In contrast to the real aperture, the cross range resolution improves with the increase in the half-power beamwidth of the real antenna. Therefore, called cross-range resolution. The resolution in the direction of motion is thus orthogonal to the radar beam and the range measuring and is, In the SAR, a distance is measured perpendicular to the direction of the movement of the radar platform. Specifying an angle for the beamwidth is impractical because it cannot be measured but only calculated. (SAR's) resolution capability has completely different contexts than that of a classical radar with a real antenna. Cross Range Resolutionĭue to the computational postprocessing, the This confounds since the variable name «theta» is commonly used for all these angles in the literature. Whether the angle used is only half the width of the main lobe or both halves. However, when applying the formula (1), it is necessary to consider the relation of However, the difference in size can be neglected in practice approximately. The half-power beamwidth and the beamwidth between nulls relate to the entire width of the main lobe (see Figure 2).īoth angles (zero angle and half-power beamwidth) are thus similar in size but not equal. The null angle thus only refers to half the width of the main lobe. The beamwidth factor depends on the antenna type and varies fromĠ.89 rad (≙ 56 degrees) for an ideal reflector antenna, up to 2 rad (≙ 114 degrees).įor the null angle of a synthetic aperture the beamwidth factor is 1.220 rad (≙ 70 degrees). Assuming a linear phase distribution, each amplitude distribution has a corresponding beamwidth factor,Įxpressed either in radians or in Radiant.
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