Patent US3696427A successfully refreshed from Google Patents.
US3696427A
Expired / Lapsed
US
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Radio-navigation system
Assignee: CGG SA
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Filing: 1970-06-02
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Granted: 1972-10-03
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Expires: 1990-06-02
Abstract
Abstract The invention concerns an improved radio-navigation system for determining the position of a moving body relative to at least two remote transmitters. In this radio-navigation system there are produced in the body carried receiver two local LF signals of frequency f1 and f2, and the phase differences are determined in phasemeters between each of the local signals and radio-navigation LF signals of the same frequencies, the phases of which are a function of the distances between the transmitters and the moving body. The radionavigation LF signals are obtained from two radio-navigation HF signals received by the body from the transmitters, the frequencies of which are equal to F + f1 and F + f2, the signals of frequencies f1 and f2 being extracted by successive mixings with signals of frequencies F - Fi and Fi.
Inventors
- 👤 Georges Pierre Nard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:00
CPC Classifications
G; G01; G01S; G01S5/00; G01S5/02; G01S5/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
200 words
In a radio-navigation system in which high frequency radio signals are transmitted from transmitters to a receiver on board a remotely located moving body for processing to obtain information on the position of the moving body relative to the transmitters, the improvement consisting in means for transmitting from at least two distinct transmitters high frequency radio-navigation signals (FA, FB) the frequency difference between which is a low frequency (FA F+ F1 and FB F+ F2), receiver means for receiving and heterodyning said high frequency radio-navigation signals in the receiver to obtain low frequency radio-navigation signals (f1, f2) the phases of which represent the phases of the respective high frequency radionavigation signals as received, means for producing locally in said receiver means independently of said high frequency radionavigation signals at least two different low frequency local signals having the same frequencies (f1 and f2) as the low frequency radio-navigation signals respectively, and means for comparing the phase of each of the local signals with the respective low frequency radio-navigation signal whereby the phase difference between each respective pair of f1 and f2 frequencies supplies information on the position of the moving body relative to each of the at least two transmitters.
Claim 2
Dependent Claim
200 words
In a radio-navigation system in which high frequency radio signals are transmitted from transmitters to a receiver on board a remotely located moving body for processing to obtain information on the position of the moving body relative to the transmitters, the improvement consisting in means for transmitting from at least two distinct transmitters high frequency radio-navigation signals (FA, FB) the frequency difference between which is a low frequency (FA F+ F1 and FB F+ F2), receiver means for receiving and heterodyning said high frequency radio-navigation signals in the receiver to obtain low frequency radio-navigation signals (f1, f2) the phases of which represent the phases of the respective high frequency radionavigation signals as received, means for producing locally in said receiver means independently of said high frequency radionavigation signals at least two different low frequency local signals having the same frequencies (f1 and f2) as the low frequency radio-navigation signals respectively, and means for comparing the phase of each of the local signals with the respective low frequency radio-navigation signal whereby the phase difference between each respective pair of f1 and f2 frequencies supplies information on the position of the moving body relative to each of the at least two transmitters.
Claim 3
Dependent Claim
160 words
A radio-navigation system according to claim 1 characterized in that in addition to the two radio-navigation HF signals, there are transmitted at least one group of two ambiguity removal HF signals F''A and F''B from the two distinct transmitters, the values of the frequencies of the ambiguity removing signals being such that they differ from a same basic high frequency F'''' by the low frequency f1 and f2, respectively (F''A F'' + f1; F''B F'' + f2), the difference between the basic frequencies F and F'' being small compared with F, means producing two ambiguity removal LF signals of frequencies f1 and f2 from the ambiguity removal HF signals, and means for comparing the phase difference between the local produced LF signals and the ambiguity removal LF signals, whereby the difference obtained between the last said phase difference and the difference obtained between the radio-navigation LF signals and the local LF signals provides wider channels, thus permitting the ambiguity removal.
Claim 4
Dependent Claim
21 words
A radio-navigation system according to claim 2 characterized in that the transmission of the two ambiguity removal HF signals is sequential.
Claim 5
Dependent Claim
86 words
A system according to claim 1 characterized in that the receiver means for obtaining the two radio-navigation LF signals from the radio-navigation HF signals comprises a first mixer for mixing the at least two radio-navigation HF signals with a heterodyning frequency F - Fi to produce two intermediate radio-navigation signals Fi + f1 and Fi + f2, and a second mixer having only one side band for mixing the two intermediate radio-navigation signals With an intermediate frequency signal Fi for obtaining the two radio-navigation LF signals.
Claim 6
Dependent Claim
46 words
A system according to claim 4 characterized in that the receiver means comprises an oscillator generating a periodic electric signal and a frequency synthesizer fed by the oscillator, the signals of frequencies F - Fi, Fi and the local LF signals being supplied by the synthesizer.
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) | 1975-10-03 | 1976-04-03 | 1976-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-10-03 | 1980-04-03 | 1980-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-10-03 | 1984-04-03 | 1984-10-03 | $7700.00 | Window Closed / Lapsed |