High-precision digital filter applicable to strapdown inertial navigation

The invention discloses a high-precision acceleration DAC (digital-to-analogue conversion) digital filter applicable to strapdown inertial navigation and relates to the field of data acquisition. The filter comprises a sampling comb filter, an FIR double-extraction compensation filter and an FIR quadruple-extraction compensation filter, wherein the sampling comb filter adopts an efficient down-sampling filter structure put forward by Hogenauer and is used for realizing high-rate underclocking; the FIR double-extraction compensation filter is generated through a fir2 function in the matlab, the function can design a multi-band random response curve phase FIR filter, the filter is mainly used for compensating the pre-stage CIC (cascaded integrator comb) filter with attenuation on band margins and realizing double extraction; the FIR quadruple-extraction compensation filter calculates coefficients of the optimal filter with the Parks-McClellan algorithm, and the filter is low in pass band ripple, narrow in transition band, large in stop band attenuation and high in filter order. The high-precision digital filter meets the strapdown inertial navigation system data sampling requirement.