDING FILTER

摘要

A second-order filter that blends accurate position information from a onesource, and velocity information from another source, both suitably scaled, ina second-order complementary filter. The filter is arranged such that aninternal integrator (106) maintains a value that represents the difference inthe rate of change of the accurate position information, and the velocityinput of the other source. This velocity difference is applied to anotherintegrator (114) outside the filter, whose initial condition is the positionerror between the two sources to the second order filter. The output of thislatter integrator (114) is a correction signal that grows at a rate equal andopposite to the rate of error built-up of position data from the source whosevelocity is used in the second order filter. This correction signal is summed(120) with the original position signal. In addition, the output of the secondorder filter may be used as a highly accurate position signal.