Signal processing
First Claim
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1. A method of discriminating a time variable target radar signal from a background including the steps of:
- I) acquiring range variable return signals from a series of radar pulses, the returns having variable amplitude and phases;
II) sampling each of the returns to produce a set of ranged signals attributable to a set of range cells, the ranged signals having variable amplitude and phase for each range cell;
characterised by the steps of;
III) obtaining an estimate for the variation in phase drift between the transmission and reception of the ranged signals for each range cell;
IV) producing a smooth function representative of the variation in phase of the ranged signals between nearby (e.g. successive) range cells in each of the returns;
V) modifying the acquired range variable returns with respect to the function representative of the variation in phase between nearby range cells in order to obtain a corrected value for the amplitude and phase of each return signal;
VI) operating on the corrected set of range variable returns so as to identify an object having a relative velocity with respect to a receiver in a range cell.
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Abstract
A method and apparatus for processing of a signal in which a variation in phase between a transmitted and reflected pulse is modelled, as is the amplitude of the pulse. The modelled phase and amplitude are used to smooth the data by reducing phase noise present on the signal thereby enhancing the signal to noise ratio.
31 Citations
13 Claims
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1. A method of discriminating a time variable target radar signal from a background including the steps of:
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I) acquiring range variable return signals from a series of radar pulses, the returns having variable amplitude and phases;
II) sampling each of the returns to produce a set of ranged signals attributable to a set of range cells, the ranged signals having variable amplitude and phase for each range cell;
characterised by the steps of;
III) obtaining an estimate for the variation in phase drift between the transmission and reception of the ranged signals for each range cell;
IV) producing a smooth function representative of the variation in phase of the ranged signals between nearby (e.g. successive) range cells in each of the returns;
V) modifying the acquired range variable returns with respect to the function representative of the variation in phase between nearby range cells in order to obtain a corrected value for the amplitude and phase of each return signal;
VI) operating on the corrected set of range variable returns so as to identify an object having a relative velocity with respect to a receiver in a range cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 12)
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10. An apparatus for discriminating a target time variable radar signal from a background, the apparatus including, a receiver and signal processing means and a transmitter for transmitting a series of pulses, the receiver being adapted to receive at least a portion of the pulses returned from a target and clutter, the receiver passing the returned portion of the pulse to the signal processing means characterised in that the signal processing means is adapted in use to
a) acquire range variable returns from a series of radar pulses having variable amplitude and phase; -
b) sample the returns to produce a set of ranged signals attributable to a set of range cells, the ranged signals having variable amplitude and phase for each range cell;
c) obtain an estimate of the variation in phase drift between the transmission and reception of the ranged signals for each range cell;
d) produce a smooth function representative of the variation in phase of the ranged signals between nearby (e.g. successive) range cells in each of the returns;
e) modify the acquired range variable returns with respect to the function representative of the variation in phase between nearby range cells in order to obtain a corrected value for the amplitude and phase of each return signal, and;
f) operate on the corrected set of range variable returns so as to identify an object having a relative velocity with respect to a receiver in a range cell - View Dependent Claims (11, 13)
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Specification