| Positioning system plays an important role in people's daily life since a longtime ago. Although satellite positioning systems such as GPS and GLONASS is usedwidely recently, terrestrial area positioning system based on beacons is still the bestchoice in many circumstance, since it has low cost and can be set up easily.This article introduced a positioning system scheme based on the TCR-153Ashortwave adaptive communication system developed by the 713th Factory. Byadding some positioning units to the communication system, the system can set up alocation network and get the position of each user. This system has a simpleconstruction, and do not need oscillator with high frequency stability and accuracy,which reduce system's cost and is suitable for widely use. The simulation resultindicates that the system's positioning error is less than 100 meters with theprobability of above 80%, and 150 meters with the probability of nearly 95%.The system's component, positioning algorithm, hardware architecture andworking procedure of each unit is introduced, and a comparative complete scheme isgiven. The maximum likelihood phase estimation algorithm for sin wave is alsointroduced. During the discussion of positioning algorithm, we analyzed the infectioncaused by unsynchronization of beacons and frequency shift of oscillators, then gaveout some means to minimize the infection. Such means can also be used in similarpositioning systems.Positioning accuracy is also discussed. Besides the error introduced in phaseestimation phase, we mainly discussed how beacon layout affect positioning accuracy.The definition and calculate method of DOP is introduced, and many simulationresults on HDOP distribution of various beacon layout are given. |
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