Chromatic correlation interferometry direction finding

Patent metadata

Field	Value
Publication number	US-11733367-B1
Application number	US-202117230011-A
Country	US
Kind code	B1
Filing date	Apr 14, 2021
Priority date	Apr 14, 2021
Publication date	Aug 22, 2023
Grant date	Aug 22, 2023

Abstract

The system and method for chromatic correlation interferometry direction finding (CIDF) used to resolve ambiguities. Ambiguities are overcome by correlating over a range of frequencies. In some cases, multiple (i.e., 2 or more) frequencies or a continuous range of frequencies are used to make a more robust correlation manifold. As the complex response manifold is frequency dependent, using a set of two or more manifolds provides a significant reduction of false peaks.

First claim

What is claimed:

1. A system for chromatic correlation interferometry direction finding (CIDF), comprising:
a transmitter configured to transmit signals at two or more frequencies;
a set of two or more antenna elements for receiving the signals;
signaling hardware configured to form I and Q data from the received signals;
a processor to control the signaling hardware and execute a chromatic CIDF algorithm, wherein the chromatic CIDF algorithm is:

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where:
|R(θ t , ϕ t )| 2 Is the correlation squared function computed at testing angles (θ t , ϕ t )
U n Antenna voltages measured on a signal that is incident on the DF array
A n (θ t , ϕ t ) Array vectors retrieved from a calibration manifold
na number of DF antennas

wherein the term A n (θ t , ϕ t ) and U n are summed over frequency as well and become A n,f (θ t , ϕ t ) and U n,f and the sum is over elements (n) and frequencies (f); and
a pre-measured or pre-calibrated response manifold, or data table, for use in comparing with the received signals.

2. The system of claim 1 , wherein the signals are radar signals.

3. The system of claim 2 , wherein the radar signals are time of flight.

4. The system of claim 1 , wherein the chromatic CIDF algorithm can be applied to single polarization, and single line of bearing solutions and to arbitrary polarization and single line of bearing in polarization sensitive bands.

5. The system of claim 1 , wherein the chromatic CIDF algorithm can be applied to multiple frequencies and active radar for super resolution techniques, including, single polarization, and multiple line of bearing solutions, or arbitrary polarization, and multiple line of bearing solutions with signal separation capabilities determined by SNR and array bandwidth.

6. A method for chromatic correlation interferometry direction finding (CIDF), comprising:
illuminating an area of interest using signals at two or more different frequencies;
receiving the signals at two or more different frequencies reflected off the area of interest;
down converting the received signals to form I and Q data that define complex antenna voltages;
computing values for each of N a antenna apertures (N a ≥2) and for each of N f frequency values (N f ≥2);
correlating N f ×N a complex antenna voltages with a pre-calibrated or pre-measured response manifold, where the pre-calibrated or pre-measured response manifold provides peaks that represent target bearings or angles of arrival;
providing the target bearings or angles of arrival to a guidance computer; and
executing a chromatic CIDF algorithm;

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Assignees

• Bae Sys Inf & Elect Sys Integ

Inventors

• Zemany Paul D
• Charette David P
• Chrobak Matthew F
• Rossman Court E

Classifications

• F41G7/2246 Primary

  Active homing systems, i.e. comprising both a transmitter and a receiver · CPC title

• F41G7/2286

  using radio waves · CPC title

• G01S13/883

  for missile homing, autodirectors (missile guidance systems F41G7/22) · CPC title

• G01S13/42 Primary

  Simultaneous measurement of distance and other co-ordinates (indirect measurement G01S13/46) · CPC title