Title :
Correlation and covariance of satellite scatterometer measurements
Author :
Yoho, Peter K. ; Long, David G.
Author_Institution :
Lincoln Lab., Massachusetts Inst. of Technol., Lexington, MA, USA
fDate :
6/1/2004 12:00:00 AM
Abstract :
Capable scatterometer designs have been developed that seek improved resolution through the use of higher pulse sampling rates. The high sampling rates bring the traditional scatterometry assumption of measurement independence into question. This paper uses fundamental scattering theory to derive general expressions for correlation and covariance between scatterometer measurements and provides practical analysis using current and future instruments as examples. The paper derives expressions for the measurement variance parameter Kp when measurement correlation due to Rayleigh fading effects is present and relates Kp to the statistics of multiple pulse measurements. A function of the transmit signal modulation and receive processing, the measurement correlation is zero for nonoverlapping measurements but can become significant for overlapping measurements at high pulse sampling rates. The paper discusses the effects of correlation on the accuracy of scatterometer measurements and evaluates tradeoffs between spatial overlap, levels of additive noise, and measurement precision.
Keywords :
Rayleigh scattering; correlation theory; covariance analysis; geophysical signal processing; geophysical techniques; remote sensing by radar; spaceborne radar; HYDROS; Hydrosphere States Mission; QuikSCAT; Rayleigh fading effects; SeaWinds; additive noise levels; covariance; measurement correlation; measurement independence; measurement precision; measurement variance parameter; multiple pulse measurements; pulse sampling rates; satellite scatterometer measurements; scattering theory; spatial overlap; transmit signal modulation; Current measurement; Genetic expression; Instruments; Noise measurement; Pulse measurements; Pulse modulation; Radar measurements; Rayleigh scattering; Sampling methods; Satellites; $K_p$ ; Correlation; HYDROS; Hydrosphere States Mission; QuikSCAT; SeaWinds; covariance; scatterometry;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2004.825588