Using pyroelectric signal amplitude method for target distance-measuring will have a greater error

because the output signal amplitude is affected by many factors（target individual differences

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sensor placement）.Without additional optical device or a Fresnel lens

pyroelectric sensors usually can only percept the present of moving target in a short distance

and can not distinguish the distance.Sensing range of the sensor extends to 30m by using an infrared lens means.After characteristically analyzing on the acquired large quantities of signal

it is found that there is linear relation between the analog signal peak time difference and the moving target distance from the nodes

by taking advantage of this relationship high precision distance-measuring is realized in 30m possible detecting range.Compared with the signal amplitude distance-measuring method

this method can obviously improve the distance-measuring reliability and accuracy.