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US 5,148,174 AGranted
Selective reception of carrier-free radar signals with large relative bandwidth
AssigneeGeophysical Survey Systems, Inc.
InventorHenning F. Harmuth
Life of this patent
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AssigneeGeophysical Survey Systems, Inc.
InventorHenning F. Harmuth
Estimating the term…
A method for generating a sequence of short radar pulses and a method plus apparatus for detecting those same short pulses when backscattered, even though they are heavily distorted by a target and have additive noise and unwanted signals superimposed on them. The method applies to pulses of long or short duration, including durations of 1 nanoseconds (1 ns) or less. The pulses are transmitted without the fine structure marking of a sinusoidal wave carrier, but organized into a coarse structure that results from incorporating them within a highly unconventional type of character, wherein a plurality of positive-going and negative-going pulses are transmitted such that each pulse is spaced apart from its neighbors. Each pulse is short, so the return signal is highly distorted. The sequence of positive-going and negative-going pulses are organized into a pattern of non-contiguous pulses that constitute a new type of "character", which may be thought of as a "spaced-apart-character". This "spaced-apart-character" is organized into a large coarse structure marking, so that a) the total transmitted energy is large, b) a receiver can selectively distinguish the wanted return signal from noise and unwanted signals, and c) reflections from targets longer than L=.DELTA.tc/2 are rejected.
In a radar transmission system having means for transmitting into a medium an electromagnetic signal comprising a plurality of positive-going and negative-going pulses, without a sinusoidal carrier as a fine structure marking, in a pattern of pulses that form a signal with coarse structure marking which is long compared to each of said pulses, the improvement comprising:
A method of forming a radar signal comprising the steps of:
A radar receiving system comprising:
Dependencies are inferred from the claim text.