CN106597492B - Satellite navigation receiver and method for resisting near-far effect and indoor positioning method thereof - Google Patents
Satellite navigation receiver and method for resisting near-far effect and indoor positioning method thereof Download PDFInfo
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- CN106597492B CN106597492B CN201710066955.0A CN201710066955A CN106597492B CN 106597492 B CN106597492 B CN 106597492B CN 201710066955 A CN201710066955 A CN 201710066955A CN 106597492 B CN106597492 B CN 106597492B
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- 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
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/29—Acquisition or tracking or demodulation of signals transmitted by the system carrier including Doppler, related
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- 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
- G01S19/24—Acquisition or tracking or demodulation of signals transmitted by the system
- G01S19/30—Acquisition or tracking or demodulation of signals transmitted by the system code related
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The invention is suitable for the field of satellite navigation, and particularly relates to a satellite navigation receiver, a method for resisting near-far effect and an indoor positioning method. The satellite navigation receiver comprises an antenna unit, a radio frequency unit, a baseband signal processing unit, a control and information processing unit and a man-machine interaction unit which are sequentially connected, wherein the baseband signal processing unit is provided with a far-near effect suppression unit, the far-near effect suppression unit comprises a signal reconstruction module, a weak satellite signal tracking module and at least one strong satellite signal tracking module, the strong satellite signal tracking module comprises a first autocorrelation module, a first cross-correlation module, a first subtracter and a second subtracter, and the weak satellite signal tracking module comprises a second autocorrelation module, a second cross-correlation module, a third subtracter and a fourth subtracter. The invention can enhance the anti-near-far effect capability of the satellite navigation receiver.
Description
Technical Field
The invention belongs to the field of satellite navigation, and particularly relates to a satellite navigation receiver, a method for resisting near-far effect and an indoor positioning method.
Background
Current GNSS (Global Navigation Satellite System, global satellite navigation system) mainly includes: the GPS (Global Positioning System ), GLONASS (GLONASS satellite navigation system) in russia, BD (beidou satellite navigation system) in china, and Galileo (Galileo satellite positioning system) in europe, GNSS is a radio positioning system that obtains a linear distance from a satellite navigation receiver to a satellite by estimating propagation delay of radio waves from the satellite to the satellite navigation receiver, which is a ranging method using arrival time.
Because of the limitations of an indoor pseudo-satellite system, such as low satellite layout height, large elevation angle change, narrow and complex indoor environment, and the like, the satellite navigation receiver has obvious change in the indoor moving process, and the power attenuation can reach 6dB when the distance is doubled. When the satellite navigation receiver is close to one or two pseudolites at the same time, the power of the pseudolites signals close to each other is obviously improved, so that the bottom noise power of the antenna end of the satellite navigation receiver is improved, namely, the near-far effect occurs, the capturing and tracking of the pseudolites signals far away from each other are influenced, even the situation of satellite loss occurs, and the positioning of the satellite navigation receiver is influenced.
Since the CA code is not strictly orthogonal and the isolation is about 24dB, when the power difference between two pseudo satellite signals exceeds the threshold, the cross-correlation power of the strong satellite signal and the weak satellite signal is significantly increased, so that the autocorrelation result of the weak satellite signal is affected, and finally the weak satellite signal is submerged in noise. The key to suppressing cross-correlation interference is to acquire parameters of a strong satellite signal to accurately reproduce the strong satellite signal. The signal parameters include carrier frequency, carrier phase, code phase, amplitude, and text bits. The effect of cross-correlation suppression directly depends on the accuracy of the locally reproduced strong satellite signal. The satellite navigation receiver can realize accurate tracking on the strong satellite signal by stably tracking on the strong satellite signal for a certain time, so that the carrier frequency, the carrier phase and the code phase can be directly extracted from the loop. The text bits may be given by a text predictor. The performance of the cross-correlation suppression then depends directly on the accuracy of the estimation of the amplitude.
Disclosure of Invention
The invention aims to provide a satellite navigation receiver capable of resisting far-near effect, a method for resisting far-near effect and an indoor positioning method.
In a first aspect, the present invention provides a satellite navigation receiver, including an antenna unit, a radio frequency unit, a baseband signal processing unit, a control and information processing unit and a man-machine interaction unit that are sequentially connected, where the baseband signal processing unit has a far-near effect suppression unit, the far-near effect suppression unit includes a signal reconstruction module, a weak satellite signal tracking module and at least one strong satellite signal tracking module, the strong satellite signal tracking module includes a first autocorrelation module, a first cross-correlation module, a first subtractor and a second subtractor, the weak satellite signal tracking module includes a second autocorrelation module, a second cross-correlation module, a third subtractor and a fourth subtractor, where an input end of the first autocorrelation module and an input end of the second autocorrelation module are respectively connected to an output end of the radio frequency unit, an input signal of the first cross-correlation module is 0, a first output end of the first autocorrelation module and a first output end of the first cross-correlation module are respectively connected to two input ends of the first subtractor, a second output end of the first autocorrelation module and a second output end of the first subtractor are respectively connected to two input ends of the second subtractor, a second output end of the first autocorrelation module and a second subtractor, a control amplitude reconstruction module is connected to the first output end of the control and amplitude reconstruction module, the input end of the control and the control unit are respectively connected to the input ends of the control and the amplitude reconstruction module, the second output end of the second autocorrelation module and the second output end of the second cross correlation module are respectively connected with two input ends of the fourth subtracter, the enabling end of the first autocorrelation module is connected with the control and information processing unit, the control and information processing unit provides enabling control, the amplitude control end of the second cross correlation module is connected with the control and information processing unit, the control and information processing unit provides amplitude control, and the output ends of the first subtracter, the second subtracter, the third subtracter and the fourth subtracter are connected with the control and information processing unit for tracking control of the control and information processing unit.
In a second aspect, the present invention provides a method for resisting near-far effect of a satellite navigation receiver, where the satellite navigation receiver is the satellite navigation receiver, and the method includes:
when the carrier-to-noise ratio of the tracked satellite signals is lower than a low threshold, the satellite navigation receiver searches whether the carrier-to-noise ratio of all the tracked satellite signals is higher than Gao Menxian;
if the satellite signal noise ratio of at least one channel is higher than Gao Menxian, determining that the near-far effect occurs, enabling a first autocorrelation module of a strong satellite signal tracking module to output a reconstruction signal by the satellite navigation receiver, enabling a signal reconstruction module to output the reconstruction signal, and sending the reconstruction signal to a second cross correlation module of a weak satellite signal tracking module; in the next tracking interruption, the satellite navigation receiver takes the integration result after the cross-correlation in the weak satellite signal tracking module is lightened as the input of the phase discriminator.
In a third aspect, the present invention provides an indoor positioning method of a satellite navigation receiver, where the satellite navigation receiver is the satellite navigation receiver, and the method includes:
starting up or resetting the satellite navigation receiver from a known position, and capturing each pseudolite signal in a code phase parallel and frequency serial mode;
after the satellite navigation receiver finishes capturing and traction of each pseudolite at a known position, the satellite navigation receiver is switched into tracking and demodulates a navigation message; after the satellite navigation receiver acquires the coordinates of the satellite from the navigation text of the pseudolite, carrying out static initialization on the carrier integer ambiguity of the satellite navigation receiver, and after all the pseudolites finish the carrier integer ambiguity initialization, completing the static initialization by the satellite navigation receiver;
after the satellite navigation receiver completes static initialization, the satellite navigation receiver freely moves, and the carrier phase measurement value of the pseudolite is extracted in real time;
according to the carrier phase measurement value of the pseudolite, a CHAN algorithm is adopted as a positioning calculation algorithm to realize the indoor positioning of the satellite navigation receiver;
and transmitting the positioning result and the coordinate parameters of each pseudolite to an upper computer for display.
In the invention, as the far and near effect suppression unit comprises a signal reconstruction module, a weak satellite signal tracking module and at least one strong satellite signal tracking module, the strong satellite signal tracking module comprises a first autocorrelation module, a first cross-correlation module, a first subtracter and a second subtracter, the weak satellite signal tracking module comprises a second autocorrelation module, a second cross-correlation module, a third subtracter and a fourth subtracter, the reconstructed signal output end of the first autocorrelation module is connected with the input end of the signal reconstruction module, the amplitude control end of the signal reconstruction module is connected with the control and information processing unit, the control and information processing unit provides amplitude control, and the output end of the signal reconstruction module is connected with the input end of the second cross-correlation module. Therefore, the tracking capability of the satellite navigation receiver for weak satellite signals under the condition of strong interference can be obviously improved, the maximum power value difference value of different pseudolites which are allowed to arrive simultaneously is greatly improved, the near-far effect resistance capability of the satellite navigation receiver is obviously enhanced, and the effective positioning area of the satellite navigation receiver in an indoor pseudolites system is enlarged.
In addition, according to the carrier phase measurement value of the pseudolite, the CHAN algorithm is adopted as a positioning calculation algorithm to realize indoor positioning of the satellite navigation receiver, so that on the premise of realizing time synchronization in the pseudolite system, the influence of the pseudolite system Zhong Piao adopting a constant temperature crystal on a ranging result can be effectively eliminated, and the high-precision positioning can be realized before the satellite navigation receiver and the pseudolite system finish time synchronization, and the method is applicable to various indoor pseudolite systems. And the CHAN calculation amount is smaller than that of a least square method commonly used by a satellite navigation receiver, so that the satellite navigation receiver can realize real-time positioning.
Drawings
Fig. 1 is a schematic structural diagram of a satellite navigation receiver according to an embodiment of the invention.
Fig. 2 is a circuit block diagram of a near-far effect suppression unit in a satellite navigation receiver according to an embodiment of the present invention.
Fig. 3 is a circuit block diagram of a first autocorrelation module and a second autocorrelation module in a near-far effect suppression unit of a satellite navigation receiver according to an embodiment of the present invention.
Fig. 4 is a circuit block diagram of a first cross-correlation module in a near-far effect suppression unit of a satellite navigation receiver according to an embodiment of the present invention.
Fig. 5 is a circuit block diagram of a second cross-correlation module in a near-far effect suppression unit of a satellite navigation receiver according to an embodiment of the present invention.
Fig. 6 is a circuit block diagram of a signal reconstruction module in a near-far effect suppression unit of a satellite navigation receiver according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantageous effects of the present invention more apparent, the present invention will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
In order to illustrate the technical scheme of the invention, the following description is made by specific examples.
Embodiment one:
referring to fig. 1, a satellite navigation receiver according to an embodiment of the present invention may be used for receiving satellite navigation signals of an indoor pseudo satellite system, where the satellite navigation receiver includes an antenna unit 11, a radio frequency unit 12, a baseband signal processing unit 13, a control and information processing unit 14, and a man-machine interaction unit 15, which are sequentially connected, wherein the baseband signal processing unit 13 has a near-far effect suppression unit 131.
Referring to fig. 2, the far-near effect suppression unit includes a signal reconstruction module 1311, a weak satellite signal tracking module 1313, and at least one strong satellite signal tracking module 1312, the strong satellite signal tracking module 1312 includes a first autocorrelation module 13121, a first cross-correlation module 13122, a first subtractor 13123, and a second subtractor 13124, the weak satellite signal tracking module 1313 includes a second autocorrelation module 13131, a second cross-correlation module 13132, a third subtractor 13133, and a fourth subtractor 13134, wherein an input end of the first autocorrelation module 13121 and an input end of the second autocorrelation module 13131 are respectively connected to an output end of the radio frequency unit, an input signal of the first cross-correlation module 13122 is 0, a first output end of the first autocorrelation module 13121 and a first output end of the first cross-correlation module 13122 are respectively connected to two input ends of the first subtractor 13123, the second output end of the first autocorrelation module 13121 is connected to two input ends of the second subtractor 13124 respectively, the reconstructed signal output end of the first autocorrelation module 13121 is connected to the input end of the signal reconstruction module 1311, the amplitude control end of the signal reconstruction module 1311 is connected to the control and information processing unit, the control and information processing unit provides amplitude control, the output end of the signal reconstruction module 1311 is connected to the input end of the second correlation module 13132, the first output end of the second autocorrelation module 13131 and the first output end of the second correlation module 13132 are connected to two input ends of the third subtractor 13133 respectively, the second output end of the second autocorrelation module 13131 and the second output end of the second correlation module 13132 are connected to two input ends of the fourth subtractor 13134 respectively, the enabling end of the first autocorrelation module 13121 is connected to the control and information processing unit, the control and information processing unit provides enabling control, the amplitude control terminal of the second cross-correlation module 13132 is connected to a control and information processing unit, which provides amplitude control. The outputs of the first subtractor 13123, the second subtractor 13124, the third subtractor 13133, and the fourth subtractor 13134 are connected to a control and information processing unit for tracking control by the control and information processing unit.
Referring to fig. 3, the first autocorrelation module and the second autocorrelation module each include a carrier digital controlled oscillator 21, a pseudo code generator 22, a first integrator 23 and a second integrator 24, where the carrier digital controlled oscillator 21 generates two paths of orthogonal carriers to be multiplied by a digital intermediate frequency signal output by the radio frequency unit, so as to obtain digital baseband signals of the stripped carrier; the pseudo code generator 22 multiplies the digital baseband signals of the stripped carrier wave respectively, the multiplied results are respectively used as the input of the first integrator 23 and the second integrator 24, and the output ends of the first integrator 23 and the second integrator 24 are respectively used as the first output end and the second output end of the first autocorrelation module and the second autocorrelation module.
The first autocorrelation module further comprises a text predictor 25, the in-phase branch of the carrier digitally controlled oscillator 21 being multiplied by the pseudo code generator 22, the text predictor 25 and the control and information processing unit provided enable signals to obtain a reconstructed signal.
Referring to fig. 4, the first cross-correlation module includes a carrier digital controlled oscillator 31, a pseudo code generator 32, a third integrator 33 and a fourth integrator 34, where the carrier digital controlled oscillator 31 generates two paths of orthogonal carriers to multiply with an input signal 0 to obtain digital baseband signals of stripped carriers respectively; the pseudo code generator 32 multiplies the digital baseband signals of the stripped carrier wave respectively, the multiplied results are respectively used as the input of the third integrator 33 and the fourth integrator 34, and the output ends of the third integrator 33 and the fourth integrator 34 are respectively used as the first output end and the second output end of the first cross correlation module. The carrier digitally controlled oscillator and the pseudo code generator of the first cross correlation module may be common to the carrier digitally controlled oscillator and the pseudo code generator of the first autocorrelation module.
Referring to fig. 5, the second cross-correlation module includes a carrier digital controlled oscillator 41, a pseudo code generator 42, a fifth integrator 43 and a sixth integrator 44, where the carrier digital controlled oscillator 41 generates two paths of orthogonal carriers to be multiplied by the reconstruction signals output by the signal reconstruction module, so as to obtain digital baseband signals of the stripped carrier; the pseudo code generator 42 multiplies the digital baseband signals of the stripped carrier wave respectively, the multiplied results are respectively used as the input of the fifth integrator 43 and the sixth integrator 44, the output signals of the fifth integrator 43 and the sixth integrator 44 are respectively multiplied by the amplitude control signals provided by the control and information processing unit, and the two multiplied output ends are respectively used as the first output end and the second output end of the second cross correlation module. The carrier digitally controlled oscillator and the pseudo code generator of the second cross correlation module may be common to the carrier digitally controlled oscillator and the pseudo code generator of the second autocorrelation module.
Referring to fig. 6, the signal reconstruction module includes an N-way multiplier 51 and a 1-way N-input adder 52 connected in sequence, where N is a natural number greater than or equal to 1. The output signal of the first autocorrelation module of each strong satellite signal tracking module is sent to an N input adder 52 after the amplitude is controlled by a multiplier 51; the N-input adder 52 is enabled when the satellite navigation receiver determines that there is near-far interference, and outputs a reconstructed signal composed of N reconstructed signals to the second cross correlation module of the weak satellite signal tracking module at each time.
Embodiment two:
the method for resisting near-far effect of the satellite navigation receiver provided by the second embodiment of the invention is the satellite navigation receiver provided by the first embodiment of the invention, and comprises the following steps:
when the carrier-to-noise ratio of the tracked satellite signals is lower than a low threshold, the satellite navigation receiver searches whether the carrier-to-noise ratio of all the tracked satellite signals is higher than Gao Menxian;
if the satellite signal noise ratio of at least one channel is higher than Gao Menxian, determining that the near-far effect occurs, enabling a first autocorrelation module of a strong satellite signal tracking module to output a reconstruction signal by the satellite navigation receiver, enabling a signal reconstruction module to output the reconstruction signal, and sending the reconstruction signal to a second cross correlation module of a weak satellite signal tracking module; in the next tracking interruption, the satellite navigation receiver takes an integral result after cross correlation in the weak satellite signal tracking module is lightened as the input of a phase discriminator;
if the satellite signal noise ratio without the channel is higher than Gao Menxian, the satellite navigation receiver judges that the near-far effect does not occur, and the coherent integration time of the weak satellite signal tracking module is prolonged.
In a second embodiment of the present invention, parameters of the strong satellite signal include: navigation text symbol D i CA code phase τ i Carrier Doppler f di Carrier phaseSignal amplitude a i . The normalized amplitude is expressed as +.>The reconstruction signal output by the signal reconstruction module is:
wherein A is the amplitude used for reference in normalization and is taken from any strong satellite signal channel; t is time; CA (CA) i Is a pseudo code variable of a strong signal; f (f) IF Is an intermediate frequency.
Parameters of the weak satellite signal include: doppler f dw Carrier phaseSum code phase tau w . The result of the cross-correlation operation between the weak satellite signal and the reconstructed signal is:
wherein CA w Is the pseudo code variable of the weak signal, and the second cross correlation module of the weak satellite signal tracking module outputsIs I c And Q c The second autocorrelation module outputs I and Q, so that the cross-correlation is mitigated I w 、Q w The way integral result is:
I w ＝I-A·I c
Q w ＝Q-A·Q c
because the algorithm normalizes all strong signal amplitudes by adopting one reference strong signal amplitude, and only one estimation channel is used for carrying out cross-correlation interference estimation on all the strong signals, the hardware cost is reduced, and the hardware implementation is facilitated.
Embodiment III:
the indoor positioning method of the satellite navigation receiver provided by the third embodiment of the present invention, where the satellite navigation receiver is the satellite navigation receiver provided by the first embodiment of the present invention, includes the following steps:
starting up or resetting the satellite navigation receiver from a known position, and capturing each pseudolite signal in a code phase parallel and frequency serial mode; on the premise that the pseudolite system realizes clock synchronization in the network, the pseudolite captured by the satellite navigation receiver should have the same carrier Doppler value, otherwise, the satellite navigation receiver will capture each pseudolite signal again;
after the satellite navigation receiver finishes capturing and traction of each pseudolite at a known position, the satellite navigation receiver is switched into tracking and demodulates a navigation message; after the satellite navigation receiver acquires the coordinates of the satellite from the navigation text of the pseudolite, carrying out static initialization on the carrier integer ambiguity of the satellite navigation receiver, and after all the pseudolites finish the carrier integer ambiguity initialization, completing the static initialization by the satellite navigation receiver;
after the satellite navigation receiver completes static initialization, the satellite navigation receiver freely moves, and the carrier phase measurement value of the pseudolite is extracted in real time;
according to the carrier phase measurement value of the pseudolite, a CHAN algorithm is adopted as a positioning calculation algorithm to realize the indoor positioning of the satellite navigation receiver; when the near-far effect occurs in the moving process, the satellite navigation receiver can adopt the method for resisting the near-far effect of the satellite navigation receiver provided by the second embodiment of the invention to inhibit the near-far effect;
and transmitting the positioning result and the coordinate parameters of each pseudolite to an upper computer for display.
The Chan algorithm is a positioning algorithm based on a TDOA positioning technology and provided with an analytical expression solution, and has good performance when the TDOA error is subjected to ideal Gaussian distribution. TDOA location technology is a method that uses time differences for location.
In the third embodiment of the present invention, the satellite navigation receiver needs to be initialized from a known position, and the initial coordinates of the satellite navigation receiver are assumed to be (x, y), and the coordinates of the ith pseudolite are assumed to be (x i ,y i ) The expression of the carrier integer ambiguity at the initial position is:
wherein [ (S)]Represents a rounding operation, N i0 Indicating the integer ambiguity of the ith pseudolite, or base station, lambda is the carrier wavelength. The carrier phase measurement of the ith pseudolite, i.e., the distance between the satellite navigation receiver and the base station, can be expressed as:
the initial coordinates can be issued by the upper computer through a serial port or obtained by other wireless communication modes. Wherein, the liquid crystal display device comprises a liquid crystal display device,is->Fractional part of->The carrier phase change value after initialization can be obtained by the code ring NCO of the satellite navigation receiver。
According to the carrier phase measurement value of the pseudolite, the positioning of the satellite navigation receiver indoors by adopting the CHAN algorithm as a positioning calculation algorithm can specifically comprise the following steps:
assuming that the signal is within the two-dimensional planar region, the signal is transmitted from the i-th base station (x i ,y i ) To satellite navigation receiver (x, y), the distance R of the satellite navigation receiver to the base station i Is the square of (1)
Wherein, the liquid crystal display device comprises a liquid crystal display device,we mark the difference in distance from the ith base station to the first base station as R i,1 Then
Where c is the speed of light in vacuum, t i,1 Is the time difference of measurement of TDOA.
And because of
When i=1, the number of the cells,
subtracting the formula (2-4) from the formula (2-3) to obtain
Wherein x is i,1 ＝x i -x 1 ，y i,1 ＝y i -y 1 . X, y, R 1 Is regarded as notKnowing the number, equation (2-5) becomes a linear system of equations.
Considering the case of only three base stations, the coordinates (x, y) of the satellite navigation receiver in equation (2-5) can be solved as
Substituting the formula (2-6)In (2) a relation to R can be obtained 1 The positive root of the equation is the position estimate of the satellite navigation receiver. When two positive roots appear in the equation, the false roots can be eliminated according to the information such as the size of the positioning area, the navigation message and the like.
When four or more base stations participate in positioning, the CHAN algorithm fully utilizes redundant TDOA measurements provided by the base stations to optimize positioning results. Is provided withAs an unknown vector, z p ＝[x,y] T For the position of the target to be determined, the error vector obtained by the formula (2-5) is
Wherein, the liquid crystal display device comprises a liquid crystal display device,
{*} 0 is a noiseless measurement, { x } refers to all expressions, n i,1 Indicating measurement noise, there isThe error vector can be expressed as
Wherein, the liquid crystal display device comprises a liquid crystal display device, n is the measurement noise matrix, which is the Schur product. In the practical application, the method has the advantages that,the error vector can be regarded as a random vector approximately following a normal distribution, the covariance of which is
Ψ＝E[ψψ T ]＝c 2 BQB (2-9)
Where Q is the covariance matrix of the TDOA measurement noise. The approximate solution of the Weighted Least Squares (WLS) of equations (2-9) is
If the pending target is far from the base station, define a distance R 0 And (3) withCloser, then B≡R 0 I, I is a unit array. The above can be replaced by
If the target to be determined is closer to the base station, an initial solution can be found by the equations (2-11)To calculate B and then derive satellite navigation receiver position from equations (2-10), the first WLS calculation above.
Next, WLS calculation is continued, and a covariance matrix of the estimated position of the satellite navigation receiver needs to be obtained. In the case of taking into account the noise,
and is also provided withh＝h 0 +Δh due to->The compounds of the formula (2-7) can be formed
Order theSubstituted into (2-10)
Only the linear disturbance of formula (2-14) is retained, and the combination of formulas (2-8) and (2-16) yields ΔZ a And covariance matrix thereof is as follows
When the TDOA measurement error is small, the deviation is negligible, Z a Is a vector with the mean value being the actual value, Z a Elements of (1) can be expressed as
Wherein e 1 ,e 2 ,e 3 Respectively areEstimation error of the component. Will Z a The first two elements are respectively associated with x 1 ,y 1 Subtracting and then squaring the elements to obtain
The upper part is simply described as
ψ′＝h′-G a ′Z a ′ (2-19)
The above equation is approximately true only when the error is relatively small. The covariance matrix of ψ' is
Psi' obeys gaussian distribution as psi, then the second step WLS estimates as
The matrix ψ 'contains the real coordinates of the satellite navigation receiver, and B' can be represented by Z a It is calculated that the data of the first time period,can be obtained by G a Approximate substitution. Substituting the result of the formula (2-21) into the substitution matrix B in the formula (2-9), if the satellite navigation receiver is far away from the base station, Z a Can be expressed as covariance matrix of (2)
In this case, the formula (2-21) can be simplified as
Thus, the final estimate of the satellite navigation receiver position is
Wherein Z is a ' is the error correction amount estimated by the WLS of the second step. And determining the final position of the satellite navigation receiver according to the information such as the size of the positioning area, the navigation message and the like.
The CHAN algorithm can also be generalized to the case of three-dimensional positioning, and will not be described here. The CHAN algorithm is a variant of the least squares method, but has small calculation amount and small hardware cost. The first-order differential result of the carrier phase measurement value between the satellites is used as input, so that positioning calculation can be realized before the satellite navigation receiver and the pseudolite have completed clock synchronization, the influence of clock bias and Zhong Piao of the pseudolite and the satellite navigation receiver is avoided, and the premise is that the pseudolite system has completed time synchronization in the network.
In the invention, as the far and near effect suppression unit comprises a signal reconstruction module, a weak satellite signal tracking module and at least one strong satellite signal tracking module, the strong satellite signal tracking module comprises a first autocorrelation module, a first cross-correlation module, a first subtracter and a second subtracter, the weak satellite signal tracking module comprises a second autocorrelation module, a second cross-correlation module, a third subtracter and a fourth subtracter, the reconstructed signal output end of the first autocorrelation module is connected with the input end of the signal reconstruction module, the amplitude control end of the signal reconstruction module is connected with the control and information processing unit, the control and information processing unit provides amplitude control, and the output end of the signal reconstruction module is connected with the input end of the second cross-correlation module. Therefore, the tracking capability of the satellite navigation receiver for weak satellite signals under the condition of strong interference can be obviously improved, the maximum power value difference value of different pseudolites which are allowed to arrive simultaneously is greatly improved, the near-far effect resistance capability of the satellite navigation receiver is obviously enhanced, and the effective positioning area of the satellite navigation receiver in an indoor pseudolites system is enlarged.
In addition, according to the carrier phase measurement value of the pseudolite, the CHAN algorithm is adopted as a positioning calculation algorithm to realize indoor positioning of the satellite navigation receiver, so that on the premise of realizing time synchronization in the pseudolite system, the influence of the pseudolite system Zhong Piao adopting a constant temperature crystal on a ranging result can be effectively eliminated, and the high-precision positioning can be realized before the satellite navigation receiver and the pseudolite system finish time synchronization, and the method is applicable to various indoor pseudolite systems. And the CHAN calculation amount is smaller than that of a least square method commonly used by a satellite navigation receiver, so that the satellite navigation receiver can realize real-time positioning.
Those of ordinary skill in the art will appreciate that all or a portion of the steps in implementing the methods of the above embodiments may be implemented by a program to instruct related hardware, where the program may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (8)
1. The satellite navigation receiver comprises an antenna unit, a radio frequency unit, a baseband signal processing unit, a control and information processing unit and a man-machine interaction unit which are sequentially connected, and is characterized in that the baseband signal processing unit is provided with a far-near effect suppression unit, the far-near effect suppression unit comprises a signal reconstruction module, a weak satellite signal tracking module and at least one strong satellite signal tracking module, the strong satellite signal tracking module comprises a first autocorrelation module, a first cross-correlation module, a first subtracter and a second subtracter, the weak satellite signal tracking module comprises a second autocorrelation module, a second cross-correlation module, a third subtracter and a fourth subtracter, wherein the input end of the first autocorrelation module and the input end of the second autocorrelation module are respectively connected with the output end of the radio frequency unit, the input signal of the first cross-correlation module is 0, the first output end of the first autocorrelation module and the first output end of the first cross-correlation module are respectively connected with the two input ends of the first subtracter, the second output end of the first autocorrelation module and the second output end of the first subtracter are respectively connected with the two input ends of the second subtracter, the first autocorrelation module and the second signal reconstruction module and the control amplitude of the first subtracter are respectively connected with the first output end of the first cross-correlation module and the second subtracter, the control amplitude of the control unit is connected with the input end of the first cross-correlation module and the first output end of the control signal reconstruction module, the second output end of the second autocorrelation module and the second output end of the second cross correlation module are respectively connected with two input ends of the fourth subtracter, the enabling end of the first autocorrelation module is connected with the control and information processing unit, the control and information processing unit provides enabling control, the amplitude control end of the second cross correlation module is connected with the control and information processing unit, the control and information processing unit provides amplitude control, and the output ends of the first subtracter, the second subtracter, the third subtracter and the fourth subtracter are connected with the control and information processing unit for tracking control of the control and information processing unit;
the first cross-correlation module comprises a carrier digital control oscillator, a pseudo code generator, a third integrator and a fourth integrator, wherein the carrier digital control oscillator generates two paths of orthogonal carriers which are multiplied by an input signal 0 to respectively obtain digital baseband signals of stripped carriers; the pseudo code generator is multiplied by the digital baseband signals of the stripped carrier wave respectively, the multiplied results are used as the input of a third integrator and a fourth integrator respectively, and the output ends of the third integrator and the fourth integrator are used as the first output end and the second output end of the first cross correlation module respectively;
the second cross-correlation module comprises a carrier digital control oscillator, a pseudo code generator, a fifth integrator and a sixth integrator, wherein the carrier digital control oscillator generates two paths of orthogonal carriers to be multiplied by the reconstruction signals output by the signal reconstruction module, and digital baseband signals of the stripped carriers are respectively obtained; the pseudo code generator is multiplied by the digital baseband signals of the stripped carrier respectively, the multiplied results are used as the input of a fifth integrator and a sixth integrator respectively, the output signals of the fifth integrator and the sixth integrator are multiplied by the amplitude control signals provided by the control and information processing unit respectively, and the two multiplied output ends are used as the first output end and the second output end of the second cross-correlation module respectively.
2. The satellite navigation receiver of claim 1, wherein the first autocorrelation module and the second autocorrelation module each comprise a carrier digitally controlled oscillator, a pseudo code generator, a first integrator and a second integrator, the carrier digitally controlled oscillator generating two paths of quadrature carriers to be multiplied by a digital intermediate frequency signal output by the radio frequency unit to obtain digital baseband signals of the stripped carriers, respectively; the pseudo code generator is multiplied by the digital baseband signals of the stripped carrier respectively, the multiplied results are respectively used as the input of a first integrator and a second integrator, and the output ends of the first integrator and the second integrator are respectively used as the first output end and the second output end of the first autocorrelation module and the second autocorrelation module.
3. The satellite navigation receiver of claim 2, wherein the first autocorrelation module further comprises a text predictor, the in-phase branch of the carrier digitally controlled oscillator being multiplied by the pseudo code generator, the text predictor, and an enable signal provided by the control and information processing unit to obtain the reconstructed signal.
4. The satellite navigation receiver of claim 1, wherein the signal reconstruction module comprises N multipliers and 1N input adders sequentially connected, N is a natural number greater than or equal to 1, and the output signal of the first autocorrelation module of each strong satellite signal tracking module is fed into the N input adders after the amplitude of the output signal is controlled by the multipliers; the N-input adder is enabled when the satellite navigation receiver judges that the satellite navigation receiver has far-near effect interference, and outputs a reconstruction signal formed by N paths of reconstruction signals to the second cross-correlation module of the weak satellite signal tracking module at each moment.
5. A method of a satellite navigation receiver against near-far effects, wherein the satellite navigation receiver is a satellite navigation receiver according to any one of claims 1 to 4, the method comprising:
when the carrier-to-noise ratio of the tracked satellite signals is lower than a low threshold, the satellite navigation receiver searches whether the carrier-to-noise ratio of all the tracked satellite signals is higher than Gao Menxian;
if the satellite signal noise ratio of at least one channel is higher than Gao Menxian, determining that the near-far effect occurs, enabling a first autocorrelation module of a strong satellite signal tracking module to output a reconstruction signal by the satellite navigation receiver, enabling a signal reconstruction module to output the reconstruction signal, and sending the reconstruction signal to a second cross correlation module of a weak satellite signal tracking module; in the next tracking interruption, the satellite navigation receiver takes the integration result after the cross-correlation in the weak satellite signal tracking module is lightened as the input of the phase discriminator.
6. The method of claim 5, wherein after the satellite navigation receiver searches for a signal having a noise ratio higher than Gao Menxian among all tracked satellite signals, the method further comprises: if the satellite signal noise ratio without the channel is higher than Gao Menxian, the satellite navigation receiver judges that the near-far effect does not occur, and the coherent integration time of the weak satellite signal tracking module is prolonged.
7. An indoor positioning method of a satellite navigation receiver, wherein the satellite navigation receiver is the satellite navigation receiver according to any one of claims 1 to 4, the method comprising:
starting up or resetting the satellite navigation receiver from a known position, and capturing each pseudolite signal in a code phase parallel and frequency serial mode;
after the satellite navigation receiver finishes capturing and traction of each pseudolite at a known position, the satellite navigation receiver is switched into tracking and demodulates a navigation message; after the satellite navigation receiver acquires the coordinates of the satellite from the navigation text of the pseudolite, carrying out static initialization on the carrier integer ambiguity of the satellite navigation receiver, and after all the pseudolites finish the carrier integer ambiguity initialization, completing the static initialization by the satellite navigation receiver;
after the satellite navigation receiver completes static initialization, the satellite navigation receiver freely moves, and the carrier phase measurement value of the pseudolite is extracted in real time;
according to the carrier phase measurement value of the pseudolite, a CHAN algorithm is adopted as a positioning calculation algorithm to realize the indoor positioning of the satellite navigation receiver;
and transmitting the positioning result and the coordinate parameters of each pseudolite to an upper computer for display.
8. The method of claim 7, wherein the satellite navigation receiver enables a first autocorrelation module of the strong satellite signal tracking module to output a reconstructed signal and enables the signal reconstruction module to output the reconstructed signal and feeds the reconstructed signal into a second cross correlation module of the weak satellite signal tracking module when a near-far effect occurs during the moving process; in the next tracking interruption, the satellite navigation receiver takes the integration result after the cross-correlation in the weak satellite signal tracking module is lightened as the input of the phase discriminator.
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| CN111650553B (en) * | 2020-06-02 | 2023-03-28 | 斯凯瑞利（北京）科技有限公司 | Signal processing system and method for time division multiplexing-based direction estimation of arriving signals |
| CN114740503A (en) * | 2022-04-07 | 2022-07-12 | 中国人民解放军国防科技大学 | Satellite navigation receiver |
| CN115166787A (en) * | 2022-08-04 | 2022-10-11 | 北京交通大学 | Pseudo satellite system capturing device and method |
| CN115356756B (en) * | 2022-10-19 | 2023-07-07 | 中移(上海)信息通信科技有限公司 | Pseudo satellite layout method and device for tunnel and terminal equipment |
Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6160837A (en) * | 1994-12-23 | 2000-12-12 | Itt Manufacturing Enterprises, Inc. | Method of avoiding near-far interference problems in an array of navigation signal beacons having selected CDMA or GPS-like navigation signals |
| DE102005046762A1 (en) * | 2005-09-29 | 2007-04-05 | Siemens Ag | System and method for displaying user information, in particular augmented reality information, with the aid of tracking information stored in RFID data memories |
| JP2009052927A (en) * | 2007-08-24 | 2009-03-12 | Japan Radio Co Ltd | Gps receiver |
| CN101571585A (en) * | 2009-03-18 | 2009-11-04 | 杭州中科微电子有限公司 | Method for eliminating interference signal of GPS receiver and system thereof |
| CN101793968A (en) * | 2010-03-10 | 2010-08-04 | 北京航空航天大学 | Double threshold detection method for weak satellite signal acquisition |
| JP2011058923A (en) * | 2009-09-09 | 2011-03-24 | Japan Radio Co Ltd | Satellite signal receiving apparatus |
| CN102043158A (en) * | 2010-12-17 | 2011-05-04 | 浙江大学 | Signal detection and judgment method and device in capture of weak satellite navigation signal |
| CN102116865A (en) * | 2009-12-30 | 2011-07-06 | 中国科学院微电子研究所 | Supersensitive carrier tracking method for global navigation satellite system (GNSS) signal |
| WO2012092099A2 (en) * | 2010-12-30 | 2012-07-05 | Telcom Ventures, Llc | Systems and methods for a terrestrial-based positioning beacon network |
| CN103176189A (en) * | 2013-03-08 | 2013-06-26 | 浙江大学 | Near-far effect suppressor for high-flexibility satellite navigation receiver and near-far effect suppressing method thereof |
| CN103176191A (en) * | 2013-03-11 | 2013-06-26 | 西北工业大学 | Pseudo-satellite near-far effect inhibition method based on multi-constrained beam forming |
| CN104280749A (en) * | 2014-06-09 | 2015-01-14 | 重庆大学 | SOC-based anti-attack system and anti-attack method of Beidou navigation system receiver |
| CN105388499A (en) * | 2015-10-22 | 2016-03-09 | 交通信息通信技术研究发展中心 | Method for overcoming near-far effect by using double antennas in pseudo-satellite foundation enhancement system |
| CN106291604A (en) * | 2016-08-02 | 2017-01-04 | 桂林电子科技大学 | The improvement code tracking method of satellite navigation signals receiver and loop |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6771214B2 (en) * | 2001-09-12 | 2004-08-03 | Data Fusion Corporation | GPS near-far resistant receiver |
-
2017
- 2017-02-06 CN CN201710066955.0A patent/CN106597492B/en active Active
Patent Citations (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6160837A (en) * | 1994-12-23 | 2000-12-12 | Itt Manufacturing Enterprises, Inc. | Method of avoiding near-far interference problems in an array of navigation signal beacons having selected CDMA or GPS-like navigation signals |
| DE102005046762A1 (en) * | 2005-09-29 | 2007-04-05 | Siemens Ag | System and method for displaying user information, in particular augmented reality information, with the aid of tracking information stored in RFID data memories |
| JP2009052927A (en) * | 2007-08-24 | 2009-03-12 | Japan Radio Co Ltd | Gps receiver |
| CN101571585A (en) * | 2009-03-18 | 2009-11-04 | 杭州中科微电子有限公司 | Method for eliminating interference signal of GPS receiver and system thereof |
| JP2011058923A (en) * | 2009-09-09 | 2011-03-24 | Japan Radio Co Ltd | Satellite signal receiving apparatus |
| CN102116865A (en) * | 2009-12-30 | 2011-07-06 | 中国科学院微电子研究所 | Supersensitive carrier tracking method for global navigation satellite system (GNSS) signal |
| CN101793968A (en) * | 2010-03-10 | 2010-08-04 | 北京航空航天大学 | Double threshold detection method for weak satellite signal acquisition |
| CN102043158A (en) * | 2010-12-17 | 2011-05-04 | 浙江大学 | Signal detection and judgment method and device in capture of weak satellite navigation signal |
| WO2012092099A2 (en) * | 2010-12-30 | 2012-07-05 | Telcom Ventures, Llc | Systems and methods for a terrestrial-based positioning beacon network |
| CN103176189A (en) * | 2013-03-08 | 2013-06-26 | 浙江大学 | Near-far effect suppressor for high-flexibility satellite navigation receiver and near-far effect suppressing method thereof |
| CN103176191A (en) * | 2013-03-11 | 2013-06-26 | 西北工业大学 | Pseudo-satellite near-far effect inhibition method based on multi-constrained beam forming |
| CN104280749A (en) * | 2014-06-09 | 2015-01-14 | 重庆大学 | SOC-based anti-attack system and anti-attack method of Beidou navigation system receiver |
| CN105388499A (en) * | 2015-10-22 | 2016-03-09 | 交通信息通信技术研究发展中心 | Method for overcoming near-far effect by using double antennas in pseudo-satellite foundation enhancement system |
| CN106291604A (en) * | 2016-08-02 | 2017-01-04 | 桂林电子科技大学 | The improvement code tracking method of satellite navigation signals receiver and loop |
Non-Patent Citations (1)
| Title |
|---|
| 黄晖 等."一种新的抗远近效应的盲DS-CDMA接收机".《电子学报》.2000,57-61. * |
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