access icon free Introduction to imaging radar

Author(s): Christoph H. Gierull
Source: Novel Radar Techniques and Applications Volume 1: Real Aperture Array Radar, Imaging Radar, and Passive and Multistatic Radar, p. 173-181
Publication date October 2017

It took almost exactly 100 years from Maxwell's first conception of the theory of electro-magnetic waves and the subsequent experimental proof by Hertz in the nineteenth century until the first patent on Doppler Beam Sharpening (DBS) was issued to Wiley in 1965. DBS was the original attempt to improve the Doppler resolution of moving pulsed radar by exploitation of a synthetically spanned aperture compared to the physical antenna with its very limited resolution. Although somewhat rudimentary because of the neglected quadratic phase history and thereby still a range-dependent azimuth resolution, it is considered the cornerstone of Synthetic Aperture or imaging Radar (SAR). The fundamental idea here is that through the motion of the radar-carrying platform a long synthetic aperture is spanned, along which the radar raw data are focussed, to achieve a high resolution in the flight direction. Besides the essential platform motion, the other vital attribute of SAR is that the recorded data by no means constitute the desired image but instead must first be processed using suitable focussing algorithms, which among others require a precise knowledge of the platform trajectory. At the onset of SAR, owing to the absence of digital signal processors, the focussing could only be achieved using systems of optical lenses whereby the SAR raw data were recorded on film. This technology was not flexible and only permitted rather moderate results that typically suffered from low resolution, defocussing and other artefacts.

Chapter Contents:

  • Introduction to imaging radar
  • Onset
  • Twentieth century
  • Twenty-first century
  • Outlook
  • Acknowledgement
  • References

Inspec keywords: radar imaging; synthetic aperture radar

Other keywords: moving pulsed radar; radar-carrying platform; imaging radar; optical lenses; Doppler beam sharpening; Doppler resolution; range-dependent azimuth resolution; SAR; synthetic aperture radar

Subjects: Radar equipment, systems and applications; Optical, image and video signal processing; Radar theory

Preview this chapter:
Zoom in
Zoomout

Introduction to imaging radar, Page 1 of 2

| /docserver/preview/fulltext/books/ra/sbra512f/SBRA512F_ptII-1.gif /docserver/preview/fulltext/books/ra/sbra512f/SBRA512F_ptII-2.gif

Related content

content/books/10.1049/sbra512f_ptii
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading