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|Title: ||Design of energy efficient pulse trains for radar|
|Authors: ||Somaini, Umberto|
|Issue Date: ||1976|
|Publisher: ||© U. Somaini|
|Abstract: ||The work presented in this thesis is concerned with the design
of discrete coded waveforms for improving range resolution and clutter
performance of radar systems. This approach to signal design offers
many advantages in terms of waveform shaping and digital implementation
of processors. Assuming a matched filter receiver, the bulk of the
work is concentrated on studying the autocorrelation function properties
of these waveforms, which are directly related to the range resolution.
The main objective is to synthesize pulse trains subject to a
fixed amplitude constraint, whose autocorrelation sidelobes are as low
as possible. Constant amplitude waveforms are attractive for a number
of reasons; the principal one being the optimum utilization of
Pulse .train signals can be synthesized directly by factorizing
the spectrum of specified autocorrelation functions. The problems which
arise if the autocorrelation function is only given in magnitude are
considered and a design method is presented. For some applications,
especially digital implementation, the design objective may be to
approximate the response characteristics of a given analogue waveform.
It is shown that virtually all the desired properties of analogue
signals can be retained if the sampling interval is chosen properly.
In addition various suggestions for reducing the range sidelobes of the
autocorrelation function are discussed.
An attempt is made to solve the signal design problem using
numerical optimization methods that incorporate the fixed amplitude
constraint. In particular, a constrained optimization technique is
developed for synthesizing binary sequences with good autocorrelation
function properties. Moreover, the problem of designing pairs of phase coded pulse trains with low autocorrelation sidelobes and small
mutual crosscorrelation is considered.
In the case of impulse-equivalent sequences known as Huffman
codes, a synthesis method based on uniform pulse trains is shown to
yield sequences with good energy efficiency. Furthermore, a new
approach to the signal design problem using Huffman codes and
parameter variational techniques is presented.
Although the range sidelobes can be reduced quite effectively
by numerical methods, for some applications they might still be too
large. Thus optimum sidelobe reduction filters, which minimize the
detection loss subject to a set of sidelobe constraints, are derived
by mismatching the receiver filter.
Finally, in the case where significant target velocity is
encountered, it becomes necessary to consider not only the range but
also the velocity resolution properties of the transmitted waveform.
This is done for the various types of pulse trains using the standard
range-doppler ambiguity description of Woodward.|
|Description: ||A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.|
|Appears in Collections:||PhD Theses (Mechanical, Electrical and Manufacturing Engineering)|
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