To eliminate the conventional air-borne SAR images using auxiliary information on the inertial navigation error correction lagged effect ,This paper proposed a new analysis of the quasi-real-time navigation filter programs and algorithms to solve the SAR/INS integrated navigation system the lagged effect of the measurement combined with previous squint SAR imaging features; This paper analyzes the squint SAR imaging-aided navigation system work characteristics, analysis of SAR measurement output model; established a quasi-real-time INS/SAR integrated navigation filter algorithm model, and then analysis of the integrated navigation system performance by simulation. Simulation results show that: the proposed INS / SAR combination of programs and algorithms can effectively overcome the lagging impact of the conventions SAR auxiliary navigation systems, and meet performance requirements.