Research On High-precision Land Doppler Velocimetry Based On MEMS/Land Doppler Velocimetry

In modern warfare, ground combat vehicles must be fast and accurate entry fighting positions, accurately determine its own position and direction. The precision of thespeed information is the important parameter of the vehicle location. Existing velocimetry methods have different drawbacks. It is difficult to get high accuracy, fast dynamic response speed parameters. Doppler velocimetry have the characteristics of high accuracy, fast dynamic response, adapt to the environment,and non-contact measurement. Ithas become an important development direction of modern speed system. Recent years， MEMS been widespread concern in the field of navigation，because of the smallsize, light weight, cheap. MEMS can provide the posture necessary information for theDoppler velocimetry. They can be each other correction to obtain more accurate velocity information. This pape research the principle of the ultrasonic Doppler velocimetry,frequency measurement algorithm and methods and principles of MEMS combination.Period that the technology has been widely used in land navigation areas.This first point out the existing land-use navigation speed main way, the lack ofthe way, advantages of the ultrasonic Doppler velocimetry relative to other produce. The paper describes the development of the land-use navigation system at home and abroad, systematic analysis of the principle of a single beam and dual beam. Pointed out that the dual-beam velocity system can effectively reduce the error of formula simplifies, and effectively restrain the error by road bumps. The system uses a dual-beam as Doppler velocimetry system. Indicated the error sources of Doppler velocimetry system, and established the system error model. The commonly frequency measurement methods, including zero-crossing detection, negative correlation and Power spectrum estimation method are compared. Multiple correlation method is established as the system frequency measurement method.The paper clarifies the feasibility of MEMS/Doppler velocimetry combination, andanalysis the different of loose combination and tight combination. Use the tight combination as combination of programs. Tight combinations not only provide error feedback correction to restrain error accumulation for MEMS, but also reduce the Doppler velocimetry scale error coefficient, improve the accuracy of Doppler velocimetry system.The MEMS and the Doppler velocimetry error model to establish a combination of system error model, establishThe state equation and measurement equation. According to the working principle of MEMS and Doppler velocimetry, established the structure of the combined system. The system includes: MEME module Dopplervelocimetry and control circuit. The paper detailed design the hardware architecture and software implementation method of the ultrasonic Doppler velocimetry. TMS320F28335digital signal processing chip (DSP) is the core of the system hardware. The DSPinternal PWM generator produces frequency square wave pulse. Class D power amplifier load impedance matching network, and filter shaping，transceiver conversion, the frequency solver speed information.Using CCS software build system debug platform, and debug the Doppler velocimetry hardware and software. And using Matlab verifies combined effect of MEMS/Doppler velocimetry. The tight combination can effectively inhibit the Doppler velocimetry scale error coefficient, increasing the velocity precision of Doppler velocimetry.