US 2007/0182622 A1Published application

Method for locating multiple angle sources using a monopulse radar

AssigneeThe United States of America as represented by the Secretary of the Navy

InventorShaun Weatherford

Life of this patent

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Abstract

A monopulse radar tracking method which analyzes boresight error information provided a monopulse radar to determine a location for two targets. The monopulse radar tracking method analyzes the boresight error information to determine an angle of arrival for a dominant target and a secondary target.

Claims20

Dependent claims

A method for locating multiple angle sources using a monopulse radar comprising the steps of:

(a) receiving a composite radio frequency (RF) signal which includes a first RF signal reflected from a dominant target and a second RF signal from a secondary target, wherein said monopulse radar receives said composite RF signal;
(b) calculating a voltage amplitude S1 for said first RF signal across a sample size wherein said voltage amplitude S1 for said first RF signal is calculated by finding a maximum automatic gain control (AGC) power level across said sample size and a minimum AGC power level across said sample size, and then adding said maximum AGC power level to said minimum AGC power level to determine said voltage amplitude S1;
(c) calculating a voltage amplitude S2 for said second RF signal across said sample size wherein said voltage amplitude S2 is calculated by subtracting said minimum AGC power level from said maximum AGC power level;
(d) looping across a preset number of samples obtained from said sample size to find a beat pattern for said first and second RF signals which are competing with each other;
(e) locating nulls in said beat pattern caused by a destructive interference between said first RF signal and said second RF signal;
(f) calculating a pitch angle and a yaw angle for said first RF signal wherein said pitch angle and said yaw angle for said first RF signal are calculated within a beat period between adjacent nulls in said beat pattern;
and
(g) calculating a pitch angle and a yaw angle for said second RF signal wherein said pitch angle and said yaw angle for said second RF signal are calculated within the beat period between said adjacent nulls in said beat pattern.

5 more elements

A method for locating multiple angle sources using a monopulse radar comprising the steps of:

(a) receiving a composite radio frequency (RF) signal which includes a first RF signal reflected from a dominant target and a second RF signal from a secondary target, wherein said monopulse radar receives said composite signal;
(b) calculating a voltage amplitude S1 for said first RF signal across a sample size wherein the voltage amplitude S1 for said first RF signal is calculated by finding a maximum automatic gain control (AGC) power level across said sample size and a minimum AGC power level across said sample size, the voltage amplitude S1 for said first RF signal being calculated according to the following expression;
S1=1/2*sqrt(Max AGC Pwr)+1/2*sqrt(Min AGC Pwr)
where:
Max AGC Pwr is the maximum AGC power level across said sample size;
and Min AGC Pwr is the minimum AGC power level across said sample size;
(c) calculating a voltage amplitude S2 for said second RF signal across said sample size, wherein the voltage amplitude S2 for said second RF signal is calculated according to the following expression;
S2=1/2*sqrt(Max AGC Pwr)−1/2*sqrt(Min AGC Pwr)
where:
Max AGC Pwr is the maximum AGC power level across said sample size;
and Min AGC Pwr the minimum AGC power level across said sample size;
(d) looping across a preset number of samples obtained from said sample size to find a beat pattern for said first and second RF signals which are competing with each other;
(e) locating nulls in said beat pattern caused by a destructive interference between said first RF signal and said second RF signal;
(f) calculating a pitch angle and a yaw angle for said first RF signal wherein said pitch angle and said yaw angle for said first RF signal are calculated within a beat period between adjacent nulls in said beat pattern;
and
(g) calculating a pitch angle and a yaw angle for said second RF signal wherein said pitch angle and said yaw angle for said second RF signal are calculated within the beat period between said adjacent nulls in said beat pattern, said pitch angle and said yaw angle for said second RF signal being calculated in accordance with the following expressions:
pbsemldc=(1/S2)2*PDC−(S1/S2)2*pbselrg
ybsemldc=(1/S2)2*YDC−(S1/S2)2*ybselrg
where pbsemldc is the pitch angle for said second RF signal;
ybsemldc is the yaw angle for said second RF signal;
pbselrg is pitch bore sight error for said first RF signal;
ybselrg is yaw bore sight error for said first RF signal;
and PDC and YDC are defined by the following expressions:
PDC=mean(pbsesum2)
YDC=mean(ybsesum2)
where pbsesum2 is linearized AGC power multiplied by the pitch bore sight error for said first RF signal and ybsesum2 is the linearized AGC power multiplied by the yaw bore sight error for said first RF signal.

23 more elements

A method for locating multiple angle sources using a monopulse radar comprising the steps of:

(a) receiving a composite radio frequency (RF) signal which includes a first RF signal reflected from a dominant target and a second RF signal from a secondary target, wherein said monopulse radar receives said composite signal;
(b) calculating a voltage amplitude S1 for said first RF signal across a sample size wherein the voltage amplitude S1 for said first RF signal is calculated by finding a maximum automatic gain control (AGC) power level across said sample size and a minimum AGC power level across said sample size, the voltage amplitude S1 for said first RF signal being calculated according to the following expression;
S1=1/2*sqrt(Max AGC Pwr)+1/2*sqrt(Min AGC Pwr)
where:
Max AGC Pwr is the maximum AGC power level across said sample size;
and Min AGC Pwr is the minimum AGC power level across said sample size;
(c) calculating a voltage amplitude S2 for said second RF signal across said sample size, wherein the voltage amplitude S2 for said second RF signal is calculated according to the following expression;
S2=1/2*sqrt(Max AGC Pwr)−1/2*sqrt(Min AGC Pwr)
where:
Max AGC Pwr is the maximum AGC power level across said sample size;
and Min AGC Pwr the minimum AGC power level across said sample size;
(d) looping across a preset number of samples obtained from said sample size to find a beat pattern for said first and second RF signals which are competing with each other;
(e) locating nulls in said beat pattern caused by a destructive interference between said first RF signal and said second RF signal;
(f) calculating a pitch angle and a yaw angle for said first RF signal wherein said pitch angle and said yaw angle for said first RF signal are calculated within a beat period between adjacent nulls in said beat pattern;
and
(g) calculating a pitch angle and a yaw angle for said second RF signal, wherein said pitch angle and said yaw angle for said second RF signal are calculated within the beat period between said adjacent nulls in said beat pattern, said pitch angle and said yaw angle being calculated in accordance with the
pbsemlac=(1/S1*S2))*PAC−pbselrg
ybsemlac=(1/S1*S2))*YAC−ybselrg
where pbsemlac is the pitch angle for said second RF signal;
ybsemlac is the yaw angle for said second RF signal;
pbselrg is pitch bore sight error for said first RF signal;
ybselrg is yaw bore sight error for said first RF signal, PAC is an AC amplitude for a pitch sine wave and YAC is an AC amplitude for a yaw sine wave, wherein said pitch sine wave is represented by the following expression:
pbsesum2=pbse*Linear Power
and said yaw sine wave is represented by the following expression:
ybsesum2=ybse*Linear Power
and each of said pitch and yaw sine waves having a DC offset.

23 more elements

Dependencies are inferred from the claim text.

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Abstract