The invention relates to a method for designing a
digital filter applied in an
inertia device. The method is characterized by comprising the following steps of: determining an amplitude attenuation allowable value according to the precision of the
inertia device, determining a phase
delay allowable value according to the
performance index of a strap-down
inertial navigation system, and determining certain technical parameters of the filter according to the actual
signal power
spectrum analysis of the
inertia device; designing a reference analog filter, converting the reference analog filter into an
infinite impulse response (IIR)
digital filter by using a bilinear transform method, observing a bode diagram in the filter parameter adjusting process, and performing off-line
simulation calculation according to the actually measured data; and performing judgment by using de-noising effect, common
cutoff frequency, amplitude attenuation and phase
delay as fuzzy variables and using fuzzy rules to optimize the integral
performance index. The
digital filter designed by using the method can effectively filter the
noise in the inertia device, meanwhile, controls the amplitude attenuation and the phase
delay in an allowable range, and ensures the precision of the signals.