Abstract: The low cost INS/GNSS integrated navigation system is susceptible and has a larger heading error in complex environment. For solving these problems, a dual antenna GPS/MEMS INS deeply integrated navigation approach is studied. Considering the tracking characteristics of signals with different intensities, three tracking structures are designed for strong signal, weak signal and loss of lock status based on vector delay locked loop (VDLL), second order phase locked loop (PLL) and velocity aided first order PLL respectively. A practical method of estimating signal intensity is presented to prevent channels with large error from participating in the calculation of navigation filter, and the navigation accuracy is improved. In order to ensure the heading accuracy, two antennas are used. The carrier phase difference of the two antennas is added into the measurement of the navigation filter. A phase difference measurement equation in which the pitch information is isolated is constructed by using the line of sight vector horizontal projection transformation. Vehicular navigation test shows that the designed navigation system can provide continuous and high precision navigation output in urban environment.

Key words: Dual antenna, Deeply integrated, Vector tracking, Kalman filter