Embedded Design Of Dual Mode Positioning Device Based On ARM

With the advancement of science and technology,GPS technology has been widely used in exploration,navigation,field exploration,scientific research and other fields.Most of the satellite navigation terminals are dominated by GPS,and the GPS terminal products have a certain monopoly in the domestic market.In recent years,we have developed a huge development in our navigation technology,independent development of Bei Dou satellite has become the fourth mature satellite navigation and positioning system in the world.From the perspective of military strategy in the future,it will not only bring higher security to our own country but also accelerate the development of civilians.The single-mode handheld positioning device based on GPS or BD has been able to mature,but the dual-mode handheld positioning devices of GPS and BD are relatively few.Many companies are also actively combining the two technologies,hoping to gradually apply their applications to people's daily lives and military fields.Therefore,a dual-mode terminal with GPS and Bei Dou satellite navigation system is developed,which not only realizes the application of the mainstream satellite navigation but also ensures the higher security,while improving the combination of multiple satellite navigation systems in our country,laying a solid foundation for the diversified development of China's satellite navigation industry.This paper presents a design scheme of a hand-held positioning device based on GPS/BD dual mode receiver.After delving into the working principle of dual mode receiver module and ARM microprocessor architecture,the main hardware circuit and software flow of the device are designed.The peripheral key function module circuit is designed with STM32 series microprocessor as the core,including satellite reception circuit design,power supply circuit design,pneumatic interface circuit design,electronic compass interface circuit design,display interface circuit design,etc.Software is developed under the u COS-? operating system,through RS232,SPI and I2 C interface,the location,height,direction,temperature and other information are collected.And through the data calculation and processing,finally,graphics or figures are displayed on the screen.Then the solution and implementation method of the key problems are emphaticallypresented.Focus on the solution of key issues and methods of implementation,including the voyage and track to the processing,compass data processing and graphics display processing three aspects.The problems of distance and track are transformed into the algorithm of solving arc length and angle.The target distance and target orientation can be obtained by calculating arc length and angle.The heading angle data is determined and filtered.The compass is calibrated with zero calibration and magnetic north calibration.This makes the compass on the interface point more accurately.The anti-aliasing technique is used in the static display of the interface to make the display of the graphics smoother and more delicate.In the dynamic display of the interface,the drawing of the fragment memory device is used to overcome the flash problem caused by the frequent refresh interface in the drawing.Finally,the comparison results of the data processing experiment and the graph anti-aliasing experiment are given.It can be seen from the comparison results that the heading angle data can not be changed frequently at the critical point of the direction,and the edge of the compass is smoother and clearer after the anti-aliasing.Through these experiments,the design of the positioning device is well supported.