GB2063003A
Expired / Lapsed
GB
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Methods of remotely sensing the state of a body of water and devices for carrying out such methods
Assignee: IFP Energies nouvelles
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Filing: 1980-11-07
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Granted: —
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Expires: 2000-11-07
Abstract
Abstract A method of remotely sensing of the state (i.e. the amplitude and frequency of the waves) of a selected zone (Z) of a body of water comprises: transmitting successive radar pulses ( DELTA ); receiving corresponding echoes ( beta ) returned by the waves of the selected zone; forming series of samples of said echoes ( beta ), each series having a different time shift ( delta 1, delta 2, delta 3) and corresponding to a different sector of the selected zone; keeping one of these series, corresponding to a reference sector, unchanged; applying to the other series correction factors for eliminating therefrom the influence of the difference in distance and/or azimuth, with respect to the transmission point, between the sectors corresponding to the series in question and the reference sector; and summing the so-corrected series or the corresponding frequency spectra with that corresponding to the reference sector, thereby improving the signal-to-noise ratio of the signals emanating from the reference sector, which are representative of the state of the selected zone. <IMAGE>
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
GB
Data Source
google_patents
Last Synchronized
2026-10-23 05:16
CPC Classifications
G; G01; G01S; G01S13/00; G01S13/88; G01S13/95; G01S13/951; Y; Y02; Y02A; Y02A90/00; Y02A90/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
303 words
A method of remotely sensing the state (i.e. the amplitude and frequency of the waves) of a selected zone of a body of water, including determining the frequency spectrum of echoes, from the waves of said zone, of sequentially transmitted radar pulses, wherein the following steps are performed;
a) a plurality of series of samples of the successive echo signals are taken, each of which series
corresponds to a separate sector of the selected zone;
b) one of the series, which corresponds to a sector which is used as a reference sector, is kept
unchanged;
c) the frequency spectrum of each series of signal samples is determined;;
d) corrections are applied to the or each other series or to the corresponding frequency spectrum or
spectra to adjust its or their values to values which would have corresponded to the reference sector,
by applying thereto (i) a correction factor related to the difference in distance from the transmission
point of the sector corresponding to the series in question and of the reference sector, in order to take
into account the different degree of weakening of the radar signals in relation to the propagation
distance, or (ii) a correction factor related to the difference in azimuth with respect to the transmission
point of the sector corresponding to the series in question and of the reference sector, in order to take
into account the different angles of incidence of the wind, resulting from the different orientation of
the sector corresponding to the series in question and of the reference sector, with respect to the wind
direction, or (iii) both of the above-mentioned correction factors, in a cumulative manner; and
e) the corrected spectrum or spectra or the spectrum or spectra of the corrected series are combined with
that of the series corresponding to the reference sector.
Claim 2
Independent Claim
303 words
A method of remotely sensing the state (i.e. the amplitude and frequency of the waves) of a selected zone of a body of water, including determining the frequency spectrum of echoes, from the waves of said zone, of sequentially transmitted radar pulses, wherein the following steps are performed;
a) a plurality of series of samples of the successive echo signals are taken, each of which series
corresponds to a separate sector of the selected zone;
b) one of the series, which corresponds to a sector which is used as a reference sector, is kept
unchanged;
c) the frequency spectrum of each series of signal samples is determined;;
d) corrections are applied to the or each other series or to the corresponding frequency spectrum or
spectra to adjust its or their values to values which would have corresponded to the reference sector,
by applying thereto (i) a correction factor related to the difference in distance from the transmission
point of the sector corresponding to the series in question and of the reference sector, in order to take
into account the different degree of weakening of the radar signals in relation to the propagation
distance, or (ii) a correction factor related to the difference in azimuth with respect to the transmission
point of the sector corresponding to the series in question and of the reference sector, in order to take
into account the different angles of incidence of the wind, resulting from the different orientation of
the sector corresponding to the series in question and of the reference sector, with respect to the wind
direction, or (iii) both of the above-mentioned correction factors, in a cumulative manner; and
e) the corrected spectrum or spectra or the spectrum or spectra of the corrected series are combined with
that of the series corresponding to the reference sector.
Claim 3
Dependent Claim
18 words
A method according to claim 1, wherein the combination of spectra of step (e) comprises summing the spectra.
Claim 4
Dependent Claim
17 words
A method according to claim 2, wherein the summing of the spectra comprises summing with weighting coefficients.
Claim 5
Independent Claim
43 words
A method of remotely sensing the state of a selected zone of a body of water, the method being substantially as herein described with reference to Figures 5 and 5, Figure 7 and 8 or Figures 9 and 10 of the accompanying drawings.
Claim 6
Independent Claim
43 words
A method of remotely sensing the state of a selected zone of a body of water, the method being substantially as herein described with reference to Figures 5 and 5, Figure 7 and 8 or Figures 9 and 10 of the accompanying drawings.
Claim 7
Dependent Claim
416 words
A device for carrying out a method according to any one of claims 1 to 4, the device comprising
means for sequentially transmitting radar pulses;
a system for receiving echoes, from the waves of the selected zone, of the transmitted pulses, said system comprising directional and orientable receiving means to selectively receive the echoes along a predetermined direction;
a reception chain comprising demodulation means and variable gain amplification means;
a system for recording and processing the received signals; and
control elements operative to modify the gain of the amplification means and/or to modify the orientation of the receiving means, the recording and processing system being operative to actuate the control elements in relation to the geographical location of the different sectors of the selected zone with respect to the reference sector. 5. A device for carrying out the method of the invention, the device comprising:
means for sequentially transmitting radar pulses;
a system for receiving echoes, from the waves of the selected zone, of the transmitted pulses, said system comprising directional and orientable receiving means to selectively receive the echoes along a predetermined direction;
a reception chain comprising demodulation means and variable gain amplification means;
a system for recording and processing the received signals; and
control elements operative to modify the gain of the amplification means and/or to modify the orientation of the receiving means, the recording and processing system being operative to actuate the control elements in relation to the geographical location -of the different sectors of the selected zone with respect to the reference sector. 6. A device according to claim 5, wherein the control elements comprises a digital memory arranged to receive a series of digital values and means for converting the digital values to an analog signal for controlling the gain of the amplification means. 7. A device according to claim 5 or claim 6, wherein the directional and orientable receiving means comprises a plurality of fixed receiving elements arranged in line and connected to a plurality of phase shifting means operative to apply a variable delay to signals received by each receiving element, and the control elements comprise means for transmitting, to the plurality of phase shifting means, control signals generated by the recording and processing system. 8. A device for carrying out a method according to any one of claims 1 to 4, the device being substantially as herein described with reference to Figure 11 of the accompanying drawings. New claims or amendments to claims filed on 29 Jan 1981.
References Cited (Backward Citations)
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