CN115144884A - Sea surface wind speed inversion method based on satellite reflection signals and chip module - Google Patents
Sea surface wind speed inversion method based on satellite reflection signals and chip module Download PDFInfo
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- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/38—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system
- G01S19/39—Determining a navigation solution using signals transmitted by a satellite radio beacon positioning system the satellite radio beacon positioning system transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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- G01S19/426—Determining position by combining or switching between position solutions or signals derived from different satellite radio beacon positioning systems; by combining or switching between position solutions or signals derived from different modes of operation in a single system by combining or switching between position solutions or signals derived from different modes of operation in a single system
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Abstract
A sea surface wind speed inversion method based on satellite reflection signals comprises the following steps: receiving positioning position information sent by a satellite navigation chip module; receiving a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct signal and the reflected signal according to the first direct signal and the reflected signal; acquiring the sensitive relevant time and time delay waveform area of the sea surface wind speed of the reflection signal according to the relevant sequence; acquiring a wind speed value according to the relevant time, the time delay waveform area and the wind speed inversion model; and acquiring the sea surface wind speed of the target area according to the positioning position information and the wind speed value. According to the method, the sea surface wind speed is measured by extracting the characteristic observation quantity of the combined multiple GEO reflection signals, a stable geometric configuration is provided by using the shore-based GEO satellite, the signal processing complexity is reduced, and the wind speed measurement precision is improved. Meanwhile, the shore-based remote sensing platform has a fixed observation area, can stably observe for a long time, and has the advantages of wide signal source, low cost, light detection equipment and the like.
Description
Technical Field
The invention relates to the field of sea surface wind speed measurement, in particular to a sea surface wind speed inversion method based on satellite reflection signals and a chip module.
Background
Sea surface wind speed, one of the physical parameters reflecting the state of the sea surface, is an important factor influencing the movement of sea water and climate change. The offshore area is closely related to human beings, and a large amount of human activities such as marine transportation, fishery, cultivation and the like exist. The method for effectively monitoring the wind speed in the offshore area has important practical significance on economic development and offshore safe operation in the offshore area. The commonly used sea surface wind speed detection means mainly comprise two types of on-site and remote sensing monitoring. The on-site monitoring mainly comprises buoys, ocean stations and the like, but the construction cost is high, so that the large-scale deployment in the offshore area is not facilitated. Satellite remote sensing technologies such as altimeters, scatterometers and radiometers can provide wind speed on a global scale, but due to the limitation of time and spatial resolution, the wind speed in offshore sea areas cannot be effectively monitored in real time. The airborne remote sensing technology has high flexibility but poor continuity, and cannot provide continuous observation for a long time.
Disclosure of Invention
The main object of the present application is to provide a sea surface wind speed inversion method based on satellite reflection signals, so as to at least partially solve the above problems, the sea surface wind speed inversion method comprising:
receiving positioning position information sent by a satellite navigation chip module;
receiving a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct signal and the reflected signal according to the first direct signal and the reflected signal;
acquiring the sensitive relevant time and time delay waveform area of the sea surface wind speed of the reflection signal according to the relevant sequence;
acquiring a wind speed value according to the relevant time, the time delay waveform area and the wind speed inversion model;
and acquiring the sea surface wind speed of the target area according to the positioning position information and the wind speed value.
Optionally, the satellite navigation chip module is a Beidou satellite navigation chip module consisting of a plurality of Beidou geosynchronous orbit satellites.
Optionally, the receiving the positioning location information sent by the satellite navigation chip module includes:
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas receive a second direct signal sent by the Beidou satellite navigation chip module;
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas send second direct signals to the dual-frequency navigation chip-on-chip module;
the chip module on the double-frequency navigation chip acquires positioning position information according to the second direct signal;
and the chip module on the dual-frequency navigation chip sends the positioning position information to the sea surface wind speed inversion module and the sea surface wind speed monitoring module.
Optionally, the receiving a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct signal and the reflected signal according to the first direct signal and the reflected signal includes:
two channels in the four-channel radio frequency front end receive direct signals sent by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas, the other two channels receive reflected signals sent by the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas, and the direct signals and the reflected signals are converted into four paths of digital intermediate frequency signals;
the four-channel radio frequency front end sends four paths of digital intermediate frequency signals to the direct/inverse signal cooperative processing module;
and the direct/inverse signal cooperative processing module processes direct signals and reflected signals according to the four paths of digital intermediate frequency signals and acquires the related sequences of the direct signals and the reflected signals of the Beidou geosynchronous orbit satellites.
Optionally, obtaining a sea-surface wind speed sensitive correlation time and time delay waveform area of the reflection signal according to the correlation sequence includes:
generating a digital carrier ref from a predetermined fixed IF frequency value of the receiver carrieri (t) multiplying the direct and reflected signals by each other, carrier stripping the direct and reflected signals, ref carrieri (t) is a local carrier of the ith channel generated by a reference signal generation module in the direct/inverse signal cooperative processing module;
performing fast Fourier transform on the direct signals and the reflected signals after carrier stripping to obtain first frequency domain forms of the direct signals and the reflected signals;
performing fast Fourier transform on the local code to obtain a second frequency domain form of the local code, and solving conjugation of the second frequency domain form by using a conjugation operator;
conjugate multiplication of the first frequency domain form and the second frequency domain form, and obtaining multi-time-delay complex correlation values of the direct signal and the reflected signal according to inverse Fourier transformAnd
the coherent integration time of a direct/reflected signal frequency domain parallel correlator of the direct/reflected signal cooperative processing module is set to be 1ms of the pseudo code period of the Beidou B1I and B3I signals, and the direct signals and the multi-time-delay complex correlation values of the reflected signals of a plurality of Beidou geosynchronous orbit satellites are outputAndand a sea surface wind speed inversion module.
Optionally, obtaining the wind speed value according to the correlation time, the time delay waveform area, and the wind speed inversion model includes:
reading data of the ith channel, including multiple time-delayed complex correlation values of the direct signal and the reflected signalAndand azimuth and elevation angles corresponding to geosynchronous orbit satellites;
when the corresponding geosynchronous orbit satellite azimuth Ai satisfies A min <A i <A max When the satellite signal is in the antenna observation range, the satellite signal is considered to be in the antenna observation range, and subsequent processing is carried out;
the reflected signal multi-delay complex correlation value is subjected to non-coherent accumulation to obtain the delay waveform of the reflected signal, namely:
And solving the signal-to-noise ratio of the time delay waveform of the reflection signal according to the peak signal-to-noise ratio, namely:
wherein, P peak And P noise Peak power and noise power for the time delay of the reflected signal:
wherein max {. Is a maximum operator; e {. Is a mean operator;indicating that the delay is less than T τ The delay waveform of (a);
when the signal-to-noise ratio is larger than a preset threshold value, entering a subsequent wind speed inversion step;
calculating the waveform area by using the normalized reflected signal time delay waveform, namely:
wherein, T h Is a given threshold;<|Y Ni (τ)| 2 >for normalized reflected signal delay waveforms:
wherein, a A And b A Are inversion model parameters;
calculating an interference complex field according to the direct and reflected complex time delay correlation values:
wherein,the complex correlation values at the time delay waveform peak values of the reflected signal and the direct signal are obtained;
wherein M is the number of interference complex field samples,is S icf (j) Calculating the correlation time:
wherein, a icf And b icf Are inversion model parameters;
fusing the independently inverted sea surface wind speeds of all channels according to a linear unbiased minimum variance estimator: u. of 10 =m·U 10
Wherein, U 10 The constituent wind speed vectors for each channel independently inverted wind speed, namely:
U 10 =[U A1 ,U icf1 ,…,U AN ,U icfN ]
m is a weighted vector of linear combination, and under the condition of constraint of m | | =1, the minimum variance criterion is utilized to ensure thatThe minimum available:
wherein, C WS The covariance matrix of the inverted wind speed for each independent characteristic parameter, the elements in the ith row and the jth column are expressed as: c WSij =<(u i -u true )·(u j -u true ) T >
Wherein u is i And u j Representing wind speed, u, inverted independently for each channel true The true wind speed is identified.
According to another aspect of the present application, there is also provided a sea surface wind speed inversion chip module based on satellite reflection signals, including:
the Beidou dual-frequency navigation chip-on-chip module is configured to receive positioning position information sent by the satellite navigation chip module;
the direct/inverse cooperative processing module is configured to receive a direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtain a correlation sequence of the direct signal and the reflected signal according to the direct signal and the reflected signal;
the sea surface wind speed inversion module is configured to receive the correlation sequence, acquire the correlation time and the time delay waveform area of the sea surface wind speed sensitivity of the reflection signal according to the correlation sequence, and acquire a wind speed value according to the correlation time and the time delay waveform area;
and the sea surface wind speed monitoring module is configured to acquire the sea surface wind speed of the target area according to the positioning position information and the wind speed value.
Optionally, the sea surface wind speed inversion chip module further includes:
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas are arranged towards the south of the sky, and receive direct signals of the Beidou geosynchronous orbit satellite navigation chip module;
the Beidou B1I and B3I dual-frequency left-handed circularly polarized antennas are arranged facing south of the sea surface, and receive reflected signals of the Beidou geosynchronous orbit satellite navigation chip module reflected by the sea surface.
Optionally, the sea surface wind speed inversion chip module further includes:
the four-channel radio frequency front end receives direct signals sent by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas and reflected signals sent by the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas.
Optionally, the direct/inverse co-processing module includes: a reference signal generation module and a direct/reflected signal frequency domain parallel correlator;
a reference signal generation module and a direct/inverse signal frequency domain parallel correlator form a signal processing channel.
Compared with the prior art, the method has the following beneficial effects:
in a coastline of China, when a sea antenna is erected towards the south, a plurality of GEO (GEostationary Orbit) satellite signals are stabilized in the same field of view of the reflecting antenna, and a plurality of characteristic parameters of the same time delay waveform are sensitive to wind speed, so that necessary conditions are provided for optimal inversion of multi-satellite multi-frequency multi-parameter fusion. By extracting the characteristic observation quantity sea surface wind speed combined with the plurality of Beidou GEO reflection signals, the GEO satellite under the shore-based scene can be fully utilized to provide stable geometric configuration, the signal processing complexity is reduced, and the wind speed measurement precision is improved. Meanwhile, the bank-based remote sensing platform has a fixed observation area, can stably observe for a long time, and has the advantages of wide signal source, low cost, light detection equipment and the like.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, serve to provide a further understanding of the application and to enable other features, objects, and advantages of the application to be more apparent. The drawings and their description illustrate the embodiments of the invention and do not limit it. In the drawings:
FIG. 1 is a flow chart of a method for sea surface wind speed inversion based on satellite reflection signals according to one embodiment of the present application;
FIG. 2 is a flow chart of a method for sea surface wind speed inversion based on satellite reflection signals according to another embodiment of the present application;
FIG. 3 is a flow chart of a method for sea surface wind speed inversion based on satellite reflection signals according to another embodiment of the present application;
FIG. 4 is an overall architecture of a shore based Beidou GEO reflection signal sea surface wind speed inversion chip module according to one embodiment of the application;
FIG. 5 is a block diagram of a multi-channel direct/inverse co-processing module according to an embodiment of the present application;
FIG. 6 is a frequency domain parallel correlator according to one embodiment of the present application;
FIG. 7 is a flow of a sea surface wind speed inversion according to an embodiment of the present application.
Detailed Description
In order to make the technical solutions better understood by those skilled in the art, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only partial embodiments of the present application, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It should be understood that the data so used may be interchanged under appropriate circumstances such that embodiments of the application described herein may be used. Moreover, the terms "comprises," "comprising," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, chip module, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments with reference to the attached drawings.
Referring to fig. 1 to 7, an embodiment of the present application provides a sea surface wind speed inversion method based on satellite reflection signals, including:
s1: receiving positioning position information sent by a satellite navigation chip module;
big dipper B1I and B3I dual mode navigation SoC (System on Chip) receive the big dipper satellite navigation Chip module group direct beam signal that the satellite antenna sent, should directly penetrate the signal and include the location position information, and go out this location position information that will receive.
S3: receiving a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct signal and the reflected signal according to the first direct signal and the reflected signal;
and the direct/reflected signal cooperative processing module receives a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and performs correlation processing on the first direct signal and the reflected signal to obtain a direct and reflected signal complex correlation sequence of N Beidou GEO satellites.
S5: acquiring the sensitive relevant time and time delay waveform area of the sea surface wind speed of the reflection signal according to the relevant sequence;
and the sea surface wind speed inversion module receives the direct and reflected signal complex correlation sequences of the N Beidou GEO satellites and extracts the correlation time and the time delay waveform area of the reflected signal sensitive to the sea surface wind speed.
S7: acquiring a wind speed value according to the relevant time, the time delay waveform area and the wind speed inversion model;
and the sea surface wind speed inversion module utilizes the wind speed inversion model to invert to obtain the sea surface wind speed.
S9: and acquiring the sea surface wind speed of the target area according to the positioning position information and the wind speed value.
And the sea surface wind speed monitoring module receives the wind speed information output by the sea surface wind speed inversion module, and the positioning position information output by the Beidou B1I and B3I dual-frequency navigation SOC is displayed.
In this embodiment, the satellite navigation chip module is a Beidou satellite navigation chip module composed of a plurality of Beidou geostationary orbit satellites, but the present invention is not limited thereto, and a person skilled in the art can use any known satellite navigation chip module according to actual situations, and all of the satellite navigation chip modules belong to the scope claimed in the present application.
In other embodiments of the present application, receiving the positioning location information sent by the satellite navigation chip module includes:
s11: the Beidou B1I and B3I double-frequency right-hand circularly polarized antennas receive a second direct signal sent by the Beidou satellite navigation chip module;
s12: the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas send second direct signals to the dual-frequency navigation chip-on-chip module;
s13: the chip module on the double-frequency navigation chip acquires positioning position information according to the second direct signal;
s14: and the double-frequency navigation chip module sends the positioning position information to the sea surface wind speed inversion module and the sea surface wind speed monitoring module.
The Beidou B1I and B3I dual-frequency RHCP antennas are arranged towards the south of the sky to receive Beidou GEO satellite navigation chip module direct signals, and the Beidou B1I and B3I dual-frequency LCHP antennas are arranged towards the south of the sea surface to receive Beidou satellite navigation chip module reflected signals reflected by the sea surface; the Beidou B1I and B3I dual-mode navigation SoC input end is connected with the Beidou B1I and B3I dual-frequency right-hand circularly polarized antenna, the Beidou satellite navigation chip module direct-injection signal output by the Beidou satellite navigation SoC input end is received to complete navigation positioning, the output end is connected with the sea surface wind speed inversion and monitoring module, and the received and positioned position information is output to the sea surface wind speed inversion module and the sea surface wind monitoring module. The rest steps are the same as the above embodiments, and are not described herein again.
In this embodiment, the big dipper B1I and B3I dual-band right-hand circularly polarized antenna is used for receiving big dipper B1I and B3I direct electromagnetic signals, and converting the electromagnetic signals into radio frequency voltage signals S d (t) of (d). The Beidou B1I and B3I dual-frequency left-handed circularly polarized antenna is used for receiving Beidou B1I and B3I electromagnetic signals reflected by the sea surface and converting the electromagnetic signals into radio frequency voltage signals S r (t) of (d). Big dipper B1I and B3I dual-frenquency navigate the SoC and be a ripe navigation SoC module, receive big dipper B1I and the signal of B3I dual-frenquency dextrorotation circular polarized antenna output and navigate the location, output azimuth angle, elevation angle and locating information.
In other embodiments of the present application, the receiving a first direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct signal and the reflected signal according to the first direct signal and the reflected signal includes:
s31: two channels in the four-channel radio frequency front end receive direct signals sent by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas, the other two channels receive reflected signals sent by the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas, and the direct signals and the reflected signals are converted into four paths of digital intermediate frequency signals;
s32: the four-channel radio frequency front end sends four paths of digital intermediate frequency signals to the direct/inverse signal cooperative processing module;
s33: and the direct/inverse signal cooperative processing module processes direct signals and reflected signals according to the four paths of digital intermediate frequency signals and acquires the related sequences of the direct signals and the reflected signals of the Beidou geosynchronous orbit satellites.
Two channels in the four-channel radio frequency front end are connected with Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas, the other two channels are connected with the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas, and four paths of digital intermediate frequency signals are output to the direct/inverse signal cooperative processing module to complete the related processing of direct projection and reflected signals; the direct/reflected signal cooperative processing module is connected with the four-channel radio frequency front end, and performs correlation processing on the direct/reflected signals output by the four-channel radio frequency front end to obtain a direct and reflected signal complex correlation sequence of the N Beidou GEO satellites. Other steps are the same as the above embodiments, and are not described herein again.
In this embodiment, four passageway radio frequency front ends include big dipper B1I signal radio frequency front end and big dipper B3I signal radio frequency front end, and two sub-radio frequency front ends comprise two radio frequency channels that the structure is the same completely, carry out frequency conversion, filtering, gain control and sampling quantization to big dipper B1I direct projection, reflection signal respectively. The RF front-end module receives RF signals S output by the right-hand circularly polarized antenna and the left-hand circularly polarized antenna d (t) and S r (t), four paths of digital intermediate frequency signals are output and respectively correspond to Beidou B1I direct injection digital intermediate frequency signals, B1I reflection digital intermediate frequency signals, beidou B3I direct injection digital intermediate frequency signals and Beidou B3I reflection digital intermediate frequency signals. The Beidou B1I and B3I signals are processed completely the same, for the convenience of description, the Beidou B1I and B3I coincidence distinction is not carried out on the intermediate frequency signals, and the direct injection intermediate frequency signals are assumed to be S d (n) reflecting the intermediate frequency signal as S r (n)。
The multi-channel direct/reflected signal cooperative processing module consists of N reference signal generation modules and N direct/reflected signal frequency domain parallel correlators. A reference signal generation module and a direct/inverse signal frequency domain parallel correlator form a signal processing channel. The processing procedures are completely the same because the local carrier generated by the B1I and B3I signal processing except the generated local carrier is consistent with the corresponding radio frequency front end intermediate frequency, the local code is consistent with the corresponding PRN number, and therefore, the B1I and B3I signals are not distinguished in the follow-up theory, and the processing channels are uniformly numbered from 1 to N. As the numbers of Pseudo-Random Noise (PRN) of the Beidou GEO are 1 to 5 and 59 to 61. The processing channel of the Beidou B1I signal is 1-N/2, and the processing channel of the Beidou B3I signal is N/2+ 1-N;
the reference signal generation module generates a local carrier and a local pseudo code sequence. In the invention, a local carrier and a local pseudo code of the Beidou GEO satellite are generated. The frequency of the local carrier is coincident with the center frequency of the radio frequency front end. The local codes generate B1I and B3I pseudo-random codes with PRN numbers 1-5 and 59-61. Suppose that the local carrier for the ith channel is noted as ref carrieri (t) local code is denoted as ref codei (t)。
In other embodiments of the present application, the direct/reflected signal frequency domain parallel correlator is composed of a multiplier, a fast fourier transform, an inverse fast fourier transform, and a conjugate operator, and mainly performs multi-delay correlation processing of B1I and B3I direct, reflected signals, and local signals. Therefore, the method for acquiring the sea surface wind speed sensitive correlation time and delay waveform area of the reflection signal according to the correlation sequence comprises the following steps:
1) Generating a digital carrier ref from a predetermined fixed IF frequency value of the receiver carrieri (t) multiplying the direct and reflected signals by each other, carrier stripping the direct and reflected signals, ref carrieri (t) is a local carrier of the ith channel generated by a reference signal generation module in the direct/inverse signal cooperative processing module;
2) Performing fast Fourier transform on the direct signals and the reflected signals after carrier stripping to obtain first frequency domain forms of the direct signals and the reflected signals;
3) Performing fast Fourier transform on the local code to obtain a second frequency domain form of the local code, and solving conjugation of the second frequency domain form by using a conjugation operator;
4) The first frequency domain form and the conjugate of the second frequency domain form are multiplied, and the multi-time delay complex correlation value of the direct signal and the reflected signal is obtained according to the inverse Fourier transformAnd
5) The coherent integration time of a direct/reflected signal frequency domain parallel correlator of the direct/reflected signal cooperative processing module is set to be 1ms of the pseudo code period of the Beidou B1I and B3I signals, and the direct signals and the multi-time-delay complex correlation values of the reflected signals of a plurality of Beidou geosynchronous orbit satellites are outputAndand a sea surface wind speed inversion module.
In other embodiments of the present application, obtaining the wind speed value according to the correlation time, the time delay waveform area and the wind speed inversion model includes:
1) Reading data of the ith channel, including multiple time-delayed complex correlation values of the direct signal and the reflected signalAndand azimuth and elevation angles corresponding to geosynchronous orbit satellites;
2) When the corresponding geosynchronous orbit satellite azimuth Ai satisfies A min <A i <A max When the satellite signal is in the antenna observation range, the satellite signal is considered to be in the antenna observation range, and subsequent processing is carried out;
3) The reflected signal multi-delay complex correlation value is subjected to non-coherent accumulation to obtain the delay waveform of the reflected signal, namely:
4) And solving the signal-to-noise ratio of the time delay waveform of the reflection signal according to the peak signal-to-noise ratio, namely:
wherein, P peak And P noise Peak power and noise power for the time delay of the reflected signal:
wherein max {. Is a maximum operator; e {. Is a mean operator;indicating that the delay is less than T τ The delay waveform of (a);
5) When the signal-to-noise ratio is larger than a preset threshold value, entering a subsequent wind speed inversion step;
6) Calculating the waveform area by using the normalized reflected signal time delay waveform, namely:
wherein, T h Is a given threshold;<|Y Ni (τ)| 2 >for normalized reflected signal delay waveforms:
wherein, a A And b A Are inversion model parameters;
8) Calculating an interference complex field according to the direct and reflected complex time delay correlation values:
wherein,the complex correlation values at the time delay waveform peak values of the reflected signal and the direct signal are obtained;
wherein M is the number of interference complex field samples,is S icf (j) Calculating the correlation time:
wherein, a icf And b icf Are inversion model parameters;
11 Fusing the independently inverted sea surface wind speeds of all channels according to a linear unbiased minimum variance estimator: u. u 10 =m·U 10
Wherein, U 10 The constituent wind velocity vectors for each channel independently invert the wind velocity, i.e.:
U 10 =[U A1 ,U icf1 ,…,U AN ,U icfN ]
m is a weighted vector of linear combination, and under the condition of constraint of m | | =1, the minimum variance criterion is utilized to ensure thatThe minimum available:
wherein, C WS The covariance matrix of the inverted wind speed for each independent characteristic parameter, the elements in the ith row and the jth column are expressed as: c WSij =<(u i -u true )·(u j -u true ) T >
Wherein u is i And u j Representing wind speed, u, inverted independently for each channel true The true wind speed is identified.
In this embodiment, when the next step is performed with the condition, the method may further include a step of determining whether the current condition satisfies a preset condition, and both of the steps are within the scope of the present application.
The invention provides a Beidou GEO reflected signal sea surface wind speed inversion method and a chip module, wherein the chip module can receive and process GEO B1I and B3I reflected signals of N satellites in the same area to invert the sea surface wind speed, and firstly, a multichannel direct reflection cooperative processing module is utilized to obtain a complex correlation value sequence of the B1I and B3I reflected signals of the N Beidou GEO satellites; and then extracting the characteristic observed quantity of the relevant time and time delay waveform area of N GEO satellite B1I and B3I reflection signals in a micro upper computer, and inverting the sea surface wind speed.
The application also provides a sea wind speed inversion chip module based on satellite reflection signal, includes: big dipper B1I and B3I dual-frequency right-hand circularly polarized antenna, big dipper B1I and B3I dual-frequency left-hand circularly polarized antenna, four-channel radio frequency front end, big dipper B1I and B3I dual-frequency navigation SoC (System on Chip); the system comprises a multi-channel direct/reflected signal cooperative processing module, a sea surface wind speed inversion module and a sea surface wind speed monitoring module. The Beidou B1I and B3I dual-frequency navigation chip-on-chip module is configured to receive positioning position information sent by the satellite navigation chip module; the direct/inverse cooperative processing module is configured to receive a direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtain a related sequence of the direct signal and the reflected signal according to the direct signal and the reflected signal; the sea surface wind speed inversion module is configured to receive the correlation sequence, obtain the sensitive correlation time and delay waveform area of the sea surface wind speed of the reflection signal according to the correlation sequence, and obtain a wind speed value according to the correlation time and the delay waveform area; and the sea surface wind speed monitoring module is configured to acquire the sea surface wind speed of the target area according to the positioning position information and the wind speed value. The Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas are arranged in the south of the sky, and receive direct signals of the Beidou geosynchronous orbit satellite navigation chip module; the Beidou B1I and B3I dual-frequency left-handed circularly polarized antennas are arranged facing south of the sea surface, and receive reflected signals of the Beidou geosynchronous orbit satellite navigation chip module reflected by the sea surface. The four-channel radio frequency front end receives direct signals sent by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas and reflected signals sent by the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas. The direct/inverse cooperative processing module comprises: a reference signal generation module and a direct/reflected signal frequency domain parallel correlator; a reference signal generating module and a direct/inverse signal frequency domain parallel correlator form a signal processing channel.
In other embodiments of the application, the Beidou B1I and B3I dual-frequency left-handed circularly polarized antennas receive Beidou satellite navigation chip module B1I and B3I signals reflected by the sea surface and convert the electromagnetic signals into voltage signals.
The four-channel radio frequency front end carries out down-conversion, filtering, gain control and sampling quantization on radio frequency signals which are directly radiated and reflected by Beidou B1I and B3I right-hand circularly polarized and left-hand circularly polarized antennas and transmitted by the Beidou B1I and B3I right-hand circularly polarized antennas, and the radio frequency signals are converted into digital intermediate frequency signals.
The Beidou B1I and B3I dual-mode navigation SoC receives signals output by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas for navigation and positioning, and outputs positioning information to the sea surface wind speed inversion and monitoring module.
The multichannel direct/reflected signal cooperative processing module consists of 4N direct/reflected signal frequency domain correlators, and carries out frequency domain parallel correlation processing on direct and reflected signals of N Beidou GEO satellites B1I and B3I to obtain complex correlation values.
The sea surface wind speed inversion module outputs B1I and B3I direct and reflected signal complex correlation values of N Beidou satellites by using the multichannel direct/inverse signal cooperative processing module, extracts characteristic parameters sensitive to the sea surface wind speed, and inverts to obtain the sea surface wind speed.
And the sea surface wind speed monitoring module receives the wind speed output by the sea surface wind speed inversion module and the positioning information output by the Beidou B1I and B3I dual-mode navigation SoC for visual display and monitoring.
The local pseudo-random code referred to in this application refers to the pseudo-random code generated at the receiver end, which is a generated entity, and is different from the pseudo-random code signal in nature, and cannot be confused and changed.
Simultaneously, in this application, B1I signal and B3I signal are the signal in the big dipper navigation chip module, and wherein the nominal carrier frequency of B1I signal is 1561.098MHz. The B1I signal bandwidth is 4.092MHz (centered on the B1I signal carrier frequency). The B1I signal is broadcast on a middle circular earth orbit (MEO) satellite, an inclined geosynchronous orbit (IGSO) satellite and a geostationary orbit (GEO) satellite of the second Beidou and the third Beidou, and public service is provided. The B3I signal is broadcast on a middle circular earth orbit (MEO) satellite, an inclined geosynchronous orbit (IGSO) satellite and a geostationary orbit (GEO) satellite of the second Beidou and the third Beidou, and public service is provided.
Chip module in this application refers in particular to "stand summer" bank base big dipper sea wind wave chip module. The shore-based Beidou sea wind and wave chip module integrates functions of Beidou satellite navigation signal real-time processing, observation station position real-time positioning, sea surface wind speed and effective wave height real-time inversion, data transmission and the like, and realizes real-time observation of effective wave height and wind speed in a single-station offshore area on the premise of not depending on external computing resources.
The Beidou-3 navigation system is innovatively applied to the 'summer' shore-based Beidou sea wind and wave chip module, the Beidou B1I signal reflected by the sea surface is applied, the near-shore single-station sea surface effective wave height and wind speed inversion is realized, and the time resolution can reach the minute level; the system level integration is realized by observing the effective wave height and the wind speed, the deployment cost of an observation network is reduced on the basis of improving the service capability, and the method is particularly suitable for the deployment of remote islands or coasts with limited power supply.
The 'standing summer' module develops a sea wind and sea wave detection technology based on a Beidou navigation satellite, breaks through the pain points that the traditional sea wind and sea wave detection is high in cost and difficult to deploy, provides a new sea wind and sea wave observation means, can change the situation that the comprehensive meteorological observation system in China is lack of marine data, effective observation means and insufficient observation capability for a long time to a certain extent, fills the blank of meteorological observation data, is particularly convenient for remote island or coast deployment with difficult power supply, can provide equipment and technical reserve for important items such as ocean engineering and the like, and provides solid support for upgrading and transferring and high-quality development of the marine meteorological observation technology in China.
The 'standing summer' shore-based Beidou sea wind and wave detection chip module realizes the real-time data quality control of the reflected signals of the Beidou satellite navigation system and the chip integration of a real-time inversion algorithm of sea surface wind speed and effective wave height, and is an innovative technology for detecting the near-sea-surface wind speed and the effective wave height with low cost and low power consumption.
The 'standing summer' module is compatible with a GPS system except for realizing the function mainly based on the Beidou satellite, and can realize dual-system cooperative detection. The "summer standing" module has preliminarily realized the outfield test. The test result shows that: the wind speed inversion accuracy of the 'standing summer' module is 2m/s (the wind speed is less than 20/s); the inversion accuracy of the effective wave height is 20cm (the effective wave height is less than 2 m) and 10% (the effective wave height is more than or equal to 2 m), and all indexes can meet the requirements of meteorological business application.
Compared with the prior art, the application has the advantages that:
the chip module is only a signal receiving chip module, and has simple structure, low cost and low power consumption;
the chip module utilizes GNSS (Global Navigation satellite System) signals as signal sources, and can carry out all-weather observation;
the chip module can provide a stable geometric configuration by fully utilizing the Beidou GEO satellite in a shore-based scene, and a multi-satellite, multi-frequency and multi-parameter fusion inversion algorithm is utilized, so that the wind speed inversion precision is high.
The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made to the present application by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims (10)
1. A sea surface wind speed inversion method based on satellite reflection signals is characterized by comprising the following steps:
receiving positioning position information sent by a satellite navigation chip module;
receiving a first direct-emitting signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtaining a correlation sequence of the first direct-emitting signal and the reflected signal according to the first direct-emitting signal and the reflected signal;
obtaining the relevant time and the time delay waveform area of the sea surface wind speed sensitivity of the reflection signal according to the relevant sequence;
acquiring a wind speed value according to the relevant time, the time delay waveform area and a wind speed inversion model;
and acquiring the sea surface wind speed of the target area according to the positioning position information and the wind speed value.
2. The sea surface wind speed inversion method based on the satellite reflection signals according to claim 1, characterized in that the satellite navigation chip module is a Beidou satellite navigation chip module consisting of a plurality of Beidou geosynchronous orbit satellites.
3. The sea surface wind speed inversion method based on the satellite reflection signals according to claim 2, wherein the receiving of the positioning position information sent by the satellite navigation chip module comprises:
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas receive a second direct signal sent by the Beidou satellite navigation chip module;
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas send the second direct signals to the dual-frequency navigation chip-on-chip module;
the double-frequency navigation chip-on-chip module acquires positioning position information according to the second direct signal;
and the double-frequency navigation chip module sends the positioning position information to the sea surface wind speed inversion module and the sea surface wind speed monitoring module.
4. The sea surface wind speed inversion method based on satellite reflection signals according to claim 3, wherein the receiving of the first direct signal of the satellite navigation chip module and the reflection signal reflected by the sea surface and the obtaining of the correlation sequence of the first direct signal and the reflection signal according to the first direct signal and the reflection signal comprise:
two channels in the four-channel radio frequency front end receive the direct signals sent by the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas, and the other two channels receive the reflected signals sent by the Beidou B1I and B3I dual-frequency left-hand circularly polarized antennas, and convert the direct signals and the reflected signals into four paths of digital intermediate frequency signals;
the four-channel radio frequency front end sends the four paths of digital intermediate frequency signals to a direct/inverse signal cooperative processing module;
and the direct/inverse signal cooperative processing module processes the direct signals and the reflected signals according to the four paths of digital intermediate frequency signals and acquires the direct and reflected signal correlation sequences of a plurality of Beidou geosynchronous orbit satellites.
5. The method of claim 4, wherein obtaining the sea surface wind speed sensitive correlation time and time delay waveform area of the reflection signal according to the correlation sequence comprises:
generating a digital carrier r according to a predetermined fixed IF frequency value of the receiveref carrieri (t) multiplying the direct and reflected signals, carrier stripping the direct and reflected signals, ref carrieri (t) is a local carrier of the ith channel generated by a reference signal generation module in the direct/inverse signal co-processing module;
performing fast Fourier transform on the direct signal and the reflected signal after carrier stripping to obtain a first frequency domain form of the direct signal and the reflected signal;
performing fast Fourier transform on a local code to obtain a second frequency domain form of the local code, and solving conjugation of the second frequency domain form by using a conjugation operator;
the conjugate of the first frequency domain form and the second frequency domain form is multiplied, and the multi-time-delay complex correlation value of the direct signal and the reflected signal is obtained according to inverse Fourier transformAnd
the coherent integration time of a direct/reflected signal frequency domain parallel correlator of the direct/reflected signal cooperative processing module is set to be 1ms of the pseudo code period of the Beidou B1I and B3I signals, and the direct signals of the plurality of Beidou geosynchronous orbit satellites and the multi-time-delay complex correlation values of the reflected signals are outputAndand the sea surface wind speed inversion module.
6. The method of claim 5, wherein obtaining a wind speed value according to the correlation time, the time delay waveform area and a wind speed inversion model comprises:
reading data of the ith channel, including multiple time delay complex correlation values of the direct signal and the reflected signalAndand azimuth and elevation angles corresponding to geosynchronous orbit satellites;
when the corresponding geosynchronous orbit satellite azimuth Ai satisfies A min <A i <A max When the satellite signal is in the antenna observation range, the satellite signal is considered to be in the antenna observation range, and subsequent processing is carried out;
the reflected signal multi-delay complex correlation value is subjected to non-coherent accumulation to obtain the delay waveform of the reflected signal, namely:
And solving the signal-to-noise ratio of the time delay waveform of the reflection signal according to the peak signal-to-noise ratio, namely:
wherein, P peak And P noise Peak power and noise power for the time delay of the reflected signal:
wherein max {. Is a maximum operator; e {. Is a mean operator;indicating that the delay is less than T τ The delay waveform of (a);
when the signal-to-noise ratio is larger than a preset threshold value, entering a subsequent wind speed inversion step;
calculating the waveform area by using the normalized reflected signal time delay waveform, namely:
wherein, T h Is a given threshold;<|Y Ni (τ)| 2 >for normalized reflected signal delay waveforms:
wherein, a A And b A Are inversion model parameters;
calculating an interference complex field according to the direct incidence complex delay correlation value and the reflection complex delay correlation value:
wherein,the complex correlation value at the peak value of the time delay waveform of the reflected signal and the direct signal is obtained;
wherein M is the number of interference complex field samples,is S icf (j) Calculating the correlation time:
wherein, a icf And b icf Are inversion model parameters;
fusing the independently inverted sea surface wind speeds of all channels according to a linear unbiased minimum variance estimator: u. of 10 =m·U 10
Wherein, U 10 The constituent wind velocity vectors for each channel independently invert the wind velocity, i.e.:
U 10 =[U A1 ,U icf1 ,…,U AN ,U icfN ]
m is a weighted vector of linear combination, and under the condition of constraint | | | m | | =1, the minimum variance criterion is utilized to ensure thatThe minimum available:
wherein, C WS The covariance matrix of the inverted wind speed for each independent characteristic parameter, the elements in the ith row and the jth column are expressed as: c WSij =<(u i -u true )·(u j -u true ) T >
Wherein u is i And u j Representing wind speed, u, independently inverted for each channel true The true wind speed is identified.
7. The utility model provides a sea wind speed inversion chip module based on satellite reflection signal which characterized in that includes:
the Beidou dual-frequency navigation chip-on-chip module is configured to receive positioning position information sent by the satellite navigation chip module;
the direct/inverse cooperative processing module is configured to receive a direct signal of the satellite navigation chip module and a reflected signal reflected by the sea surface, and obtain a related sequence of the direct signal and the reflected signal according to the direct signal and the reflected signal;
the sea surface wind speed inversion module is configured to receive the correlation sequence, obtain the correlation time and the time delay waveform area of the sea surface wind speed sensitivity of the reflection signal according to the correlation sequence, and obtain a wind speed value according to the correlation time and the time delay waveform area;
and the sea surface wind speed monitoring module is configured to acquire the sea surface wind speed of the target area according to the positioning position information and the wind speed value.
8. The sea surface wind speed inversion chip module based on satellite reflection signals of claim 7, wherein the sea surface wind speed inversion chip module further comprises:
the Beidou B1I and B3I dual-frequency right-hand circularly polarized antennas are arranged facing south in the sky and receive the direct signals of the Beidou geosynchronous orbit satellite navigation chip module;
the Beidou B1I and B3I dual-frequency left-handed circularly polarized antennas are arranged facing south of the sea surface, and receive reflected signals of the Beidou geosynchronous orbit satellite navigation chip module reflected by the sea surface.
9. The sea surface wind speed inversion chip module based on satellite reflection signals of claim 8, wherein the sea surface wind speed inversion chip module further comprises:
and the four-channel radio frequency front end receives the direct signals sent by the Beidou B1I and B3I double-frequency right-hand circularly polarized antennas and the reflected signals sent by the Beidou B1I and B3I double-frequency left-hand circularly polarized antennas.
10. The sea surface wind speed inversion chip module based on satellite reflection signals of claim 9, wherein the direct/inverse co-processing module comprises: a reference signal generation module and a direct/reflected signal frequency domain parallel correlator;
and the reference signal generation module and the direct/inverse signal frequency domain parallel correlator form a signal processing channel.
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