Book Review

Review

Richard A. Poisel, Electronic Warfare Target Location Methods, Artech House, Boston, 2012 (ISBN 978-1-60807-523-3).

Reviewed by: Mike Ryan, University of New South Wales, Canberra

Communications electronic warfare is mostly concerned with the intercept and analysis of transmissions from non-cooperative emitters. The principal divisions of EW are electronic support (ES), electronic attack (EA), and electronic protection (EP). The major functions of ES are search, intercept, direction finding, and analysis. The third of these functions—direction finding—involves the determination of the direction in which the transmission is received at the EW intercept station. Direction finding results in the determination of a line of bearing (LOB) from the intercept station to the target transmitter. The manipulation of more than one LOB results in the target location, position fixing, or geolocation of the transmitter.

Geolocation is a critical function of tactical communications EW systems. Knowledge of the locations of transmitters is very useful since it provides information regarding the disposition of forces which can located on the battlefield and then be tracked as their emitters move with them. Further, geolocation of particular types of emitters can assist intelligence analysts in determining the nature of the unit at that location. Finally, geolocation assists in providing targeting information to precision weapons.

The original 2005 edition of Poisel’s text addresses the methods available for target location. This second edition updates the methods and includes new material on estimating the fundamental parameters required for geolocation—measurement of angle of arrival, time of arrival, or some parameter related to the amplitude, frequency, or phase of the received signal. New chapters are included on time delay estimation, direction finding techniques, and the MUSIC algorithm.

The book is a professional reference for engineers and scientists interested in implementing target location algorithms. It is targeted at four-year trained engineers or scientists who are new to the field of EW or who require a reference on emitter geolocation—the significant mathematical. Consequently, engineering content throughout the text means that it is not accessible without considerable mathematical background. The book is not designed as a course text, although it could be used as such with the addition of revision questions and problems at the end of each chapter.

Chapter 1 provides an introduction to the book and to emitter geolocation. Chapter 2 (with few changes to that chapter in the first edition) outlines the concepts behind triangulation, which is based on the use of the LOB calculated from angles of arrival (AOA) at two or more intercept sites—the intersection of the LOB provides an estimate of the location of the emitter. Chapter 3 (new to this edition) provides details on several methods for obtaining the AOA at the intercept locations. In particular, one of the most important AOA methods, Multiple Signal Classification (MUSIC), is described in detail in Chapter 4 and compared with other super-resolution AOA techniques. MUSIC is one of the most robust subspace methods available, although its performance suffers with fully correlated signals.

Chapter 5, little changed from the first edition, covers quadratic position fixing methods including time difference of arrival, time of arrival, differential Doppler, and range difference methods. In another new chapter in this edition, Chapter 6 considers techniques for estimating the time delay of signals arriving at a number of intercept stations. Chapter 7 in this edition expands on the first-edition chapter and provides a comprehensive coverage of single-site location techniques for skywave HF signals (the ability to geolocate using only a single intercept site). The book concludes with two appendices into which the more complicated mathematics has been relegated to facilitate comprehension in the preceding chapters.

Electronic Warfare Target Location Methods is a unique resource that is an essential inclusion on the reference shelf of any engineer or scientist involved in communications EW. It not only covers the fundamental mathematics underlying classical and current geolocation techniques, but it also provides critical design information to allow the implementation of those methods.

Electronic Warfare Target Location Methods can be ordered online through Artech House at: www.artechhouse.com.