The direct algorithm of interferometric synthetic aperture radar measuring is to directly introduce the absolute phase difference into range equation and Doppler equation to resolve the ground coordinates.

In this paper,it is indicated that: in the range equation of IR systems,the atmospheric transmittance τa itself is a rapidly varying function of range R,therefore,the range equation of IR systems is modified into a more exact expression.

The T-square study of Betula albo-sinensis population on the west slope of Jiuding Mountain showed that the population was mainly in random distribution, and in aggregated distribution in a few lines because of the negative human activities and severe destructions.

In this paper, firstly the noise level in laser warning is analyzed, then the signal to noise ratio and detection probability are researched, and at last the distance equation and dynamic range are also researched.