US3842420A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Step tracking system
Assignee: TDK Micronas GmbH
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Filing: 1972-10-13
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Granted: 1974-10-15
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Expires: 1992-10-13
Abstract
Abstract This step tracking system is applicable to the angle tracking of any source of energy and includes a pair of stepper motors to mechanically move an antenna, one motor moving the antenna in azimuth and the other motor moving the antenna in elevation. The stepper motors are alternately driven for step scanning by a common source of a pseudo-random step scan waveform having balanced positive and negative excursions. A tracking error control signal is generated from the difference in amplitude of the amplitudes of two adjacent samples of a received waveform. The received waveform is similar to the pseudo-random step scan waveform and one sample is taken in one of adjacent higher and lower intervals of the received waveform while the other sample is taken in the other of the adjacent higher and lower intervals under control of the pseudo-random step scan waveform. A second order servo control system is provided for each of the stepper motors. The servo control system associated with the scanning stepper motor is coupled to respond to the tracking error control signal to cause the scanning stepper motor to take a tracking step to reduce a detected tracking error in the associated one of the aximuthal and elevational motion. A backup programmed tracking control circuit is provided for coupling to the servo control systems to cause the antenna to track the source of energy in place of the tracking error control signal.
Inventors
- 👤 G Rabow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 11:42
CPC Classifications
G; G01; G01S; G01S3/00; G01S3/02; G01S3/14; G01S3/38; G01S3/44; G01S3/56
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
389 words
A step racking system to track a source of energy comprising: an antenna; first means coupled to said antenna capable of mechanically moving said antenna independently in azimuth and in elevation; second means to generate a single pseudo-random step waveform; third means coupled to said antenna to detect the amplitude of said energy received by said antenna; fourth means coupled to said second means and said third means responsive to said pseudo-random step waveform and said amplitude and said received energy to produce a single tracking error control signal; fifth means capable of being coupled to said first means and said fourth means and capable of responding to said tracking error control signal to produce a first tracking drive signal which is capable of driving said first means to reduce tracking error in azimuth; sixth means capable of being coupled to said first means and said fourth means and capable of responding to said tracking error control signal to produce a second tracking drive signal which is capable of driving said first means to reduce tracking error in elevation; and seventh means operative during first given spaced time intervals to couple said fourth means to said fifth means to enable said fifth means to produce said first tracking drive signal, to couple said second means to said first means to step scan said antenna in azimuth in response to said pseudo-random step waveform during first spaced portions of said first time intervals, and to couple said fifth means to said first means to couple said first tracking drive signal to said first means during second spaced portions of said first time intervals different than said first portions of said first time intervals and operative during second given spaced time intervals different than said first time intervals to couple said fourth means to said sixth means to enable said sixth means to produce said second tracking drive signal, to couple said second means to said first means to step scan said antenna in elevation in response to said pseudo-random step waveform during first spaced portions of said second time intervals, and to couple said sixth means to said first means to couple said second tracking drive signal to said first means during second spaced portions of said second time intervals different than said first portions of said second time intervals.
Claim 2
Dependent Claim
389 words
A step racking system to track a source of energy comprising: an antenna; first means coupled to said antenna capable of mechanically moving said antenna independently in azimuth and in elevation; second means to generate a single pseudo-random step waveform; third means coupled to said antenna to detect the amplitude of said energy received by said antenna; fourth means coupled to said second means and said third means responsive to said pseudo-random step waveform and said amplitude and said received energy to produce a single tracking error control signal; fifth means capable of being coupled to said first means and said fourth means and capable of responding to said tracking error control signal to produce a first tracking drive signal which is capable of driving said first means to reduce tracking error in azimuth; sixth means capable of being coupled to said first means and said fourth means and capable of responding to said tracking error control signal to produce a second tracking drive signal which is capable of driving said first means to reduce tracking error in elevation; and seventh means operative during first given spaced time intervals to couple said fourth means to said fifth means to enable said fifth means to produce said first tracking drive signal, to couple said second means to said first means to step scan said antenna in azimuth in response to said pseudo-random step waveform during first spaced portions of said first time intervals, and to couple said fifth means to said first means to couple said first tracking drive signal to said first means during second spaced portions of said first time intervals different than said first portions of said first time intervals and operative during second given spaced time intervals different than said first time intervals to couple said fourth means to said sixth means to enable said sixth means to produce said second tracking drive signal, to couple said second means to said first means to step scan said antenna in elevation in response to said pseudo-random step waveform during first spaced portions of said second time intervals, and to couple said sixth means to said first means to couple said second tracking drive signal to said first means during second spaced portions of said second time intervals different than said first portions of said second time intervals.
Claim 3
Dependent Claim
24 words
A system according to claim 1, wherein said pseudo-random step waveform includes a plurality of randomly disposed steps having balanced positive and negative excursions.
Claim 4
Dependent Claim
40 words
A system according to claim 1, wherein said first means includes a first stepper motor to mechanically move said antenna in either direction in azimuth, and a second stepper motor to mechanically move said antenna in either direction in elevation.
Claim 5
Dependent Claim
24 words
A system according to claim 1, wherein said third means includes an automatic Gain control detector incorporated in a receiver coupled to said antenna.
Claim 6
Dependent Claim
27 words
A system according to claim 1, wherein said fourth means includes a synchronous detector responding to said amplitude of said received energy and said pseudo-random step waveform.
Claim 7
Dependent Claim
20 words
A system according to claim 1, wherein said fifth and sixth means each include a second order servo control system.
Claim 8
Dependent Claim
102 words
A system according to claim 1, wherein said third means provides an output signal having a waveform substantially the same as said pseudo-random step waveform but having a direct current offset with respect thereto proportional to the magnitude and sense of a tracking error, and said fourth means produces said tracking error control signal by determining the amplitude difference between two adjacent samples of said output signal, one of said two adjacent samples being taken during a high interval of said output signal and the other of said two adjacent samples being taken during an adjacent low interval of said output signal.
Claim 9
Dependent Claim
174 words
A system according to claim 7, wherein said fourth means includes a binary counter incremented at a rate greater than a scan rate, a digital to analog converter to produce an analog output signal equal to the count of said counter, a first sampling circuit coupled to said third means and said second means to sample said output signal during one of said high and low intervals under control of said pseudo-random step waveform, eighth means coupled to said counter, said converter and said first sampling circuit to inhibit incrementing said counter when the amplitude of said analog output signal equals the amplitude of the sample at the output of said first sampling circuit, a second sampling circuit coupled to said third means and said second means to sample said output signal during the other of said high and low intervals under control of said pseudo-random step waveform, and a subtracting circuit coupled to said converter and said second sampling circuit to subtract the output signals therefrom to produce said tracking error control signal.
Claim 10
Dependent Claim
131 words
A system according to claim 1, wherein said fifth and sixth means each include an integrator coupled to said fourth means by said seventh means, a threshold device having positive and negative threshold levels coupled to the output of said integrator, said threshold device providing an output signal each time either of said positive and negative threshold levels are exceeded, said output signal being coupled to said integrator to reset said integrator, a bidirectional counter coupled to said threshold device responsive to said output signal therefrom, and a bidirectional accumulator having an integral input coupled to the output of said counter, a proportional input coupled to said threshold device responsive to said output signal therefrom and an output to provide the associated one of said first and second tracking drive signals.
Claim 11
Dependent Claim
33 words
A system according to claim 1, further including a backup programmed tracking control circuit capable of being coupled to both said fifth and sixth means in place of said tracking error control signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |