ALOS Data Users Handbook

Section 6 ALOS Data Products6.3.3 Pixel SpacingTable 6.3-4 shows the pixel spacing of level 1.5 products for each observational mode.Table 6.3-4 Pixel Spacing of Level 1.5 ProductsProcessingLevel1.5Fine modeScanSAR modeDirectDownlinkmodePolarimetrymodeSingle DualBurst mode 1 Burst mode 2polarization polarization6.25m(2look)12.5m(4look) 100m 100m 12.5m(4look) 12.5m(4look)12.5m(4look)6.3.4 Products SizeThe definitions of the scene size are summarized in Table 6.3-5, the image frame sizes of level 1.5 are shownin Table 6.3-6. And shows sample numbers for each observational mode, off-nadir angle and others.ProcessingScene SizelevelRange direction1.0 Input signal data length[corresponds to signal gate width]1.1 Valid signal data length[corresponds to signal gate width -pulse width]Table 6.3-5 Definitions of Scene SizeScene SizeAzimuth directionThe size corresponds to the followinglength (includes synthetic aperture length)- Except ScanSAR mode:16.4 sec (corresponding to 110km)- ScanSAR mode:57.0 sec (corresponding to 385km)Fine/Direct Downlink modes: 51 to 79 kmPolarimetry mode: 62 to 83kmRemarksIn the case ofScanSAR mode,data is extracted atburst boundariesExcept ScanSARmodeRemark: For level 1.0, the number of records and the record length are fixed according to observationalmodes and off-nadir angles.Table 6.3-6 Image Sizes of Level 1.5 DataObservation modeImage Size Image SizeRange direction Azimuth directionoff-nadir angle 9.9 deg. - 43.4 deg. 70 kmFine/Directoff-nadir angle 45.2 deg. - 50.0 deg. 50 kmDownlink modesoff-nadir angle 50.8 deg.40 kmRemarkPolarimetry mode off-nadir angle 9.7 deg. - 26.2 deg. Remark Remark5 scan 350 kmScanSAR mode 4 scan 300 km350 km3 scan 250 kmRemark: Image size of azimuth direction is variable according to PRF and off-nadir angle.Fine mode and Direct Downlink mode: 51 – 79 km (Azimuth direction)Polarimetry mode: 20 – 65 km (Range direction), 62 – 83 km (Azimuth direction)6-12