Radiating target direction finding system

Claim 3

The method defined in claim 1 which includes the additional step of altering the direction of the axis of rotation until the difference signals vanish throughout a cycle of rotation of the detector, whereupon the axis of rotation coincides with the line-of-sight to the target.

Claim 4

The method defined in claim 2 which includes the further step of deriving the direction of the axis of rotation when the axis of rotation coincides with the line-of-sight to the target.

Claim 7

The method defined in claim 4 which includes the further step of deriving the direction of the axis of rotation when the axis of rotation coincides with the line of sight to the target.

Claim 8

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. detector means for detecting the radiated wave; b. means for continuously rotating said detector means about a predetermined spin axis; c. means coupled to said means for rotating for generating two phase-related sinusoidal waves, each having a frequency integrally related to the frequency of rotation of said detector means; d. sensor means coupled to said detector means and including a phase detector for continuously detecting the phase modulation of the detected signal; and e. a demodulator coupled to said phase detector and to said means for generating said waves for deriving an error signal indicative of a direction between said platform and said target.

Claim 9

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. detector means for detecting the radiated wave; b. means for continuously rotating said detector means about a predetermined spin axis; c. means coupled to said means for rotating for generating two phase-related sinusoidal waves, each having a frequency integrally related to the frequency of rotation of said detector means; d. sensor means coupled to said detector means and including a phase detector for continuously detecting the phase modulation of the detected signal; and e. a demodulator coupled to said phase detector and to said means for generating said waves for deriving an error signal indicative of a direction between said platform and said target.

Claim 10

Apparatus as defined in claim 6 wherein said detector means consists of two antennas.

Claim 11

Apparatus as defined in claim 7 wherein each of said antennas is a circularly polarized antenna.

Claim 12

Apparatus as defined in claim 6 wherein said antenna means is a single antenna having a principal axis forming an angle with the spin axis about which said antenna is being rotated.

Claim 13

Apparatus for determining the elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting the radiated wave; b. means for rotating said antennas about a predetermined axis; c. means for adjusting the azimuth position of said rotating antennas; d. means for adjusting the elevation position of said rotating antennas; e. a phase detector coupled to said antennas for detecting the phase difference of the waves received by each one of said antennas; f. means coupled to said means for rotating said antennas for generating two phase-related waves; and g. an azimuth signal channel including a demodulator having two input terminals, one for receiving one of said sinusoidal waves, the other terminal being coupled to said phase detector to generate an azimuth output signal.

Claim 14

Apparatus for determining the elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting the radiated wave; b. means for rotating said antennas about a predetermined axis; c. means for adjusting the azimuth position of said rotating antennas; d. means for adjusting the elevation position of said rotating antennas; e. a phase detector coupled to said antennas for detecting the phase difference of the waves received by each one of said antennas; f. means coupled to said means for rotating said antennas for generating two phase-related waves; and g. an azimuth signal channel including a demodulator having two input terminals, one for receiving one of said sinusoidal waves, the other terminal being coupled to said phase detector to generate an azimuth output signal.

Claim 15

Apparatus for determining elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting said wave; b. a motor for rotating said antennas about an axis, said motor being fixed with respect to the platform; c. a sensor electronics channel for amplifying the wave received by each one of said antennas; d. a phase detector coupled to said sensor electronics for detecting the phase difference of the waves received by each of said antennas; e. means coupled to said phase detector for correlating the phase difference detected by said phase detector with the instantaneous position of said antennas with respect to a point about the spin axis thereof; and f. means coupled to said phase detector and to said means for correlating for deriving an elevational signal and an azimuth signal indicative of the phase difference between adjacent pairs of opposite points of antenna positions about the spin axis, thereby to derive elevation and azimuth angles between the platform and the target.

Claim 16

Apparatus for determining elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting said wave; b. a motor for rotating said antennas about an axis, said motor being fixed with respect to the platform; c. a sensor electronics channel for amplifying the wave received by each one of said antennas; d. a phase detector coupled to said sensor electronics for detecting the phase difference of the waves received by each of said antennas; e. means coupled to said phase detector for correlating the phase difference detected by said phase detector with the instantaneous position of said antennas with respect to a point about the spin axis thereof; and f. means coupled to said phase detector and to said means for correlating for deriving an elevational signal and an azimuth signal indicative of the phase difference between adjacent pairs of opposite points of antenna positions about the spin axis, thereby to derive elevation and azimuth angles between the platform and the target.

Claim 17

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. direction sensitive detector means including an antenna assembly for detecting the radiated wave; b. means for continuously rotating at a uniform rate said detector means including said antenna assembly about a predetermined axis of rotation, thereby to develop a modulated output signal; c. means coupled to said means for rotating for comparing the modulated output signal to the rotation rate of said detector means, thereby to develop an error signal representative of the direction between the platform and the target; and d. additional means for orienting said predetermined axis until the fundamental and odd harmonics of thE modulated output signal vanish, whereupon the axis coincides with the line of sight to the target.

Claim 18

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. direction sensitive detector means including an antenna assembly for detecting the radiated wave; b. means for continuously rotating at a uniform rate said detector means including said antenna assembly about a predetermined axis of rotation, thereby to develop a modulated output signal; c. means coupled to said means for rotating for comparing the modulated output signal to the rotation rate of said detector means, thereby to develop an error signal representative of the direction between the platform and the target; and d. additional means for orienting said predetermined axis until the fundamental and odd harmonics of thE modulated output signal vanish, whereupon the axis coincides with the line of sight to the target.

Claim 19

Apparatus as defined in claim 12 wherein further means is provided for generating an output indicative of the orientation of said predetermined axis when said predetermined axis coincides with the line of sight to the target.

Claim 20

Apparatus for determining the elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting the radiated wave; b. means for rotating said antennas about a predetermined axis; c. means for adjusting the azimuth position of said rotating antennas; d. means for adjusting the elevation position of said rotating antennas; e. a phase detector coupled to said antennas for detecting the phase difference of the waves received by each one of said antennas; f. means coupled to said means for rotating said antennas for generating two phase-related sinusoidal waves, each having a frequency integrally related to that of the frequency of rotation of said antennas; g. an azimuth signal channel including a demodulator having two input terminals, one for receiving said phase difference and the other one for receiving one of said sinusoidal waves to generate an azimuth output signal; h. an elevation signal channel including a demodulator having two input terminals, one for receiving the other one of said sinusoidal waves and the other one for receiving said phase difference for generating an elevation output signal; i. means coupled to said means for adjusting said antennas in the azimuth and elevation directions and responsive to said azimuth and elevation output signals for pointing said predetermined axis in the direction of the target; and j. encoding means coupled to said antenna adjusting means for deriving azimuth and elevation angles representative of the adjusted position of said predetermined axis.

Claim 21

Apparatus for determining the elevation and azimuth directions from a platform to a target radiating a wave, said apparatus comprising: a. a pair of antennas for detecting the radiated wave; b. means for rotating said antennas about a predetermined axis; c. means for adjusting the azimuth position of said rotating antennas; d. means for adjusting the elevation position of said rotating antennas; e. a phase detector coupled to said antennas for detecting the phase difference of the waves received by each one of said antennas; f. means coupled to said means for rotating said antennas for generating two phase-related sinusoidal waves, each having a frequency integrally related to that of the frequency of rotation of said antennas; g. an azimuth signal channel including a demodulator having two input terminals, one for receiving said phase difference and the other one for receiving one of said sinusoidal waves to generate an azimuth output signal; h. an elevation signal channel including a demodulator having two input terminals, one for receiving the other one of said sinusoidal waves and the other one for receiving said phase difference for generating an elevation output signal; i. means coupled to said means for adjusting said antennas in the azimuth and elevation directions and responsive to said azimuth and elevation output signals for pointing said predetermined axis in the direction of the target; and j. encoding means coupled to said antenna adjusting means for deriving azimuth and elevation angles representative of the adjusted position of said predetermined axis.

Claim 24

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. direction sensitive detector means including an antenna assembly for detecting the radiated wave, and developing output signals; b. means for rotating said detector means including said antenna assembly about a predetermined axis of rotation; c. means for comparing to each other the output signals obtained from said detector means; and d. means coupled to said means for rotating, for correlating said output signals at each of a plurality of pairs of points diametrically opposite to each other with respect to said predetermined axis to provide a set of difference signals for deriving an error signal indicative of the direction between the platform and the target.

Claim 25

Apparatus for determining a direction from a platform to a target radiating a wave, said apparatus comprising: a. direction sensitive detector means including an antenna assembly for detecting the radiated wave, and developing output signals; b. means for rotating said detector means including said antenna assembly about a predetermined axis of rotation; c. means for comparing to each other the output signals obtained from said detector means; and d. means coupled to said means for rotating, for correlating said output signals at each of a plurality of pairs of points diametrically opposite to each other with respect to said predetermined axis to provide a set of difference signals for deriving an error signal indicative of the direction between the platform and the target.

Claim 26

Apparatus as defined in claim 16 wherein additional means is provided for orienting said predetermined axis until said difference signals become a minimum throughout a period of rotation of said detector means, whereupon the axis coincides with the line-of-sight to the target.

Claim 27

Apparatus as defined in claim 17 wherein further means is provided for deriVing an output indicative of the orientation of said predetermined axis when said predetermined axis coincides with the line of sight to the target.