For the GNSS/INS Integrated Navigation System in the loose coupling mode, the global satellite navigation system (GNSS) signal is vulnerable to environmental impact, which may lead to signal loss in some scenes. In view of the GNSS lock out situation, the non integrity constraint (NHC) is applied to the wheel tachometer (OD)/strapdown inertial navigation system (INS), which can effectively suppress the error divergence of pure inertial navigation in the case of GNSS signal lock out. At the same time, an adaptive Kalman filter algorithm based on innovation and an adaptive NHC noise method considering the vehicle motion relationship are proposed, which can effectively enhance the navigation and positioning ability in the GNSS lock out and vehicle turning scenarios. The verification of the scene measured data shows that the integrated navigation system using adaptive Kalman filter and adaptive NHC noise can ensure the navigation accuracy of "cm" level in the case of GNSS signal losing lock for 10s. Compared with the traditional extended Kalman filter scheme and the scheme using only adaptive NHC noise, its positioning accuracy is improved by 10%, and the speed measurement accuracy is improved by about 30%, which can meet the high accuracy of the navigation system in the GNSS losing lock environment High reliability navigation and positioning service.