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The associated resolution loss from sharing the synthetic aperture among different swaths is compensated by collecting radar echoes with multiple displaced azimuth apertures. A possible drawback of multichannel ScanSAR or TOPS approaches is the rather high Doppler centroid, [ 9 ] which is one of the most important parameters need to be ...
However, the azimuth resolution become much lower than the stripmap mode due to the decreased azimuth bandwidth. Clearly there is a balance achieved between the azimuth resolution and the scan area of SAR. [37] Here, the synthetic aperture is shared between the sub swaths, and it is not in direct contact within one subswath.
AN/APG-66(V)2A – AN/APG-66(V)2 with a new combined signal and data processor providing seven times the speed and 20 times the memory of the older radar computer and digital signal processor line replaceable units. Displayed resolution in ground-mapping mode quadrupled, and is reported to be close to that offered by SAR techniques. Used for ...
To obtain fine azimuth resolution, a physically large antenna is needed to focus the transmitted and received energy into a sharp beam. The sharpness of the beam defines the azimuth resolution. An airborne radar could collect data while flying this distance and process the data as if it came from a physically long antenna.
The world's first airborne monopulse radar system was the British Ferranti-designed AIRPASS system which went into service in 1960 on the RAF's English Electric Lightning interceptor aircraft. An early monopulse radar development, in 1958, was the AN/FPS-16, on which NRL and RCA collaborated. The earliest version, XN-1, utilised a metal plate lens.
At any range, with similar azimuth and elevation angles and as viewed by a radar with an unmodulated pulse, the range resolution is approximately equal in distance to half of the pulse duration times the speed of light (approximately 300 meters per microsecond). Radar echoes, showing a representation of the carrier
The radar "looks" with the looking angle θ (or so called off-nadir angle). The angle α between x-axis and the line of sight (LOS) is called cone angle, the angle φ between the x-axis and the projection of the line of sight to the (x; y)-plane is called azimuth angle. Cone- and azimuth angle are related by cosα = cosφ ∙ cosε.
Location accuracy is a dependent on the certainty of the position of the radar, the radar-pointing accuracy, azimuth resolution, and range resolution. A long antenna or very short wavelength can provide fine azimuth resolution.