Performance of a MEMS IMU deeply coupled with a GNSS receiver under jamming

Satellite navigation signals are very weak in power and, therefore, rather easy to jam for various purposes in both military operations and civilian life. This paper studies the jamming mitigation performance of deep GNSS-INS coupling when a low-cost MEMS inertial measurement unit (IMU) is being used. Deep coupling refers to the integration architecture which implements inertial-aided vector GNSS tracking instead of independent (scalar) tracking loops. In this paper the most important equations involved in noncoherent deep coupling are presented and the tracking performance using the MEMS IMU is compared to the performance obtained using the true antenna position instead of inertial navigation computations. Moreover, the convergence of the integration filter is investigated in the case where only four satellites are available. The results show that the MEMS IMU cannot quite bridge a jamming period of 35 seconds but still outperforms standard unassisted scalar tracking. Moreover, it is observed that an adverse satellite geometry significantly slows down the convergence of the accelerometer bias states of the integration filter while some other states reach a steady state normally.