Focus on the GPS information errors; compare several popular solu-tions; and reach a conclusion.
1.  Analysis on current situations of GPS information errors,description of DGPS test details.
2.  Introduction of Multipath effect, option to improve on long delay Multipath, and Multipath reduction comparison.
3.  Dead Reckoning -Blending, influence of temperature compensation. As a conclusion, the speech suggested that Effective Multipath Rejection improves position accuracy,but still cannot provide position fixes when sky view is closed; and sensor-based dead-reckoning can provide 100% position availability to allow accurate and uninterrupted position fixes at all time.