CN106656256B - A kind of positioning signal generation method and device - Google Patents

A kind of positioning signal generation method and device Download PDF

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Publication number
CN106656256B
CN106656256B CN201611216882.0A CN201611216882A CN106656256B CN 106656256 B CN106656256 B CN 106656256B CN 201611216882 A CN201611216882 A CN 201611216882A CN 106656256 B CN106656256 B CN 106656256B
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code
spreading code
correlation
value
spreading
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CN106656256A (en
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邓中亮
莫君
贾步云
李三川
刘志超
肖占蒙
边新梅
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Beijing University of Posts and Telecommunications
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Beijing University of Posts and Telecommunications
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/69—Spread spectrum techniques
    • H04B1/707—Spread spectrum techniques using direct sequence modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04J—MULTIPLEX COMMUNICATION
    • H04J13/00—Code division multiplex systems
    • H04J13/10—Code generation

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Mobile Radio Communication Systems (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

An embodiment of the present invention provides a kind of positioning signal generation methods and device, method to include：Transmitting terminal can obtain the ratio of spread-spectrum code rate and information rate according to the spread-spectrum code rate and information rate of acquisition；And according to the first spreading code of acquisition, obtain the first spreading code code length；Then according to ratio and the first spreading code code length, the first spreading code number and the second spreading code code length are obtained, and then according to the second spreading code code length and the first spreading code, generate the second spreading code；Further, according to the first spreading code number, the first spreading code and the second spreading code, target spread spectrum code is generated, wherein target spread spectrum code code length is equal to ratio；Band spectrum modulation is carried out to preset quantity bit navigation message using target spread spectrum code later, generates positioning signal.Using the embodiment of the present invention so that the positioning signal generated with target spread spectrum modulation navigation message is easy to be captured, and improves the acquisition sensitivity to GNSS positioning signals.

Description

A kind of positioning signal generation method and device
Technical field
The present invention relates to fields of communication technology, more particularly to a kind of positioning signal generation method and device.
Background technology
In recent years, LBS (Location Based Service, location-based service) has incorporated in our daily life, GNSS (Global Navigation Satellite System, Global Satellite Navigation System) refers to utilizing navigation satellite, right A kind of navigator fix technology that ocean, ground, spatial user are positioned.Global Satellite Navigation System send positioning signal be A kind of modulated spread spectrum signal.Modulated spread spectrum signal is in transmitting terminal PN (Pseudo-Noise, pseudorandom) code as spreading code What modulation intelligence code generated.
In Global Satellite Navigation System GNSS, direct sequence spread spectrum skill is generally used, in transmitting terminal high-speed Spreading code goes to extend the frequency spectrum of original navigation message signals, is de-spread with identical spreading code in receiving terminal, to exhibition Wide spread-spectrum signal is reduced into original navigation telegraph signal.In engineer application, when the ratio between spread-spectrum code rate and information rate no When being the integral multiple of pseudo noise code code length, new pseudo noise code is obtained frequently with the method for truncating pseudo noise code, and is truncated Pseudo noise code destroy the balance of original pseudo noise code, once pseudo noise code is uneven, spectral characteristic will be deteriorated, with quilt The positioning signal that truncated pseudo-random code spread-spectrum modulation navigation message generates is not easy to be captured, also, in receiving terminal with identical The pseudo noise code being truncated is de-spread, and the autocorrelation of pseudo noise code due to being truncated and cross correlation reduce, further So that positioning signal is not easy to be captured, thus the acquisition sensitivity of GNSS positioning signals is caused to reduce.
Invention content
The embodiment of the present invention is designed to provide a kind of positioning signal generation method and device, is positioned to GNSS with improving The acquisition sensitivity of signal.
In order to achieve the above objectives, an embodiment of the present invention provides a kind of positioning signal generation methods, are applied to global satellite Navigation system GNSS, the GNSS include transmitting terminal and receiving terminal, the method includes：
The transmitting terminal obtains the spread-spectrum code rate and the letter according to the spread-spectrum code rate and information rate of acquisition Cease the ratio of rate；
The transmitting terminal obtains the first spreading code code length according to the first spreading code of acquisition；
The transmitting terminal according to the ratio and the first spreading code code length, obtain the first spreading code number with And the second spreading code code length, wherein the first spreading code number is obtained by the ratio divided by the first spreading code code length The quotient arrived, the second spreading code code length are the ratio divided by the obtained remainder of the first spreading code code length；
The transmitting terminal generates the second spreading code according to the second spreading code code length and first spreading code；
The transmitting terminal generates mesh according to the first spreading code number, first spreading code and second spreading code Mark spreading code, wherein the target spread spectrum code code length is equal to the ratio；
The transmitting terminal carries out band spectrum modulation using the target spread spectrum code to preset quantity bit navigation message, and it is fixed to generate Position signal.
Optionally, the method further includes：
The positioning signal and the data-pushing signal of acquisition are multiplexed by the transmitting terminal with frequency, obtain multiplexed signals；
The multiplexed signals is packaged into signal frame and is sent to receiving terminal by the transmitting terminal, wherein each signal frame includes At least one time slot.
Optionally, which is characterized in that the method further includes：
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital signal by the receiving terminal；
The digital signal and the first spreading code are carried out related operation by the receiving terminal, obtain the first correlation, wherein First correlation is the correlation more than predetermined threshold value；
The receiving terminal determines corresponding first sampling instant of each first correlation, according to first sampling instant, Difference between adjacent first correlation of acquisition two corresponding two neighbouring sample moment；
The case where being equal to target difference for the difference, the receiving terminal obtain noise according to the first default calculation formula Threshold value, wherein the target difference is：First preset value of the second spreading code code length times, alternatively, first spread spectrum The first preset value times of the difference of code code length and the second spreading code code length；
The receiving terminal is determined according to first correlation, first sampling instant and the noise threshold Whether the digital signal meets the condition of being successfully captured；
If it is, the receiving terminal determination captures navigation message.
Optionally, described according to first correlation, first sampling instant and the noise threshold, it determines Whether the digital signal meets the condition of being successfully captured, including；
According to first sampling instant, the initial samples moment is determined；
Obtain the initial samples moment and default sampling instant and value；
Described and value is determined as the destination sample moment；
Judge whether the destination sample moment corresponding target correlation is more than the noise threshold；
If the target correlation is more than the noise threshold, initial samples moment corresponding counter is updated Count value is：The sum of current count value and the second preset value；
Judge whether the count value reaches pre-set count values；
If it is determined that the count value is less than pre-set count values, then updating the destination sample moment is：Current goal is adopted The sum of sample moment and default sampling instant；Return execution is described to judge whether the target correlation is more than the noise threshold The step of, until judging that the count value reaches pre-set count values, determine that the digital signal satisfaction is successfully captured condition.
Optionally, if being more than the noise threshold in the target correlation, initial samples moment correspondence is updated The count value of counter be：Before the sum of current count value and the second preset value, the method further includes：
If the target correlation is less than or equal to the noise threshold, by the corresponding counting of initial samples moment The count value of device resets to preset initial value.
Optionally, the quantity at least two at each initial samples moment, each initial samples moment correspond to one Counter,
It is described to judge whether the count value reaches pre-set count values, including：
When the count value of corresponding counter of at least one initial samples moment reaches pre-set count values, institute is judged It states count value and reaches pre-set count values；
When the count value of corresponding counter of each initial samples moment is not up to pre-set count values, institute is judged It states count value and is not up to pre-set count values.
In order to achieve the above objectives, the embodiment of the present invention additionally provides a kind of positioning signal generating means, which is characterized in that answers For Global Satellite Navigation System GNSS, the GNSS includes transmitting terminal and receiving terminal, and described device includes：
First obtains module, for the transmitting terminal according to the spread-spectrum code rate and information rate of acquisition, described in acquisition The ratio of spread-spectrum code rate and described information rate；
Second obtains module, for the transmitting terminal according to the first spreading code of acquisition, obtains the first spreading code code It is long；
Third obtains module, for the transmitting terminal according to the ratio and the first spreading code code length, obtains institute State the first spreading code number and the second spreading code code length, wherein the first spreading code number is the ratio divided by described The first obtained quotient of spreading code code length, the second spreading code code length are the ratio divided by the first spreading code code length institute Obtained remainder；
First generation module, for the transmitting terminal according to the second spreading code code length and first spreading code, Generate the second spreading code；
Second generation module, for the transmitting terminal according to the first spreading code number, first spreading code and described Second spreading code generates target spread spectrum code, wherein the target spread spectrum code code length is equal to the ratio；
Third generation module, for the transmitting terminal using the target spread spectrum code to preset quantity bit navigation message into Row band spectrum modulation generates positioning signal.
Optionally, described device further includes：
4th obtains module, for the transmitting terminal that the positioning signal and the data-pushing signal of acquisition is multiple with frequency With acquisition multiplexed signals；
The multiplexed signals is packaged into signal frame for the transmitting terminal and is sent to receiving terminal by sending module, wherein every A signal frame includes at least one time slot.
Optionally, described device further includes：
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital signal by conversion module for the receiving terminal；
5th obtains module, and the digital signal and the first spreading code are carried out related operation for the receiving terminal, obtained Obtain the first correlation, wherein first correlation is the correlation more than predetermined threshold value；
6th obtains module, and corresponding first sampling instant of each first correlation is determined for the receiving terminal, according to First sampling instant, the difference between adjacent first correlation of acquisition two corresponding two neighbouring sample moment；
7th obtains module, and for being directed to the case where difference is equal to target difference, the receiving terminal is pre- according to first If calculation formula obtains noise threshold, wherein the target difference is：First preset value of the second spreading code code length Times, alternatively, the first preset value of the difference of the first spreading code code length and the second spreading code code length times；
First determining module, for the receiving terminal according to first correlation, first sampling instant and institute Noise threshold is stated, determines whether the digital signal meets the condition of being successfully captured；
Second determining module is when being for the result in first determining module, and the receiving terminal determination captures Navigation message.
Optionally, first determining module, including；
First determination sub-module, for according to first sampling instant, determining the initial samples moment；
Submodule is obtained, for obtain the initial samples moment and default sampling instant and value；
Second determination sub-module, for described and value to be determined as the destination sample moment；
First judging submodule, for judging whether the destination sample moment corresponding target correlation is more than described make an uproar Glottis limit value；
First update submodule is when being, to update the initial samples moment for the result in first judging submodule The count value of corresponding counter is：The sum of current count value and the second preset value；
Second judgment submodule, for judging whether the count value reaches pre-set count values；
Second update submodule, for when the result of the second judgment submodule is no, updating the destination sample Moment is：The sum of current goal sampling instant and default sampling instant；Return to whether execution is described judges the target correlation The step of more than the noise threshold；Until judging that the count value reaches pre-set count values, determine that the digital signal is full Foot is successfully captured condition.
Optionally, first determining module further includes：
Submodule is reset, is used for when the result of first judging submodule is no, the initial samples moment is corresponding The count value of counter resets to preset initial value.
Optionally, the quantity at least two at each initial samples moment, each initial samples moment correspond to one Counter,
The second judgment submodule, including：
First judging unit, for reaching pre- when the count value of corresponding counter of at least one initial samples moment When design value, judge that the count value reaches pre-set count values；
Second judging unit, the count value for working as corresponding counter of each initial samples moment are not up to pre- When design value, judge that the count value is not up to pre-set count values.
As seen from the above technical solutions, positioning signal generation method provided in an embodiment of the present invention and device, transmitting terminal The ratio of spread-spectrum code rate and information rate can be obtained according to the spread-spectrum code rate and information rate of acquisition；And according to obtaining The first spreading code obtained obtains the first spreading code code length；Then according to ratio and the first spreading code code length, the first spread spectrum is obtained Code number and the second spreading code code length, wherein the first spreading code number is that ratio divided by the first spreading code code length are obtained Quotient, the second spreading code code length are ratio divided by the first obtained remainder of spreading code code length；And then according to the second spreading code code length And first spreading code, generate the second spreading code；Further, according to the first spreading code number, the first spreading code and second Spreading code generates target spread spectrum code, and wherein target spread spectrum code code length is equal to ratio；Utilize target spread spectrum code to preset quantity later Bit navigation message carries out band spectrum modulation, generates positioning signal.As it can be seen that using the embodiment of the present invention, the target spread spectrum code that uses It is made of multiple first spreading codes and second spreading code, and target spread spectrum code code length is equal to spread-spectrum code rate and information speed The ratio of rate, when carrying out band spectrum modulation navigation message using the target spread spectrum code, since target spread spectrum code code length is spread-spectrum code rate With the integral multiple of the ratio between information rate, the target spread spectrum code need not be truncated, the spectral characteristic of target spread spectrum code is not destroyed, because This, is easy to be captured, improves and positioned to GNSS using the positioning signal that the target spread spectrum code band spectrum modulation navigation message generates The acquisition sensitivity of signal.
Description of the drawings
In order to more clearly explain the embodiment of the invention or the technical proposal in the existing technology, to embodiment or will show below There is attached drawing needed in technology description to be briefly described, it should be apparent that, the accompanying drawings in the following description is only this Some embodiments of invention for those of ordinary skill in the art without creative efforts, can be with Obtain other attached drawings according to these attached drawings.
Fig. 1 is a kind of flow diagram of positioning signal generation method provided in an embodiment of the present invention；
Fig. 2 is the flow diagram of another positioning signal generation method provided in an embodiment of the present invention；
Fig. 3 is a kind of structural schematic diagram of signal frame provided in an embodiment of the present invention；
Fig. 4 is the flow diagram of another positioning signal generation method provided in an embodiment of the present invention；
Fig. 5 is the schematic diagram that a kind of parallel matched filters in the prior art carry out related operation；
Fig. 6 is a kind of emulation schematic diagram of correlation result provided in an embodiment of the present invention；
Fig. 7 is the emulation schematic diagram of another correlation result provided in an embodiment of the present invention；
Fig. 8 is a kind of structural schematic diagram of positioning signal generating means provided in an embodiment of the present invention；
Fig. 9 is the structural schematic diagram of another positioning signal generating means provided in an embodiment of the present invention；
Figure 10 is the structural schematic diagram of another positioning signal generating means provided in an embodiment of the present invention.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other Embodiment shall fall within the protection scope of the present invention.
The embodiment of the invention discloses a kind of positioning signal generation method and devices, are applied to Global Satellite Navigation System GNSS, the GNSS include transmitting terminal and receiving terminal, are described in detail separately below.
Referring to Fig. 1, Fig. 1 is a kind of flow diagram of positioning signal generation method provided in an embodiment of the present invention, including Following steps：
S101, transmitting terminal obtain spread-spectrum code rate and information rate according to the spread-spectrum code rate and information rate of acquisition Ratio.
It should be noted that spread-spectrum code rate refers to the transmission rate of target spread spectrum code, information rate refers to navigation message Transmission rate.In engineer application, spread-spectrum code rate is fixed with information rate, and spreading code code length depends on system Spread-spectrum code rate and information rate ratio, in practical applications, the size of spread-spectrum code rate and information rate can basis User demand is previously set, and this is not limited by the present invention.It is existing specifically to set spread-spectrum code rate and the method for information rate There is technology, this will not be repeated here by the present invention.
Exemplary, spread-spectrum code rate 5MHz, information rate 40Hz, the ratio for obtaining spread-spectrum code rate and information rate is 12500。
S102, transmitting terminal obtain the first spreading code code length according to the first spreading code of acquisition.
It should be noted that the first spreading code is a kind of pseudo noise code, also referred to as PN codes.Pseudo noise code have it is good with Machine and correlation function close to white noise, and have advance confirmability and repeatability.These characteristics make it is pseudo- with Machine sequence is widely used, especially in CDMA (Code Division Multiple Access, CDMA) system Spreading code is used as in system.Common pseudo noise code includes：Walsh codes, Gold codes, m-sequence etc..
In practical applications, user can preset the type and the first spreading code code length of the first spreading code, and first After spreading code setting, the first spreading code code length just immobilizes, to which transmitting terminal can be obtained according to the first spreading code of acquisition Obtain the first spreading code code length.First spreading code can be generated by driver, and be transferred to transmitting terminal.Specific driver generates The method of spreading code and the method that spreading code is transferred to transmitting terminal is belonged into the prior art, details are not described herein by the present invention.
In practical applications, the type of the first spreading code and the first spreading code code length can be set according to user demand, This is not limited by the present invention.Specifically the type of the first spreading code and the method for the first spreading code code length are set as existing skill Art, details are not described herein by the present invention.
Illustratively, the first spreading code is Gold codes, and the first spreading code code length is 8191, then transmitting terminal is according to the of acquisition One spreading code, it is 8191 to obtain the first spreading code code length.
S103, transmitting terminal obtain the first spreading code number and the second spread spectrum according to ratio and the first spreading code code length Code code length.
Wherein, the first spreading code number is：Ratio divided by the first obtained quotient of spreading code code length, the second spreading code code length For：Ratio divided by the first obtained remainder of spreading code code length.It is understood that quotient and the remainder are all integer, therefore, with the The code length for the spreading code that several the first spreading codes and second spreading code of one spreading code is composed is equal to the ratio.
Illustratively, ratio 12500, the first spreading code code length are 8191, obtained by ratio divided by the first spreading code code length The quotient arrived is 15, and ratio divided by the first obtained remainder of spreading code code length are 2135, then it is 15 to obtain the first spreading code number, Second spreading code code length is 2135.
S104, transmitting terminal generate the second spreading code according to the second spreading code code length and the first spreading code.
It should be noted that the second spreading code is identical as the type of the first spreading code, but code length is different, can intercept The preceding second spreading code code length chip of one spreading code can also intercept the rear second spreading code code length code of the first spreading code Piece can also intercept the second spreading code code length chip at random, to generate the second spreading code from the first spreading code.It is specific logical The method that interception chip is crossed to generate spreading code is the prior art, and details are not described herein by the present invention.
Illustratively, the first spreading code is Gold codes, and the second spreading code code length is 2135, then intercepts preceding the 2135 of Gold codes A chip, to generate the second spreading code.
S105, transmitting terminal generate target spread spectrum according to the first spreading code number, the first spreading code and the second spreading code Code.
It is understood that being by the first spreading code number：The quotient that ratio divided by the first spreading code code length are obtained, second Spreading code code length is：The remainder that ratio divided by the first spreading code code length are obtained, target spread spectrum code is by the first spreading code and second Spreading code forms, and the number of the first spreading code is the first spreading code number, and the number of the second spreading code is 1, it is seen that is found out, target Spreading code code length is equal to ratio, and therefore, target spread spectrum code code length is the integral multiple of the ratio between spread-spectrum code rate and information rate, i.e. mesh Mark spreading code code length is 1 times of the ratio between spread-spectrum code rate and information rate, so target spread spectrum code is not required to be truncated, Ke Yizhi It connects for band spectrum modulation navigation message, to generate positioning signal.Since target spread spectrum code is not truncated, the auto-correlation of the spreading code Property and cross correlation are not destroyed, and its balance is also uninfluenced, and spectral characteristic is still kept completely, therefore, with this The positioning signal that target spread spectrum code band spectrum modulation navigation message generates is easy captured.
Since ratio is to be determined according to the spread-spectrum code rate and information rate of acquisition, and spread-spectrum code rate is by system Clock frequency determines, it is therefore contemplated that being according to system clock frequency and information rate, to obtain spread-spectrum code rate and letter The ratio of breath rate determines target spread spectrum code code length, when can solve target spread spectrum code length by system according to the ratio in turn The problem of clock frequency constraint.
Can be first continuous arrange there are many first spreading code is combined with the second spreading code in a manner of generating target spread spectrum code The first spreading code of row, then arranges the second spreading code, can also first arrange the second spreading code, and then continuous arrangement first is spread Code, can be with the first spreading code of random alignment and the second spreading code, and the arrangement of specific first spreading code and the second spreading code is suitable Sequence can be arranged according to user demand, and the present invention does not limit this.
Illustratively, the first spreading code number is 15, then first by 15 the first spreading code continuous arrangements, then at the 15th 1 the second spreading code is arranged after first spreading code, to generate target spread spectrum code.
S106, transmitting terminal carry out band spectrum modulation to preset quantity bit navigation message using target spread spectrum code, generate positioning Signal.
It should be noted that GNSS of the embodiment of the present invention generates positioning signal, the positioning based on CDMA using CDMA technology Signal has good anti-noise ability, autocorrelation, and can solve the location problem of wireless communication.CDMA is direct sequence One application of spread spectrum technic.The embodiment of the present invention is in transmitting terminal using target spread spectrum code to preset quantity bit navigation electricity Text carries out band spectrum modulation, to generate positioning signal.Navigation message can be generated by text box, and be transferred to transmitting terminal.Navigation It is included at least in text：Base station IDs, base station coordinates, clock compensation parameter, height auxiliary information and check information.Specific electricity Literary box generates navigation message and the method for being transferred to transmitting terminal is the prior art, and details are not described herein by the present invention.
Illustratively, transmitting terminal modulates 1 bit navigation message using the target spread spectrum code of a cycle, generates positioning letter Number.
As it can be seen that using the embodiment of the present invention, the target spread spectrum code used is spread by multiple first spreading codes and one second Code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate, is expanded using the target spread spectrum code When frequency modulation navigation message, since target spread spectrum code code length is the integral multiple of the ratio between spread-spectrum code rate and information rate, do not need The target spread spectrum code is truncated, the spectral characteristic of target spread spectrum code is not destroyed, therefore, is led using the target spread spectrum code band spectrum modulation The positioning signal that avionics text generates is easy to be captured, and improves the acquisition sensitivity to GNSS positioning signals.
It is to be appreciated that, the spectral characteristic of target spread spectrum code is not destroyed, it is ensured that the cross correlation of spreading code not by It destroys, i.e., anti-multiple access capability is not destroyed, and sensitivity can reflect the antimierophonic ability of GNSS positioning signals.
Referring to Fig. 2, Fig. 2 is the flow diagram of another positioning signal generation method provided in an embodiment of the present invention, this On the basis of invention embodiment illustrated in fig. 2 embodiment shown in Fig. 1, increase S107 and S108.
Positioning signal and the data-pushing signal of acquisition are multiplexed by S107, transmitting terminal with frequency, obtain multiplexed signals.
In order to boost the efficiency of frequency resources utilization, the transmitting terminal of the embodiment of the present invention is by the data-pushing of positioning signal and acquisition Signal is multiplexed with frequency, to obtain multiplexed signals.In practical applications, data-pushing signal can be CMMB (China Mobile Multimedia Broadcasting, China Mobile Multimedia Broadcasting) signal.CMMB is to be based on OFDM The signal of (Orthogonal Frequency Division Multiplexing, orthogonal frequency division multiplexing), CMMB signals have High spectrum utilization and outstanding anti-multipath, anti fading performance.CMMB signals based on OFDM are believed with the positioning based on CDMA It number is multiplexed with frequency, the multiplexed signals obtained is properly termed as TC-OFDM (Time&Code Division-Orthogonal Frequency Division Multiplexing) signal.
It should be noted that the method that transmitting terminal obtains data-pushing signal can be：Data-pushing signal transmitter is given birth to It is pushed to transmitting terminal at CMMB signals, and by CMMB signals.The method that specific transmitting terminal obtains data-pushing signal can root It is designed according to user demand, the present invention does not limit this.
In practical applications, CMMB signals are normally received in order to not influence receiving terminal, can be arranged in positioning signal The mean power of target spread spectrum code is less than the mean power of CMMB signals, and both sides relation can meet following formula：
Wherein, PCMMBIndicate the mean power of CMMB signals, PPNIndicate the power of the mean power of target spread spectrum code.
Illustratively, γ values can be 20dB.
Multiplexed signals is packaged into signal frame and is sent to receiving terminal by S108, transmitting terminal.
In practical applications, each signal frame includes at least one time slot, and the time span of each time slot is fixed, Ke Yiwei 25ms, 30ms etc., specific slot length can be set according to user demand, and the present invention does not limit this.Each time slot In include multiple first spreading codes and second spreading code, the time span of each first spreading code is equal, the first spreading code It is fixed with the time span of the second spreading code, can determine according to the time span of time slot and the number of the first spreading code The time span of one spreading code and the second spreading code.Specifically the structural schematic diagram of signal frame provided in an embodiment of the present invention can be The shown form of Fig. 3.
It is assumed that each signal frame includes n time slot, 1 bit navigation message of each time slot modulation, then a signal frame is the The signal of n time slot can be expressed as：
Wherein,
Wherein, D (t) indicates navigation message, sPNx(t) the first spreading code being superimposed upon on CMMB signals, s are indicatedPNy(t) table Show the second spreading code being superimposed upon on CMMB signals, sCMMBIndicate that CMMB signals, α indicate decay factor, TFIndicate slot length, TLIndicate the time span of the second spreading code.
As it can be seen that using positioning signal generation method provided in an embodiment of the present invention, the target spread spectrum code used is by multiple One spreading code and the second spreading code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate Value, when carrying out band spectrum modulation navigation message using the target spread spectrum code, since target spread spectrum code code length is spread-spectrum code rate and information The integral multiple of the ratio between rate need not truncate the target spread spectrum code, and the spectral characteristic of target spread spectrum code is not destroyed, therefore, is made It is easy to be captured with the positioning signal that the target spread spectrum code band spectrum modulation navigation message generates, improve to GNSS positioning signals Acquisition sensitivity, also, it is further, it is multiplexed with frequency with the positioning signal based on CDMA by the CMMB signals based on OFDM, Improve frequency resource utilization rate.
Referring to Fig. 4, Fig. 4 is the flow diagram of another positioning signal generation method provided in an embodiment of the present invention, this On the basis of invention embodiment illustrated in fig. 4 embodiment shown in Fig. 1, increase S109-S114.
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital signal by S109, receiving terminal.
It should be noted that receiving terminal by the positioning signal of acquisition after radio-frequency front-end down coversion and low-pass filtering treatment, Can obtain complex signal is：
rIF(t)=AIFD(t-τ)c(t-τ)exp{j[2π(fIF+fd)(t-τ)+θIF]}+n(t)
Wherein, rIF(t) complex signal that receiving terminal is obtained in t-th of sampling instant, A are indicatedIFIndicate intermediate-freuqncy signal amplitude, τ Indicate that propagation delay of the signal from transmitting terminal to receiving terminal, D (t- τ) indicate the navigation message of (t- τ) a sampling instant, c (t- τ) indicate first spreading code of (t- τ) a sampling instant, fIFIndicate IF frequency, fdIt indicates to be missed by Doppler frequency shift and crystal oscillator Intermediate frequency frequency deviation caused by difference, θIFIt is intermediate frequency first phase, n (t) is noise signal of the receiving terminal in t-th of sampling instant.
The radio frequency chip that receiving terminal uses can be MTV818, export zero intermediate frequency complex signal, i.e. IF frequency fIFIt is zero Complex signal.Zero intermediate frequency complex signal can obtain digital signal after ADC is converted：
I (n)=aD (n- τ) c (n- τ) sin (2 π fdt(n)+θIF)+ni(n)
Q (n)=aD (n- τ) c (n- τ) cos (2 π fdt(n)+θIF)+nq(n)
Wherein, i (n) indicates that the i railway digital signals of n-th of sampling instant, q (n) indicate the q ways of n-th of sampling instant Word signal, a indicate weight, ni(n) roads the i noise signal of n-th of sampling instant, n are indicatedq(n) q of n-th of sampling instant is indicated Road noise signal.
The positioning signal of acquisition can be first passed through radio-frequency module and received and processed as zero intermediate frequency complex signal by receiving terminal, then It carries out ADC conversions and zero intermediate frequency complex signal is converted into digital signal, and then digital signal is inputted into FPGA (Field Programmable Gate Array, field programmable gate array) carry out localization process.
Also it is the correlation peaks more than one reduced because of non-integral multiple sample strip to improve the resource utilization of FPGA A situation, the digital signal that can be exported radio-frequency module in receiving terminal carry out down-sampled processing, make the sampling of digital signal Rate is reduced to 1/2 or 1/3 or 1/4 of positioning signal sample rate etc..When carrying out down-sampled processing, in order to avoid across when Problem caused by the processing of clock domain, the mode that average filter may be used carry out down-sampled processing, can use down-sampled factor table Show the variation of sample rate, such as：Down-sampled processing is carried out by the way of average filter, and the down-sampled factor is 2, that is, is indicated The sample rate of digital signal is reduced to the 1/2 of positioning signal sample rate.
Digital signal and the first spreading code are carried out related operation by S110, receiving terminal, obtain the first correlation.
It is based on it should be noted that digital signal can be i railway digitals signal and q railway digital signals, the embodiment of the present invention Parallel matched filters carry out the capture of positioning signal, and receiving terminal is by i railway digitals signal and q railway digitals signal with certain sampling Rate is input in parallel matched filters, and the first spreading code is inputted the PARALLEL MATCHING as local code using same sample rate In filter, such as：I railway digitals signal and q railway digitals signal are subjected to the down-sampled processing that the down-sampled factor is 2, obtained Sample rate is：22kHZ, the then sample rate that the first spreading code inputs the parallel matched filters as local code are all：22kHZ. It is thus possible to related operation as shown in Figure 5 be carried out in parallel matched filters, to obtain the first correlation.It is specific logical The process that related operation is crossed to obtain the first correlation is the prior art, and details are not described herein by the present invention.
Illustratively, the related operation of progress can be non-coherent integration operation, and the first correlation of acquisition may include： Maximum related value, secondary big correlation and the third-largest correlation.
Parallel matched filters are a component parts of receiving terminal, are that receiving terminal is used for carrying out related operation to obtain phase Pass value, the length of parallel matched filters is related with the down-sampled factor, the first spreading code code length, the length of parallel matched filters Spending to be：Down-sampled the first spreading codes of factor * code length, related operation can be non-coherent integration, the number of non-coherent integration Related with the down-sampled factor, the first spreading code number, the number of non-coherent integration can be：Down-sampled the first spreading codes of factor * Number+1, the correlation number that a non-coherent integration can obtain are：Down-sampled the first spreading codes of factor * code length.
Illustratively, the down-sampled factor is 2, and the first spreading code code length is 8191, and the first spreading code number is 15, then parallel The length of matched filter can be：2*8191=16382, the number for carrying out non-coherent integration are：2*15+1=31.
In practical applications, the calculation formula of related operation can be：
Wherein, V (n) indicates that the correlation of n-th of sampling instant, N indicate that the length of parallel matched filters, a indicate letter Number range value, R (τ) indicate auto-correlation function, TcohIndicate the time of integration, nIIndicate the roads I noise, nQIndicate that the roads Q noise, τ indicate Propagation delay of the signal from transmitting terminal to receiving terminal, I (n) indicate the coherent integration of n-th of i railway digital signal using the moment Value, Q (n) indicate that the coherent integration value of the q railway digital signals of n-th of sampling instant, C (k) indicate that local code is filtered in PARALLEL MATCHING The value of k-th of position of wave device, in(k) kth of the i railway digitals signal in parallel matched filters of n-th of sampling instant is indicated The value of a position, qn(k) indicate the q railway digitals signal of n-th of sampling instant in k-th of position of parallel matched filters Value.
Application the embodiment of the present invention GNSS carry out indoor positioning when, due to the transmitting terminal of GNSS be it is fixed, Doppler shift between receiving terminal and transmitting terminal is limited, and the crystal oscillator precision of receiving terminal can be by TCXO (Temperature Compensate X'tal (crystal) Oscillator, temperature compensating type quartz-crystal resonator) ensure.Assuming that receiving terminal Movement velocity is 5m/s, carrier frequency 754MHz, TCXO precision 0.1ppm, then maximum frequency deviation fd≤ 110Hz, TcohFor 1.6ms, sinc2(fdTcoh) influence to V (n) is no more than 10%, therefore, when the value maximum of auto-correlation function R (τ), V (n) There is maximum value, since as τ=0, the value of auto-correlation function R (τ) is maximum, and therefore, as τ=0, V (n) has maximum value.When going out When existing code phase synchronization, τ=0, it can be seen that when there is code phase synchronization, correlation peak will occur.
According to related operation as a result, the first correlation can be obtained, wherein the first correlation is more than predetermined threshold value Correlation.
Illustratively, predetermined threshold value 0.9*107, first spreads to Gold codes, code length 8191, the first spreading code number It is 15, carries out the emulation schematic diagram for the operation result that 31 non-coherent integrations obtain as shown in fig. 6, then the first correlation has three It is a, respectively 57378038,66080974,13236589, alternatively, as shown in fig. 7, then there are three the first correlations, respectively 72700825、9558057、63143607。
S111, receiving terminal determine corresponding first sampling instant of each first correlation, according to the first sampling instant, obtain Difference between two adjacent first correlations corresponding two neighbouring sample moment.
It should be noted that according to the calculation formula of related operation, it can obtain in a sampling period, each when sampling The correlation at quarter records the first correlation and first correlation at this time when the correlation of acquisition is the first correlation Corresponding sampling instant, therefore, after a sampling period, receiving terminal can determine each first correlation in the sampling period Corresponding first sampling instant of value, so as to which according to the first sampling instant, it is corresponding to obtain two adjacent first correlations Difference between two neighbouring sample moment.
Illustratively, first 72700825 corresponding first sampling instant of the first correlation is 208, second the first phase Value 9558057 corresponding first sampling instant in pass is 4478, when the first correlation of third 63143607 corresponding first samples It is 12320 to carve, then first difference is 4478-208=4270, and second difference is 12320-4478=12112.
S112, for the difference be equal to target difference the case where, the receiving terminal is obtained according to the first default calculation formula Obtain noise threshold.
Wherein, target difference is：First preset value of the second spreading code code length times, alternatively, the first spreading code code length and the First preset value of the difference of two spreading code code lengths times.It should be noted that user can expand according to the down-sampled factor and second Frequency code code length presets target difference：Down-sampled the second spreading codes of factor * code length；It can also be according to the down-sampled factor, One spreading code code length and the second spreading code code length, presetting target difference is：Down-sampled factor * (the first spread spectrum code lengths-the Two spreading code code lengths).
Illustratively, the first spreading code a length of 8191, the down-sampled factor are 2, and the second spreading code code length is 2135, then target Difference can be：2*2135=4270 can also be：2* (8191-2135)=12112.
In practical applications, the calculating process of noise threshold can be：It is divided to two by the result of last time related operation Section processing, obtains two average value raAnd rb, and take smaller value therein and factor alpharProduct as final noise threshold rnoise, the first default calculation formula can be：
Wherein,
Wherein, αrIndicate coefficient, NnoiseThe correlation number of calculating noise gate is indicated, when V (k) indicates k-th of sampling The correlation at quarter.
It should be noted that calculating the correlation number N of noise gatenoiseIt can be set according to user demand, Ke Yishi Less than the arbitrary value of the second spreading code code length, this is not limited by the present invention.
Whether S113, receiving terminal determine digital signal according to the first correlation, the first sampling instant and noise threshold Satisfaction is successfully captured condition；If so, executing S114.
Specifically, according to the first correlation, the first sampling instant and noise threshold, determine whether digital signal meets It is successfully captured condition, Ke Yiwei；According to the first sampling instant, the initial samples moment is determined；Obtain the initial samples moment with it is pre- If sampling instant and value；It will be determined as the destination sample moment with value；Judging destination sample moment corresponding target correlation is It is no to be more than noise threshold；If target correlation is more than noise threshold, initial samples moment corresponding counter is updated Count value be：The sum of current count value and the second preset value；Judge whether count value reaches pre-set count values；If it is determined that meter Numerical value be less than pre-set count values, update the destination sample moment be：The sum of current goal sampling instant and default sampling instant；It returns Execution judges the step of whether target correlation is more than noise threshold, until judging that count value reaches pre-set count values, determines The digital signal satisfaction is successfully captured condition.
In practical applications, it may be determined that the last one first sampling instant is the initial samples moment, can also determine the One the first sampling instant is the initial samples moment, first sampling instant can also be randomly selected, when as initial samples It carves, this is not limited by the present invention.
Illustratively, there are three the first sampling instants altogether, respectively：208,4478,12320, then it can determine last A first sampling instant 12320 is the initial samples moment.
It should be noted that can be in one initial count value of setting in advance, if update initial samples are not carried out The step of carving the count value of corresponding counter, then current count value is initial count value, when target correlation is more than Noise gate When limit value, then the step of can executing the count value of update initial samples moment corresponding counter, after more new count value, just The count value of the corresponding counter of beginning sampling instant is：The sum of current count value and the second preset value.
Second preset value can be set according to user demand, and it is not limited in the embodiment of the present invention, such as can be 1, Either 2 or 3 equal numerical value.
Illustratively, initial count value 0, the second preset value are 1, are corresponded to if the update initial samples moment is not carried out Counter count value the step of, then current count value be 0, when target correlation be more than noise threshold when, can hold The step of count value of row primary update initial samples moment corresponding counter, after more new count value, the initial samples moment The count value of corresponding counter is：0+1=1.
It is understood that default sampling instant is preset one section of sampling interval point, whenever judging initial samples The count value for carving corresponding counter is less than pre-set count values, is with regard to updating the destination sample moment：Current goal sampling instant with The sum of default sampling instant.The size of default sampling instant can be set according to user demand, and the present invention does not limit this, compared with Good, the size of default sampling instant can be equal to the second spreading code code length.
It is assumed that the initial samples moment is 12320, it is 4270 to preset sampling instant, noise threshold 1111222, second Preset value is 1, preset initial value 0, current count value 14, pre-set count values 15, then the destination sample moment can be： 12320+4270=16590, the correlation for obtaining the 16590th sampling instant is 6612345, and then is more than according to 6612345 1111222, the update initial samples moment count value of corresponding counter is：14+1=15 reaches pre-set count values, determines number Word signal satisfaction is successfully captured condition.
In order to improve the success rate of capture locating signals, in practical applications, make an uproar if can be more than in target correlation Glottis limit value, the then count value for updating initial samples moment corresponding counter are：The sum of current count value and the second preset value Before, increase step：If target correlation is less than or equal to noise threshold, by initial samples moment corresponding counter Count value reset to preset initial value.Preset initial value is the preset count value of user, and specific size can root It is set according to user demand, the present invention does not limit.
Illustratively, preset initial value can be 0.
In order to accelerate the acquisition speed to positioning signal, in practical applications, the quantity at each initial samples moment can be with At least two, each initial samples moment can correspond to a counter, judge whether count value reaches pre-set count values, can Think：When the count value of corresponding counter of at least one initial samples moment reaches pre-set count values, judgement count value reaches To pre-set count values；When the count value of corresponding counter of each initial samples moment is not up to pre-set count values, judgement Count value is not up to pre-set count values.
It should be noted that according to the first sampling instant, first initial samples moment is determined, and then according at the beginning of first Beginning sampling instant determines that other initial samples moment, the number at initial samples moment can set according to user demand, the present invention This is not limited.
According to first initial samples moment, other initial samples moment is determined, can utilize following formula：
Li=L0+i×a×NGS
Wherein, L0Indicate first initial samples moment, LiIndicate the i+1 initial samples moment, a expression it is down-sampled because Son, NGSIndicate the second spreading code code length.
Illustratively, determine that the number at initial samples moment is 4, the down-sampled factor is 2, and the second spreading code code length is 2135, first initial samples moment is 400, then second initial samples moment, third initial samples moment, at the beginning of the 4th Beginning sampling instant is respectively：400+1*2*2135=4670,400+2*2*2135=8940,400+3*2*2135=13210.
S114, receiving terminal determination capture navigation message.
When digital signal satisfaction is successfully captured condition, it may be determined that receiving terminal captures navigation message.
As it can be seen that using the embodiment of the present invention, the target spread spectrum code used is spread by multiple first spreading codes and one second Code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate, is expanded using the target spread spectrum code When frequency modulation navigation message, since target spread spectrum code code length is the integral multiple of the ratio between spread-spectrum code rate and information rate, do not need The target spread spectrum code is truncated, the spectral characteristic of target spread spectrum code is not destroyed, therefore, is led using the target spread spectrum code band spectrum modulation The positioning signal that avionics text generates is easy to be captured, and improves the acquisition sensitivity to GNSS positioning signals, also, further , it improves and is captured as power, accelerates acquisition speed.
Corresponding with above-mentioned embodiment of the method, the embodiment of the present invention also provides a kind of positioning signal generating means, application In Global Satellite Navigation System GNSS, the GNSS includes transmitting terminal and receiving terminal.
Referring to Fig. 8, a kind of structural schematic diagram for positioning signal generating means that Fig. 8 is provided by the embodiment of the present invention, packet It includes：
First obtains module 401, for the transmitting terminal according to the spread-spectrum code rate and information rate of acquisition, obtains institute State the ratio of spread-spectrum code rate and described information rate；
Second obtains module 402, for the transmitting terminal according to the first spreading code of acquisition, obtains first spreading code Code length；
Third obtains module 403, for the transmitting terminal according to the ratio and the first spreading code code length, obtains The first spreading code number and the second spreading code code length, wherein the first spreading code number is the ratio divided by institute The first obtained quotient of spreading code code length is stated, the second spreading code code length is the ratio divided by the first spreading code code length Obtained remainder；
First generation module 404, for the transmitting terminal according to the second spreading code code length and first spread spectrum Code generates the second spreading code；
Second generation module 405, for the transmitting terminal according to the first spreading code number, first spreading code and institute The second spreading code is stated, target spread spectrum code is generated, wherein the target spread spectrum code code length is equal to the ratio；
Third generation module 406, for the transmitting terminal using the target spread spectrum code to preset quantity bit navigation electricity Text carries out band spectrum modulation, generates positioning signal.
As it can be seen that using positioning signal generating means provided in an embodiment of the present invention, the target spread spectrum code used is by multiple One spreading code and the second spreading code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate Value, when carrying out band spectrum modulation navigation message using the target spread spectrum code, since target spread spectrum code code length is spread-spectrum code rate and information The integral multiple of the ratio between rate need not truncate the target spread spectrum code, and the spectral characteristic of target spread spectrum code is not destroyed, therefore, is made It is easy to be captured with the positioning signal that the target spread spectrum code band spectrum modulation navigation message generates, improve to GNSS positioning signals Acquisition sensitivity.
Referring to Fig. 9, Fig. 9 is the structural schematic diagram of another positioning signal generating means provided in an embodiment of the present invention, with Flow shown in Fig. 2 is corresponding, on the basis of Fig. 9 embodiments embodiment shown in Fig. 8 of the present invention, increases the 4th and obtains module 407 and sending module 408.
4th obtains module 407, for the transmitting terminal by the positioning signal and the data-pushing signal of acquisition with frequency Multiplexing obtains multiplexed signals；
The multiplexed signals is packaged into signal frame for the transmitting terminal and is sent to receiving terminal by sending module 408, In, each signal frame includes at least one time slot.
As it can be seen that using positioning signal generating means provided in an embodiment of the present invention, the target spread spectrum code used is by multiple One spreading code and the second spreading code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate Value, when carrying out band spectrum modulation navigation message using the target spread spectrum code, since target spread spectrum code code length is spread-spectrum code rate and information The integral multiple of the ratio between rate need not truncate the target spread spectrum code, and the spectral characteristic of target spread spectrum code is not destroyed, therefore, is made It is easy to be captured with the positioning signal that the target spread spectrum code band spectrum modulation navigation message generates, improve to GNSS positioning signals Acquisition sensitivity, also, it is further, it is multiplexed with frequency with the positioning signal based on CDMA by the CMMB signals based on OFDM, Improve frequency resource utilization rate.
Referring to Figure 10, Figure 10 is the structural schematic diagram of another positioning signal generating means provided in an embodiment of the present invention, Flow as shown in fig. 4 is corresponding, on the basis of Figure 10 embodiments embodiment shown in Fig. 8 of the present invention, increases conversion module 409, the 5th the acquisition acquisition of module the 411, the 7th of module the 410, the 6th module 412, the determination of the first determining module 413, second are obtained Module 414.
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital letter by conversion module 409 for the receiving terminal Number；
5th obtains module 410, and the digital signal and the first spreading code are carried out related operation for the receiving terminal, Obtain the first correlation, wherein first correlation is the correlation more than predetermined threshold value；
6th obtains module 411, and corresponding first sampling instant of each first correlation, root are determined for the receiving terminal According to first sampling instant, the difference between adjacent first correlation of acquisition two corresponding two neighbouring sample moment；
7th obtains module 412, and for being directed to the case where difference is equal to target difference, the receiving terminal is according to first Default calculation formula obtains noise threshold, wherein the target difference is：First preset value of the second spreading code code length Times, alternatively, the first preset value of the difference of the first spreading code code length and the second spreading code code length times；
First determining module 413, for the receiving terminal according to first correlation, first sampling instant and The noise threshold, determines whether the digital signal meets the condition of being successfully captured；
Second determining module 414 is when being for the result in first determining module, and the receiving terminal determines capture To navigation message.
Wherein, first determining module 413, including；
First determination sub-module (not shown), for according to first sampling instant, determining the initial samples moment；
Submodule (not shown) is obtained, for obtain the initial samples moment and default sampling instant and value；
Second determination sub-module (not shown), for described and value to be determined as the destination sample moment；
First judging submodule (not shown), for judging that the destination sample moment corresponding target correlation is It is no to be more than the noise threshold；
First update submodule (not shown) is update when being for the result in first judging submodule The initial samples moment count value of corresponding counter is：The sum of current count value and the second preset value；
Second judgment submodule (not shown), for judging whether the count value reaches pre-set count values；
Second update submodule (not shown), for when the result of the second judgment submodule is no, updating The destination sample moment is：The sum of current goal sampling instant and default sampling instant；It returns and executes the judgement mesh The step of whether corresponding correlation of sampling instant is more than the noise threshold marked；Until judging that the count value reaches default Count value determines that the digital signal satisfaction is successfully captured condition.
Wherein, first determining module 413 can also include；
Submodule (not shown) is reset, for when the result of first judging submodule is no, will initially adopt The sample moment count value of corresponding counter resets to preset initial value.
Wherein, the quantity at least two at each initial samples moment, each initial samples moment correspond to a meter Number device,
The second judgment submodule (not shown), including：
First judging unit (not shown), for working as corresponding counter of at least one initial samples moment When count value reaches pre-set count values, judge that the count value reaches pre-set count values；
Second judging unit (not shown), the counting for working as corresponding counter of each initial samples moment When value is all not up to pre-set count values, judge that the count value is not up to pre-set count values.
As it can be seen that using the embodiment of the present invention, the target spread spectrum code used is spread by multiple first spreading codes and one second Code composition, and target spread spectrum code code length is equal to the ratio of spread-spectrum code rate and information rate, is expanded using the target spread spectrum code When frequency modulation navigation message, since target spread spectrum code code length is the integral multiple of the ratio between spread-spectrum code rate and information rate, do not need The target spread spectrum code is truncated, the spectral characteristic of target spread spectrum code is not destroyed, therefore, is led using the target spread spectrum code band spectrum modulation The positioning signal that avionics text generates is easy to be captured, and improves the acquisition sensitivity to GNSS positioning signals, also, further , it improves and is captured as power, accelerates acquisition speed.
For device embodiments, since it is substantially similar to the method embodiment, so fairly simple, the correlation of description Place illustrates referring to the part of embodiment of the method.
It should be noted that herein, relational terms such as first and second and the like are used merely to a reality Body or operation are distinguished with another entity or operation, are deposited without necessarily requiring or implying between these entities or operation In any actual relationship or order or sequence.Moreover, the terms "include", "comprise" or its any other variant are intended to Non-exclusive inclusion, so that the process, method, article or equipment including a series of elements is not only wanted including those Element, but also include other elements that are not explicitly listed, or further include for this process, method, article or equipment Intrinsic element.In the absence of more restrictions, the element limited by sentence "including a ...", it is not excluded that There is also other identical elements in process, method, article or equipment including the element.
Each embodiment in this specification is all made of relevant mode and describes, identical similar portion between each embodiment Point just to refer each other, and each embodiment focuses on the differences from other embodiments.Especially for system reality For applying example, since it is substantially similar to the method embodiment, so description is fairly simple, related place is referring to embodiment of the method Part explanation.
The foregoing is merely illustrative of the preferred embodiments of the present invention, is not intended to limit the scope of the present invention.It is all Any modification, equivalent replacement, improvement and so within the spirit and principles in the present invention, are all contained in protection scope of the present invention It is interior.

Claims (10)

1. a kind of positioning signal generation method, which is characterized in that include applied to Global Satellite Navigation System GNSS, the GNSS Transmitting terminal and receiving terminal, the method includes：
The transmitting terminal obtains the spread-spectrum code rate and described information speed according to the spread-spectrum code rate and information rate of acquisition The ratio of rate；
The transmitting terminal obtains the first spreading code code length according to the first spreading code of acquisition；
The transmitting terminal obtains the first spreading code number and the according to the ratio and the first spreading code code length Two spreading code code lengths, wherein the first spreading code number is that the ratio divided by the first spreading code code length are obtained Quotient, the second spreading code code length are the ratio divided by the obtained remainder of the first spreading code code length；
The transmitting terminal intercepts the second spreading code code length chip from first spreading code, generates the second spreading code； Wherein, the type of second spreading code is identical as the type of the first spreading code, the second spreading code code length with it is described First spreading code code length is different；
The transmitting terminal generates target and expands according to the first spreading code number, first spreading code and second spreading code Frequency code, wherein the target spread spectrum code code length is equal to the ratio；
The transmitting terminal carries out band spectrum modulation using the target spread spectrum code to preset quantity bit navigation message, generates positioning letter Number.
2. according to the method described in claim 1, it is characterized in that, the method further includes：
The positioning signal and the data-pushing signal of acquisition are multiplexed by the transmitting terminal with frequency, obtain multiplexed signals；
The multiplexed signals is packaged into signal frame and is sent to receiving terminal by the transmitting terminal, wherein each signal frame includes at least One time slot.
3. according to the method described in claim 1, it is characterized in that, the method further includes：
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital signal by the receiving terminal；
The digital signal and the first spreading code are carried out related operation by the receiving terminal, obtain the first correlation, wherein described First correlation is the correlation more than predetermined threshold value；
The receiving terminal determines corresponding first sampling instant of each first correlation, according to first sampling instant, obtains Difference between two adjacent first correlations corresponding two neighbouring sample moment；
The case where being equal to target difference for the difference, the receiving terminal obtain noise gate according to the first default calculation formula Value, wherein the target difference is：First preset value of the second spreading code code length times, alternatively, the first spreading code code The first preset value times of the difference of the long and described second spreading code code length；
The receiving terminal according to first correlation, first sampling instant and the noise threshold, determine described in Whether digital signal meets the condition of being successfully captured；
If it is, the receiving terminal determination captures navigation message.
4. according to the method described in claim 3, it is characterized in that, it is described according to first correlation, it is described first sampling Moment and the noise threshold, determine whether the digital signal meets the condition of being successfully captured, including；
According to first sampling instant, the initial samples moment is determined；
Obtain the initial samples moment and default sampling instant and value；
Described and value is determined as the destination sample moment；
Judge whether the destination sample moment corresponding target correlation is more than the noise threshold；
If the target correlation is more than the noise threshold, the counting of initial samples moment corresponding counter is updated Value is：The sum of current count value and the second preset value；
Judge whether the count value reaches pre-set count values；
If it is determined that the count value is less than pre-set count values, then updating the destination sample moment is：When current goal samples The sum of quarter and default sampling instant；It returns and executes the step for judging the target correlation and whether being more than the noise threshold Suddenly, until judging that the count value reaches pre-set count values, determine that the digital signal satisfaction is successfully captured condition.
5. if according to the method described in claim 4, it is characterized in that, be more than the noise gate in the target correlation Value, the then count value for updating initial samples moment corresponding counter are：Before the sum of current count value and the second preset value, institute The method of stating further includes：
If the target correlation is less than or equal to the noise threshold, by initial samples moment corresponding counter Count value resets to preset initial value.
6. according to the method described in claim 4, it is characterized in that, the quantity at each initial samples moment is at least two A, each initial samples moment corresponds to a counter,
It is described to judge whether the count value reaches pre-set count values, including：
When the count value of corresponding counter of at least one initial samples moment reaches pre-set count values, the meter is judged Numerical value reaches pre-set count values；
When the count value of corresponding counter of each initial samples moment is not up to pre-set count values, the meter is judged Numerical value is not up to pre-set count values.
7. a kind of positioning signal generating means, which is characterized in that include applied to Global Satellite Navigation System GNSS, the GNSS Transmitting terminal and receiving terminal, described device include：
First obtains module, for the transmitting terminal according to the spread-spectrum code rate and information rate of acquisition, obtains the spread spectrum The ratio of bit rate and described information rate；
Second obtains module, for the transmitting terminal according to the first spreading code of acquisition, obtains the first spreading code code length；
Third obtains module, for the transmitting terminal according to the ratio and the first spreading code code length, obtains described the One spreading code number and the second spreading code code length, wherein the first spreading code number is the ratio divided by described first The obtained quotient of spreading code code length, the second spreading code code length are obtained by the ratio divided by the first spreading code code length Remainder；
First generation module intercepts the second spreading code code length code for the transmitting terminal from first spreading code Piece generates the second spreading code；Wherein, the type of second spreading code is identical as the type of the first spreading code, and described Two spreading code code lengths are different from the first spreading code code length；
Second generation module, for the transmitting terminal according to the first spreading code number, first spreading code and described second Spreading code generates target spread spectrum code, wherein the target spread spectrum code code length is equal to the ratio；
Third generation module expands preset quantity bit navigation message using the target spread spectrum code for the transmitting terminal Frequency modulation system generates positioning signal.
8. device according to claim 7, which is characterized in that described device further includes：
4th obtains module, is multiplexed the positioning signal and the data-pushing signal of acquisition with frequency for the transmitting terminal, obtains Obtain multiplexed signals；
The multiplexed signals is packaged into signal frame for the transmitting terminal and is sent to receiving terminal, wherein Mei Gexin by sending module Number frame includes at least one time slot.
9. device according to claim 7, which is characterized in that described device further includes：
The intermediate-freuqncy signal of the positioning signal of acquisition is converted into digital signal by conversion module for the receiving terminal；
5th obtains module, and the digital signal and the first spreading code are carried out related operation for the receiving terminal, obtains the One correlation, wherein first correlation is the correlation more than predetermined threshold value；
6th obtains module, corresponding first sampling instant of each first correlation is determined for the receiving terminal, according to described First sampling instant, the difference between adjacent first correlation of acquisition two corresponding two neighbouring sample moment；
7th obtains module, and for being directed to the case where difference is equal to target difference, the receiving terminal is pre-designed according to first It calculates formula and obtains noise threshold, wherein the target difference is：First preset value of the second spreading code code length times, or First preset value of the difference of person, the first spreading code code length and the second spreading code code length times；
First determining module according to first correlation, first sampling instant and described is made an uproar for the receiving terminal Glottis limit value, determines whether the digital signal meets the condition of being successfully captured；
Second determining module is when being for the result in first determining module, and the receiving terminal determination captures navigation Text.
10. device according to claim 9, which is characterized in that first determining module, including；
First determination sub-module, for according to first sampling instant, determining the initial samples moment；
Submodule is obtained, for obtain the initial samples moment and default sampling instant and value；
Second determination sub-module, for described and value to be determined as the destination sample moment；
First judging submodule, for judging whether the destination sample moment corresponding target correlation is more than the Noise gate Limit value；
First update submodule, is when being for the result in first judging submodule, the update initial samples moment corresponds to The count value of counter be：The sum of current count value and the second preset value；
Second judgment submodule, for judging whether the count value reaches pre-set count values；
Second update submodule, for when the result of the second judgment submodule is no, updating the destination sample moment For：The sum of current goal sampling instant and default sampling instant；Return execution is described to judge whether the target correlation is more than The step of noise threshold, determines that the digital signal meets quilt until judging that the count value reaches pre-set count values Success contact conditions.
CN201611216882.0A 2016-12-26 2016-12-26 A kind of positioning signal generation method and device Active CN106656256B (en)

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