S.R. Heister, N.G. Parhomenko, A.S. Heister
Inverse antenna aperture synthesis (IAAS) is considered in regard to the problem of a traffic control. The control is performed by inverse synthetic aperture radar (ISAR).
Algorithm of IAAS with total focusing is represented. The algorithm provides formation of a vision matrix. The matrix is a set of synthesized beam widths (resolution elements). Coherent summation of received signals after compensation of phase incursion for moving center of the element during the sampling period of received signal is implemented in every matrix element. As a result of such signal processing azimuthal radiolocating portrait is formed. The portrait is a collection of complex amplitudes of signals that correspond to different resolution elements of automobile.
ISAR with monochromatic probing signal (carrier frequency is 24GHz) and antenna directivity diagram equal to 12 degrees was used in the experiment. IAAS with interval of resolution element placement equal to 0.2 meters was implemented in the radar. Duration of IAAS was equal to 0.743 seconds. Hamming weighting in a temporary realm was used to degrade the level of side lobes of synthesized antenna directivity diagrams.
Experimental radiolocating portraits of a passenger car (VAZ-2105, length is equal to 4.07m) and a bus (MAZ-1034, length is equal to 11.985m) are represented as example. Echo signal is concentrated in radiolocating portrait elements that correspond to resolution elements located on the surface of observed vehicles. Lengths of observed vehicles were evaluated according to the experimental radiolocating portraits. Estimation error of VAZ-2105 length measurement is 3.2% and 1.5% for MAZ-1034.
The experimental research has justified possibility of automobile length measurement using its azimuthal radiolocating portrait formed by means of IAAS. Magnitude of relative error totals from 1 to 5 percents. Magnitude of error increases if there is a mistake in automobile velocity and initial position adaptation.