Autofocus correction of phase distortion effects on SHARAD echoes

Bruce A. Campbell, Nathaniel E. Putzig, Lynn M. Carter, Roger J. Phillips

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


SHARAD is a frequency-modulated (15-25 MHz) radar sounder that probes the upper few kilometers of the Martian crust and polar layered deposits. At solar zenith angles less than about 100°, the ionosphere of Mars can induce phase distortion in surface and subsurface radar echoes that substantially degrades the signal-to-noise ratio and vertical resolution of the range-compressed data. We present a range-compression autofocus approach that estimates the phase distortion of SHARAD data along ground-track segments of about 100 km, using a power-law image-sharpness metric and an empirically derived scaling between the phase correction and radar frequency. This method is rapid, yields a greatly improved subsurface image, and provides a means to track regional and temporal changes in the Martian ionosphere.

Original languageEnglish (US)
Article number5770180
Pages (from-to)939-942
Number of pages4
JournalIEEE Geoscience and Remote Sensing Letters
Issue number5
StatePublished - Sep 2011
Externally publishedYes


  • Mars
  • radar signal processing
  • spaceborne radar

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Electrical and Electronic Engineering


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