Abstract
The restart of the receiver will lead to the change in the non-overlapping frequency inter-system biases (ISB), which will make it difficult to apply the tightly combined RTK method of pre-calibrating ISB to the actual scene. Particle swarm optimization (PSO) algorithm can be used to estimate the fractional part of the inter-system phase bias (F-ISPB) in real time, which is not affected by the receiver restart. However, the standard PSO can easily fall into local optimum and cannot accurately estimate the value of F-ISPB. In this contribution, based on the characteristics of F-ISPB, we propose an improved PSO with adaptive search space and elite reservation strategy to estimate the F-ISPB in real time. When the value of F-ISPB is close to the boundary of the search space, the improved PSO will transform the search space so that F-ISPB will be located near the central region of the new search space, which will greatly reduce the situation of the standard PSO easily falling into local optimum. Since F-ISPB is very stable, an elite retention strategy will help us to estimate F-ISPB faster and more accurately. Three sets of short baseline static data were selected for testing. The results show that the inter-system differenced model based on the improved PSO has a higher ambiguity fixed rate and positioning accuracy than the inter-system differenced model based on the standard PSO and the classical intra-system differenced model, and the fewer the number of satellites, the more obvious the effect.
Highlights
With the gradual completion and improvement of the multitude of global and regional navigation statellite systems (GNSS/RNSS), the compatible and interoperable joint positioning among multiple systems has become the inevitable trend of global navigation satellite system (GNSS) development in the future [1,2]
Unlike the inter-system bias (ISB) generated by the code signals, the integer part of the phase ISB is usually absorbed by the integer carrier phase ambiguity, so we only need to analyze the fractional part of the inter-system phase bias (F-ISPB)
When the value of F-ISPB is close to the boundary of search space, the standard particle swarm optimization algorithm is easy to fall into local optimum
Summary
With the gradual completion and improvement of the multitude of global and regional navigation statellite systems (GNSS/RNSS), the compatible and interoperable joint positioning among multiple systems has become the inevitable trend of GNSS development in the future [1,2]. The stability of F-ISPB is the precondition of using the method of prior calibration F-ISPB [20] This means that this method is not applicable to the case of receiver restart and receiver temperature drastic change at non-overlapping frequencies. Paziewski and Wielgosz [21] proposed to use the time-divided arc method for F-ISPB estimation, which can cope with temperature induced non-overlapping frequency F-ISPB changes. These methods still cannot solve the non-overlapping frequency F-ISPB jump caused by the receiver restart.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
