Generally standard receiver architectures cannot provide an accuracy level sufficient for use in all environments,especially in the urban canyon environment.High sensitivity receivers that can track GNSS signals in those circumstances were proposed; even with degraded signals,the receiver can still extract the pseudorange and Doppler information.However,the challenge with high sensitivity receivers is the measurements are not always reliable and can produce large errors in the standalone and integrated navigation solution.In order to overcome the drawbacks of GNSS only applications,a dead-reckoning (DR) system is often integrated with GNSS.Such systems use a variety of vehicle sensors including wheel speed sensor,accelerometers,gyros and steering angle sensors,and have proven to work well in harsh downtown environments.By extension,GNSS/DR integrated navigation systems take advantage of the complementary characteristics of the two systems.The combined system offers significantly increased performance in terms of accuracy and robustness compared to the standalone usage of either.In this paper,loosely coupled and tightly coupled integration architectures are evaluated and compared.Moreover,two different high sensitivity receivers are integrated with DR.These architectures aim to improve measurement reliability,which,in turn,would improve the integrated GNSS/DR solution.