	US 12,270,937 B2
	Detection of an unknown rank-1 signal in interference and noise with unknown covariance matrix
Ramachandran S Raghavan, Centerville, OH (US)
Assigned to United States of America as represented by Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed by Government of the United States, as represented by the Secretary of the Air Force, Wright-Patterson AFB, OH (US)
Filed on Mar. 3, 2023, as Appl. No. 18/117,168.
Application 18/117,168 is a continuation in part of application No. 17/479,641, filed on Sep. 20, 2021, abandoned.
Claims priority of provisional application 63/080,889, filed on Sep. 21, 2020.
Prior Publication US 2023/0204719 A1, Jun. 29, 2023
Int. Cl. G01S 7/40 (2006.01); G08B 21/18 (2006.01)

CPC G01S 7/40 (2013.01) [G08B 21/182 (2013.01)]

6 Claims

1. A method for improving a radar unit's efficiency comprising, for a pre-specified probability of false alarm and a set of pre-specified system parameters:

a) determining a required threshold η using the following first set of equations:

wherein the variable definitions for said first set of equations are:

N: Number of degrees of freedom (length of received space-time vector)

K: Number of interference-plus-noise training vectors (K≥N)

Z: Received space-time vectors for two consecutive CPIs (N×2)

Y: Interference-plus-noise training vectors (N×K)

S: Sample covariance matrix of interference-plus-noise (=YY^H)

W: Detection statistic

η: Precomputed detection threshold

H₀: Null hypothesis (i.e. no target present hypothesis)

H₁: Alternative hypothesis (i.e. target present hypothesis);

b) computing a detection statistic for a set of space time sample returns over two consecutive coherent processing intervals for one or more given ranges using the following second set of equations:

Y=[y₁y₂. . . y_K]

Compute sample interference-plus-noise covariance matrix from training data

Z=[z₁z₂] received space-time vectors over two consecutive CPIs

Detection Statistic

Decision Rule;

c) comparing said threshold η and said detection statistic; and

d) if said detection statistic is greater than or equal to said threshold n send an alert that a target exists to a radar operator.