CN104808223A - Mirror point high dynamic suppressing correlator adaptive to spaceborne GNSS-R receiver - Google Patents

Mirror point high dynamic suppressing correlator adaptive to spaceborne GNSS-R receiver Download PDF

Info

Publication number
CN104808223A
CN104808223A CN201510218180.5A CN201510218180A CN104808223A CN 104808223 A CN104808223 A CN 104808223A CN 201510218180 A CN201510218180 A CN 201510218180A CN 104808223 A CN104808223 A CN 104808223A
Authority
CN
China
Prior art keywords
point
module
high dynamic
signal
mirror
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN201510218180.5A
Other languages
Chinese (zh)
Other versions
CN104808223B (en
Inventor
修春娣
于成辉
李伟强
高洪兴
杨东凯
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beihang University
Original Assignee
Beihang University
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beihang University filed Critical Beihang University
Priority to CN201510218180.5A priority Critical patent/CN104808223B/en
Publication of CN104808223A publication Critical patent/CN104808223A/en
Application granted granted Critical
Publication of CN104808223B publication Critical patent/CN104808223B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • 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
    • G01S19/13—Receivers
    • G01S19/35—Constructional details or hardware or software details of the signal processing chain
    • G01S19/37—Hardware or software details of the signal processing chain

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

The invention discloses a mirror point high dynamic suppressing correlator adaptive to a spaceborne GNSS-R receiver. The correlator comprises a direct signal tracking module (1), a delay module (2), a mirror point high dynamic suppressing control module (3), a mirror point high dynamic suppressing processing module (4), a mirror point high dynamic suppressing infusing module (5), a carrier compensation module (6) and an interference processing module (7). The certain delay processing is performed on direct signals after carrier tracking firstly, the mirror reflection high dynamic suppressing is performed, interference processing is performed on reflection signals after carrier compensation, and the two-dimensional delay Doppler correlation power is acquired finally. The correlator is used for producing local copying carriers, local copying code generation is omitted, interference processing is performed on the direct signals and reflection signals after delay Doppler compensation processing, the Doppler frequency shift of one mirror reflection point in different sampling times can be acquired, the speckle noise of a mirror reflection region is suppressed, and the signal-noise ratio of the signals is increased.

Description

A kind ofly be applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point
Technical field
The present invention relates to a kind of GNSS-R receiver, more particularly, refer to and be a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point.By processing the specular reflection point of high-speed mobile, spaceborne GNSS-R receiver is made to carry out improving sea altimetry precision in the inverting of sea.
Background technology
GPS (Global Position System) (Global Navigation Satellite System, GNSS) be exactly satellite-based radio navigation system using artificial earth satellite as guidance station, all kinds of the army and the people's carriers for global land, sea, air, sky provide all-weather, high-precision Position, Velocity and Time information, and thus it is also called space-based location, navigation and time service (PNT) system.GPS (Global Position System) (GNSS) is the unified appellation to these single satellite navigation and location systems such as GPS (GPS), glonass system (GLONASS) and Galileo (Galileo) systems.With reference to the 1st printing September in 2013, author Xie Gang, " GLONASS (Global Navigation Satellite System) principle---GPS, GLONASS and Galileo system " chapter 1 introduction section, the 1st page.
Although GPS, GLONASS and Galileo three digest journals may have definition slightly different separately to its System's composition, substantially can be made up of three parts by a GNSS, i.e. space constellation part, ground monitoring part and customer equipment part.With reference to the 1st printing September in 2013, author Xie Gang, " GLONASS (Global Navigation Satellite System) principle---GPS, GLONASS and Galileo system " chapter 1 introduction section, the 4th page.Be designated as Fig. 1 in this article, in figure, the main body of space constellation part is the satellite being distributed in the some run in space orbit, and their forms usually in earth middle orbit (MEO), the static earth (GEO) or inclination geostationary orbit (IGSO) satellite occur.As transit satellite.In order to distinguish the unlike signal that different satellite (or same satellite) is launched, GNSS needs to adopt a kind of multiple access technology mechanism.Multiple access technology is generally divided into CDMA (CDMA), frequency division multiple access (FDMA) and time division multiple access (TDMA) (TDMA) three kinds, wherein, CDMA can broadcast unlike signal in same carrier frequency through different pseudo noise (PPN) code band spectrum modulation, unlike signal is broadcast on a different carrier frequency by FDMA, and TDMA can broadcast unlike signal composition in same carrier frequency to share a channel by timesharing.
With reference to the 1st printing September in 2013, author Xie Gang, " GLONASS (Global Navigation Satellite System) principle---GPS, GLONASS and Galileo system " chapter 1 introduction section, 8-12 page.In the design of GNSS receiver, be designated as Fig. 2 in this article.In figure, correlator is carried out related calculation at local replica pseudo-code and Received signal strength, makes satellite-signal despreading and improve the signal to noise ratio (S/N ratio) of Received signal strength immediately.
In the application of numerous GNSS-R receiver, what also have has installed GNSS-R receiver on low orbit satellite.Obtain a large amount of observation data such as Ocean Wind-field, soil moisture, sea ice by airborne, land experiment, have studied corresponding inverse model.GNSS-R and Global Navigation Satellite System-Reflection, translation is the GPS (Global Position System) based on reflected signal.
Traditional spaceborne GNSS-R receiver receiving, process sea surface reflection signal is when carrying out surveying high, compared to 3dB areal coverage (region that the fixed gain isoline lower than the maxgain value 3dB of antenna boresight direction defines is called 3dB areal coverage) and the sea surface reflection signal r of ocean surface oceanbe not fully utilized, the high dynamic mobile of the specular reflection point especially in spaceborne situation.The speckle noise existed in district of glittering belonging to specular reflection point will have an impact to tradition spaceborne GNSS-R receiver processing signals, and this can produce larger time delay error, and speckle noise reduces the signal to noise ratio (S/N ratio) of signal, thus reduces ocean altimetry precision.
Summary of the invention
In order to make spaceborne GNSS-R receiver carry out the raising to sea altimetry precision in the refutation process of sea, the present invention devises and is a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppresses the high dynamic correlator of mirror point.This correlator makes full use of the sea surface reflection signal r in antenna 3dB overlay area on the one hand ocean, utilize specular reflection point Doppler frequency (fa, fb) to carry out frequency compensation to direct signal d on the other hand, the third aspect is by the direct signal after delay-Doppler compensates with noise Z dreflected signal after (t) and carrier compensation with speckle signal Z rt () carries out interference treatment, thus be conducive to improving altimetry precision.
The present invention's design a kind of is applicable to having of spaceborne GNSS-R receiver and can suppresses the high dynamic correlator of mirror point, it is characterized in that: this correlator includes direct signal tracking module (1), time delay module (2), suppresses mirror point high Dynamic control module (3), suppresses mirror point high dynamic process module (4), suppresses mirror point high dynamic fusion module (5), carrier compensation module (6) and interference treatment module (7);
Direct signal tracking module (1) is for digital direct projection intermediate-freuqncy signal R d ( t ) = A RF d ( t ) × S d ( t ) × D d ( t ) Follow the tracks of;
Time delay module (2) foundation delay volume τ is to digital direct projection intermediate-freuqncy signal carry out time delay, when obtaining, delay direct signal
Suppress mirror point high dynamic process module (3) first direct signal after receive time delay scattering point-Doppler frequency is poor poor with reflection spot-Doppler frequency then, scattering point-Doppler frequency is applied poor poor with reflection spot-Doppler frequency carry out direct signal after delay compensation rear direct signal must be compensated
Mirror point high Dynamic control module (4) first aspect is suppressed to receive navigation data Na (t); Second aspect, obtains number and a specular reflection point sp of the scattering point sa in scattering region according to navigation data Na (t); The third aspect, adopt the specular reflection point algorithm for estimating based on line segment dichotomy to obtain the position of specular reflection point sp, the position of specular reflection point sp is designated as (x sp, y sp); Fourth aspect, calculates scattering point-Doppler frequency poor; 5th aspect, computational reflect point-Doppler frequency is poor;
Suppress mirror point high dynamic fusion module (5) in N number of shift position of a specular reflection point, and M scattering point in antenna 3dB overlay area is averaged cumulative, the direct signal obtaining exporting is
Carrier compensation module (6) is to the numeral reflection intermediate-freuqncy signal R received rt () carries out carrier compensation;
Interference treatment module (7) is by what receive with carry out interference treatment, obtain delay-Doppler two-dimensional correlation power
Having of the present invention's design can suppress the advantage of the high dynamic correlator of mirror point to be:
1. correlator of the present invention is by estimating the Doppler frequency n Δ f of specular reflection point to the calculating of specular reflection point position, speed s(specular reflection point within N number of sampling period N movement, and obtain the Doppler shift n Δ f of the specular reflection point after N movement s), wherein using above-mentioned frequency displacement after the Doppler effect correction of reflected signal, being averaged to add up to N number of different specular reflection point reflector space makes full use of sea return resource; For individual reflection region, receiving trap utilizes known navigation information, according to receiver speed, position and satellite velocities, positional information, estimates M the Doppler frequency mf relative to specular reflection point in this reflector space s, wherein, the number that Doppler frequency is ahead of the scattering point of specular reflection point sp is designated as m in advance, the number that Doppler frequency lags behind the scattering point of specular reflection point sp is designated as m delayed, and m in advance+ m delayed=M, m represent the summing target of scattering point, carry out can reducing speckle noise power after track Doppler effect correction on average adds up, and improve signal to noise ratio (S/N ratio).
2., in the present invention's design " suppressing mirror point high dynamic fusion module ", after integral mean is carried out to the two-dimentional delay-Doppler of gained, the speckle noise in different reflector space can be effectively reduced.
3. on the basis of conventional receiver device, add the high dynamically suppression module of specular reflection point, optimize receiving trap resource and improve the performance of receiving trap, make receiving trap can make full use of navigational satellite reflected signal in antenna 3dB overlay area, compensate for because mirror point height dynamically produces Doppler shift, inhibit the speckle noise in areas of specular reflection, improve the signal to noise ratio (S/N ratio) of signal.
Accompanying drawing explanation
Fig. 1 is the schematic diagram of three ingredients of passive type GNSS.
Fig. 2 is the baseband digital signal process block diagram of GNSS receiver.
Fig. 3 of the present inventionly has the structured flowchart that can suppress the high dynamic correlator of mirror point.
Fig. 4 is at the irrelevant sea altimetry precision simulated effect figure under counting that adds up of different sampled point.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in further detail.
When spaceborne GNSS-R receiver carries out work on the low orbit satellite of high-speed flight, many conditions such as environment, state and position of work are all completely different from the GNSS receiver of ground general work, and these factors determine to the technical requirement and the conventional GNSS receiver used on the ground of spaceborne GNSS-R receiver that some is different.
Shown in Figure 3, the present invention devises and is a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppresses the high dynamic correlator of mirror point, and this correlator includes direct signal tracking module 1, time delay module 2, suppresses mirror point high Dynamic control module 3, suppresses mirror point high dynamic process module 4, suppresses mirror point high dynamic fusion module 5, carrier compensation module 6 and interference treatment module 7.The correlator first aspect of the present invention's design is for generation of local replica carrier wave second aspect does not need to produce local copy codes; The third aspect is that direct signal d after delay-Doppler compensation deals and reflected signal r is carried out interference treatment, thus obtain the Doppler shift of a specular reflection point under different sampling stages, thus inhibit the speckle noise in areas of specular reflection, improve the signal to noise ratio (S/N ratio) of signal.
Direct signal tracking module 1
Direct signal tracking module 1 is for digital direct projection intermediate-freuqncy signal R dt () follows the tracks of, wherein R d ( t ) = A RF d ( t ) × S d ( t ) × D d ( t ) , the amplitude leyel of representative digit direct projection intermediate-freuqncy signal, S dthe carrier wave of (t) representative digit direct projection intermediate-freuqncy signal, D dthe range finding spreading code of (t) representative digit direct projection intermediate-freuqncy signal.In the present invention, local replica carrier wave is made by following the tracks of in sampling time t with described R dthe carrier wave S of (t) dt () has identical Doppler frequency and phase place.
Described j represents the imaginary part of plural number, and t represents present sample time point, and π represents circular constant, value 3.14, f drepresent the frequency reproduction of the local direct signal produced, what represent the local direct signal produced copies initial phase.
In the present invention, direct signal tracking module 1 carries out carrier track for the navigation direct signal received antenna, and extract local replica carrier wave, then coherent accumulation is utilized to carry out coherent integration to local replica carrier wave, integration-remover is utilized to eliminate radio-frequency component in coherent signal and noise by integrating low-pass filter, to improve signal to noise ratio (S/N ratio), the local replica carrier wave after coherent integration is made to have identical Doppler frequency with the navigation direct signal received.But carrier tracking loop utilize second order FLL to assist under third order pll coherent integration results is carried out to the tracking of carrier wave, using the phase pushing figure that obtains as phase compensation, the local carrier copied finally is made to have the frequency identical with the direct signal received and identical phase place.
Time delay module 2
In the present invention, time delay module 2 according to delay volume τ to digital direct projection intermediate-freuqncy signal R dt () carries out time delay, delay direct signal when obtaining
Described
In the present invention, utilize delay volume τ (t) to digital direct projection intermediate-freuqncy signal R dt () carries out time delay processing, be the related power for obtaining associating with reflected signal in follow-up interference treatment module.
Suppress mirror point high Dynamic control module 4
Shown in Figure 3, suppress mirror point high Dynamic control module 4 first aspect to receive navigation data Na (t);
In the present invention, this navigation data Na (t) calculate for spaceborne GNSS-R receiver satellite ephemeris, clock correction, ionosphere time revise, the almanac of other satellites and duty etc. in GPS constellation.Spaceborne GNSS-R receiver is by carrying out carrier modulation and pseudo-code despreading to the satellite-signal received, and it can be compiled into navigation message the most at last according to the form of navigation message, this navigation message is mainly used to measure customer location, speed and the data of time basis.
Suppress the second aspect of mirror point high Dynamic control module 4, obtain number and a specular reflection point sp of the scattering point sa in scattering region according to navigation data Na (t);
If scattering point is designated as sa, the number of scattering point is designated as M, then all scattering points in scattering region are designated as SA={sa 1, sa 2..., sa m.Sa 1be first scattering point, sa 2be second scattering point, sa mfor last scattering point, for convenience of description sa malso referred to as any scattering point.Any scattering point sa mposition coordinates in scattering region is designated as
In the present invention, an a satellite only corresponding specular reflection point.
Suppress the third aspect of mirror point high Dynamic control module 4, adopt the specular reflection point algorithm for estimating based on line segment dichotomy to obtain the position of specular reflection point sp, the position of specular reflection point sp is designated as (x sp, y sp);
Calculate the Euclidean distance between all scattering points in specular reflection point sp and scattering region, then have:
Specular reflection point sp and scattering point sa 1between Euclidean distance be designated as and D sa 1 sp = ( x sa 1 - x sp ) 2 + ( y sa 1 - y sp ) 2 ;
Specular reflection point sp and scattering point sa 2between Euclidean distance be designated as and D sa 2 sp = ( x sa 2 - x sp ) 2 + ( y sa 2 - y sp ) 2 ;
Specular reflection point sp and scattering point sa mbetween Euclidean distance be designated as and D sa M sp = ( x sa M - x sp ) 2 + ( y sa M - y sp ) 2 .
In the present invention, specular reflection point to the Euclidean distance of scattering point is
Suppress the fourth aspect of mirror point high Dynamic control module 4, calculate scattering point-Doppler frequency poor;
In the present invention, to the Euclidean distance of scattering point, differentiate is carried out to specular reflection point, obtains scattering point-Doppler frequency poor λ represents carrier wavelength, represent the differential to 2 distances, dt is the differential to the sampling time, and t represents present sample time point.
To specular reflection point sp and scattering point sa 1between Euclidean distance differentiate, obtains scattering point-Doppler frequency poor represent specular reflection point sp and scattering point sa 1between Euclidean distance differential;
To specular reflection point sp and scattering point sa 2between Euclidean distance differentiate, obtains scattering point-Doppler frequency poor represent specular reflection point sp and scattering point sa 2between Euclidean distance differential;
To specular reflection point sp and scattering point sa mbetween Euclidean distance differentiate, obtains scattering point-Doppler frequency poor represent specular reflection point sp and scattering point sa mbetween Euclidean distance differential.
In the present invention, scattering point-Doppler frequency is poor difference between the Doppler frequency referring to the reflected signal of the scattering point in scattering region and the reflected signal of specular reflection point.
Suppress the 5th aspect of mirror point high Dynamic control module 4, computational reflect point-Doppler frequency is poor;
Adopt the computing method of satellite velocity to calculate the ephemeris in navigation data Na (t), obtain the travelling speed v of specular reflection point sp sp;
In the present invention, the computing method of satellite velocity please refer to " GPS principle and Receiver Design " the 63rd, 64,65 page of content of the 3rd printing Dec in 2012, author Xie Gang.
In the present invention, in a sampling period T, specular reflection point sp will move, and the specular reflection point moving to next position is designated as sp mobile(move sp referred to as mirror point mobile), mirror point moves sp mobileposition be designated as and the distance of movement is designated as (referred to as mirror point displacement ), described in in the present invention, some t of multiple sampling time is included in a sampling period T.
In the present invention, spaceborne GNSS-R receiver is in N number of sampling period T, and specular reflection point sp will have N movement, then the movement of all specular reflection points is designated as for the position of specular reflection point sp after first sampling period (is moved referred to as first mirror point ), for the position of specular reflection point sp after second sampling period (is moved referred to as second mirror point ), for the position of specular reflection point sp after last sampling period (is moved referred to as last mirror point ), for convenience of description, move referred to as any mirror point.The present invention under spaceborne condition in order to the specular reflection point in suppressing antenna 3dB areal coverage moves, for the different sampling periods all with specular reflection point sp for reference point.
Calculate the Euclidean distance between the specular reflection point of mobile front and back, then have:
Specular reflection point sp and first mirror point moves between Euclidean distance be designated as and
First mirror point moves move with second mirror point between Euclidean distance be designated as and
Second mirror point moves move with last mirror point between Euclidean distance be designated as and
To mirror point displacement carry out differentiate, obtain reflection spot-Doppler frequency poor λ represents carrier wavelength, represent the differential to mirror point displacement, dt is the differential to the sampling time, and T represents the sampling period.
Right carry out differentiate, obtain reflection spot-Doppler frequency poor represent the differential to mirror point displacement.
Right carry out differentiate, obtain reflection spot-Doppler frequency poor represent the differential to mirror point displacement.
Right carry out differentiate, obtain reflection spot-Doppler frequency poor represent the differential to mirror point displacement.
In the present invention, reflection spot-Doppler frequency is poor difference between the Doppler frequency referring to the reflected signal of former and later two specular reflection points of movement in scattering region.
Suppress mirror point high dynamic process module 3
Suppress mirror point high dynamic process module 3 first direct signal after receive time delay scattering point-Doppler frequency is poor poor with reflection spot-Doppler frequency then, scattering point-Doppler frequency is applied poor poor with reflection spot-Doppler frequency carry out direct signal after delay compensation rear direct signal must be compensated
In the present invention,
Suppress mirror point high dynamic fusion module 5
Reflected signal processing procedure is the process of coherently despreading, with the time span T that the cycle of navigational range code is correlation integral in the present invention c(referred to as coherent accumulation time T c), consider the displacement of specular reflection point sp under Different sampling period, in order to suppress the high dynamic impact of specular reflection point in correlation integral process, described T c=T.
In the present invention, the frequency bandwidth of spaceborne GNSS-R receiver is designated as Bw, according to frequency bandwidth Bw and the relation in sampling period, obtains the number in sampling period, i.e. N=Bw × T.Then have and suppress mirror point high dynamic fusion module 5 in N number of shift position (mirror point moves) of a specular reflection point, and M scattering point in antenna 3dB overlay area is averaged cumulative, the direct signal obtaining exporting is
In the present invention, the number that Doppler frequency is ahead of the scattering point of specular reflection point sp is designated as m in advance, the number that Doppler frequency lags behind the scattering point of specular reflection point sp is designated as m delayed, and m in advance+ m delayed=M.M represents the summing target of scattering point, and n represents the summing target in sampling period.
Considering the existence of thermonoise for needing during direct signal process, supposing that the additive noise of input signal is Z (n), be average is 0, and variance is σ 2white Gaussian noise, then after the high dynamically suppression module process of mirror point, the noise of output is u represents the discrete element of scattering point, and W represents the discrete element in sampling period.
According to white noise feature, each sampled point is separate, and the noise variance after the high dynamically suppression module process of mirror point is σ ‾ 2 = 1 M × N σ 2 .
In the present invention, the coherent accumulation time T in mirror point high dynamic fusion module 5 is suppressed cusing the time span foundation in the sampling period as suppression mirror point high Dynamic control module 4.
Carrier compensation module 6
Carrier compensation module 6 is to the numeral reflection intermediate-freuqncy signal R received rt () carries out carrier compensation.In the present invention, make the reflected signal after compensation with direct signal after tracking there is identical Doppler frequency.
In the present invention, the carrier compensation module of reflected signal be used under the navigation reflected signal that receives depending on antenna carry out carrier compensation, the method for carrier compensation mainly adopts traditional coherent accumulation, carrier tracking loop and carrier wave NCO module to produce the carrier compensation component of signal of reflected signal.Carrier wave NCO produces local replica carrier wave by traditional look-up table method, and the local replica carrier wave that carrier wave NCO produces is carried out traditional coherent integration by coherent accumulation, integration-remover is utilized to eliminate radio-frequency component in coherent signal and noise by integrating low-pass filter, to improve signal to noise ratio (S/N ratio), the navigation reflected signal after carrier compensation is made to have identical Doppler frequency with direct signal.Third order pll under carrier tracking loop utilizes traditional second order FLL to assist carries out the tracking of carrier wave to coherent integration results, the phase pushing figure obtained being fed back to carrier wave NCO as phase compensation, finally making the local carrier copied have the frequency identical with receiving reflected signal and identical phase place.
Interference treatment module 7
See accompanying drawing 3, interference treatment module 7 will receive with carry out interference treatment, obtain delay-Doppler two-dimensional correlation power
Described
τ is the time delay relative to specular reflection point;
F is the Doppler shift relative to specular reflection point place reflected signal frequency;
T cfor the coherent accumulation time;
link thermonoise is looked in GNSS-R receiver direct projection passage;
Z rt () looks link thermonoise under in GNSS-R receiver reflectance passage.
In the present invention, by delay-Doppler two-dimensional correlation power launch, respectively:
The coherent component W of direct signal and reflected signal d_r, and
The coherent component W of direct projection passage thermonoise and reflection channel speckle noise dz_rz, and W dz _ rz = 1 T c × ∫ T c Z d ( t ) ‾ × Z r ( t + τ ) dt ;
The coherent component W of direct signal and reflection channel speckle noise d_rz, and W d _ rz = 1 T c × ∫ T c f 5 - 7 d ( t ) × Z r ( t + τ ) dt With
Direct projection passage thermonoise and reflected signal coherent component W dz_r, and
In spaceborne GNSS-R receiver, consider direct signal white Gaussian noise and reflected signal speckle noise separate, uncorrelated, assembly average is obtained, i.e. <|W to above-mentioned four components d_r| 2>, <|W dz_rz| 2>, <|W d_rz| 2> and <|W dz_r| 2>, these four assembly averages are also the Output rusults of interference treatment correlator of the present invention.
<|W in the present invention dz_rz| 2>, <|W d_rz| 2> and <|W dz_r| 2> is containing noise component, according to signal to noise ratio (S/N ratio) formula can be in the hope of interference treatment module 7 output signal-to-noise ratio SNR = &lang; | W d _ r | 2 &rang; &lang; | W dz _ rz | 2 &rang; + &lang; | W d _ rz | 2 &rang; + &lang; | W dz _ r | 2 &rang; . Be 0 for average, variance is σ 2white Gaussian noise, its watt level equals variance, thus through specular reflection point is high dynamically suppress after its direct signal output noise power can reduce.After signal to noise ratio (S/N ratio) improves, altimetry precision also can be improved accordingly.
Embodiment 1
In order to better illustrate that the advantage place of conventional correlator compared by correlator that the present invention designs, first simulated environment is described below:
Parameter Numerical value Unit
Orbit altitude 756 Km
The minute surface launching site elevation angle 28 Deg
Wind speed 6.5 m/s
Significant wave height 1.5 m
On depending on antenna and under look antenna gain 25 dBi
Receiver bandwidth 50 MHz
On look antenna noise temperature 40 K
Under look antenna noise temperature 120 K
Receiver noise temperature 280 K
Receiver noise value 3 dB
Satellite signal transit power 26 dBW
Spatial resolution in-orbit 100 Km
Wherein the elevation of satellite at specular reflection point place is between 29 ~ 32 degree.Sea return receiving antenna adopts high-gain (12dB), narrow beam (38 degree) left-hand circular polarization antenna.Under the condition adding up and count of being correlated with adopting different samplings, emulating, obtain simulation result as shown in Figure 4 to sea altimetry precision, in figure, the correlator of the present invention's design improves sea altimetry precision.
The present invention's design a kind of is applicable to having of spaceborne GNSS-R receiver and can suppresses the high dynamic correlator of mirror point, to be solved is that traditional spaceborne GNSS-R receiver is receiving, when process sea surface reflection signal carries out surveying high, the technical matters of the high dynamic mobile of the specular reflection point in spaceborne situation, correlator of the present invention by first on carry out carrier compensation and time delay depending on direct signal, and suppression specular reflection point high dynamic process is carried out to the direct signal after compensating, obtain mirror point and suppress the direct signal after processing, then relevant treatment is carried out to the direct signal after process and reflected signal, the two-dimentional delay-Doppler of process gained is carried out to the technological means of integral mean, thus inhibit speckle noise in areas of specular reflection on the impact of two-dimensional correlation power, improve the technique effect of the signal to noise ratio (S/N ratio) of signal.
In the present invention, the physical significance of the letter quoted is:

Claims (4)

1. be applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point, it is characterized in that: this correlator includes direct signal tracking module (1), time delay module (2), suppresses mirror point high Dynamic control module (3), suppresses mirror point high dynamic process module (4), suppresses mirror point high dynamic fusion module (5), carrier compensation module (6) and interference treatment module (7);
Direct signal tracking module (1) is for digital direct projection intermediate-freuqncy signal R d ( t ) = A RF d ( t ) &times; S d ( t ) &times; D d ( t ) Follow the tracks of;
Time delay module (2) foundation delay volume τ is to digital direct projection intermediate-freuqncy signal carry out time delay, when obtaining, delay direct signal
Suppress mirror point high dynamic process module (3) first direct signal after receive time delay scattering point-Doppler frequency is poor poor with reflection spot-Doppler frequency then, scattering point-Doppler frequency is applied poor poor with reflection spot-Doppler frequency carry out direct signal after delay compensation rear direct signal must be compensated
Mirror point high Dynamic control module (4) first aspect is suppressed to receive navigation data Na (t); Second aspect, obtains number and a specular reflection point sp of the scattering point sa in scattering region according to navigation data Na (t); The third aspect, adopt the specular reflection point algorithm for estimating based on line segment dichotomy to obtain the position of specular reflection point sp, the position of specular reflection point sp is designated as (x sp, y sp); Fourth aspect, calculates scattering point-Doppler frequency poor; 5th aspect, computational reflect point-Doppler frequency is poor;
Suppress mirror point high dynamic fusion module (5) in N number of shift position of a specular reflection point, and M scattering point in antenna 3dB overlay area is averaged cumulative, the direct signal obtaining exporting is
Carrier compensation module (6) is to the numeral reflection intermediate-freuqncy signal R received rt () carries out carrier compensation;
Interference treatment module (7) is by what receive with carry out interference treatment, obtain delay-Doppler two-dimensional correlation power
2. be according to claim 1ly a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point, it is characterized in that: suppress the coherent accumulation time T in mirror point high dynamic fusion module (5) cwill as the time span foundation in the sampling period of suppression mirror point high Dynamic control module (4).
3. be according to claim 1ly a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point, it is characterized in that: by delay-Doppler two-dimensional correlation power launch, respectively:
The coherent component W of direct signal and reflected signal d_r, and
The coherent component W of direct projection passage thermonoise and reflection channel speckle noise dz_rz, and W dz _ rz = 1 T c &times; &Integral; T c Z d ( t ) &OverBar; &times; Z r ( t + &tau; ) dt ;
The coherent component Wd_rz of direct signal and reflection channel speckle noise, and W d _ rz = 1 T c &times; &Integral; T c f 5 - 7 d ( t ) &times; Z r ( t + &tau; ) dt With
Direct projection passage thermonoise and reflected signal coherent component W dz_r, and
4. be according to claim 3ly a kind ofly applicable to having of spaceborne GNSS-R receiver and can suppress the high dynamic correlator of mirror point, it is characterized in that: <|W dz_rz| 2>, <|W d_rz| 2> and <|W dz_r| 2> is containing noise component, according to signal to noise ratio (S/N ratio) formula can be in the hope of interference treatment module (7) output signal-to-noise ratio SNR = &lang; | W d _ r | &rang; 2 &lang; | W dz _ rz | 2 &rang; + &lang; | W d _ rz | 2 &rang; + &lang; | W dz _ r | 2 &rang; .
CN201510218180.5A 2015-04-30 2015-04-30 It is a kind of suitable for spaceborne GNSS R receivers with the correlator that can suppress mirror point high dynamic Expired - Fee Related CN104808223B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201510218180.5A CN104808223B (en) 2015-04-30 2015-04-30 It is a kind of suitable for spaceborne GNSS R receivers with the correlator that can suppress mirror point high dynamic

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201510218180.5A CN104808223B (en) 2015-04-30 2015-04-30 It is a kind of suitable for spaceborne GNSS R receivers with the correlator that can suppress mirror point high dynamic

Publications (2)

Publication Number Publication Date
CN104808223A true CN104808223A (en) 2015-07-29
CN104808223B CN104808223B (en) 2017-07-04

Family

ID=53693209

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201510218180.5A Expired - Fee Related CN104808223B (en) 2015-04-30 2015-04-30 It is a kind of suitable for spaceborne GNSS R receivers with the correlator that can suppress mirror point high dynamic

Country Status (1)

Country Link
CN (1) CN104808223B (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106371110A (en) * 2016-08-16 2017-02-01 上海航天测控通信研究所 GNSS-R double time compensation and delayed interference processing system and method
CN110632620A (en) * 2019-09-04 2019-12-31 北京航空航天大学 Satellite-borne forwarding type deception jamming system capable of simultaneously supporting GPS civil code and military code
CN112069595A (en) * 2020-08-19 2020-12-11 西安空间无线电技术研究所 Constellation design method and device for GNSS-R sea surface wind field detection
CN112397109A (en) * 2020-11-19 2021-02-23 成都海光集成电路设计有限公司 Time delay compensation method for memory signal line

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6232922B1 (en) * 1998-05-12 2001-05-15 Mcintosh John C. Passive three dimensional track of non-cooperative targets through opportunistic use of global positioning system (GPS) and GLONASS signals
CN101846746A (en) * 2010-03-24 2010-09-29 中国科学院空间科学与应用研究中心 Carrier phase height measurement device based on GNSS-R technology and method thereof
US20120050103A1 (en) * 2010-07-10 2012-03-01 Thales Synthetic aperture device for receiving signals of a system comprising a carrier and means for determining its trajectory
CN102749067A (en) * 2012-06-21 2012-10-24 北京航空航天大学 Telemetering device for accurately inverting sea level elevation with self-adaptive multistage calculation

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6232922B1 (en) * 1998-05-12 2001-05-15 Mcintosh John C. Passive three dimensional track of non-cooperative targets through opportunistic use of global positioning system (GPS) and GLONASS signals
CN101846746A (en) * 2010-03-24 2010-09-29 中国科学院空间科学与应用研究中心 Carrier phase height measurement device based on GNSS-R technology and method thereof
US20120050103A1 (en) * 2010-07-10 2012-03-01 Thales Synthetic aperture device for receiving signals of a system comprising a carrier and means for determining its trajectory
CN102749067A (en) * 2012-06-21 2012-10-24 北京航空航天大学 Telemetering device for accurately inverting sea level elevation with self-adaptive multistage calculation

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
杨威 等: "星载GNSS-R镜面反射点计算的硬件系统实现", 《 第七届全国信号和智能信息处理与应用学术会议会刊 》 *

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106371110A (en) * 2016-08-16 2017-02-01 上海航天测控通信研究所 GNSS-R double time compensation and delayed interference processing system and method
CN106371110B (en) * 2016-08-16 2018-12-25 上海航天测控通信研究所 A kind of GNSS-R giving young employees remedial-courses in general knowledge and vocational skills time delay interference processing system and method
CN110632620A (en) * 2019-09-04 2019-12-31 北京航空航天大学 Satellite-borne forwarding type deception jamming system capable of simultaneously supporting GPS civil code and military code
CN112069595A (en) * 2020-08-19 2020-12-11 西安空间无线电技术研究所 Constellation design method and device for GNSS-R sea surface wind field detection
CN112069595B (en) * 2020-08-19 2024-05-14 西安空间无线电技术研究所 Constellation design method and device for GNSS-R sea surface wind field detection
CN112397109A (en) * 2020-11-19 2021-02-23 成都海光集成电路设计有限公司 Time delay compensation method for memory signal line
CN112397109B (en) * 2020-11-19 2023-05-09 成都海光集成电路设计有限公司 Method for compensating time delay of memory signal line

Also Published As

Publication number Publication date
CN104808223B (en) 2017-07-04

Similar Documents

Publication Publication Date Title
Xie et al. Precise orbit determination for BDS-3 satellites using satellite-ground and inter-satellite link observations
Antoniou et al. GNSS-based bistatic SAR: A signal processing view
Rius et al. Altimetry with GNSS-R interferometry: First proof of concept experiment
US9075126B2 (en) Ground location inertial navigation geopositioning system (groundlings)
CN110118978B (en) Navigation anti-interference system and navigation anti-interference method based on low-earth-orbit satellite
US20120050103A1 (en) Synthetic aperture device for receiving signals of a system comprising a carrier and means for determining its trajectory
Musumeci et al. Design of a High Sensitivity GNSS receiver for Lunar missions
Capuano et al. Orbital filter aiding of a high sensitivity GPS receiver for lunar missions
CN104808223A (en) Mirror point high dynamic suppressing correlator adaptive to spaceborne GNSS-R receiver
Weill A high performance code and carrier tracking architecture for ground-based mobile GNSS receivers
Ferre et al. Comparison of MEO, LEO, and terrestrial IoT configurations in terms of GDOP and achievable positioning accuracies
De Lorenzo et al. Navigation accuracy and interference rejection for an adaptive GPS antenna array
Musumeci et al. Design of a very high sensitivity acquisition system for a space GNSS receiver
Tamazin et al. GNSSs, signals, and receivers
Pinell et al. Receiver architectures for positioning with low earth orbit satellite signals: a survey
Huang et al. Navigation domain multipath characterization using GNSS direct position estimation in urban canyon environment
Xue et al. Overview of multipath mitigation technology in global navigation satellite system
Montenbruck et al. GNSS visibility and performance implications for the GENESIS mission
Qi et al. Robust unambiguous ranging technique for BDS-3 B1 wideband composite signals
Tamazin High resolution signal processing techniques for enhancing GPS receiver performance
Sánchez-Naranjo et al. GNSS vulnerabilities
Varner DGPS carrier phase networks and partial derivative algorithms
CN115327530A (en) External radiation source radar reference signal reconstruction method based on Beidou satellite
US11280911B2 (en) System and method for synthetic aperture based position, navigation, and timing
Sunehra et al. Estimation of total electron content and instrumental biases of low latitude global positioning system stations using Kalman filter

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
EXSB Decision made by sipo to initiate substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20170704

Termination date: 20180430