The GNSS signal suffers from quality degradation or outages due to blockages in the urban environment,leading to the error divergence of precise point positioning(PPP)/inertial navigation system(INS)tightly coupled system.Although the traditional height constraint models based on the constant height hypothesis can effectively suppress INS error accumulation un-der flat surface,it is difficult to enhance the PPP/INS tightly coupled model because of unadapting the change of surface under the high occlusion environment.In this paper,considering the similar characteristic of short-term height variation rate during vehicle experiment,an adaptive short-term height variation rate constraint(ASTHVRC)model of PPP/INS tightly coupled system is proposed.The effectiveness of the proposed model is verified by both simulated occlusive environment and real urban environment.In the real urban environment,comparing with the height constraint-free(HCF),the height rate-weighted con-stant height constraint(HRWHC)and the inter-epoch constant height constraint(ICHC),the results show that ASTHVRC model improves the accuracy of PPP/INS tightly coupled height solution by 52.2％,49.2％,70.9％,respectively.
PPP/INSadaptive short-term height variation rate constraintstochastic model of height constraintsatellite out-age
NETL
NSTL
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