In UAVSAR's various working modes, the theoretical azimuth resolution
follows [DX.sub.spot] = 0.15 m, [DX.sub.sliding] = 140 m, and [DX.sub.TOPS] = 2.70 m.
Approximate analytical expressions for the degradation of the azimuth resolution
are derived and criteria for the acceptable phase errors are given both for the LQPE and LLPE.
As described in Section 2.2, the Doppler bandwidth needed for MEOSAR can be less than LEOSAR for a given azimuth resolution
. So we know that the PRF can be less for MEOSAR from the left inequation in Equation (5).
The correlation shows consistency of the radar picture up to an azimuth resolution
of 0.1 degrees, which is well below the resolution provided by the most directive antenna employed (2 deg of azimuthal resolution for the microstrip patch antennas).
A similar configuration is adopted for the SAR-High antenna, with the same basic radiating element, but working at dual linear polarization and assuming an array of 2 x 8 elements in order to increase the azimuth resolution
On condition that the range between radar and target does not change, the antenna beamwidt h must be reduced to improve the azimuth resolution
. However, the reduction of antenna beamwidth is very difficult due to other limitations.
The azimuth resolution
of a radar depends on the beam width of its antenna.
Intrinsically, the challenge of processing synthetic aperture radar (SAR) data comes from the fact that a long coherent aperture is needed to improve target's azimuth resolution
. This mainly results in two opposite effects: 1) the desired longer illuminating time for each target in the imaged scene to improve azimuth resolution
; and 2) the range dependent signal dispersion along azimuth direction in the two dimensional (2D) signal domain (range compression assumed).
Stack name Shanghai Number of images 36 Orbit Descending Workmode Strip map Azimuth resolution
3.3m Range resolution 1.2m Incidence angle 26 degrees
However, high azimuth resolution
and wide range swath imaging pose contradicting requirement on conventional SAR system design.
Assuming that the azimuth beam steering direction from aft to fore is positive, progressive azimuth beam steering introduces an azimuth shrinking factor, which is response for the reduced target Doppler bandwidth and the coaster azimuth resolution
. The shrinking factor is as follows :
The equipment's range resolution is 25 m (typ), with an azimuth resolution
value of 0.1[degrees] (typ).