Measurement of range-weighting function for range imaging of VHF atmospheric radars using range oversampling

Jenn Shyong Chen, Ching Lun Su, Yen Hsyang Chu, Ruey Ming Kuong, Jun Ichi Furumoto

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Multifrequency range imaging (RIM) used with the atmospheric radars at ultra- and very high-frequency (VHF) bands is capable of retrieving the power distribution of the backscattered radar echoes in the range direction, with some inversion algorithms such as the Capon method. The retrieved power distribution, however, is weighted by the range-weighting function (RWF). Modification of the retrieved power distribution with a theoretical RWF may cause overcorrection around the edge of the sampling gate. In view of this, an effective RWF that is in a Gaussian form and varies with the signal-to-noise ratio (SNR) of radar echoes has been proposed to mitigate the range-weighting effect and thereby enhance the continuity of the power distribution at gate boundaries. Based on the previously proposed concept, an improved approach utilizing the range-oversampled signals is addressed in this article to inspect the range-weighting effects at different range locations. The shape of the Gaussian RWF for describing the range-weighting effect was found to vary with the off-center range location in addition to the SNR of radar echoes-that is, the effective RWF for the RIMwas SNR and range dependent. The use of SNR- and range-dependent RWF can be of help to improve the range imaging to some degree at the range location outside the range extent of a sampling gate defined by the pulse length. To verify the proposed approach, several radar experiments were carried out with the Chung-Li (24.98°N, 121.18°E) and middle and upper atmosphere (MU; 34.858°N, 136.118°E) VHF radars.

Original languageEnglish
Pages (from-to)47-61
Number of pages15
JournalJournal of Atmospheric and Oceanic Technology
Volume31
Issue number1
DOIs
StatePublished - Jan 2014

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