Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
157 words
A method for automatically tracking a target along the boresight axis of a scanning antenna, which comprises locking the antennas to a null in the tracking pattern, displacing the antenna slightly relative to the lock point to obtain measurements of at least one preselected variable parameter of the antenna signal pattern whose value about the boresight null differs from its value about a false null, repeating the displacement of said antenna to other points relative to the lock point to obtain measurements of said at least one preselected variable parameter at several different points relative to the target, comparing the measured values of said at least one parameter with known values of the same parameter about the boresight null, and scanning said antenna in a preselected mode to acquire a lock on the boresight null when the measured values of said at least one parameter differ from the values about the boresight null by a predetermined amount.
Claim 2
Independent Claim
157 words
A method for automatically tracking a target along the boresight axis of a scanning antenna, which comprises locking the antennas to a null in the tracking pattern, displacing the antenna slightly relative to the lock point to obtain measurements of at least one preselected variable parameter of the antenna signal pattern whose value about the boresight null differs from its value about a false null, repeating the displacement of said antenna to other points relative to the lock point to obtain measurements of said at least one preselected variable parameter at several different points relative to the target, comparing the measured values of said at least one parameter with known values of the same parameter about the boresight null, and scanning said antenna in a preselected mode to acquire a lock on the boresight null when the measured values of said at least one parameter differ from the values about the boresight null by a predetermined amount.
Claim 3
Dependent Claim
39 words
The method of claim 1, wherein measurements are obtained for more than one preselected variable parameter at each of the points of displacement of said antenna, for comparison with known values of the same parameters about the boresight null.
Claim 4
Dependent Claim
38 words
The method of claim 1, wherein the step of comparing measured values includes comparing the measured value of error voltage gradient, error voltage gradient symmetry, and interchannel crosstalk with known values of these parameters about the boresight null.
Claim 5
Dependent Claim
18 words
The method of claim 2, wherein said antenna is moved in discrete steps to the desired measurement points.
Claim 6
Dependent Claim
53 words
The method of claim 2, wherein said antenna is driven in a circular scan about the lock point and said parameter values are measured at precise spatial positions by sampling the parameter values synchronously based upon the scan start time and start position and upon the time waveform used to generate the scan.
Claim 7
Dependent Claim
66 words
The method of claim 2, wherein the comparison of measured values with known values is achieved using window detectors for each measured value, generating a predetermined one of two binary values when the measured parameter value is within the window, exercising a majority vote of the generated binary values, and deciding whether the null is false or at boresight on the basis of the majority vote.
Claim 8
Dependent Claim
26 words
The method of claim 6, including performing normal tracking and data collection functions when the decision is that the antenna lock point is at boresight null.
Claim 9
Dependent Claim
82 words
The method of claim 6, wherein said scanning in a preselected mode to acquire a lock on the boresight null when the decision is that the antenna is locked to a false null, is performed by a series of concentric circular scans at radii derived from the circular symmetry of false null locations, and detecting the point at which the sum pattern is within a predetermined deviation from a known maximum as the desired lock point for tracking at the boresight null.
Claim 10
Dependent Claim
79 words
In a system for automatically tracking a target along the boresight axis of a scanning antenna, the combination comprising means for sampling from the antenna signal pattern at least one preselected variable parameter whose value differs according to whether the antenna is locked to the boresight null or to a false null in the tracking pattern, and means responsive to the value of each sample of said parameter for detecting the locking of said antenna to a false null.
Claim 11
Dependent Claim
79 words
In a system for automatically tracking a target along the boresight axis of a scanning antenna, the combination comprising means for sampling from the antenna signal pattern at least one preselected variable parameter whose value differs according to whether the antenna is locked to the boresight null or to a false null in the tracking pattern, and means responsive to the value of each sample of said parameter for detecting the locking of said antenna to a false null.
Claim 12
Dependent Claim
28 words
The combination according to claim 9, wherein said system is a monopulse system and said at least one parameter is sampled from the difference pattern of said antenna.
Claim 13
Dependent Claim
59 words
The combination according to claim 10, wherein said at least one parameter is selected from one of the difference pattern gradient at the null to which the antenna is locked, the degree of crosstalk in the difference patterns, the symmetry of each difference pattern, and the symmetry between difference patterns in the azimuth and elevation channels of the system.
Claim 14
Independent Claim
66 words
A method for eliminating the locking of a scanning antenna to a false null in an automatic tracking system, comprising measuring the sum channel signal level while the antenna is locked to a false null, setting an acquisition threshold level in the sum channel based on the ratio of the sum pattern peak gain to sidelobe gain, and returning the tracking system to the scanning mode.
Claim 15
Independent Claim
66 words
A method for eliminating the locking of a scanning antenna to a false null in an automatic tracking system, comprising measuring the sum channel signal level while the antenna is locked to a false null, setting an acquisition threshold level in the sum channel based on the ratio of the sum pattern peak gain to sidelobe gain, and returning the tracking system to the scanning mode.