An Innovative Remote Testing System for GNSS Receiver Based on IF Sampled Signal Library of Various Scenarios

摘要

With the development of the satellite navigation system, the satellite navigation industry has become a national essential infrastructure system and played a significant role in transportation, infrastructure construction, measurement of surveying and mapping, industrial and agricultural production, national defense construction and other fields. Satellite navigation system is composed of space constellation, ground control segment and user terminals[1]. Among the three parts, the user terminal which is connected to users, directly determines the navigation and positioning performance provided to the users. At present, there is a growing need of tests for GNSS receivers, since the development of Global Navigation Satellite System (GNSS). As there exists obvious difference among application circumstance, carrier platforms and performance requirements for user terminals, a testing method that satisfies various applications of navigation terminals is on demand. Currently, most of the developers are testing their algorithms and receivers using simulated signals, for different environment conditions and scenarios, based on hardware or software simulators. Those simulators use classical orbital mechanics equations, ephemeris broadcast standard and wireless signal transmission theory model to emulate the satellite signals. However, simulated signals are different from real world signals, because the simulating method cannot provide accurate model of environment for navigation signals. To solve this problem, the existing solution is to use the signal sampling and playback equipment which acquires real navigation data from typical environment and transfers playback signals to the test terminals. But this method has a limitation of lack of data for multiple scenarios. Under these circumstances, a system is required that can provide real test signals under multiple scenarios and environmental conditions. In this paper we proposed a system that can provide real GNSS test signals according to predefined scenarios and conditions. The proposed system consists of a database of signal library covering a wide range of typical scenarios and a playback equipment to reproduce real satellite signals. This system also provides PVT (position, velocity and time) data which is precisely calibrated by signal record part as reference. Users can use this system to improve the performance of their designed GNSS systems.