Abstract: To lower the computational requirement for embedded processor,sequential measurement update algorithm is implemented.The result of road test in urban canyon verified the algorithm and architecture.This navigation system can estimate vehicle's position,velocity and heading even when autonomous GPS receiver fails to work.The proposed application includes high-performance car navigation system,altitude estimation system,etc.Another purpose of this project is to provide a altitude reference for ultra-tightly coupled navigation system based on software radio(SDR) GNSS receiver.