Physics
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufm.p53a1445s&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #P53A-1445
Physics
5464 Remote Sensing, 5494 Instruments And Techniques, 6280 Saturnian Satellites
Scientific paper
The Cassini RADAR instrument on-board the Cassini Orbiter is currently being employed to obtain SAR imagery of the surface of Saturn's largest moon, Titan. The viewing geometry of Cassini RADAR is different from most imaging radars because the Cassini Orbiter flies by Titan rather than entering into orbit about it. This unusual viewing geometry leads to variable noise characteristics throughout the SAR swath. Due to large changes in range to target and number of looks, noise characteristics and effective resolution vary widely throughout the swath. A good understanding of these parameters is important in order to draw scientific conclusions from the SAR images. Changes in noise bias could be misinterpreted as changes in reflectivity from the surface. Changes in resolution or noise variance could be misinterpreted as changes in the heterogeneity of the surface. The purpose of this paper is to quantify noise variance, bias, and effective radiometric resolution throughout the SAR swath in order to aid scientists in interpreting the data. Of the three parameters, the easiest to model is noise bias which increases with the range to the target. Noise variance is more complicated. The thermal noise (SNR) contribution to the overall variance increases with range, but the fading (speckle) noise contribution varies inversely with number of looks and thus with range. Effective resolution becomes coarser as range increases, but cross track and along track resolution vary differently. Along track resolution varies continuously, but cross track resolution has a discontinuity at 1600 km altitude, due to a change in commanded bandwidth. This paper presents the equations governing the noise characteristics and effective resolution as well as providing pseudo-color images of each quantity in SAR image coordinates for the October 2004 Cassini RADAR observation of Titan. This work was performed at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration.
Gim Yonggyu
Hamilton Gary A.
Johnson Timothy W.
Shimada J. G.
Stiles Bryan W.
No associations
LandOfFree
Radiometric Characteristics of Cassini RADAR Imagery does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Radiometric Characteristics of Cassini RADAR Imagery, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Radiometric Characteristics of Cassini RADAR Imagery will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1454359