Design And Implementation Of Indoor Location And Navigation Device Based On Ultrasonic

In recent years,the system of outdoor location has been matured gradually,but the development of system for indoor location has been lagged to some extent.The people in the indoor environment,such as the shopping mall and basement parking,tend to obtain the information of the position and navigation.Therefore,it is necessary to study a system for location navigation with high accuracy and low cost.In this paper,based on the approach of distance measurement with ultrasonic,in order to overcome the problems of single function and radio frequency communication in the traditional system for location,the research has been carried out on the simplification of algorithms and the optimization of base stations via ultrasonic communication.Firstly,this paper has analyzed the current situation of system for outdoor location and indoor location,and found the causes of the large demand but small conversion for the system of indoor location.According to the specialties of the system,the entire scheme and strategy can be designed.In order to optimize the operation of the whole system,the two points location algorithm is adopted to improve the non-contact trilateral location algorithm,which can reduce the complexity and the execution time of the algorithm without changing the accuracy.Then the ultrasonic communication is introduced systematically.By the spread-spectrum,coding,modulation and demodulation,the communication function can be loaded to the ultrasonic besides distance measurement function,which can not take up other radio frequency resources,and can greatly reduce the cost of implementation and enhance the ability of conversion of the system.Cross line laser is firstly employed in the setting of base stations,which can determine the origin of the reference and help correct the whole system in the process of initialization.Meanwhile,it can achieve the location and navigationby two base stations instead of three base stations or nodes in the traditional system of location,which can save the cost and enhance the accuracy.Finally,after determining the hardware design and software platform,the system of location and navigation via ultrasonic based on STM32F407ZGT6micro-controller can be established through the way of theory combined with the practice.By testing every function of the system,the error values of location and navigation can be controlled in the range of 5 cm,and the absolute values of error are mostly concentrated in the area of 1.6-3.8 cm.After analyzing the causes of error,an improved approach is proposed in order to reduce the error.On the whole,the system of location and navigation can achieve various functions with high accuracy.