The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
Aalto

Tools and Methods for Radar Performance Evaluation and Enhancement

Jukka Ruoskanen

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Department of Electrical and Communications Engineering for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 21st of October, 2005, at 12 o'clock noon.

Overview in PDF format (ISBN 951-22-8144-9)   [1828 KB]
Dissertation is also available in print (ISBN 951-25-1600-4)

Abstract

The purpose of this thesis has been to create tools for radar performance estimation in true operational environments and to evaluate the feasibility of millimeter wave band for radar applications. Radar wave propagation and backscattering was studied in different environments using real radar data obtained from field measurement campaigns.

Measurement results of radar clutter in typical illumination geometries encountered using a ground-based radar are presented for Ka- and V-band. The low grazing angle (<5°) clutter backscattering measurements as well as measurements at perpendicular incidence presented in this work are completely new results, for which comparisons can not be found in open literature. For example, the snow covered ground backscattering coefficient at V-band was found to be on average 12 dB larger than at Ka-band. Additionally, new volumetric backscattering coefficients of rain and snow at Ka-band are given. Also new spectral dependency values for vegetation clutter spectrum at Ka-band are proposed. The cross-over level from Gaussian low-frequency components to Lorentzian high-frequency components for vegetation clutter, according to our measurements, is 5 dB higher than what was previously reported.

Phenomena related to radar wave propagation are discussed and new measurement results concerning clear sky backscattering variations due to meteorological inversion layer are presented. A lens-effect theory proposed by Schneider (1998) is verified to be valid also in connection to long radar ranges up to 3 kilometers and for successive concave and convex terrain profiles. Furthermore, this thesis addresses several details concerning arranging and conducting practical radar measurements in true operational environments, including calibration issues and definition of antenna beamwidth in clutter measurements. A 1.2 dB uncertainty has been achieved in practical field measurements of clutter and target backscattering. Also a novel and easy-to-use approach for radar pulse width optimization has been introduced, taking into account the effect that radar receiver bandwidth has on thermal noise floor and the pulse width to the effective clutter cell area or volume. For example, for rain clutter volumetric backscattering coefficient of η = 5 · 10−4 m2/m3 and target RCS of 100 m2, the optimal pulse width is found to be 150 ns and the corresponding maximum radar range is 5700 m.

The new measurement results presented in this work provide tools for developing of signal processing algorithms for millimeter wave radar. Several practical tools and methods for radar performance estimation have been given, and new observations of backscattering and radar wave propagation are reported.

This thesis consists of an overview and of the following 11 publications:

  1. J. Ruoskanen, P. Eskelinen, H. Heikkilä, M. Nieminen, A. Serkola and J. Peltonen, Millimeter Wave Backscattering Experiments in Arctic Winter, Proceedings of the 33rd European Microwave Conference, Munich, Germany, October 2003, pp. 1159-1162.
  2. J. Ruoskanen, P. Eskelinen and H. Heikkilä, Millimeter Wave Radar with Clutter Measurements, IEEE Aerospace and Electronic Systems Magazine, Vol. 18, No. 10, October 2003, pp. 19-23.
  3. J. Ruoskanen, P. Eskelinen and H. Heikkilä, Target Detection Trials with A Millimeter Wave Radar System, IEEE Aerospace and Electronic Systems Magazine, Vol. 18, No. 11, November 2003, pp. 26-30.
  4. J. Ruoskanen, P. Eskelinen, H. Heikkilä and A. Serkola, Pulse Width Considerations for a Short Range Millimeter Wave Radar, IEEE Aerospace and Electronic Systems Magazine, Vol. 19, No. 1, January 2004, pp. 14-17.
  5. H. Heikkilä, P. Eskelinen, J. Ruoskanen and P. Hautala, Upgrading Armored Vehicle Sensor Systems, IEEE Aerospace and Electronic Systems Magazine, Vol. 19, No. 1, January 2004, pp. 26-31.
  6. J. Ruoskanen, P. Eskelinen and H. Heikkilä, A Light-Weight Q-Band Millimeter Wave Radar Master Oscillator, Proceedings of the European Frequency and Time Forum 2004, Surrey, United Kingdom, April 2004, 4 p.
  7. J. Ruoskanen, P. Eskelinen, H. Heikkilä, P. Kuosmanen and T. Kiuru, A Practical Millimeter-Wave Radar Calibration Target, IEEE Antennas and Propagation Magazine, Vol. 46, No. 2, April 2004, pp. 94-97.
  8. J. Ruoskanen, P. Eskelinen and H. Heikkilä, HF Radio as a Way to Synchronize a Multistatic Radar Network, Proceedings of the 7th Nordic HF Conference, Växjö, Sweden, August 2004, pp. 7.1.1-7.1.6.
  9. J. Ruoskanen, P. Eskelinen, H. Heikkilä and A. Serkola, Ka- and V-Band Clutter Measurements at Grazing Angle Extremes, Proceedings of the 1st European Radar Conference, Amsterdam, Netherlands, October 2004, pp. 325-328.
  10. J. Ruoskanen, P. Eskelinen and H. Heikkilä, Measuring the Frequency Stability of Mobile Radar Oscillators, Proceedings of the 2004 IEE International Radar Conference, Toulouse, France, October 2004, 5 p.
  11. P. Eskelinen, J. Ruoskanen and H. Heikkilä, Millimetre Radar Propagation Measurements in Long Road Canyons, Proceedings of the International Radar Symposium 2005, Berlin, Germany, September 2005, accepted for publication.

Keywords: millimeter wave radar, radar performance, wave propagation, backscattering, field measurements

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© 2006 Helsinki University of Technology

Last update 2011-05-26