CN101833090B - Airborne ocean microwave remote sensing system utilizing signal sources of global satellite positioning system - Google Patents

Abstract

The invention discloses an airborne ocean microwave remote sensing system utilizing signal sources of a global satellite positioning system. A GNSS-R remote sensor receives and processes navigational satellite collineation and sea echo signals, and outputs Doppler related power and navigational positioning solutions at different time delays; a task monitoring work station carries out sea route planning, remote sensor task state real-time monitoring and data storage management; a data processing and application work station carries out screening, sorting and noise reduction preprocessing on data collected by the remote sensor, and carries out imaging processing and element playback on the processed data to obtain ocean environment monitoring information, such as sea level wind fields, sea level elevations, significant wave heights and the like; and an analog analysis work station provides GNSS-R entire route analog signals. The system effectively solves the problems of lack of ocean microwave remote sensing equipment, low data application timeliness and the like in the prior art, and can provide novel task equipment and a processing analysis means for manned/unmanned airborne platforms, wherein the novel task equipment is available at all weathers and all day long, and has the advantages of multiple signal sources, wide coverage and high space-time resolution.

Description

Utilize the airborne ocean microwave remote sensing system of Global Positioning System (GPS) signal source

Technical field

The present invention relates to a kind of ocean microwave remote sensing technology, more particularly say, be meant a kind of airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source.

Background technology

The ocean remote sensing monitoring range is big, dynamic is high, meteorological condition is complicated, and microwave remote sensing becomes the important means of regional and global marine environment remote sensing monitoring.At present, microwave remote sensing means such as existing SAR (Synthetic Aperture Radar), scatterometer, altitude gauge are all utilized the mode of back scattering homology observation, and the data transmit-receive cost is high, ageingly still can not satisfy the monitoring application demand.Global Positioning System (GPS) is not merely the spatial information user navigator fix information is provided, and L-band microwave signal resource endlessly also is provided.GNSS-R (Global Navigation Satellite System-Reflection) application advantages such as the ocean microwave remote sensing system is round-the-clock with it, round-the-clock, multisignal source, wide covering, high-spatial and temporal resolution based on Global Positioning System (GPS); In the marine environment remote sensing monitoring, show wide application prospect; Will be collaborative to sea observation with existing microwave remote sensing means, improve the collecting efficiency of marine environment information.

Summary of the invention

The purpose of this invention is to provide a kind of airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source, this system comprises GNSS-R microwave remote sensor, Mission Monitor workstation, data processing and application work station and simulation analysis workstation four partial contents.System of the present invention efficiently solves that present ocean remote sensing equipment lacks, data are utilized ageing problem such as not high, will the novel task device and the Treatment Analysis means of round-the-clock, round-the-clock, multisignal source, wide covering, high-spatial and temporal resolution be provided for people/unmanned plane aviation platform is arranged.

The GNSS-R microwave remote sensor has the direct projection of multi-source Navsat and the echo scattered signal receives synchronously, magnanimity original signal sampling and relevant treatment, navigator fix are found the solution, different delay/Doppler shift/related power calculates, the data in real time output function.

The Mission Monitor workstation has functions such as GNSS-R microwave remote sensor mode of operation and parameter setting, mission planning, remote sensor acquisition data storage and management, task state real-time monitoring.

Marine Environmental Elements inverting functions such as data processing and application work station have that sea surface observation point position and signal path delay are calculated, different delay Doppler's related power spectrum imaging processing and Ocean Wind-field, significant wave height, sea-level elevation.

The simulation analysis workstation has remote sensing geometric relationship, sea incoming signal, surface scattering echoed signal, remote sensor acquired signal analog functuion through parameter input, Model Selection, numerical evaluation.

Airborne ocean microwave remote sensing of the present invention system has following advantage:

1. the present invention will provide new type of microwave remote sensing means for marine environmental monitoring, utilize Navsat L-band signal to carry out round-the-clock, round-the-clock the sea is observed.

2. the GNSS-R microwave remote sensor adopts the double-basis radar mode, need not high power transmitter and associated electronic device, and complexity and the cost of remote sensor descend greatly, and volume is little, in light weight, low in energy consumption, help observing with machine is collaborative with other equipment.

3. the GNSS-R microwave remote sensor to the multi-source multi-angle direct projection of all kinds of navigational satellite systems and sea echo signal Synchronization receive with machine on handle in real time; Doppler/time delay related power the data of output are convenient to real-time Transmission, but the automatic time show navigator satellite-signal distribution of Mission Monitor system, remote sensor duty, flying platform status information.

4. data processing and application work station have realized that first different delay/multispectral to the collection of GNSS-R remote sensor reins in related power and navigator fix and fast automatic pre-service of remotely-sensed data and imaging processing such as separate, and can carry out Marine Environmental Elements Inversion Calculation such as sea wind speed and direction, sea-level elevation, significant wave height automatically.

5. the simulation analysis workstation can be realized the complete trails emulation of GNSS direct signal, surface scattering signal, geometry dynamic relationship, remote sensor acquired signal, for remote sensor designs with application the simulation analysis means is provided, and reduces the dependence to sea examination data.

6. the remote sensing of ocean common vetch ripple can as ocean, meteorological department people/unmanned airborne and ground support equipment equipment arranged, high timeliness, the low-cost marine environmental monitoring information of gathering are served marine disaster prevention and reduction, marine economy development, maritime safety guarantee.

Description of drawings

Fig. 1 is the structured flowchart of airborne ocean microwave remote sensing of the present invention system.

Fig. 2 is the structured flowchart of machine data processing of the present invention and application work station.

Fig. 3 is that satellite, receiver and specular reflection point space geometry concern synoptic diagram.

Fig. 4 is Marine Environmental Elements inverting of the present invention interface.

Fig. 4 A is the different wind speed and direction related power of a present invention theoretical waveforms.

Fig. 4 B is sea relative altitude inversion result figure of the present invention.

Fig. 4 C is that the mode function of significant wave height of the present invention characterizes synoptic diagram.

Fig. 5 is an imaging processing module interfaces of the present invention.

Fig. 5 A is the three-dimensional related power figure of the present invention.

Fig. 6 is that the parameter of simulation analysis workstation of the present invention is provided with the interface.

Fig. 6 A is GNSS-R ocean remote sensing signal transmission path figure.

Fig. 6 B is a sea of the present invention probability gradient density profile.

Fig. 6 C is a sea forward scattering coefficient distribution plan of the present invention.

Fig. 6 D is sea of the present invention Fresnel reflection coefficient and incident angle graph of a relation.

Fig. 6 E is the two-dimensional curve of surface scattering signal time delay related power of the present invention.

Fig. 6 F is the multispectral two-dimensional curve of reining in related power of surface scattering signal of the present invention.

Embodiment

To combine accompanying drawing that the present invention is done further detailed description below.

Referring to shown in Figure 1; The present invention is a kind of airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source, and this system includes GNSS-R microwave remote sensor, Mission Monitor workstation, data processing and application work station and simulation analysis workstation four parts.

One, GNSS-R microwave remote sensor

The GNSS-R microwave remote sensor includes dextrorotation antenna, left-handed antenna and delay mapping receiver, and said delay mapping receiver includes dijection front end, analog to digital converter, direct signal processing module and echoed signal processing module frequently.Said delay mapping receiver is that fpga chip+dsp chip+programming constitutes.Fpga chip is chosen the EP2S60F672C5 model, and dsp chip is chosen the TMS320C6713BGDP300 model.The DK-DSP-2S60-N developing instrument is used in programming, under Quartus II software environment, adopts the exploitation of Verlog hardware description language.

The dextrorotation antenna is to the direct signal of the L-band of the GNSS satellite that receives, and this direct signal gained amplify the back and form right-handed circular polarization signal RF _RExport to dijection front end frequently.In the present invention, the dextrorotation antenna is single array aviation type antenna, and the gain of this antenna is 3dB, 180 ° of field angles.

Left-handed antenna is to the echoed signal of the L-band of the sea surface reflection GNSS satellite that receives, and this echoed signal gained amplify the back and form left-hand circular polarization signal RF _LExport to dijection front end frequently.In the present invention, left-handed antenna is four array antennas, and the gain of this antenna is 12dB, 30 ° of field angles.This left-handed antenna has following characteristics: through the single feed point structure, realize the group battle array of antenna array unit; Through adopting continuous rotating feed structure, reduce the The mutual coupling coefficient between each antenna element; Through rotation serial feed technology, increase the antenna impedance bandwidth, reduce the secondary lobe of E face and H face and utilize its parasitic radiation to improve the circular polarization characteristics of antenna.

Dijection front end frequently has the dual input structure, on the one hand to right-handed circular polarization signal RF _RCarry out the analog if signal IF of output direct signal after frequency conversion, amplification and the Filtering Processing _RLeft-hand circular polarization signal RF on the other hand _LCarry out the analog if signal IF of output echoed signal after frequency conversion, amplification and the Filtering Processing _LIn the present invention, the autonomous channel in the dijection frequency front end has accurate frequency conversion, amplification, filtering and gain control circuit.In order to prevent that mirror image from disturbing, radio-frequency front-end adopts super-heterodyne architecture, and adopts twin-stage down coversion scheme.

The 1575.42MHz signal that Navsat sends is through converting analog if signal into after its two-stage down coversion.The 1st grade of sheet interior phaselocked loop generation 2456MHz local oscillation signal and the 1575.42MHz that receives are mixed down the 1st grade of intermediate-freuqncy signal of 881MHz; The 2nd grade is that 881MHz intermediate-freuqncy signal and local frequency with the 1st grade of generation is mixed down 46.42MHz for the 927MHz local oscillation signal, promptly exports analog if signal.

The module output frequency-outer inhibition of 3dB band is same signal bandwidth, each road of output level is 0dBm ± 1dB/50 Ω.The temperature compensating crystal oscillator of the integrated 10MHz of this module simultaneously, for the rear end digitizer provides reference clock, its reference frequency degree of stability ± 5 * 10 ^-7Hz is connected with the anti-level of a digital module employing property line interface on the public previous day, and realizes the physical shielding isolation, effectively reduces the noise between high frequency simulation and the digital circuit, and signal quality is further optimized.Automatic gain control (AGC) also is the important ingredient of radio-frequency front-end, and its effect is when applied signal voltage alters a great deal, and keeps the radio-frequency front-end output voltage almost constant.As a kind of feedback control loop, it basic composition is AGC detection, LPF, direct current and amplifies three parts.

The analog to digital converter that postpones in the mapping receiver is used for IF _RAnd IF _LChange, thus output direct projection digital sampled signal IFD _RWith echo digital sampled signal IFD _L

The IFD of direct signal processing module to receiving _RCatch, follow the tracks of, when the location that tracking satellite can be realized receiver during more than 4, the output navigator fix is separated information FB and is given Mission Monitor and data management; The digital medium-frequency signal FA that will be in 1～12 direct projection passage of tracking mode on the other hand exports to the echoed signal processing module.

The echoed signal processing module is at first according to the customized channel information ID of mission planning in the Mission Monitor workstation _n(n representes 1,2 ..., 12 passages) and it is carried out channel arrangement, then with signal and the IFD of FA behind time delay and Doppler frequency-shift _LCarrying out the two-dimensional correlation computing obtains the multispectral two-dimensional correlation power FD that reins in of time delay and exports to Mission Monitor and data management module.

In the present invention, fpga chip EP2S60F672C5 is mainly as direct projection passage and reflection channel dedicated correlator and module interface logic control use, comprising 12 direct projection passage dedicated correlator and 12 reflection channel dedicated correlator.Dsp chip TMS320C6713BGDP300 mainly accomplishes the passage and the loop control function of signal Processing work and direct signal and reflected signal.

Two, Mission Monitor workstation

The Mission Monitor workstation comprises display, Mission Monitor industrial computer, data processing industrial computer and switch.

In the present invention, Mission Monitor industrial computer first aspect output channel Information ID _nThe echoed signal processing module is carried out channel arrangement;

Second aspect receives navigator fix and separates information FB and two-dimensional correlation power FD, and comes through the graphic presentation in the display, and the duty of GNSS-R microwave remote sensor is monitored;

The third aspect is monitored the line of flight that carries machine;

Fourth aspect is separated information FB and two-dimensional correlation power FD to navigator fix and is carried out unruly-value rejecting respectively and handle back output and revise the back navigator fix and separate NFB, two-dimensional correlation power NFD.

In the present invention, the data processing industrial computer receives direct projection digital sampled signal IFD through two serial ports _RWith echo digital sampled signal IFD _L, and data are stored.

In the present invention, the technological difficulties of miniaturization Mission Monitor workstation are to use a cover keyboard, mouse, display that Mission Monitor and two industrial computers of data management are carried out timesharing management and operation.Adopt the multi-functional switch of one-to-two that the industrialization display is connected with two industrial computers with a cover keyboard, mouse, the user can realize the switching controls of 2 industrial computers calculating with displaying contents through the double-button structure of exterior design easily.

Type	Model	Quantity	Configuration/performance index
				The technical grade display	CPI-151	1	Satisfy the technical grade request for utilization
Industrial computer	Grind magnificent IPC-6606	1	P4 3.0G CPU/4G internal memory/1T hard disk/integrated 100M network interface card/DVD imprinting (2 ISA slots, 3 PCI slots) data management is used
				Industrial computer	The new Chinese 3100	1	IPM 1.6M CPU/1G internal memory/USB2.0 interface/2,120G hard disk/6 serial ports Mission Monitor is used
Switch	Step and open up MT-KVM8A	1	Possess the connection keyboard, mouse, the interface of display, control is divided into two

Mission Monitor workstation of the present invention can provide data storage, mission planning and condition monitoring, data management guarantee for the GNSS-R microwave remote sensor.Export correctly reading and storing of serial data in real time at remote sensor; Utilize Mission Monitor interface and the data processing that is provided with in the display and application work station communicates and graphical playback demonstration of record data, back-end data format conversion etc., realized integrated with remote sensor.

Three, data processing and application work station

Data processing and application work station are made up of computing machine (also claiming the A computing machine) and the Marine Environmental Elements calculation procedure that operates in this A computing machine, and described Marine Environmental Elements calculation procedure comprises has data preprocessing module, key element inverting module (Ocean Wind-field inverting, sea-level elevation inverting and significant wave height inverting) and imaging processing module.

Referring to shown in Figure 2, in the present invention, data preprocessing module includes receiver antenna position estimation model, GNSS satellite interpolation model, sea surface observation point position calculation model, path delay model and Doppler shift model.

To carry out regular and the processing of screening noise filtering from the correction two-dimensional correlation power NFD data of GNSS-R microwave remote sensor output, to improve the quality of data and reliability among the NFD.To revise navigator fix and separate processing such as NFB carries out respectively in receiving antenna position estimation, the Navsat position inserting, sea surface observation point position calculation, Doppler shift calculating, signal path delay calculating, thereby precise parameters will be provided for key element inverting module and imaging processing module.The receiver antenna position module

The left-handed aerial position appraising model of receiver does $\left(\begin{array}{c}{\hat{X}}_L\\ {\hat{Y}}_L\\ {\hat{Z}}_L\end{array}\right)=\left(\begin{array}{c}{\hat{X}}_D\\ {\hat{Y}}_D\\ {\hat{Z}}_D\end{array}\right)+M_{\mathrm{LR}}\left(\begin{array}{c}{X}_{\mathrm{LD}}\\ Y_{\mathrm{LD}}\\ Z_{\mathrm{LD}}\end{array}\right).$

Receiver dextrorotation aerial position appraising model does $\left(\begin{array}{c}{\hat{X}}_R\\ {\hat{Y}}_R\\ {\hat{Z}}_R\end{array}\right)=\left(\begin{array}{c}{\hat{X}}_D\\ {\hat{Y}}_D\\ {\hat{Z}}_D\end{array}\right)+M_{\mathrm{LR}}\left(\begin{array}{c}{X}_{\mathrm{RD}}\\ Y_{\mathrm{RD}}\\ Z_{\mathrm{RD}}\end{array}\right).$

Footmark L is left-handed antenna (LHCP);

Footmark R is dextrorotation antenna (RHCP);

left and right, respectively Antenna Antenna estimated coordinates;

(X _LD, Y _LD, Z _LD), (X _RD, Y _RD, Z _RD) be respectively the displacement between left-handed, dextrorotation antenna and the dual-frequency receiver antenna; Be receiver pseudo range difference coordinate;

M _LRBe body space rotation matrix M _LR=[cos θ+(1-cos θ) x ², change with the body attitude.

Be rotation angle, $\hat{v}=(x,y,z)$ Direction vector for turning axle.

GNSS satellite interpolation model

In the present invention, adopt Chebyshev polynomials to realize the interpolative operation of GNSS satellite position, the initial time of establishing interpolation is t ₀, the match time span is Δ t, the moment t naturalization that at first will calculate the GNSS satellite position is to [1,1] interval, then naturalization constantly τ have $\mathrm{\τ}=\frac{2}{\mathrm{\Δ\; t}}(t-t_0)-1$ , and t ∈ [t ₀, t ₀+ Δ t]; Then co-ordinates of satellite (x (τ), y (τ), z (τ)) Chebyshev's parametric equation do $\left\{\begin{array}{c}x\left(\mathrm{\τ}\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_{\mathrm{Xi}}\·T_i\left(\mathrm{\τ}\right)\\ y\left(\mathrm{\τ}\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_{\mathrm{Yi}}\·T_i\left(\mathrm{\τ}\right),\\ z\left(\mathrm{\τ}\right)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_{\mathrm{Zi}}\·T_i\left(\mathrm{\τ}\right)\end{array}\right.$ N representes polynomial exponent number, and i representes the item number of required calculating, C _Xi, C _Yi, C _ZiThe expression multinomial coefficient, T _i(τ) the recursion intermediate quantity of expression Chebyshev parameter.

T then _iRecurrence relation formula (τ) does $\begin{array}{c}{T}_0\left(\mathrm{\τ}\right)=1\\ T_1\left(\mathrm{\τ}\right)=\mathrm{\τ}\\ \·\·\·\\ T_n\left(\mathrm{\τ}\right)=2\mathrm{\τ}\·T_n\left(\mathrm{\τ}\right)-T_{n-2}\left(\mathrm{\τ}\right),n\≥2\end{array},$ T _n(τ) the recursion amount of n Chebyshev's parameter of expression.

In the present invention, utilize T _iRecurrence relation formula (τ) is obtained recursive matrix $B=\left[\begin{array}{cccc}{T}_0\left({\mathrm{\τ}}_1\right)& T_1\left({\mathrm{\τ}}_1\right)& \·\·\·& T_n\left({\mathrm{\τ}}_1\right)\\ T_0\left({\mathrm{\τ}}_2\right)& T_1\left({\mathrm{\τ}}_2\right)& \·\·\·& T_n\left({\mathrm{\τ}}_2\right)\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ \·& \·& \·& \·\\ T_0\left({\mathrm{\τ}}_m\right)& T_1\left({\mathrm{\τ}}_m\right)& \·\·\·& T_n\left({\mathrm{\τ}}_m\right)\end{array}\right],$ N representes polynomial exponent number, and m representes the number of difference basic point.

In the formula, τ ₁, τ ₂..., τ _mBe given time, the matrix number of setting up departments $C=\left[\begin{array}{ccc}{C}_{x0}& C_{y0}& C_{z0}\\ C_{x1}& C_{y1}& {\mathrm{<figure-callout\; id="1"\; label="C\; z"\; filenames="HSA00000049119100091.png"\; state="\{\{state\}\}">C</figure-callout>}}_z\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ C_{\mathrm{Xn}}& C_{\mathrm{Yn}}& C_{\mathrm{Zn}}\end{array}\right],$ Coordinates matrix $A=\left[\begin{array}{ccc}{x}_1& y_1& z_1\\ x_2& y_2& {\mathrm{<figure-callout\; id="2"\; label="z"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">z</figure-callout>}}_2\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ \&CenterDot;& \&CenterDot;& \&CenterDot;\\ x_m& y_m& z_m\end{array}\right],$ A=BC is then arranged.According to the principle of least square, can get matrix of coefficients is C=(B ^TB) ^-1BA.With this matrix of coefficients C=(B ^TB) ^-1BA is introduced into Chebyshev's parametric equation

$\left\{\begin{array}{c}x\left(\mathrm{\&tau;}\right)=\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}{C}_{\mathrm{Xi}}\&CenterDot;T_i\left(\mathrm{\&tau;}\right)\\ y\left(\mathrm{\&tau;}\right)=\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}{C}_{\mathrm{Yi}}\&CenterDot;T_i\left(\mathrm{\&tau;}\right)\\ z\left(\mathrm{\&tau;}\right)=\underset{i=0}{\overset{n}{\mathrm{\&Sigma;}}}{C}_{\mathrm{Zi}}\&CenterDot;T_i\left(\mathrm{\&tau;}\right)\end{array}\right.$ In calculate at interval [t ₀, t ₀+ Δ t] the GNSS satellite position (x (τ), y (τ), z (τ)) of interior any time.

Sea surface observation point position calculation model

Be a desirable spheroid and do not consider under the condition of surface irregularity at the supposition earth, only need know that GNSS satellite and receiver location can be concerned by space geometry try to achieve sea surface observation point position.

Sea surface observation point (also claiming specular reflection point) is the surface scattering point minimum apart from sum to transmitter and receiver.Because of GNSS satellite, receiver and specular reflection point in same plane, its space geometry relation is as shown in Figure 3.Among the figure, T, R, S, O represent GNSS satellite transmitter, receiver, specular reflection point and the earth's core respectively;

is respectively the vector representation of transmitter, receiver and specular reflection point; H, h, γ are respectively transmitter height, receiver height and the GNSS satellite elevation angle with respect to local sea level.

Specular reflection point in space geometry relation as shown in Figure 3 is:

$\mathrm{\&rho;}(L_S,B_S)=|{\stackrel{\&RightArrow;}{R}}_r-{\stackrel{\&RightArrow;}{R}}_{\mathrm{sp}}|+|{\stackrel{\&RightArrow;}{R}}_{\mathrm{sp}}-{\stackrel{\&RightArrow;}{R}}_t|=\sqrt{{(X_R-X_S)}^2+{(Y_R-Y_S)}^2+{(Z_R-Z_S)}^2}+$

$\sqrt{{(X_T-X_S)}^2+{(Y_T-Y_S)}^2+{(Z_T-Z_S)}^2}$ , in the formula,

(X _T, Y _T, Z _T), (X _R, Y _R, Z _R), (X _S, Y _S, Z _S) be respectively transmitter, receiver and the coordinate of surface scattering point under geocentric coordinate system.And if only if when following formula obtains minimum value, (X _S, Y _S, Z _S) be mirror point.The ρ expression signal arrives the path of receiver through sea surface observation point.(L _S, B _S) be the latitude and longitude coordinates of surface scattering point (being the sea surface observation point) under earth coordinates:

$X_S=\frac{a^2\cos B_S\cos L_S}{\sqrt{a^2{\cos }^2{B}_S+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">b</figure-callout>}}^2{\sin }^2{L}_S}}+N\cos B_S\cos L_S$

$Y_S=\frac{a^2\cos B_S\sin L_S}{\sqrt{a^2{\cos }^2{B}_S+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">b</figure-callout>}}^2{\sin }^2{L}_S}}+N\cos B_S\sin L_S$

$Z_S=\frac{{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">b</figure-callout>}}^2\sin B_S}{\sqrt{a^2{\cos }^2{B}_S+{\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">b</figure-callout>}}^2{\sin }^2{L}_S}}+N\sin B_S$

Wherein, a representes the major semi-axis of the ellipse body of the earth, and b representes the minor semi-axis of the ellipse body of the earth, and N is the reference ellipsoid radius of curvature in prime vertical, and $N=\frac{a}{\sqrt{1-{\mathrm{<figure-callout\; id="2"\; label="e"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">e</figure-callout>}}^2\mathrm{Sin}{B}_S}},$ E representes the excentricity of earth's spheroid.

The Doppler shift model

Doppler shift is because the relative motion between transmitter and scattering point and receiver and the scattering point produces.Under ground local coordinate system, be positioned on the surface level arbitrary scattering point at a time the pairing Doppler shift computation model of t do $f_d(\stackrel{\&RightArrow;}{r},t)=\frac{{\stackrel{\&RightArrow;}{V}}_t\left(t\right)\&CenterDot;\hat{m}(\stackrel{\&RightArrow;}{r},t)-{\stackrel{\&RightArrow;}{V}}_r\left(t\right)\&CenterDot;\hat{n}(\stackrel{\&RightArrow;}{r},t)}{\mathrm{\&lambda;}},$ Wherein, Be the scattering point position vector,

Be respectively the velocity of transmitter and receiver,

Be the unit vector of signal incident direction and scattering direction, λ is the carrier wavelength of GNSS satellite emission signal.

Path delay model

The calculating that realizing route postpones under earth axes.Setting a trap, a certain scattering point does on the portion sea level

Then path delay, model did ${\mathrm{\&tau;}}_r=\frac{|\stackrel{\&RightArrow;}{R}-\stackrel{\&RightArrow;}{r}|+|\stackrel{\&RightArrow;}{T}-\stackrel{\&RightArrow;}{r}|-|\stackrel{\&RightArrow;}{R}-\stackrel{\&RightArrow;}{T}|}{c},$ In the formula,

Be the receiver location vector,

Be GNSS satellite position vector, the c propagation velocity of electromagnetic wave gets 3.0 * 10 ⁸Meter per second.

As

when being mirror point, do path delay

${\mathrm{\&tau;}}_{\mathrm{<figure-callout\; id="0"\; label="r"\; filenames="HSA00000049119100041.png,HSA00000049119100051.png"\; state="\{\{state\}\}">r</figure-callout>}0}=\frac{(H+h)\&times;\csc \mathrm{\&gamma;}-\sqrt{({\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">H</figure-callout>}}^2+h^2){\&times;\mathrm{<figure-callout\; id="2"\; label="csc"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">csc</figure-callout>}}^2\mathrm{\&gamma;}+2H\&times;h({\mathrm{ctg}}^2\mathrm{\&gamma;}-1)}}{c}.$

The minimalist configuration of A computing machine is more than the CPU:PIII 500MHz; Internal memory: more than the 256MB Installed System Memory reaches, the maximum internal memory 4GB that supports; Hard-disk capacity:＞250G; Video card: standard VGA, 24 RGBs; CD-ROM drive, mouse.The operating system of Windows2000/XP/2003/Vista.

The imaging processing module

In the present invention, the related data according to interface (referring to shown in Figure 5) input demonstrates two and three dimensions related power configuration figure (shown in Fig. 5 A) in the A computing machine.

Key element inverting module

In the present invention, the key element inverting is carried out following function inverting according to the related data of interface (referring to shown in Figure 4) input in the A computing machine:

(A) wind field inverting: the wind field inverting includes wind speed and direction and calculates, and inversion result can characterize through having the theoretical power curve.Shown in Fig. 4 A, the related power curve among the figure can demonstrate the difference under the different wind speed and direction situation comparatively intuitively.

(B) high inverting is surveyed on the sea: relative altitude and the dynamic height inverting that high inverting includes the sea surveyed on the sea, and inversion result can characterize through having the theoretical power curve.Shown in Fig. 4 B, curve table illustrates the inversion result of relative altitude among the figure.

The relative altitude inverting has calculating horizontal mean level of the sea relative altitude function.

The dynamic height inverting has the calculating observation point with respect to average observed sea level elevation function.

(C) wave significant wave height inverting: have ocean wave factor inverting functions such as significant wave height.Inversion result can characterize by the application model function parameter, shown in Fig. 4 C.

Four, simulation analysis workstation

The simulation analysis workstation is made up of computing machine (also claiming the B computing machine) and the GNSS-R simulated program that operates in this B computing machine, and described GNSS-R simulated program includes parameter module, Model Selection module and simulation calculation module are set.The Model Selection module includes sea incoming signal realistic model, surface scattering signal simulation and remote sensor acquired signal realistic model.In the present invention, whenever choose a model then to the relevant parameters setting should be arranged, this parameter setting is carried out the numeral login through interface (referring to shown in Figure 6).

The GNSS-R signal transmission path is seen Fig. 6 A.Simulation analysis system is exported GNSS-R remote sensing whole process emulated data through parameter setting, Model Selection, simulation calculation.

Sea incoming signal realistic model

Incoming signal power calculation: the power when arriving the sea after the calculating incoming signal process atmospheric attenuation.

Incident angle is calculated: the incident angle of the relative earth ellipsoid of incoming signal.

The incoming signal carrier-to-noise ratio is calculated: the incoming signal carrier-to-noise ratio that arrives the sea according to corresponding snr computation model.

Surface scattering signal simulation model

Sea surface slope density calculation: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set, calculate the distribution of sea surface slope probability density in the surface scattering zone, shown in Fig. 6 B.Sea surface slope density calculation relation $P_{\mathrm{Pdf}}=\frac{1}{{2\mathrm{\&pi;\; \&sigma;}}_{\mathrm{Sx}}{\mathrm{\&sigma;}}_{\mathrm{Sy}}\sqrt{1-{\mathrm{<figure-callout\; id="2"\; label="b\; Xy"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">b</figure-callout>}}_{\mathrm{Xy}}^{}}}\mathrm{Exp}[-\frac{1}{2(1-b_{\mathrm{Xy}}^2)}(\frac{s_x^2}{{\mathrm{\&sigma;}}_{\mathrm{Sx}}^2}-{2b}_{\mathrm{Xy}}\frac{s_x{s}_y}{{\mathrm{\&sigma;}}_{\mathrm{Sx}}{\mathrm{\&sigma;}}_{\mathrm{Sy}}}+\frac{s_{\mathrm{<figure-callout\; id="2"\; label="y"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">y</figure-callout>}}^2}{{\mathrm{\&sigma;}}_{\mathrm{Sy}}^2})],$ S wherein _x, s _yBe respectively along the sea surface slope of x, y direction; σ _Sx ², σ _Sy ²And b _{X, y}Be respectively along the gradient mean square deviation and the covariance of x, y direction.

Forward scattering coefficient calculations: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set, calculate the distribution of forward scattering coefficient in the surface scattering zone, shown in Fig. 6 C.Forward scattering coefficient calculations relation ${\mathrm{\&sigma;}}_0\left(r\right)=\mathrm{\&pi;}{\left|R\left(r\right)\right|}^2\frac{q^4}{q_z^4}{P}_{\mathrm{Pdf}}(-\frac{q_{\&perp;}}{q_z}),$ R (r) is r=(x, the Fresnel reflection coefficient of y) locating; P _PdfProbability density function (PDF) for the sea surface slope distribution; Q is a Scattering of Vector, and its expression formula does $q=k(\hat{n}-\hat{m})=(q_x,q_y,q_z)=(q_{\&perp;},q_z),$ Wherein k=2 π/λ is a GNSS carrier wave wave number; q _x, q _y, q _zBe respectively the x of Scattering of Vector, y, z component; q _⊥=(q _x, q _y) expression Scattering of Vector horizontal component;

Be respectively transmitter T to scattering point S, scattering point S is to the unit vector of receiver R, and its concrete expression does $\hat{m}=\frac{R_t}{\left|R_t\right|}=\frac{S-T}{|S-T|},$ $\hat{n}=\frac{R_r}{\left|R_r\right|}=\frac{R-S}{|R-S|},$ R _t=| S-T| and R _r=| R-S| is respectively transmitter and the receiver distance to scattering point.

Surface scattering signal correction is calculated: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set; The qualitative analysis (polarization mode, watt level and scattering direction) of surface scattering zone inscattering signal is shown in Fig. 6 D.Surface scattering signal correction calculated relationship is calculated polarization mode from Fresnel reflection coefficient, $R_{\mathrm{VV}}=\frac{\mathrm{\&epsiv;}\mathrm{Sin}\mathrm{\&theta;}-\sqrt{\mathrm{\&epsiv;}-{\mathrm{<figure-callout\; id="2"\; label="Cos"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">Cos</figure-callout>}}^2\mathrm{\&theta;}}}{\mathrm{\&epsiv;}\mathrm{Sin}\mathrm{\&theta;}+\sqrt{\mathrm{\&epsiv;}-{\mathrm{<figure-callout\; id="2"\; label="Cos"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">Cos</figure-callout>}}^2\mathrm{\&theta;}}},$ $R_{\mathrm{HH}}=\frac{\mathrm{Sin}\mathrm{\&theta;}-\sqrt{\mathrm{\&epsiv;}-{\mathrm{<figure-callout\; id="2"\; label="Cos"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">Cos</figure-callout>}}^2\mathrm{\&theta;}}}{\mathrm{Sin}\mathrm{\&theta;}+\sqrt{\mathrm{\&epsiv;}-{\mathrm{<figure-callout\; id="2"\; label="Cos"\; filenames="HSA00000049119100051.png,HSA00000049119100091.png"\; state="\{\{state\}\}">Cos</figure-callout>}}^2\mathrm{\&theta;}}},$ In the formula, R _VV, R _HHBe respectively vertical and horizontal polarization reflection coefficient, ε is the complex permittivity of seawater; θ is the elevation angle of electromagnetic wave emission source.

Remote sensor acquired signal realistic model

Antenna gain is calculated: the used left-handed antenna gain of software emulation is 12dB, field angle 30 degree (having in the product description of producer when providing).

Related powers etc. postpone two dimension and calculate: under the simulated conditions of setting, and the retardation of direct projection and scattered signal related power waveform peak; The time delay of scattered signal (with respect to mirror point)-related power two-dimensional curve.(shown in Fig. 6 E)

Related power Doppler two dimension is calculated: under the simulated conditions of setting, and the Doppler frequency that direct projection and scattered signal related power waveform peak are corresponding; The Doppler shift of scattered signal (with respect to mirror point)-related power two-dimensional curve.(shown in Fig. 6 F)

The minimalist configuration of B computing machine is more than the CPU:PIII 500MHz; Internal memory: more than the 256MB Installed System Memory reaches, the maximum internal memory 4GB that supports; Hard-disk capacity:＞250G; Video card: standard VGA, 24 RGBs; CD-ROM drive, mouse.The operating system of Windows2000/XP/2003/Vista.

Claims (4)

1. airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source, it is characterized in that: this airborne ocean microwave remote sensing system comprises GNSS-R microwave remote sensor, Mission Monitor workstation, data processing and application work station and simulation analysis workstation four partial contents;

The GNSS-R microwave remote sensor has the direct projection of multi-source Navsat and the echo scattered signal receives synchronously, magnanimity original signal sampling and relevant treatment, navigator fix are found the solution, different delay/Doppler shift/related power calculates, the data in real time output function; The GNSS-R microwave remote sensor includes dextrorotation antenna, left-handed antenna and delay mapping receiver, and said delay mapping receiver includes dijection front end, analog to digital converter, direct signal processing module and echoed signal processing module frequently;

The Mission Monitor workstation has GNSS-R microwave remote sensor mode of operation and parameter setting, mission planning, remote sensor acquisition data storage and management, task state real-time monitoring function; The Mission Monitor workstation comprises display, Mission Monitor industrial computer, data processing industrial computer and switch; Mission Monitor industrial computer first aspect output channel Information ID _nEchoed signal processing module in the GNSS-R microwave remote sensor is carried out channel arrangement; Second aspect receives navigator fix and separates information FB and two-dimensional correlation power FD, and comes the duty of GNSS-R microwave remote sensor is monitored through the graphic presentation in the display; The third aspect is monitored the line of flight that carries machine; Fourth aspect is separated information FB and two-dimensional correlation power FD to navigator fix and is carried out unruly-value rejecting respectively and handle back output and revise the back navigator fix and separate NFB, revise back two-dimensional correlation power NFD; The data processing industrial computer receives direct projection digital sampled signal IFDR and echo digital sampled signal IFDL through two serial ports, and data are stored;

Data processing and application work station have that sea surface observation point position and signal path delay are calculated, the Marine Environmental Elements inverting function of different delay Doppler's related power spectrum imaging processing and Ocean Wind-field, significant wave height, sea-level elevation; Data processing and application work station are made up of computing machine and the Marine Environmental Elements calculation procedure that operates in this computing machine, and described Marine Environmental Elements calculation procedure comprises has data preprocessing module, Ocean Wind-field inverting, sea-level elevation inverting, significant wave height inverting and imaging processing module; Data preprocessing module includes receiver antenna position estimation model, GNSS satellite interpolation model, sea surface observation point position calculation model, path delay model and Doppler shift model;

The left-handed aerial position appraising model of receiver is

Receiver dextrorotation aerial position appraising model is

Wherein,

Be respectively left-handed antenna and dextrorotation antenna estimation coordinate, (X _LD, Y _LD, Z _LD), (X _RD, Y _RD, Z _RD) be respectively the displacement between left-handed, dextrorotation antenna and the dual-frequency receiver antenna, M _LRFor body space rotation matrix, change with the body attitude,

Be receiver pseudo range difference coordinate;

GNSS satellite interpolation model adopts Chebyshev polynomials to realize the interpolative operation of GNSS satellite position, and the initial time of establishing interpolation is t ₀, the match time span is Δ t, the moment t naturalization that at first will calculate the GNSS satellite position is to [1,1] interval, then naturalization constantly τ have

And t ∈ [t ₀, t ₀+ Δ t]; Then co-ordinates of satellite (x (τ), y (τ), z (τ)) Chebyshev's parametric equation do

N representes polynomial exponent number, and i representes the item number of required calculating, C _Xi, C _Yi, C _ZiThe expression multinomial coefficient, T _i(τ) the recursion intermediate quantity of expression Chebyshev parameter;

T then _iRecurrence relation formula (τ) does

T _n(τ) the recursion amount of n Chebyshev's parameter of expression;

Utilize T _iRecurrence relation formula (τ) is obtained recursive matrix

N representes polynomial exponent number, and m representes the number of difference basic point;

In the formula, τ ₁, τ ₂..., τ _mBe given time, the matrix number of setting up departments

Coordinates matrix

A=BC is then arranged; According to the principle of least square, can get matrix of coefficients is C=(B ^TB) ^-1BA; With this matrix of coefficients C=(B ^TB) ^-1BA is introduced into Chebyshev's parametric equation

In calculate at interval [t ₀, t ₀+ Δ t] the GNSS satellite position (x (τ), y (τ), z (τ)) of interior any time;

Sea surface observation point in the sea surface observation point position calculation model is the surface scattering point minimum apart from sum to transmitter and receiver; Because of GNSS satellite, receiver and specular reflection point in same plane;

The space geometry relation of specular reflection point is:

In the formula, (X _T, Y _T, Z _T), (X _R, Y _R, Z _R), (X _S, Y _S, Z _S) be respectively transmitter, receiver and the coordinate of surface scattering point under geocentric coordinate system; And if only if when following formula obtains minimum value, (X _S, Y _S, Z _S) be specular reflection point; The ρ expression signal arrives the path of receiver through sea surface observation point; (L _S, B _S) be the latitude and longitude coordinates of surface scattering point under earth coordinates:

Wherein, A representes the major semi-axis of the ellipse body of the earth; B representes the minor semi-axis of the ellipse body of the earth; N is the reference ellipsoid radius of curvature in prime vertical, and

e representes the excentricity of earth's spheroid;

Doppler shift is because the relative motion between transmitter and scattering point and receiver and the scattering point produces; Under ground local coordinate system; Be positioned on the surface level arbitrary scattering point at a time the pairing Doppler shift computation model of t for wherein; is the scattering point position vector;

is respectively the velocity of transmitter and receiver;

is the unit vector of signal incident direction and scattering direction, and λ is the carrier wavelength of GNSS satellite emission signal;

The model calculating that realizing route postpones under earth axes in path delay; Setting a trap, a certain scattering point does on the portion sea level

Then path delay, model did

In the formula, Be the receiver location vector,

Be GNSS satellite position vector, the c propagation velocity of electromagnetic wave gets 3.0 * 10 ⁸Meter per second;

As

when being specular reflection point; Be

H path delay; H, γ are respectively transmitter height, receiver height and the GNSS satellite elevation angle with respect to local sea level;

The simulation analysis workstation has remote sensing geometric relationship, sea incoming signal, surface scattering echoed signal, remote sensor acquired signal analog functuion through parameter input, Model Selection, numerical evaluation; The simulation analysis workstation is made up of computing machine and the GNSS-R simulated program that operates in this computing machine, and described GNSS-R simulated program includes parameter module, Model Selection module and simulation calculation module are set; The Model Selection module includes sea incoming signal realistic model, surface scattering signal simulation model and remote sensor acquired signal realistic model; The simulation analysis workstation is exported GNSS-R remote sensing whole process emulated data through parameter setting, Model Selection, simulation calculation;

Sea incoming signal realistic model:

Incoming signal power calculation: the power when arriving the sea after the calculating incoming signal process atmospheric attenuation;

Incident angle is calculated: the incident angle of the relative earth ellipsoid of incoming signal;

The incoming signal carrier-to-noise ratio is calculated: the incoming signal carrier-to-noise ratio that arrives the sea according to corresponding snr computation model;

Surface scattering signal simulation model:

Sea surface slope density calculation: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set, calculate the distribution of sea surface slope probability density in the surface scattering zone; Sea surface slope density calculation relation

S wherein _x, s _yBe respectively along the sea surface slope of x, y direction;

And b _XyBe respectively along the gradient mean square deviation and the covariance of x, y direction;

Forward scattering coefficient calculations: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set, calculate the distribution of forward scattering coefficient in the surface scattering zone; Forward scattering coefficient calculations relation R (r) is r=(x, the Fresnel reflection coefficient of y) locating; P _PdfBe sea surface slope density; Q is a Scattering of Vector, and its expression formula does

Wherein k=2 π/λ is a GNSS carrier wave wave number; q _x, q _y, q _zBe respectively the x of Scattering of Vector, y, z component; q _⊥=(q _x, q _y) expression Scattering of Vector horizontal component;

Be respectively transmitter T to scattering point S, scattering point S is to the unit vector of receiver R, and its concrete expression does

| R _t|=| S-T| and | R _r|=| R-S| is respectively transmitter and the receiver distance to scattering point;

Surface scattering signal correction is calculated: under the condition of sea conditions, GNSS satellite parametric reduction, receiving platform parameter, ocean wave spectrum model and the scattering model set, the qualitative analysis of surface scattering zone inscattering signal comprises polarization mode, watt level and scattering direction; Surface scattering signal correction calculated relationship is to calculate polarization mode from Fresnel reflection coefficient, promptly

In the formula, R _VV, R _HHBe respectively vertical and horizontal polarization reflection coefficient, ε is the complex permittivity of seawater; θ is the elevation angle of electromagnetic wave emission source;

Remote sensor acquired signal realistic model:

Antenna gain is calculated: the used left-handed antenna gain of software emulation is 12dB, field angle 30 degree;

Related powers etc. postpone two dimension and calculate: under the simulated conditions of setting, and the retardation of direct projection and scattered signal related power waveform peak; The time delay of scattered signal-related power two-dimensional curve;

Related power Doppler two dimension is calculated: under the simulated conditions of setting, and the Doppler frequency that direct projection and scattered signal related power waveform peak are corresponding; The Doppler shift of scattered signal-related power two-dimensional curve.

2. the airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source according to claim 1; It is characterized in that: left-handed antenna is four array antennas, can satisfy the effective reception of 500m～8000m airborne remote sensing height to the sea echo signal.

3. the airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source according to claim 1 is characterized in that: postpone the mapping receiver and adopt fpga chip+dsp chip+programming to constitute; Fpga chip is chosen the EP2S60F672C5 model, and dsp chip is chosen the TMS320C6713BGDP300 model; The DK-DSP-2S60-N developing instrument is used in programming, under Quartus II software environment, adopts the exploitation of Verlog hardware description language.

4. the airborne ocean microwave remote sensing system that utilizes the Global Positioning System (GPS) signal source according to claim 1; It is characterized in that: the dextrorotation antenna receives the direct signal of the L-band of GNSS satellite, and this direct signal is gained amplify the back and form right-handed circular polarization signal RF _RExport to dijection front end frequently; Left-handed antenna receives the echoed signal of the L-band of sea surface reflection GNSS satellite, and this echoed signal is gained amplify the back and form left-hand circular polarization signal RF _LExport to dijection front end frequently; Dijection front end frequently has the dual input structure, and dijection frequency front end is on the one hand to right-handed circular polarization signal RF _RCarry out the analog if signal IF of output direct signal after frequency conversion, amplification and the Filtering Processing _RDijection frequency front end is left-hand circular polarization signal RF on the other hand _LCarry out the analog if signal IF of output echoed signal after frequency conversion, amplification and the Filtering Processing _LThe analog to digital converter that postpones in the mapping receiver is used for IF _RAnd IF _LChange, thus output direct projection digital sampled signal IFD _RWith echo digital sampled signal IFD _LThe IFD of direct signal processing module to receiving _RCatch, follow the tracks of, when the location that tracking satellite can be realized receiver during more than 4, the output navigator fix is separated information FB and is given the Mission Monitor industrial computer; The digital medium-frequency signal FA that the direct signal processing module will be in 1～12 direct projection passage of tracking mode on the other hand exports to the echoed signal processing module; The echoed signal processing module is at first according to the customized channel information ID of mission planning in the Mission Monitor workstation _nIt is carried out channel arrangement, then with signal and the IFD of FA behind time delay and Doppler shift _LCarrying out the two-dimensional correlation computing obtains time delay Doppler two-dimensional correlation power FD and exports to the Mission Monitor industrial computer.

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