In-Receiver Analysis and Estimation of GNSS Biases
Date
2021-08-27
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Abstract
Global navigation satellite system (GNSS) biases significantly degrade performance when using GNSS for precise positioning, ionospheric remote sensing, and time transfer. To date, research on GNSS biases has been primarily based on measurements output from receivers. This thesis investigates the concept and method of bias analysis and estimation within receivers with a focus on the analysis and estimation of receiver-induced biases, the correlator spacing influence on single-frequency positioning, fractional cycle bias estimation, and differential code bias estimation based on a correlator spacing flexible software receiver. The in-receiver bias analysis and estimation approach will open doors for bias calibration within receivers to output measurements with biases eliminated. The calibration of GNSS in-receiver front-end local oscillator, chip, ADC, and baseband correlator spacing-induced biases has been investigated and analyzed for the same frequency. The results show that the front-end-induced biases cannot be ignored and cannot be simply included in a certain error. The correlator spacing-induced biases have significant differences between satellites based on an analysis of both simulated signals and live signals.
The between-spacing real-time differential positioning method (BSRTD) and the between-spacing real-time kinematic positioning method (BSRTK) have been developed to improve the performance of single-receiver single-frequency positioning after an analysis of inter-spacing bias influence on single point positioning (SPP). The results show that the BSRTD and BSRTK methods can significantly improve the stability of single-frequency positioning with a smaller standard deviation, and the BSRTK method can offer faster ambiguity resolution. A cascaded FCB estimation method, named the multi-spacing single-receiver estimated FCB (MSFCB) method, has been developed based on different correlator spacing pseudorange and carrier phase observations. The MSFCB method can be used in the ambiguity resolution process. A software receiver-based multi-spacing DCB estimation method has been proposed to improve DCB real-time performance. By comparing the MSDCBs to the IGS DCB products, the results show that the proposed correlator spacing flexible software receiver is able to estimate satellite DCBs with increased flexibility and cost-effectiveness compared to the current hardware receiver-based DCB estimation approach.
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Keywords
In-receiver biases, BSRTD, BSRTK, Fractional cycle biases, Differential code biases
Citation
Wang, Y. (2021). In-Receiver Analysis and Estimation of GNSS Biases (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.