AMTI target/clutter discriminator
First Claim
1. In an AMTI processing apparatus of the type which processes return signals so as to provide Δ
- I and Δ
Q signals which indicate the cosine and sine of the difference between the phase of the return signal in a given range bin during one PRI from the phase of the return signal of a corresponding range bin in a preceding PRI, and which includes averaging means which provides Δ
I and Δ
Q signals indicative of the average of the Δ
I and Δ
Q signals over some number of range bins in the range vicinity of the given range bin, clutter discrimination apparatus comprising;
first means responsive to said Δ
I and said Δ
I signals for providing a first absolute value signal indicative of the absolute value of the difference between the magnitudes of said Δ
I and Δ
I signals;
second means responsive to said Δ
Q and Δ
Q signals for providing a second absolute value signal indicative of the absolute value of the difference between the magnitudes of said Δ
Q and Δ
Q signals;
summation means responsive to the outputs of said first and second means for providing sum signals indicative of the summation of the absolute values of the differences between said Δ
I and Δ
I signal magnitudes and said Δ
Q and Δ
Q signal magnitudes;
discriminant means for presenting D signals indicative of the magnitude of a rectangular distance discriminant;
comparison means responsive to said D signals and to said sum signals for providing a compare signal indicative of the relative magnitudes thereof; and
switch means responsive to said Δ
I and Δ
I signals and to said Δ
Q and Δ
Q signals, respectively, and operative in response to said compare signal for alternatively selecting either said Δ
I signals and said Δ
Q signals or said Δ
I signals and said Δ
Q signals for presentation to said averaging means in dependence on said sum signals representing a value less than or more than that of said D signals, respectively.
2 Assignments
0 Petitions
Accused Products
Abstract
In an AMTI radar of the type in which the difference between the phase of a current radar return signal and the phase of a radar return signal in a corresponding range bin of a preceding pulse repetition interval (PRI) is averaged over a number of range bins in the range vicinity of the current range bin, phase differences for current range bins are determined as being clutter-like or non-clutter-like by comparison with the previously-determined average phase difference by means of a rectangular distance discriminator which compares the normalized in-phase and quadrature components (cosine and sine, respectively) of the current phase difference with the normalized in-phase and quadrature components of the average phase difference in a rectangular distance discriminator. The rectangular distance discriminator sums the absolute values of the in-phase difference and the quadrature difference and compares them against a rectangular distance discriminant, which in a preferred embodiment is unity. When the summation of the absolute value of the in-phase and quadrature differences exceed the discriminant, the previously-determined phase average components are reintroduced into the phase averaging process; but when it is less than the discriminant, the current phase differences are introduced into the phase averaging process.
28 Citations
2 Claims
-
1. In an AMTI processing apparatus of the type which processes return signals so as to provide Δ
- I and Δ
Q signals which indicate the cosine and sine of the difference between the phase of the return signal in a given range bin during one PRI from the phase of the return signal of a corresponding range bin in a preceding PRI, and which includes averaging means which provides Δ
I and Δ
Q signals indicative of the average of the Δ
I and Δ
Q signals over some number of range bins in the range vicinity of the given range bin, clutter discrimination apparatus comprising;first means responsive to said Δ
I and said Δ
I signals for providing a first absolute value signal indicative of the absolute value of the difference between the magnitudes of said Δ
I and Δ
I signals;second means responsive to said Δ
Q and Δ
Q signals for providing a second absolute value signal indicative of the absolute value of the difference between the magnitudes of said Δ
Q and Δ
Q signals;summation means responsive to the outputs of said first and second means for providing sum signals indicative of the summation of the absolute values of the differences between said Δ
I and Δ
I signal magnitudes and said Δ
Q and Δ
Q signal magnitudes;discriminant means for presenting D signals indicative of the magnitude of a rectangular distance discriminant; comparison means responsive to said D signals and to said sum signals for providing a compare signal indicative of the relative magnitudes thereof; and switch means responsive to said Δ
I and Δ
I signals and to said Δ
Q and Δ
Q signals, respectively, and operative in response to said compare signal for alternatively selecting either said Δ
I signals and said Δ
Q signals or said Δ
I signals and said Δ
Q signals for presentation to said averaging means in dependence on said sum signals representing a value less than or more than that of said D signals, respectively. - View Dependent Claims (2)
- I and Δ
Specification