The　strapdown　inertial　measurement　algorithm　was　firstly　derived　on　the　basis　of　the　set　coordinate　systems.　Secondly,　both　the　state　and　the　measure　equations　of　errors　were　established　based　on　the　indirect　feedback　and　non-tight　integrated　position/velocity/course　angle　measuring　model　between　the　middle-and-low　precision　IMU　(inertial　measurement　unit)　and　the　high　precision　CP-DGPS　(carrier-phase-differential　GPS).　Then　the　improved　self-adapting　Kalman　filter　was　employed　to　simulate　the　measurement　model.　Finally,　the　measurement　system　was　developed　for　the　model　certification　and　the　roadway　tests　were　conducted.　The　comparative　study　on　the　simulation　and　the　roadway　tests　showed　that　the　simulation　results　are　in　good　agreement　with　the　experimental　result,　which　further　justified　the　effectiveness　of　the　developed　integrated　system　for　the　vehicle　active　safety　roadway　test.