An Indoor Positioning Method Based On Simulated GNSS Signals

Currently the traditional global navigation satellite system(GNSS) signals is wildly applied in outdoor positioning problem, normal user receivers can achieve high precision navigation and positioning work as long as they can receive signals from four or more than 4 available GNSS satellites. However, when applying GNSS signals to indoor positioning, due to the affect of the enclosed or semi-enclosed environment, available GNSS satellites signals were severely blocked or completely invalid, GNSS positioning technology does not work normally, this problem seriously hampered the development and application of GNSS signals in the field of indoor positioning. Conventional positioning technology such as WIFI and Bluetooth has disadvantages such as lower accuracy and signal incompatible with GNSS. This paper mainly studied a simulated GNSS signals based indoor positioning method, and verified this method by building system and programming.The indoor positioning method studied in this paper was based on simulated GNSS signal, which can fully simulate real outdoor GNSS satellite signal frequency and message, use radio frequency antenna to simulate GNSS satellite to broadcast signal, and add large distance constant in Pseudo-range information when transmitting indoor simulation signals, transform the original indoor simulation satellite equally into outdoor simulation satellite, realized receiving simulation signals using standard GNSS receiver indoor, without software changes made in the receiver port, achieved real-time navigation and positioning. The study method in this paper is a exploration in seamless indoor and outdoor high-precision GNSS positioning problem. First of all, this paper demonstrated the feasibility of the method from aspect of GNSS navigation and positioning principle, and designed a system. Secondly, built the corresponding hardware simulation platform through experimental study. Finally, programmed a software processing system which is suitable to computer and mobile phone port, tested the proposed method and validated accuracy using the real measurement data. The experimental result based on real indoor environment shows that: without the deduction of the Multipath effect and with the deduction of the Multipath effect, positioning accuracy of the proposed method can be achieved decimeter level and millimeter level, respectively. The study results have some reference value for the realization of indoor and outdoor GNSS signals unity, seamless positioning, indoor high-precision GNSS instrument calibration, etc.