METHODS AND SYSTEMS PROVIDING AN ADAPTIVE THRESHOLD FOR A BEAM SHARPENED PULSE RADAR

• US 20070273572A1
• Filed: 05/26/2006
• Published: 11/29/2007
• Est. Priority Date: 05/26/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Winstead, Benjamin J., Thomas, Steven H., Reilly, Timothy J.
• Granted Patent: US 7,652,615 B2
• Time in Patent Office: Days
• US Class Current: 342/68
• CPC Class Codes: F42C 13/042 based on distance determination by coded radar techniques
• CPC Class Codes: G01S 13/60 wherein the transmitter and receiver are mounted on the moving object, e.g. for determining ground speed, drift angle, ground track G01S13/64 takes precedence
• CPC Class Codes: G01S 13/882 for altimeters measuring height using barometric means G01C5/06

Abstract

A radar sensor is described that includes a radar transmitter, a radar receiver configured to receive reflected returns of signals output by the radar transmitter, and a signal processing unit configured to process signals received by the radar receiver. The signal processing unit includes a comparator, a first filter comprising an output coupled to a reference input of the comparator, and a second filter comprising an output coupled to a signal input of the comparator. The first and second filters are configured to receive a common input related to the reflected returns. The first filter is configured to have a time constant such that a rise time of the first filter output is faster than a rise time of the second filter output.

Claims

1. A radar sensor comprising:

a radar transmitter;

a radar receiver configured to receive reflected returns of signals output by said radar transmitter; and

a signal processing unit configured to process signals received by said radar receiver, said signal processing unit comprising;

a comparator;

a first filter comprising an output coupled to a reference input of said comparator; and

a second filter comprising an output coupled to a signal input of said comparator, said first and said second filters configured to receive a common input related to the reflected returns, said first filter configured to have a time constant such that a rise time of said first filter output is faster than a rise time of said second filter output.

2. A radar sensor according to claim 1 wherein said output of said first filter output is coupled to a reference voltage.

3. A radar sensor according to claim 1 wherein said first filter and said second filter comprise low pass filters.

4. A radar sensor according to claim 1 further comprising a band pass filter, said band pass filter configured to receive signals received by said radar receiver and provide an output to each of said first filter and said second filter.

5. A radar sensor according to claim 4 further comprising a plurality of rectifiers, said rectifiers configured to receive an output of said band pass filter, each of said rectifiers configured to output a signal to a respective one of said first and said second filters.

6. A radar sensor according to claim 1 further comprising a plurality of diodes, said diodes configured to couple the output of said first filter output to the reference voltage in a diode OR configuration.

7. A radar sensor according to claim 1 wherein said comparator comprises an output, said comparator output configured to initiate a weapon detonation sequence when said second filter output attains an amplitude greater than said first filter output.

8. A method for generating a weapon detonation signal at a desired weapon detonation altitude, said method comprising:

applying radar return signals to a radar range gate, the radar range gate set to correspond to a reference altitude;

applying an output of the radar range gate to first and second filters; and

initiating a countdown to detonation when an output of the second filter attains an amplitude greater than an output of the first filter.

9. A method according to claim 8 further comprising coupling an output of the first filter to a reference voltage.

10. A method according to claim 8 further comprising configuring the range gate as a band pass filter.

11. A method according to claim 8 further comprising:

configuring the first filter with a first response; and

configuring the second filter with a second response time slower than the first response time.

12. A method according to claim 8 wherein initiating a countdown to detonation when an output of the second filter attains an amplitude greater than an output of the first filter comprises:

inputting an output of the first filter to a reference input of a comparator; and

inputting an output of the second filter to a signal input of the comparator.

13. A munition comprising:

a radar processing circuit comprising;

a band pass filter configured to receive digitized radar signal returns; and

a unit configured to determine whether a signal received from said band pass filter is close enough to a center frequency of said band pass filter to output a signal to initiate a detonation sequence; and

a circuit for initiating a detonation signal for said munition based on a state of a signal received from said unit.

14. A munition according to claim 13 wherein said unit comprises:

a comparator;

a first filter comprising an output coupled to a reference input of said comparator; and

a second filter comprising an output coupled to a signal input of said comparator, said first and said second filters configured to receive a common input from said band pass filter, said first filter configured to have a time constant such that a rise time of said first filter output is faster than a rise time of said second filter output.

15. A munition according to claim 14 wherein said output of said first filter output is coupled to a reference voltage.

16. A munition according to claim 14 wherein said first filter and said second filter comprise low pass filters.

17. A munition according to claim 14 further comprising a plurality of rectifiers, said rectifiers configured to receive an output of said band pass filter, each of said rectifiers configured to output a signal to a respective one of said first and said second filters.

18. A munition according to claim 14 wherein said comparator comprises an output, said comparator output configured to cause said circuit to initiate a weapon detonation sequence when said second filter output attains an amplitude greater than said first filter output.