Adaptive GNSS Velocimetry Combining Doppler and Carrier Phase Measurements Based on Online Variance Component Estimation

Instantaneous velocity is an important variable for navigation and measurement tasks, and its estimation using a stand-alone global navigation satellite system (GNSS) receiver has important theoretical and practical significance for many applications. Adopting a stand-alone receiver to determine the instantaneous velocity in real-time has the advantages of independence of reference station, simple equipment, superior real-time performance and low cost. With these advantages, a new method is proposed to determine the instantaneous velocity by combining Doppler and carrier phase measurements based on online variance component estimation. This is a data fusion problem described by a state space model, in which the uncertainty of the state space model is tuned online through adaptive filtering. The adaptive variables are optimized using the locally best invariant quadrature unbiased estimate (BIQUE), which are directly estimated without iteration. The GNSS velocimetry principle and Doppler and carrier phase combined velocimetry process are provided in the abstract figure. To verify the proposed approach, simulation and real GNSS data with different sampling intervals are used in experiments. All results demonstrate the efficacy and stability of the proposed approach compared to the conventional approaches.