A Filtering Algorithm on Ionospheric Delay Calculation in Multi-constellation Satellite Navigation Systems

Shan Wang, Jun Zhang, Rui Li, Qifeng Xu

Abstract:	With the development of Global Navigation Satellite System (GNSS), more and more Satellite-Based Augmentation Systems (SBAS) are under trial and development. The objective of SBAS is to augment Global Position System (GPS) by way of improving its accuracy, integrity, continuity and availability in order to satisfy civil aviation requirements for navigation and landing. For single frequency users, ionospheric delay uncertainty creates the largest restriction to the accuracy and availability of satellite navigation. With the signals from SBAS, it is able to directly estimate the ionospheric delay of single frequency users at any point in the service volume, but its accuracy and integrity need to be improved. The next generation GNSS would include GPS, GLONASS, Galileo and Compass satellites, the minimum number of visible satellites would be over two dozen. It has agreed that the use of two or more space-based navigation systems should provide better service than can be achieved by relying solely on any one system, thus investigation on interoperability of signals from these systems to get better performance is of significance. Therefore in this paper, we will discuss on how to calculate ionospheric delay of single frequency users in SBAS when multi-constellation navigation satellite systems are available. Specially, in Compass system, the IPPs are motionless, and the Kalman filter is more and more widely used in navigation, the filtering algorithm is proposed to be used in ionospheric delay calculation at Ionospheric Grid Point (IGP). Furthermore, the analyzed results will be shown afterward. Due to this method in SBAS, it could save the hardware consumption, as well as get a certain performance enhancement. Five sections are included in the paper. In section 1, we give the background information about SBAS and its ionospheric delay correction theory. The planar fit method which is widely used in SBAS is presented in details in section 2. In section 3, we propose the Kalman Filtering method in ionospheric delay calculation at IGPs. Detailed description of simulation condition, test and analysis are shown in section 4. Section 5 is the conclusion and the potential problems we will go on study.
Published in:	Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011) September 20 - 23, 2011 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	2520 - 2525
Cite this article:	Wang, Shan, Zhang, Jun, Li, Rui, Xu, Qifeng, "A Filtering Algorithm on Ionospheric Delay Calculation in Multi-constellation Satellite Navigation Systems," Proceedings of the 24th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2011), Portland, OR, September 2011, pp. 2520-2525.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In