Method and apparatus for simultaneous synthetic aperture radar and moving target indication

• US 20120056780A1
• Filed: 11/01/2011
• Published: 03/08/2012
• Est. Priority Date: 04/28/2006
• Status: Abandoned Application

• Current Assignee: Michael C. Wicks, Paul Antonik
• Original Assignee: Michael C. Wicks, Paul Antonik
• Inventors: Antonik, Paul, Wicks, Michael C.
• Application Number:
  US13/373,248
• Publication Number:
  US 20120056780A1
• Time in Patent Office: Days
• US Class Current: 342/25.B
• CPC Class Codes: G01S 13/28 with time compression of received pulses
• CPC Class Codes: G01S 13/9029 specially adapted for moving target detection within a single SAR image or within multiple SAR images taken at the same time
• CPC Class Codes: G01S 13/9052 Spotlight mode
• CPC Class Codes: G01S 13/9054 Stripmap mode
• CPC Class Codes: G01S 2013/0245 Radar with phased array antenna
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: G01S 7/288 Coherent receivers

Abstract

Method and apparatus for simultaneous synthetic aperture radar and moving target detection. A plurality, of independent radio frequency signals are generated and applied to separate radiating/receiving antenna elements. Signals are generated as basis functions, such that moving target detection and synthetic aperture radar signals are constructed from individual waveform components in space, time, frequency, and coding. Waveform components are sorted and combined at reception. Received data is simultaneously processed to extract synthetic aperture radar images and moving target indication detections.

Claims

1. An apparatus for producing simultaneous synthetic aperture radar and moving target indication having a signal and data processor, wherein said signal and data processor further comprises:

means for storing and sorting the following so as to arrange data by pulses;

radio frequency signals having been created by a plurality of waveform generators, having transited a transmit/receive module, and having been emitted from a plurality of radiating/receiving elements as radio frequency pulses;

said emitted radio frequency pulses; and

received radio frequency pulses, being those said emitted radio frequency pulses reflected by the environment and received at said plurality of radiating/receiving elements;

a pulse compression unit for compressing said received radio frequency pulses;

a synthetic aperture radar processor for producing a synthetic radar image from data derived from said compressed pulses; and

a moving target indicator processor for producing moving target indications from data derived from said compressed pulses.

2. The apparatus of claim 1, wherein said synthetic aperture radar processor further comprises:

a first corner turn memory for storing and retrieving said data according to the sequencing of said compressed pulses;

an accumulator for selectively summing only that said stored and retrieved data corresponding to selected said compressed pulses;

a receiver for selectively vector match filtering only that said summed data which corresponds to selected spatial channels; and

a registration unit for selectively summing only that said vector matched filtered data which corresponds to selected combinations of monostatically and bistatically received radio frequency pulses.

3. The apparatus of claim 1, wherein said moving target indicator processor further comprises:

a second corner turn memory for storing and retrieving said data according to the sequencing of said compressed pulses;

a differencing unit for performing pulse cancellation on said data;

a third corner turn memory for storing and retrieving said data corresponding to only those selected apertures and radiating/receiving elements on which said pulses were received;

a phase detector for generating a phase compensation signal for selectively correcting said data for phase variation;

a frequency compensation signal for selectively correcting said data for Doppler effects according to the apertures and radiating/receiving elements on which pulses corresponding to said data were received;

a multiplier for applying said phase compensation signal and said frequency compensation signal with said data output from said third corner turn memory;

an accumulator for integrating said data output from said multiplier over selected apertures and selected moving target indication filters;

a registration unit for combining data corresponding to selected combinations of monostatically and bistatically received radio frequency pulses; and

a detector for performing;

magnitude detection;

threshold setting; and

detection declaration.

4. The apparatus of claim 2, wherein said first corner turn memory further comprises a data cube.

5. The apparatus of claim 3, wherein said second and third corner turn memories each further comprises a data cube.

6. The apparatus of claim 4 wherein said data comprises:

selected frequency versus selected radiating/receiving element;

selected radiating/receiving element versus selected time; and

selected frequency versus selected time.

7. The apparatus of claim 5 wherein said data comprises:

selected frequency versus selected radiating/receiving element;

selected radiating/receiving element versus selected time; and

selected frequency versus selected time.

8. The apparatus of claim 3, wherein said phase detector for generating a phase compensation signal further comprises means for producing a quantized phase vector V₁ by adding an incremental phase vector Δ

V₁ to a received phase vector V.

9. A method for producing simultaneous synthetic aperture radar and moving target indication, comprising the step of extracting synthetic aperture image data and moving target indication data from received radio frequency signals, wherein said step of extracting further comprises the steps of:

storing and sorting the following so as to arrange said data by pulses;

radio frequency signals having been created by a plurality of waveform generators, each said signal having transited a transmit/receive module, and each said signal then having been emitted from a plurality of radiating/receiving elements into free space as radio frequency pulses;

said emitted radio frequency pulses; and

received radio frequency pulses from free space, being those said emitted radio frequency pulses reflected by the environment and received at said plurality of radiating/receiving elements;

compressing said received radio frequency pulses;

a first step of processing the data derived from said compressed pulses so as to produce a synthetic radar image therefrom; and

a second step of processing data derived from said compressed pulses so as to produce moving target indications therefrom.

10. The method of claim 9, wherein said first step of processing said data derived from said compressed pulses so as to produce a synthetic radar image further comprises the steps of:

a first step of storing and retrieving said data according to the sequencing of said compressed pulses;

a first step of selectively summing only that said stored and retrieved data corresponding to selected said compressed pulses;

selectively vector match filtering only that said summed data which corresponds to selected spatial channels; and

a second step of selectively summing only that said vector matched filtered data which corresponds to selected combinations of monostatically and bistatically received radio frequency pulses.

11. The method of claim 9, wherein said second step of processing data derived from said compressed pulses so as to produce moving target indications, further comprises the steps of:

a second step of storing and retrieving said data according to the sequencing of said compressed pulses;

performing pulse cancellation on said data;

a third step of storing and retrieving said data corresponding to only those selected apertures and radiating/receiving elements on which said pulses were received;

a first step of generating a phase compensation signal;

a second step of generating a frequency compensation signal;

a first step of selectively correcting said data for phase variation according to said phase compensation signal;

a second step of selectively correcting said data for Doppler effects according to the apertures and radiating/receiving elements on which pulses corresponding to said data were received, and further according to said frequency compensation signal;

integrating said phase and Doppler corrected data over selected apertures and selected moving target indication filters;

combining said corrected data corresponding to selected combinations of monostatically and bistatically received radio frequency pulses;

performing a detection of the following;

magnitude detection;

threshold setting; and

declaring a moving target detection.

12. The method of claim 10, wherein said first step of storing and retrieving said data further comprises the steps of simultaneously storing and retrieving data sorted by:

selected frequency versus selected radiating/receiving element;

selected radiating/receiving element versus selected time; and

selected frequency versus selected time.

13. The method of claim 11, wherein said second step of storing and retrieving said data further comprises the steps of simultaneously storing and retrieving data sorted by

selected frequency versus selected radiating/receiving element;

selected radiating/receiving element versus selected time; and

selected frequency versus selected time.

14. The method of claim 12, wherein said steps for simultaneously storing and retrieving data further comprise being sorted by coding.

15. The method of claim 13, wherein said steps for simultaneously storing and retrieving data further comprise being sorted by coding.

16. The method of claim 11, wherein said step of generating a phase compensation signal further comprises computing a quantized phase vector V₁ by adding an incremental phase vector Δ

V₁ to a received phase vector V.

17. The method of claim 11, wherein said step of performing pulse cancellation on said data further comprises the step of performing a plurality of two-pulse cancellation operations for each said selected aperture on which pulses were received.

18. The method of claim 11, wherein said second step of processing further comprises the step of performing sequential phase detection.

19. The method of claim 11, wherein said step of sequential phase detection further comprises the step of quantizing said received pulse phase into an arbitrary number of discrete phase steps.

20. The method of claim 11, further comprising the step of combining said corrected data corresponding to selected combinations of monostatically and bistatically received radio frequency pulses prior to said step of magnitude detection.