Advanced Visible and Near-Infrared Radiometer type 2 (AVNIR-2)

Abstract

Advanced visible and near infrared radiometer type 2(AVNIR- 2) is a high resolution land observation sensor, which will be loaded on ALOS. AVNIR-2 is composed of a multispectral and panchromatic subsystem. THese former subsystem is recently named as AVNIR-2; same with the old instrument name. The latter subsystem is named PRISM. The multispectral subsystem has ground resolution of 10m and four spectral bands which have same spectral range with that of AVNIR loaded on ADEOS. PRISM has three line detectors and characteristics of B/H equals 1.0 and ground resolution of 2.5m. By means of these characteristics, topographic maps with contour of 5m elevation interval are planned to be produced from those panchromatic data. Because observing data rate of PRISM is very high, on-board lossy data compression will be applied in order to reduce down link data rate. In this report, influences of the on-board lossy compression for terrain elevation measurements are evaluated. As the results, it is clear that: (1) measurement error of terrain elevation does not increase by on-board lossy data compression, (2) measurement error of terrain elevation decreases by on-board lossy data compression under the condition of turbid atmosphere and (3) measurement error of terrain elevation decreases in spite of atmospheric conditions when block coding is used as a lossy compression method.