Noise correlation radar devices and methods for detecting targets with noise correlation radar

• US 8,035,551 B1
• Filed: 12/02/2009
• Issued: 10/11/2011
• Est. Priority Date: 06/05/2008
• Status: Expired due to Fees

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Govoni, Mark A.
• Primary Examiner(s): SOTOMAYOR, JOHN B
• Application Number:
  US12/655,688
• Time in Patent Office: 678 Days
• Field of Search: 342/189, 342/196, 342/131, 342/132, 342/134, 342/135, 342159-162
• US Class Current: 342/189
• CPC Class Codes: G01S 13/282 using a frequency modulated carrier wave G01S13/286 takes precedence
• CPC Class Codes: G01S 7/292 Extracting wanted echo-signals

Abstract

A pulsed compression noise correlation radar uses noise modulation and pulse compression technology to scramble recognizable transmit signal characteristics and reduce transmit energy. The pulsed noise correlation radar advantageously uses pulse compression technology, a pulsed linear frequency modulated noise correlation mixer, and a new and innovative noise fused waveform to automatically correlate the pulsed linear frequency modulated (LFM) noise waveform with the received signal. The pulsed noise correlation radar apparatus and system now make it possible to effectively reduce transmitting power, preserve high band widths through oversampling in the receiver, and achieve multi-channel array frequency diversity. A secure pulsed compression noise correlation radar system and methods for undetected target detection with pulsed noise correlation radar and a pulsed LFM fused noise waveform are also provided.

Claims

1. A pulsed compression noise correlation radar target detection apparatus, comprising:

a wide sense stationary Gaussian noise signal generator generates a Gaussian noise signal and a normally distributed probability density function;

a means for generating a pulse train combines said Gaussian noise signal with a linear frequency modulated noise waveform, generates a pulse train modulating said Gaussian noise signal and provides a pulsed linear frequency modulated fused noise waveform x(t) to a means for sensing targets;

said target sensing means sends a signal to a target and generates a range and radar cross section of targets;

a frequency demodulator detects a received signal r(t) from said target;

said frequency demodulator, having a means for calculations, calculates a time dilation effect induced by target scintillation and generates a time dilated received signal r(t) that includes said time dilation effect;

said frequency demodulator sends said time dilated received signal r(t) to a means for correlation mixing;

said correlation mixing means integrates a product over time of said pulsed linear frequency modulated fused noise waveform x(t) and a conjugate of said time dilated received signal r(t) to provide an auto-correlated signal R_yy(τ

);

a Fast Fourier Transformer converts said auto-correlated signal R_yy(τ

) into a transformed auto-correlated signal, S_yy(f), that provides a plurality of discrete frequencies corresponding to said target causing the user to detect said target with a reduced transmit power, without emitting a detectable electronic signature, and without being intercepted.

2. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 1, further comprising said transformed auto-correlated signal realizing a power spectral density that exploits a plurality of time dilation effects induced by target scintillation.

3. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 2, further comprising said pulsed linear frequency modulated fused noise waveform x(t) increasing a carrier frequency to realize a plurality of band widths.

4. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 3, further comprising said pulse generating means being a frequency modulator.

5. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 4, further comprising said target sensing means being a single phase antenna.

6. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 4, further comprising said target sensing means being a multi-channel antenna array.

7. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 4, further comprising a means for data processing means and a software program.

8. A secure pulsed compression noise correlation radar system, comprising:

a wide sense stationary Gaussian noise signal generator generates a Gaussian noise signal and a normally distributed probability density function;

a means for generating a pulse train combines said Gaussian noise signal with a linear frequency modulated noise waveform, generates a pulse train modulating said Gaussian noise signal and provides a pulsed linear frequency modulated fused noise waveform x(t) to a means for sensing targets;

said target sensing means sends a signal to a target and generates a range and radar cross section of targets;

a frequency demodulator detects a received signal r(t) from said target;

said frequency demodulator, having a means for calculations, calculates a time dilation effect induced by target scintillation and generates a time dilated received signal r(t) that includes said time dilation effect;

said frequency demodulator sends said time dilated received signal r(t) to a means for correlation mixing;

said correlation mixing means integrates a product over time of said pulsed linear frequency modulated fused noise waveform x(t) and a conjugate of said time dilated received signal r(t) to provide an auto-correlated signal R_yy(τ

); and

a Fast Fourier Transformer converts said auto-correlated signal R_yy(τ

) into a transformed auto-correlated signal, S_yy(f), that provides a plurality of discrete frequencies corresponding to said target causing the user to detect said target with a reduced transmit power, without emitting a detectable electronic signature, and without being intercepted.

9. The secure pulsed compression noise correlation radar system, as recited in claim 8, further comprising said transformed auto-correlated signal realizing a power spectral density that exploits a plurality of time dilation effects induced by target scintillation.

10. The secure pulsed compression noise correlation radar system, as recited in claim 9, further comprising said pulsed linear frequency modulated fused noise waveform x(t) increasing a carrier frequency to realize a plurality of band widths.

11. The secure pulsed compression noise correlation radar system, as recited in claim 10, further comprising said pulse generating means being a frequency modulator.

12. The secure pulsed compression noise correlation radar system, as recited in claim 11, further comprising said target sensing means being a single phase antenna.

13. The secure pulsed compression noise correlation radar system, as recited in claim 11, further comprising said target sensing means being a multi-channel antenna array.

14. The pulsed compression noise correlation radar target detection apparatus, as recited in claim 11, further comprising a means for data processing means and a software program.

15. A method for secure target detection with pulsed noise correlation radar and a pulsed linear frequency modulated noise waveform, comprising the steps of:

generating a Gaussian noise signal with a normally distributed probability density function and that it is wide sense stationary;

sending the Gaussian noise signal to a means for generating a pulse train;

combining said Gaussian noise signal with a linear frequency modulated noise waveform in said pulse train generating means;

generating a pulsed linear frequency modulated fused noise waveform x(t);

sending said pulsed linear frequency modulated fused noise waveform x(t) to a means for sensing targets;

sending a signal from said target sensing means to a target;

generating a range and radar cross section of said target;

detecting a received signal r(t) from said target in a frequency demodulator;

calculating a time dilation effect induced by target scintillation;

generating a time dilated received signal r(t) that consolidates said received signal with said time dilation effect in a frequency demodulator;

sending said time dilated received signal r(t) from said frequency demodulator to a means for correlation mixing;

providing an auto-correlated signal, R_yy(τ

), with said correlation mixing means integrating a product over time of said pulsed linear frequency modulated fused noise waveform x(t) and a conjugate of said time dilated received signal r(t);

generating a Fast Fourier Transform of said auto-correlated signal, R_yy(τ

); and

converting said auto-correlated signal, R_yy(τ

), to a transformed auto-correlated signal, S_yy(f), that provides a plurality of discrete frequencies corresponding to said target causing the user to detect said target with a reduced transmit power, without emitting a detectable electronic signature, and without being intercepted.

16. The method for secure target detection with pulsed noise correlation radar and the pulsed linear frequency modulated noise waveform, as recited in claim 15, further comprising the step of realizing a power spectral density that exploits a plurality of time dilation effects induced by target scintillation during said converting step.

17. The method for secure target detection with pulsed noise correlation radar and the pulsed linear frequency modulated noise waveform, as recited in claim 16, further comprising the step of increasing a carrier frequency to realize a plurality of band widths with said pulsed linear frequency modulated fused noise waveform x(t).

18. The method for secure target detection with pulsed noise correlation radar and the pulsed linear frequency modulated noise waveform, as recited in claim 17, wherein:

said pulse generating means is a frequency modulator; and

said target sensing means is a single phase antenna.

19. The method for secure target detection with pulsed noise correlation radar and the pulsed linear frequency modulated noise waveform, as recited in claim 17, wherein:

said pulse generating means is a frequency modulator; and

said target sensing means is a multi-channel antenna array.

20. The method for secure target detection with pulsed noise correlation radar and the pulsed linear frequency modulated noise waveform, as recited in claim 17, further comprising the step of controlling said pulsed noise correlation radar with a means for data processing means and a software program.

21. A pulsed compression noise correlation radar target detection apparatus, comprising:

a wide sense stationary Gaussian noise signal generator generates a Gaussian noise signal and a normally distributed probability density function;

a means for generating a pulse train combines said Gaussian noise signal with a linear frequency modulated noise waveform, generates a pulse train modulating said Gaussian noise signal and provides a pulsed linear frequency modulated fused noise waveform x(t) to a means for sensing targets;

said target sensing means sends a signal to a target and generates a range and radar cross section of targets;

a frequency demodulator detects a received signal r(t) from said target;

said frequency demodulator, having a means for calculations, calculates a time dilation effect induced by target scintillation and generates a time dilated received signal r(t) that includes said time dilation effect;

said frequency demodulator sends said time dilated received signal r(t) to a means for correlation mixing;

said correlation mixing means integrates a product over time of said pulsed linear frequency modulated fused noise waveform x(t) and a conjugate of said time dilated received signal r(t) to provide an auto-correlated signal R_yy(τ

);

a Transformer converts said auto-correlated signal R_yy(τ

) into a transformed auto-correlated signal, S_yy(f), that provides a plurality of discrete frequencies corresponding to said target causing the user to detect said target with a reduced transmit power, without emitting a detectable electronic signature, and without being intercepted.

22. A method for secure target detection with pulsed noise correlation radar and a pulsed linear frequency modulated noise waveform, comprising the steps of:

generating a Gaussian noise signal with a normally distributed probability density function and that it is wide sense stationary;

sending the Gaussian noise signal to a means for generating a pulse train;

combining said Gaussian noise signal with a linear frequency modulated noise waveform in said pulse train generating means;

generating a pulsed linear frequency modulated fused noise waveform x(t);

sending said pulsed linear frequency modulated fused noise waveform x(t) to a means for sensing targets;

sending a signal from said target sensing means to a target;

generating a range and radar cross section of said target;

detecting a received signal r(t) from said target in a frequency demodulator;

calculating a time dilation effect induced by target scintillation;

generating a time dilated received signal r(t) that consolidates said received signal with said time dilation effect in a frequency demodulator;

sending said time dilated received signal r(t) from said frequency demodulator to a means for correlation mixing;

providing an auto-correlated signal, R_yy(τ

), with said correlation mixing means integrating a product over time of said pulsed linear frequency modulated fused noise waveform x(t) and a conjugate of said time dilated received signal r(t);

generating a Transform of said auto-correlated signal, R_yy(τ

); and

converting said auto-correlated signal, R_yy(τ

), to a transformed auto-correlated signal, S_yy(f), that provides a plurality of discrete frequencies corresponding to said target causing the user to detect said target with a reduced transmit power, without emitting a detectable electronic signature, and without being intercepted.