Abstract. For detecting the precise range and velocity of a collection of
small near-Earth space objects and resolving individual elements of complex
space objects and small Earth-surface objects, broadband sounding signals with
a high slant range and radial velocity resolution should be used. To provide a
high angular resolution of small space objects or their elements based on the
inverse antenna aperture synthesis effect, long-duration sounding signals
should be used. The broadband long-duration signals to be used are a train of
linear frequency modulated (LFM) pulses with a high repetition rate and signals
with ‘spectrum synthesis’ that are a train of square radio pulses with a
duration Tp, pulse-to-pulse spacing 1/Tp
and pulse ratio q > 2. However, it is commonly known that
frequency modulated and manipulated signals have an oblique ambiguity function
resulting in range ambiquity. Ambiguity peaks appear in the autocorrelation
function of the LFM pulse train.
For the purpose of detecting
the precise range and velocity of
small near-Earth space objects and resolving individual elements of complex
space objects, a polyphase (p-phase, where p is a prime) radar
signal is synthesized, which signal has a region of zero sidelobes in the
vicinity of the central peak of the autocorrelation function. The signal, which
is called polyphase coherent complementary signal, represents a train of p
coherent phase-code manipulated pulses encoded by complementary sequences of a p-ary D-code with
the length of
N=pk , k>=2 - integer. A method for forming a set of 2k-2 p-ary D-code ensembles is
proposed for synthesis of the signal. The correlation characteristics of the
synthesized signal are analyzed.
Keywords:
pulse train, polyphase signal,
complementary sequences, autocorrelation function, zero correlation zone,
Vilenkin-Chrestenson functions.
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