Signal conversion device for accelerometer in strapdown inertial navigation system

Abstract

The invention discloses a signal conversion device for an accelerometer in a strapdown inertial navigation system. An analog current signal output by the accelerometer is converted into an analog voltage signal; the analog voltage signal is subjected to integration by a voltage-to-frequency (V / F) conversion module; one path of analog voltage subjected to integration is output to a pre-amplification circuit, and the other path of analog voltage subjected to integration is converted into a pulse signal and the pulse signal is output to a field programmable gate array (FPGA) processing module; the pre-amplification circuit matches a range of the input analog voltage with an input voltage range of an analog-to-digital (A / D) conversion module; the A / D conversion module converts the analog voltage into a digital value signal and outputs the digital value signal to the FPGA processing module; the FPGA processing module acquires number of pulses output by the V / F conversion module in unit time, the number of the pulses is used as an integer part for calculating the number of pulses, the acquired number of pulses and the digital value signal input by the A / D conversion module are stored in fixed time, and a decimal value of the number of pulses in an acquisition period corresponding to the digital value signal is calculated; and a digital value corresponding to the analog current signal output by the accelerometer is determined according to the integer part and the decimal value of the number of pulses, so that the signal of the accelerometer is converted.

Description

technical field [0001] The invention relates to a signal collection, measurement and processing technology suitable for an accelerometer in a strapdown inertial navigation system. Background technique [0002] The strapdown inertial navigation system is a system that relies on inertial devices (accelerometers, gyroscopes) fixed on the carrier to obtain absolute acceleration, and then obtains the position of the carrier in a relative coordinate system through two integrations, so as to achieve navigation purposes. An "autonomous navigation system". In the strapdown inertial navigation system, the accelerometer is used to measure the linear acceleration of the carrier along a certain direction, and after necessary integral calculation and coordinate transformation, the instantaneous velocity and position of the carrier relative to the reference coordinate system are determined. When the acceleration parameters of the carrier change, the accelerometer will detect this change a...

AI Technical Summary

Problems solved by technology

Although this method is extremely fast, it is difficult to implement when the resolution is above 10bit, the hardware scale is too large, and the cost is difficult to reduce

There is a D / A converter inside the successive comparison type, and a digital code is obtained by the binary search method, so that the corresponding voltage is closest to the input voltage. When this method uses a MOS integrated circuit, the D / A conversion uses a large number of capacitors constituted, the manufacturing process is difficult to achieve

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