US4035802A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for wind measurement
Assignee: Individual
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Filing: 1976-01-27
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Granted: 1977-07-12
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Expires: 1996-01-27
Abstract
Abstract A wind measuring system utilizing a very low frequency (VLF) radio navigation system including an observation station, at least three transmitting stations for sending out the VLF signal, and a sounding device positioned in the atmosphere for receiving the VLF signals from the transmitting stations and retransmitting them by way of a telemetric link to the observation station where processing equipment measures the phases of the signal transmission and determines therefrom the position or velocity directions of the sounding device. The processing equipment includes a receiving circuit for receiving the VLF signal from the sounding device, and limiting circuitry for amplitude limiting the VLF signal. A local signal generator included in the observation station generates a reference signal which has the same frequency as the VLF signal. Polar cross correlation circuitry is also included for forming cross correlation functions of the amplitude limited VLF signals and the reference signal. The phase angles of the cross correlation functions are representative of the location of the sounding device.
Inventors
- 👤 Ove Jagermalm
- 👤 Keijo Luukkonen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:54
CPC Classifications
G; G01; G01S; G01S11/00; G01S11/02; G01S5/00; G01S5/02; G01S5/10
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
150 words
In a wind measurement apparatus, utilizing a VLF radio navigation system comprising an observation station having processing means, at least three transmitting stations for sending VLF signals, and a sounding device positioned for receiving the VLF signals from the transmitting stations and retransmitting them by means of a telemetric link to said observation station for measurement of the phases of the VLF signal transmissions, said processing means comprising receiving means for receiving said VLF signals from said sounding device, limiting means coupled to said receiving means for amplitude limiting the VLF signals, signal generating means for generating a reference signal having the same frequency as the VLF signals, and polar cross correlation means for participating in the formation of a cross correlation function between said amplitude limited VLF signals and said reference signal, wherein phase angles of said cross correlation functions are representative of the position of the sounding device.
Claim 2
Dependent Claim
150 words
In a wind measurement apparatus, utilizing a VLF radio navigation system comprising an observation station having processing means, at least three transmitting stations for sending VLF signals, and a sounding device positioned for receiving the VLF signals from the transmitting stations and retransmitting them by means of a telemetric link to said observation station for measurement of the phases of the VLF signal transmissions, said processing means comprising receiving means for receiving said VLF signals from said sounding device, limiting means coupled to said receiving means for amplitude limiting the VLF signals, signal generating means for generating a reference signal having the same frequency as the VLF signals, and polar cross correlation means for participating in the formation of a cross correlation function between said amplitude limited VLF signals and said reference signal, wherein phase angles of said cross correlation functions are representative of the position of the sounding device.
Claim 3
Dependent Claim
39 words
The combination of claim 1 and further comprising computer means for receiving the output of said polar cross correlation means and forming therefrom said cross correlation functions, and for computing therefrom said phase angles of said cross correlation functions.
Claim 4
Dependent Claim
70 words
The combination of claim 1 and wherein said observation station further includes ground VLF receiving means for receiving the VLF signals directly from the transmitting stations wherein said processing means forms correction cross correlation functions between said directly received VLF signals and said reference signal, and further comprising means for correcting the error caused by propagating conditions by comparing said correction cross correlation functions with said first-mentioned cross correlation functions.
Claim 5
Dependent Claim
39 words
The combination of claim 1 and wherein said limiting means further comprises, in series circuit combination, amplifying means, filtering means, and amplitude limiting means, whereby the received VLF signal from the sounding device is transformed into a digital signal.
Claim 6
Dependent Claim
118 words
The combination of claim 4 and wherein said generating means comprises a reference oscillator means for forming a rectangular wave signal having the same frequency as the VLF signals, and for forming clock pulses, said polar cross correlation means comprises a shift register under control of said clock pulses for receiving said rectangular wave signal and providing successively delayed sequences of said rectangular wave signal, wherein said polar cross correlation means further comprises a plurality of gating means receiving said digital signal and each gating means respectively receiving one of said successively delayed sequences of rectangular wave signals, and further comprising a corresponding plurality of counting means for respectively receiving the outputs of said plurality of gating means.
Claim 7
Dependent Claim
46 words
The combination of claim 5 and wherein there are a plurality of transmitting stations each producing a VLF signal of a different phase, and wherein said processing means further comprises control means for controlling the operation of said gating means and for selecting the desired stations.
Claim 8
Dependent Claim
52 words
The combination of claim 6 and further comprising sequence generator means coupled between said reference oscillator means and said control means for receiving said clock pulses and for varying the frequency thereof until the sequence of the clock pulses are synchronized with the sequence of the VLF signals of the desired stations.
Claim 9
Dependent Claim
17 words
The combination of claim 5 and further comprising sampling means coupled to said plurality of counting means.
Claim 10
Dependent Claim
23 words
The combination of claim 5 and further comprising readout means coupled to said plurality of counting means for recording the cross correlation function.
Claim 11
Dependent Claim
34 words
The combination of claim 5 and wherein said successively delayed sequences respectively represent differently phased reference signals, and wherein the phases thereof are equally distributed over the total period of the rectangular wave signal.
Claim 12
Dependent Claim
57 words
The combination of claim 2 and further comprising monitor means coupled to said computer means and wherein said cross correlation functions are read into said computer means at fixed intervals, whereby the development of the cross correlation function can be observed on said monitor means and the quality of the received VLF signals can be thereby monitored.
Claim 13
Dependent Claim
36 words
The combination of claim 1 and wherein a period of integration used in the formation of the cross correlation function with regard to one transmission sequence is the same as the duration of a VLF signal.
Claim 14
Independent Claim
124 words
A method for wind measurement utilizing a VLF radio navigation system including an observation station, at least three transmitting stations and a sounding device, said method comprising the steps of: (a) transmitting VLF signals from said transmitting stations; (b) receiving said VLF signals at said sounding device and retransmitting them to said observation station; (c) receiving said VLF signals from said sounding device at said observation station; (d) amplitude limiting said VLF signals received at said observation station; (e) generating at said observation station a reference signal having the same frequency as the VLF signals; (f) forming at said observation station cross correlation functions between said amplitude-limited VLF signals and said reference signal; and (g) determining the phase angles of said cross correlation functions.
Claim 15
Independent Claim
124 words
A method for wind measurement utilizing a VLF radio navigation system including an observation station, at least three transmitting stations and a sounding device, said method comprising the steps of: (a) transmitting VLF signals from said transmitting stations; (b) receiving said VLF signals at said sounding device and retransmitting them to said observation station; (c) receiving said VLF signals from said sounding device at said observation station; (d) amplitude limiting said VLF signals received at said observation station; (e) generating at said observation station a reference signal having the same frequency as the VLF signals; (f) forming at said observation station cross correlation functions between said amplitude-limited VLF signals and said reference signal; and (g) determining the phase angles of said cross correlation functions.
Claim 16
Dependent Claim
70 words
The method of claim 13 and further comprising the steps of: (a) directly receiving at said observation station the VLF signals from said transmitting stations; (b) forming correction cross correlation functions between said directly received VLF signals and said reference signal; and (c) correcting said cross correlation functions between said amplitude-limited VLF signal and reference signal for errors caused by propagating conditions, by combining therewith said correction cross correlation functions.
Claim 17
Dependent Claim
61 words
The method of claim 13 and wherein said step of forming the cross correlation functions further comprises the steps of: (a) forming a plurality of correlation coefficients of differently phased reference signals, respectively, the phases of which are equally distributed over the total period of the reference signal; and (b) obtaining the cross correlation function from said plurality of correlation coefficients.
Claim 18
Dependent Claim
49 words
The method of claim 15, wherein the observation station includes a computer and further comprising steps of reading the cross correlation function values into the computer at appropriate intervals and monitoring the development of the cross correlation functions whereby the quality of the received VLF signals can be monitored.
Claim 19
Dependent Claim
36 words
The method as in claim 13, wherein a period of integration used in the calculation of the cross correlation function with regard to one transmission sequence is the same as the duration of the VLF signal.
Claim 20
Dependent Claim
140 words
In combination, a wind measuring apparatus utilizing a VLF radio navigation system comprising at least three transmitting stations for sending out VLF signals, a sounding device positioned for receiving the VLF signals from the transmitting stations and retransmitting them by means of a telemetric link, a ground observation station for measuring phases of the VLF signal transmissions, said ground observation station including receiving means for receiving said VLF signals from said sounding device, limiting means coupled to said receiving means for amplitude limiting the VLF signals, signal generating means for generating a reference signal having the same frequency as the VLF signal, and polar cross correlation means for forming a cross correlation function between said amplitude-limited VLF signals and said reference signal, wherein the phase angles of said cross correlation functions are representative of the position of the sounding device.
Claim 21
Dependent Claim
140 words
In combination, a wind measuring apparatus utilizing a VLF radio navigation system comprising at least three transmitting stations for sending out VLF signals, a sounding device positioned for receiving the VLF signals from the transmitting stations and retransmitting them by means of a telemetric link, a ground observation station for measuring phases of the VLF signal transmissions, said ground observation station including receiving means for receiving said VLF signals from said sounding device, limiting means coupled to said receiving means for amplitude limiting the VLF signals, signal generating means for generating a reference signal having the same frequency as the VLF signal, and polar cross correlation means for forming a cross correlation function between said amplitude-limited VLF signals and said reference signal, wherein the phase angles of said cross correlation functions are representative of the position of the sounding device.
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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |