Resolution Cells

Each emitted pulse is reflected by the surface and is returned to the altimeter a few milliseconds later. As the illuminated area grows, the return signal strength grows rapidly until an annulus is formed. It then remains constant until the growing annulus (or ring) reaches the edge of the radar antenna beam, and then starts to diminish. The signal acquired by the altimeter at each Ku-band burst is initially the same as in LRM. It is made up of a series of 64 elementary range measurements that correspond to ground resolution cells (i.e. concentric rings).

Figure 1: LRM Footprint (Credit: TAS-F)
Figure 2: LRM Resolution Cell (Credit: TAS-F)
Figure 3: SAR Range Gates (Credit: TAS-F)

Figure 4: SAR Resolution Cell (Credit: TAS-F)
LRM along-track resolution = 1,64 km
LRM across-track resolution = 1,64 km
SAR along-track resolution = 300 m
SAR across-track resolution = 1,64 km


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