US3851159A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic waypoint bearing converter
Assignee: RTX Corp
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Filing: 1973-08-02
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Granted: 1974-11-26
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Expires: 1993-08-02
Abstract
Abstract Signals comprising 30 Hz north reference and 30 Hz distance to way point vectors derived from an area navigation computer are utilized to generate a count equivalent to the true bearing (relative to north) of a way point from an aircraft. The count is used to preset a down counter operated at 400 Hz, thereby to derive in-phase and quadrature signals at 400 Hz, the phase of which are indicative of the true bearing of a way point. These signals are combined in synchronous demodulators with converted compass gyro signals at 400 Hz, and the outputs of the synchronous demodulators are summed with various positive and negative scale factors so as to generate synchro driving signals equivalent to the relative bearing of the way point with respect to the aircraft heading, thereby to drive a way point bearing indicator relatively with respect to a compass card of an RMI indicator.
Inventors
- 👤 J Games
- 👤 C Casper
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 02:58
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
260 words
An electronic waypoint bearing indicator converter responsive to first input signals derived from an area navigation computer, indicative of true bearing of a way point, and second input signals derived from a directional gyro compass with respect to a synchro carrier signal, indicative of aircraft heading, to provide output signals indicative of relative way point bearing, said synchro carrier signal also being provided as an input to said converter, said converter comprising: first electronic circuit means responsive to said first input signals and to said synchro carrier signal for providing first intermediate signals at the frequency of said synchro carrier signal and having a phase related to said synchro carrier signal in proportion to the true bearing of the way point as indicated by said first input signals; second electronic means responsive to said second input signals for providing second intermediate signals at the frequency of said synchro carrier signal the magnitude of which varies as a function of the heading of said aircraft; third electronic circuit means for combining said first intermediate signals and said second intermediate signals so as to provide a plurality of third intermediate signals, the magnitudes of which vary as a function of the heading of said aircraft and the phase of which vary from the phase of said synchro carrier signal as a function of the true bearing of the way point; and fourth electronic circuit means responsive to said third electronic circuit means for providing said output signals as a function of weighted sums and differences of said plurality of third intermediate signals.
Claim 2
Dependent Claim
260 words
An electronic waypoint bearing indicator converter responsive to first input signals derived from an area navigation computer, indicative of true bearing of a way point, and second input signals derived from a directional gyro compass with respect to a synchro carrier signal, indicative of aircraft heading, to provide output signals indicative of relative way point bearing, said synchro carrier signal also being provided as an input to said converter, said converter comprising: first electronic circuit means responsive to said first input signals and to said synchro carrier signal for providing first intermediate signals at the frequency of said synchro carrier signal and having a phase related to said synchro carrier signal in proportion to the true bearing of the way point as indicated by said first input signals; second electronic means responsive to said second input signals for providing second intermediate signals at the frequency of said synchro carrier signal the magnitude of which varies as a function of the heading of said aircraft; third electronic circuit means for combining said first intermediate signals and said second intermediate signals so as to provide a plurality of third intermediate signals, the magnitudes of which vary as a function of the heading of said aircraft and the phase of which vary from the phase of said synchro carrier signal as a function of the true bearing of the way point; and fourth electronic circuit means responsive to said third electronic circuit means for providing said output signals as a function of weighted sums and differences of said plurality of third intermediate signals.
Claim 3
Dependent Claim
130 words
An electronic converter according to claim 1 wherein said first electronic circuit means includes a first counter, a second counter having a plurality of selectively enabled preset inputs, said preset inputs being connected for response to the output of said first counter, means responsive to said first input signals for providing a count in said first counter proportional to the true bearing of the way point and providing an indication of when the count in said first counter is complete, means responsive to the indication of the count being complete to enable the preset inputs of said second counter, and means responsive to said synchro carrier signal for causing said second counter to count, said first intermediate signals being derived in response to high order outputs of said second counter.
Claim 4
Dependent Claim
63 words
An electronic converter according to claim 1 wherein said third electronic circuit means comprises a plurality of synchronous demodulators, the signal inputs of which are connecteD for response to said second intermediate signals, the reference inputs of which are connected for response to said first intermediate signals for demodulating said second intermediate signals in accordance with the phase of said first intermediate signals.
Claim 5
Dependent Claim
164 words
An electronic converter according to claim 3 wherein said first intermediate signals are of the form E1 sin ( omega t + W) E1 cos ( omega t + W), where omega relates to said synchro carrier signal, W is the phase proportional to said true bearing to the way point, and wherein said second intermediate signals are of the form E cos H sin omega t E sin H sin omega t where E sin H is the amplitude, E being an arbitrary maximum amplitude, and H being proportional to the aircraft heading, and wherein said third intermediate signals provided by said synchronous demodulators are of the form A E cos H cos W B E sin H cos W C E cos H sin W D E sin H sin W, said output signals being of the form Ex (.5(C - B) + .866 (A + D)) sin omega t Ey (.5(C - B) - .866 (A + D)) sin omega t.
Claim 6
Dependent Claim
154 words
An electronic converter according to claim 4 wherein said fourth electronic circuit means comprises a differencing amplifier to provide a signal C-B, and a pair of summation amplifiers, each having an input with the scale factor +.5 connected for response to said first summing amplifier, one of said second summing amplifiers having two inputs with scale factors +.866, one connected for response to the one of said synchronous demodulators providing said signal A, and the other connected for response to the one of said synchronous demodulators providing said signal D, said third synchronous demodulator having a pair of inputs with scale factors -.866, one connected to the one of said synchronous demodulators providing said signal A, and the other connected to the one of said synchronous demodulators providing said signal D; and means responsive to the output of said second and third summing amplifiers for providing said output signals on a periodic carrier wave.
Claim 7
Dependent Claim
54 words
An electronic converter according to claim 5 wherein said responsive means comprises a set of apparatus responsive to each of said second and third amplifiers, each set comprising a low pass filter feeding a square wave chopper the output of which feeds a power amplifier, the output of which comprise the desired output signals.
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) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |