| Integrated navigation system has become a research hotspot in the field of navigation because it can make use of the navigation information of several independent navigation sub-systems and achieve higher navigation precision and performance than single navigation sub-system.With the development of MEMS technology and embedded technology,the integrated navigation system based on MIMU/GNSS has a wide application prospect in both military and civil fields because of its small volume,high reliability and high cost performance.Hardware platform is the base of the system,so it is significant to design a hardware platform with low power consumption,high reliability and versatility to support the algorithm research and implementation of integrated navigation system.In this paper,the hardware platform of MIMU/GNSS integrated navigation has been studied and designed to meet the needs of practical application and theoretical research.Firstly,by analyzing and comparing the research status of MIMU/GNSS integrated navigation system at home and abroad,the current research direction,achievements and existing problems of MIMU/GNSS integrated navigation hardware platform are obtained.The main problem of this paper is to improve the reliability and generality of the hardware platform,optimize the size and power consumption of the hardware platform.Secondly,this paper analyzes the theory of MIMU/GNSS integrated navigation system,defines the basic tasks of MIMU/GNSS integrated navigation hardware platform and carries on the requirement analysis.According to the result of requirement analysis,the general design framework and relevant design standards are obtained.Thirdly,according to the overall design framework and design standards,design scheme demonstration and device selection.A design scheme based on high integration devices is proposed.The design of MIMU signal acquisition circuit based on six-axis integrated chip MPU6050 and GNSS signal acquisition circuit based on dual-system navigation and positioning chip UM220 are presented The integrated navigation computer system based on ARM Cortex-M4 processor is designed,which ensures that the hardware platform can obtain better cost,power consumption and volume characteristics,and conforms to the trend of MIMU/GNSS integrated navigation system to monolithic integrated system.A redundant power supply circuit based on MOSFET and diode is proposed,which can realize the automatic switching of main power supply to standby power supply without interval when the main power supply fails,and effectively improve the reliability of hardware platform.The design of four-channel multiplex communication circuit based on RS-232 serial communication,USB serial communication,ethernet communication and bluetooth communication is put forward.The utility model effectively improves the universality of the hardware platform and broadens the application scope of the hardware platform.Lastly,the hardware circuit and software of MIMU/GNSS integrated navigation hardware platform are designed in detail according to the proposed design scheme.the test results show that the scale of the main board of the MIMU/GNSS hardware platform is 83mm×79mm,and the miniaturization is realized.The measured power consumption of the system is 975 mW,which meets the need of low power consumption by using low-power chip-level devices.By analyzing the GNSS receiver measurement data,it is proved that the GNSS module can realize effective positioning and the static positioning accuracy is better than 5 meters.In order to reduce the error,the mean shift compensation is proposed to correct the error,and the Kalman filter is used to reduce the effect of random noise.The experimental results show that the proposed method can suppress the error effectively and improve the accuracy of MIMU measurement data. |
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