High-Precision Two-Way Ranging and Timing Method for High-Dynamic Asynchronous Nodes

Many applications such as intelligent transportation systems, spacecraft or autonomous aerial vehicles formation are very dependent on high-precision relative navigation solutions. This paper proposes a two-way ranging and timing (TRT) method that can provide high-precision inter-node relative ranging and timing results for relative navigation. Affected by the high-dynamics between nodes and nonuniform measuring interval caused by measurement instant jitter, the conventional TRT methods cannot achieve high-precision ranging and timing. To this end, we propose a TRT method using osculating polynomial timestamp unification. In this method, we first use the piecewise osculating function to construct the generalized-order timestamp unification model, and then use binomial theorem and boundary conditions to solve the unknown coefficients. Next, we implement time-varying interval processing and symmetry processing skills to reduce computational burden. Finally, we provide the estimator of the actual distance and clock offset (considering clock drift and initial clock offset) between two asynchronous nodes. Based on the proposed TRT method, we further propose a measuring precision improvement strategy based on the measurement interval adaptive optimization. This strategy can adaptively adjust the measurement interval according to the dynamics. The superiority of the proposed TRT method in terms of precision is verified by simulations under different measurement instant jitter, dynamics, and standard deviation of measurement noise.