High-frequency indicator phase system and method

• US 9,857,453 B1
• Filed: 06/30/2014
• Issued: 01/02/2018
• Est. Priority Date: 06/30/2014
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: DeSimone, Jr., Anthony J., Akhund, Yusif K., Falkenbach, Jeffrey C., Bergenfeld, Bruce C., Quinn, Brian J.
• Primary Examiner(s): Bythrow, Peter M
• Assistant Examiner(s): Pervin, Nuzhat
• Application Number:
  US14/319,794
• Time in Patent Office: 1,282 Days
• Field of Search: 342175, 342104, 342196
• CPC Class Codes: G01S 13/28 with time compression of received pulses
• CPC Class Codes: G01S 13/30 using more than one pulse per radar period
• CPC Class Codes: G01S 13/36 with phase comparison between the received signal and the contemporaneously transmitted signal
• CPC Class Codes: G01S 13/582 adapted for simultaneous range and velocity measurements
• CPC Class Codes: G01S 7/414 Discriminating targets with respect to background clutter
• CPC Class Codes: G01S 7/415 Identification of targets based on measurements of movement associated with the target

Abstract

A radar system includes a transmitter configured to generate a series of electromagnetic pulses, and a receiver configured to receive return signals reflected by an object of interest from the series of electromagnetic pulses. A phase processor is operatively connected to the output of the receiver and configured to extract phase data as a function of time from the received return signals, convert the extracted phase data to the frequency domain, and analyze the phase data to identify phase changes indicative of one or more types of motion, such as complex or simple dynamic motion of the object of interest.

Claims

1. A radar system comprising:

a transmitter for generating a predetermined number of electromagnetic pulses;

a receiver;

a signal processing system operatively connected to the receiver and configured to identify return signals associated with a target, and determine the radial velocity of the target; and

a phase processor responsive to the signal processing system and configured to;

extract phase data as a function of time from a received return signal associated with the target,

convert the extracted phase data to the frequency domain,

analyze the converted phase data to identify phase changes indicative of a type of motion of the target,

wherein the phase changes indicative of a type of motion are independent of phase changes indicative of the radial velocity of the target.

2. The system of claim 1, wherein the signal processing system includes a target detection processor.

3. The system of claim 2, wherein the phase processor is operatively connected to an output of the target detection processor for performing the steps of extracting phase data, converting the extracted phase data, and analyzing the converted phase data from the identified return signals associated with the target.

4. The system of claim 1, wherein the step of extracting the phase data as a function of time includes the step of removing known phase changes indicative of the radial velocity of the target from the received return signal.

5. The system of claim 1, wherein the phase processor is further configured to perform the step of calculating a mean frequency of the extracted phase data.

6. The system of claim 1, wherein the received return signal is associated with at least one of the predetermined number of electromagnetic pulses, and wherein the phase processor is further configured to perform the step of normalizing the extracted phase data according to the predetermined number of electromagnetic pulses.

7. The system of claim 1, wherein the step of analyzing the converted phase data to identify phase changes indicative of a type of motion includes comparing the frequency of the converted phase data to a predetermined threshold value.

8. The system of claim 7, wherein the phase processor is further configured to associate converted phase data having a frequency above the predetermined threshold value with complex dynamic motion, and associate converted phase data having a frequency below the predetermined threshold value with simple dynamic motion.

15. The system of claim 1, wherein the step of analyzing the converted phase data to identify phase changes indicative of a type of motion includes associating the converted phase data with a first type of non-zero motion if the converted phase data comprises a frequency above a predetermined threshold value, and associating the converted phase data with a second non-zero type of motion if the converted phase data comprises a frequency below the predetermined threshold value.

18. The system of claim 4, wherein the step of extracting the phase data as a function of time further includes the steps of:

calculating periodic phase data of the received return signal; and

converting the periodic phase data to a continuous function of time.

9. A method of distinguishing between types of target motion in radar return signals with a radar system comprising:

transmitting a predetermined number of electromagnetic pulses;

receiving, with a receiver of the radar system, a return signal from at least one of the transmitted electromagnetic pulses;

identifying a target from the return signal;

determining a radial velocity of the identified target;

with at least one phase processor of the radar system;

extracting phase data as a function of time from the return signal associated with the identified target;

removing known phase changes indicative of the determined radial velocity of the target from the extracted phase data;

converting the extracted phase data with known phase changes removed to the frequency domain; and

analyzing the converted phase data to identify phase changes indicative of a type of motion of the identified target.

10. The method of claim 9, wherein the step of extracting the phase data as a function of time includes the steps of:

calculating the periodic phase of the return signal; and

converting the periodic phase data to a continuous function of time.

11. The method of claim 9, further comprising the step of calculating a mean frequency of the extracted phase data.

12. The method of claim 9, further comprising the step of normalizing the extracted phase data according to the predetermined number of transmitted electromagnetic pulses.

13. The method of claim 9, wherein the step of analyzing the converted phase data to identify phase changes indicative of a type of motion includes comparing the frequency of the converted phase data to a predetermined threshold value.

14. The method of claim 13, wherein the step of analyzing the converted phase data to identify phase changes indicative of a type of motion includes associating converted phase data having a frequency above the predetermined threshold value with complex motion, and associating converted phase data having a frequency below the predetermined threshold value with simple dynamic motion.

16. The method of claim 9, wherein the step of analyzing the converted phase data to identify phase changes indicative of a type of motion of the identified target includes associating the converted phase data with a first type of non-zero motion if the converted phase data comprises a frequency above a predetermined threshold value, and associating the converted phase data with a second type of non-zero motion if the converted phase data comprises a frequency below the predetermined threshold value.

17. The method of claim 9, wherein the phase changes indicative of a type of motion are independent of phase changes indicative of the radial velocity of the identified target.