Method and apparatus for precursor based radar

• US 6,429,801 B1
• Filed: 10/19/2000
• Issued: 08/06/2002
• Est. Priority Date: 10/19/2000
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Pergande, Al
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US09/691,177
• Time in Patent Office: 656 Days
• Field of Search: 342/21, 342/22, 342/27, 342/28, 342/134-144, 342/175, 342/192-197, 342/202-204, 342/118, 342/176-186, 375/256
• US Class Current: 342/21
• CPC Class Codes: G01S 7/03 Details of HF subsystems specially adapted therefor, e.g. common to transmitter and receiver
• CPC Class Codes: G01S 7/282 Transmitters
• CPC Class Codes: G01S 7/41 using analysis of echo signal for target characterisation; Target signature; Target cross-section
• CPC Class Codes: G01S 7/418 Theoretical aspects

Abstract

A method and apparatus is described for signal processing to identify an object in an environment. A precursor associated with an electromagnetic wave interacting with the object is received and a property of the object identified using precursor characteristics. The electromagnetic wave is transmitted with a characteristic including a pulse having a sharp rise time so as to generate the precursor. The pulse is generated using a circuit including capacitive discharge and a semiconductor device such as a Drift Step Recovery Diode. Alternatively the pulse may be generated using a microwave diode switch and a broadband semiconductor amplifier or a traveling wave tube amplifier. The characteristic may also includes a signal with a phase reversal generated by dividing the electromagnetic signal and phase modulating the first electromagnetic signal with the divided signal to generate the phase reversal so as to generate the precursor. A receiver may further establish channels corresponding to the possible precursor spectra and associate each channel with a corresponding possible material property associated with the object including water generated precursor spectra, radar absorptive material generated precursor spectra, and metallic oxides generated precursor spectra. A color display may include an image of the object with possible material properties displayed in a corresponding color in proportion to respective values associated with received precursor spectra.

Claims

1. A method for signal processing to identify an object in an environment, the method comprising the steps of:

receiving a precursor associated with a first electromagnetic wave interacting with the object; and

identifying a property of the object using one or more characteristics associated with the received precursor.

2. The method of claim 1, further comprising the step of transmitting the first electromagnetic wave with a characteristic so as to generate the precursor when the first electromagnetic wave interacts with the object.

3. The method of claim 2, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the step of transmitting further comprises the steps of:

generating the pulse using a circuit including capacitive discharge; and

generating the sharp rise time using the circuit including a semiconductor device.

4. The method of claim 3, wherein the semiconductor device includes a Drift Step Recovery Diode.

5. The method of claim 2, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the step of transmitting further comprises the steps of:

generating the first electromagnetic wave using a microwave diode switch; and

amplifying the first electromagnetic wave through a broadband semiconductor amplifier.

6. The method of claim 2, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the step of transmitting further comprises the steps of:

generating the first electromagnetic wave using a microwave diode switch; and

amplifying the first electromagnetic wave through a traveling wave tube amplifier.

7. The method of claim 2, wherein the characteristic of the first electromagnetic wave includes at least one phase reversal, and wherein the step of transmitting further comprises the step of phase modulating the first electromagnetic wave to generate the at least one phase reversal so as to generate the precursor when the phase modulated first electromagnetic wave interacts with the object.

8. The method of claim 1, wherein the step of receiving further comprises the steps of:

establishing one or more channels corresponding to the one or more possible characteristics associated with the precursor; and

associating each of the one-or-more channels with a corresponding one of one or more possible material properties associated with the object.

9. The method of claim 8, wherein the each of one or more possible characteristics includes a corresponding precursor spectra associated with the corresponding one or the one or more possible material properties and wherein the corresponding precursor spectra include one of:

water generated precursor spectra, radar absorptive material generated precursor spectra, and metallic oxides generated precursor spectra.

10. The method of claim 9, further comprising the steps of:

presenting a color display including an image of the object; and

indicating which of the one or more possible material properties are associated with the object by displaying each of the one or more material properties with a corresponding color in proportion to one or more respective values associated with one or more received precursor spectra.

11. An apparatus for signal processing to identify an object in an environment, the apparatus comprising:

a receive antenna; and

a receiver coupled to the antenna, the receiver configured to;

receive a precursor associated with a first electromagnetic wave interacting with the object; and

identify a property of the object using one or more characteristics associated with the received precursor.

12. The apparatus of claim 11, further comprising:

a transmit antenna; and

a transmitter coupled to the transmit antenna, the transmitter configured to;

transmit the first electromagnetic wave with a characteristic so as to generate the precursor when the first electromagnetic wave interacts with the object.

13. The apparatus of claim 12, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the transmitter is further configured to:

generate the pulse using a circuit including capacitive discharge; and

generate the sharp rise time using the circuit including a semiconductor device.

14. The apparatus of claim 13, wherein the semiconductor device includes a Drift Step Recovery Diode.

15. The apparatus of claim 12, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the transmitter is further configured to:

generate the first electromagnetic wave using a microwave diode switch; and

amplify the first electromagnetic wave through a broadband semiconductor amplifier.

16. The apparatus of claim 12, wherein the characteristic of the first electromagnetic wave includes a pulse having a sharp rise time, and wherein the transmitter is further configured to:

generate the first electromagnetic wave using a microwave diode switch; and

amplify the first electromagnetic wave through a traveling wave tube amplifier.

17. The apparatus of claim 12, wherein the characteristic of the first electromagnetic wave includes at least one phase reversal, and wherein the transmitter is further configured to phase modulate the first electromagnetic wave to generate the at least one phase reversal so as to generate the precursor when the first electromagnetic wave interacts with the object.

18. The apparatus of claim 11, wherein the receiver is further configured to:

establish one or more channels corresponding to the one or more possible characteristics associated with the precursor; and

associate each of the one or more channels with a corresponding one of one or more possible material properties associated with the object.

19. The apparatus of claim 18, wherein the each of one or more possible characteristics includes a corresponding precursor spectra associated with the corresponding one or the one or more possible material properties and wherein the corresponding precursor spectra include one of:

water generated precursor spectra, radar absorptive material generated precursor spectra, and metallic oxides generated precursor spectra.

20. The apparatus of claim 19, further comprising:

a display coupled to the receiver, the receiver further configured to;

present a color display including an image of the object on the display; and

indicate which of the one or more possible material properties are associated with the object by displaying each of the one or more material properties with a corresponding color in proportion to one or more respective values associated with one or more received precursor spectra.