Abstract. In this article
we consider a problem of digital simulation of a received signal for SAR, which
uses pulse package with chirp. Chirp demodulation is carried out in a receiver
mixer by local oscillator, which has chirp with the same steepness. Surface
surveillance is performing in a sector scan mode. Surface model contains
thousands of resolution elements. It is necessary to calculate hundreds of
thousands of time samples for each point. The direct calculation for so many samples
results in unacceptable time expenditure. The method of fast calculation is known. This
method is based on multiplication of two matrices of samples. The first matrix
includes the chirp law and contains samples for one repetition period. The
second matrix includes slow processes and contains one sample for each
repetition period. Factorization of computational formula speeds up model
operation hundreds times as much. However, known method does not allow the
peculiarities of pulse package processing in the SAR under consideration. By
sector scan, the target has greater radial velocity caused by SAR moving. In the
task of modeling of received signal the fast moving makes factorization of
computational formula difficult. The method of fast calculation of the received
signal for the model of the described SAR is offered in this work. Admissible
conditions of practical application of the offered method of analysis are
estimated. Compensation of relative motion of SAR is carried out before
factorization of the design formula in order to expand the conditions of
practical application. The method provided more than 200 times acceleration of
the calculation.
Key words: SAR,
chirp,
digital simulation, factorization, compensation of motion.
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