US3778831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Compatible double precision doppler omnidirectional bearing system
Assignee: Individual
•
Filing: 1971-04-07
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Granted: 1973-12-11
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Expires: 1991-04-07
Abstract
Abstract A circular antenna array has a first antenna and second and third antennas or a first antenna and two pairs of antennas arranged around the first antenna on a circular perimeter of which the first antenna is the center of the circular array. A frequency modulation is generated in the signals associated with the second and third antennas or the two pairs of antennas characteristic of a rotational condition of the second and third antennas or the two pairs of antennas on the perimeter at a low frequency in a manner whereby the second and third antennas or two pairs of antennas are rotated in opposite directions around the perimeter to provide a phase difference in electrical degrees in the modulation of the signals which are radiated which is double the actual displacement in azimuth degrees. A signal radiated from the center antenna is used as a reference to eliminate the 180* ambiguity.
Inventors
- 👤 N Marchand
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 18:21
CPC Classifications
G; G01; G01S; G01S1/00; G01S1/02; G01S1/08; G01S1/38; G01S1/40
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
138 words
In an omnidirectional radio bearing system utilizing the Doppler principle, an antenna system comprising a circular antenna array including a first antenna and second and third antennas arranged around the first antenna on a circular perimeter of which the first antenna constitutes the center of the circular array; and rotating means for generating a frequency modulation in the signals associated with the second and third antennas characteristic of a rotational condition of said second and third antennas on the perimeter at a low frequency in a manner whereby said second and third antennas are rotated in opposite directions around said perimeter to provide a phase difference in electrical degrees in the modulation frequency of the signals which is double the actual displacement in azimuth degrees, the signals associated with the first antenna being unaffected by the frequency modulation.
Claim 2
Dependent Claim
138 words
In an omnidirectional radio bearing system utilizing the Doppler principle, an antenna system comprising a circular antenna array including a first antenna and second and third antennas arranged around the first antenna on a circular perimeter of which the first antenna constitutes the center of the circular array; and rotating means for generating a frequency modulation in the signals associated with the second and third antennas characteristic of a rotational condition of said second and third antennas on the perimeter at a low frequency in a manner whereby said second and third antennas are rotated in opposite directions around said perimeter to provide a phase difference in electrical degrees in the modulation frequency of the signals which is double the actual displacement in azimuth degrees, the signals associated with the first antenna being unaffected by the frequency modulation.
Claim 3
Dependent Claim
60 words
An antenna system as claimed in claim 1, wherein the second antenna is a 9960 cps subcarrier antenna which is rotated at 30 cps in one of A clockwise and counterclockwise direction and the third antenna is a subcarrier antenna between 4 and 8 kcs which is rotated at 30 cps in the other of a clockwise and counterclockwise direction.
Claim 4
Dependent Claim
72 words
An antenna system as claimed in claim 2, wherein the second antenna is rotated in a counterclockwise direction so that the 30 cps signal modulated on the 9960 cps subcarrier arrives earlier in phase when the direction of reception moves in a clockwise direction and the third antenna is rotated in a clockwise direction so that the 30 cps signal modulated on the 4 to 8 kcs subcarrier arrives later in phase.
Claim 5
Dependent Claim
79 words
The antenna system as claimed in claim 2, wherein the Doppler signal at the second antenna is 9960 + or - 480 cps and the Doppler signal at the third antenna is between 4 and 8 kcs + or - 480 cps and the phase difference in electrical degrees between the 30 cps modulation signals is double the actual displacement in azimuth degrees, one signal advancing in phase and the other signal being retarded equally in phase with azimuth.
Claim 6
Dependent Claim
92 words
An omnidirectional radio bearing system comprising a transmitter including means for producing two oppositely rotating Doppler generated frequencies and an omnidirectional antenna modulated by a reference frequency equal to the rates of rotation; and a receiver for receiving the three signals produced by the transmitter and including rough indicating means for providing a rough indication of the direction of reception by utilizing one Doppler signal and the omnidirectional reference frequency and indicating means for providing a fine indication of the direction of reception by comparing the two received frequency modulated Doppler signals.
Claim 7
Dependent Claim
92 words
An omnidirectional radio bearing system comprising a transmitter including means for producing two oppositely rotating Doppler generated frequencies and an omnidirectional antenna modulated by a reference frequency equal to the rates of rotation; and a receiver for receiving the three signals produced by the transmitter and including rough indicating means for providing a rough indication of the direction of reception by utilizing one Doppler signal and the omnidirectional reference frequency and indicating means for providing a fine indication of the direction of reception by comparing the two received frequency modulated Doppler signals.
Claim 8
Dependent Claim
130 words
An omnidirectional radio bearing system comprising a beacon transmitter which transmits a carrier with amplitude modulated low frequency voltage reference signals and two subcarriers frequency modulated with low frequency voltages at the same frequency which vary in phase according to the direction of reception from the transmitter, one of the low frequency voltages increasing in phase and another decreasing in phase; and a receiver for receiving signals from the transmitter, said receiver including comparing means for comparing the phases of the two low frequency voltages modulating the subcarriers to provide the precise direction of reception and additional comparing means for removing 180* ambiguity by comparing the phase of one of the low frequency voltages modulating one of the subcarriers with the phase of the low frequency voltage modulating the carrier.
Claim 9
Dependent Claim
130 words
An omnidirectional radio bearing system comprising a beacon transmitter which transmits a carrier with amplitude modulated low frequency voltage reference signals and two subcarriers frequency modulated with low frequency voltages at the same frequency which vary in phase according to the direction of reception from the transmitter, one of the low frequency voltages increasing in phase and another decreasing in phase; and a receiver for receiving signals from the transmitter, said receiver including comparing means for comparing the phases of the two low frequency voltages modulating the subcarriers to provide the precise direction of reception and additional comparing means for removing 180* ambiguity by comparing the phase of one of the low frequency voltages modulating one of the subcarriers with the phase of the low frequency voltage modulating the carrier.
Claim 10
Dependent Claim
26 words
An omnidirectional radio bearing system as claimed in claim 6, wherein the transmitter includes antenna means for producing two double sideband signals rotating in opposite directions.
Claim 11
Dependent Claim
71 words
An omnidirectional radio bearing system as claimed in claim 6, wherein the transmitter includes antenna means for producing two double sideband signals rotating in opposite directions and wherein one subcarrier is amplitude modulated on the carrier and the other subcarrier is frequency modulated on the subcarrier and the low frequency voltage reference signal is amplitude modulated on the carrier by adjusting the relative phases of each of the double sideband signals.
Claim 12
Dependent Claim
76 words
An omnidirectional radio bearing system as claimed in claim 8, wherein the carrier is amplitude modulated by a 30 cps low frequency signal, a subcarrier is 9960 cps and is frequency modulated by a 30 cps low frequency signal and is amplitude modulated on the carrier, and another subcarrier is between 4 and 8 kcs and is frequency modulated by a 30 cps low frequency signal of opposite phase and is frequency modulated on the carrier.
Claim 13
Dependent Claim
63 words
An omnidirectional radio bearing system as claimed in claim 9, wherein the comparing means compares the phases of two 30 cps low frequency voltages modulating the carriers, and the additiOnal comparing means removes 180* ambiguity by comparing the phases of one 30 cps low frequency voltage modulating a subcarrier with the phase of a 30 cps low frequency voltage amplitude modulating the carrier.
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) | 1976-12-10 | 1977-06-11 | 1977-12-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-10 | 1981-06-11 | 1981-12-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-10 | 1985-06-11 | 1985-12-11 | $7700.00 | Window Closed / Lapsed |