Radar Systems for Technicians
Combining historical insight and technical information, this text takes the reader as far back as original World War II concepts to illustrate the logical reasoning behind state-of-the-art radar designs.
TABLE OF CONTENTS Radar Systems for Technicians
Chapter 12: Moving Target Indicators and The Doppler Effect
When this author entered the radar field in 1955, moving target indicator (mti) systems had been in existence for less than ten years, and were still viewed as new. The non-mti AN/MPN-1 was still the world s most extensively-used air traffic control radar. Of all radar subject material, technicians and engineers in 1955 saw mti as the greatest mental challenge. With that challenge to his senses of responsibility and competence, the author has devoted the years since 1955 to learning about, writing, and teaching mti theory. The approach in this chapter is purely his own, and represents years of work and study.
The Frequency and Time Domains
Most understandings of radar theory are based on the time relationships between events that occur during a system interval. And, this is logical, because it results from a good grasp of the radar ranging concept. Further, the most-used test equipment at a radar site is usually an oscilloscope, which has to be synchronized by a system trigger to provide an intelligible display. The technician, then, works and thinks purely in the time domain, most of the time. However, absolute, tunnel-vision, reliance on these purely temporal concepts may make it difficult to grasp concepts in the frequency domain, which is a major portion of the basis for Doppler theory and mti principles. For but one example of the importance of the frequency domain, and something not considered in the time domain, imagine how a radar set might operate if only a single pulse...
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