CN104168040A - Frequency-band-sharing navigation accompanying multiplexing signals and intelligent despreading demodulation method and device - Google Patents
Frequency-band-sharing navigation accompanying multiplexing signals and intelligent despreading demodulation method and device Download PDFInfo
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Abstract
The invention relates to frequency-band-sharing navigation accompanying multiplexing signals, and an intelligent despreading demodulation method and a device used thereby. The method specifically includes the following steps: generating a parasitized signal telegraph text and a parasitic navigation timing telegraph text; modulating parasitized signals and parasitic signals to an intermediate frequency or a radio frequency; and carrying out power control on the parasitic signals, and the like. The intelligent despreading demodulation device includes a parasitic signal generation module, a positioning stamp signal generation module and an intermediate frequency or radio frequency combiner module and the like. Beneficial effects of the method and the device are that the method which realizes pseudo-range measurement and positioning through accompanying navigation positioning signals on a communication broadcast channel uses a pseudo random-code spectrum-spread technology and uses spectrum spread gain to compensate for a condition of low-power parasitism of the accompanying navigation positioning signals. On the premise that parasitized communication broadcast signals are not affected, pseudo distance measurement and positioning can be realized through use of the accompanying navigation positioning signals; and the accompanying navigation positioning signals of pseudo code spectrum spread is elusive and interference resisting.
Description
Technical field
The present invention relates to communication, broadcast and navigation field, is a kind of method and apparatus that utilizes communication or broadcast channel to realize location navigation.
Background technology
At present, satellite navigation system has been widely used in outdoor navigator fix and time service, but between the high building of the street in city, in high and steep mountains, in the deep mountain stream of valley and Jungln Jam, satellite navigation signals can be blocked, signal strength signal intensity can be declined significantly, thereby affects the effect of navigator fix.In the time of particularly under indoor environment, the signal of satellite navigation system be difficult to direct projection enter indoor, even signal through reflection or diffraction after enter indoor, signal strength signal intensity also can be attenuated significantly, signal is very disorderly, and even signal can distort, and is difficult to meet indoor positioning, navigation and time service demand.
And there is stronger signal covering power the base station of land mobile communication broadcast system, both can make up outdoor and be blocked or by the application of some occasion of when decline when satellite navigation signals, also direct most of region in covering chamber, makes up satellite navigation signals and is difficult to the situation in indoor covering.Like this, if can make full use of the signal transmission of land mobile communication system, terrestrial broadcast system and various information sensing nets, just can make up the deficiency of satellite navigation system some regional signal covering power on ground, particularly can make up the navigator fix under indoor environment, thereby realize indoor and outdoor seamless navigation location.
In the prior art, for example application for a patent for invention number is CN201010503298.X, denomination of invention is a kind of satellite navigation locating method, described method comprises: steps A, receive navigation satellite signal, obtain the signal strength signal intensity of current navigation satellite, calculate the current location of described satellite navigation positioning device; Step B, according to the last time resulting current location of receiving satellite signal, the speed of described navigational satellite receiver and the time difference of twice receiving satellite signal, estimates the current location of described satellite navigation positioning device; Step C, according to distance difference and the CEP value between the current location of described calculating gained and the current location of described estimation gained, judges whether the current location of described calculating gained needs to proofread and correct; Step D, if need to proofread and correct the current location of proofreading and correct described satellite navigation positioning device.Adopt after technical scheme of the present invention, by utilizing CEP value under receiver speed and unlike signal intensity to combine, can improve the precision of receiver system to receiver locator data Smoothing fit, can adapt to the various global global position systems such as the Big Dipper and GPS.
And for example in prior art, application for a patent for invention number is CN201310044075.5, denomination of invention is " a kind of Beidou satellite navigation and positioning system radio frequency transceiver ", it is characterized in that comprising: the low-noise amplification circuit connecting successively, the first frequency mixer, external filter, amplifier, I/Q frequency mixer, intermediate frequency variable gain amplifier, low pass filter, 2 analog/digital converters, receiver phase-locked loop, transmitter phase-locked loop; The opener power amplifier, radio frequency attenuator, frequency mixer, the low pass filter that connect successively; And left voltage controlled oscillator, voltage controlled oscillator auto-calibration circuits, right voltage controlled oscillator, 50MHz phase-locked loop, SPI register, upper voltage controlled oscillator, automatic gain control loop; Described frequency mixer, transmitter phase-locked loop, left voltage controlled oscillator, voltage controlled oscillator auto-calibration circuits, right voltage controlled oscillator, 50MHz phase-locked loop connect successively; Described SPI register, voltage controlled oscillator auto-calibration circuits, upper voltage controlled oscillator, receiver phase-locked loop, the first frequency mixer connect successively; Described SPI register is connected with automatic gain control loop; Described automatic gain control loop is connected with intermediate frequency variable gain amplifier.Described receiver phase-locked loop and transmitter phase-locked loop all adopt the voltage controlled oscillator of lc circuit structure.Described radio frequency transceiver is provided with voltage controlled oscillator auto-calibration circuits.Described radio frequency transceiver adopts the power supply with power management function.
Foregoing invention patent application is all difficult to solve satellite navigation system between the high building of the street in city, in high and steep mountains, in the deep mountain stream of valley and the transmission of Jungln Jam, cause satellite navigation signals to be blocked, signal strength signal intensity can be declined significantly, affects the effect of navigator fix.
In the time of particularly under indoor environment, the signal of satellite navigation system is difficult to direct projection and enters indoor and also can be attenuated significantly to signal strength signal intensity, and signal is very disorderly, and even signal can distort, and is difficult to meet the technical barrier that indoor positioning etc. is difficult to go beyond.
Summary of the invention
Head of the present invention puies forward the theory of location stamp signal, be a kind of on existing communication channel the navigation communicating integral signal system of parasitic navigator fix information, the signal generation, transmission, intelligent method and the related device thereof receiving that provide and realized navigation communicating integral, reached the object of utilizing communication channel to realize the seamless location navigation of high accuracy indoor and outdoor.
Concrete technical solution of the present invention is, navigator fix information pseudo noise code band spectrum modulation, and form the location stamp signal that can find range.Pseudo noise code can be the various ways such as Gold code, Walsh code or Chaotic Sequence Code.
Location stamp signal parasitism forms navigation and communicating integral signal to signal of communication, and its parasitic method is divided into two kinds.A kind of is that stamp signal in location mixes the synthesis mode that superposes while transmitting in space with signal of communication; Another kind be after two kinds of each automodulations of signal in intermediate frequency or the synthetic mode of radio frequency, through power amplifier device, amplify again after synthetic, finally from antenna end toward spatial emission.This two classes synthetic method forms conveniently, the device structure of its use is simple.
When navigation communicating integral signal is transferred to user's receiving terminal place, signal is amplified, is downconverted to after intermediate frequency by antenna reception, low-noise amplifier, is sampled into digital signal.Location stamp signal is spread-spectrum signal (spreading gain is designated as A), and location stamp signal level is B lower than the value of signal background level, and B value is generally got lower than more than signal of communication 20dB, and at this moment stamp signal in location can not affect the normal reception of signal of communication.When spreading gain A meets A and subtracts B and be greater than demodulation threshold, just can realize despreading and the demodulation of location stamp signal, the propagation time that can record signal during despreading, obtain signal source to the distance between user, be Positioning Creates condition.
The intensity of parasitic location stamp signal is lower, less on the impact of the signal of communication by parasitic, but the spreading gain of location stamp signal requires to increase accordingly, to guarantee still can meet the requirement of demodulation threshold.The intelligent modulation demodulation method that the present invention proposes, can reduce the requirement to spreading gain.Because during intelligent despreading, try hard to cancellation or most of cancellation by parasitic signal of communication power, while making intelligent despreading, the background-noise level of location stamp signal can significantly reduce.At this moment, constant if the threshold of demodulation requires, to the requirement of spreading gain, just can reduce.If known by parasitic signal of communication or easily identification, want cancellation by parasitic signal of communication, can realize comparatively speaking; If unknown or be difficult to identification by parasitic signal of communication, need to adopt modal analysis method, singular value decomposition method etc. to remove master mode or several less important mode of signals of communication, can reach equally the object of the signal background level that reduces location stamp signal.
The reduction that the navigator fix signal spread-spectrum gain of association is required, the code that be conducive to increase navigator fix information rate, forces down spreading code frequently, reduce by parasitic communication broadcast channel band width, thereby make the navigator fix signal of association and apply more generalization.
The air pressure at the work state information of the numbering that the content of navigator fix information comprises source and position, clock time and correction factor, base station and place, base station, temperature information etc.Navigator fix information can independently be worked out, and also can adopt the navigator fix textual information form of standard, and the navigator fix textual information form of employing standard is conducive to the realization of terminal, is also conducive to the recycling of chip.
Receiver user is measured time delay with pseudo code correlation, and the navigator fix information data of utilizing location text to transmit just can calculate position, speed and the time at its place.The data volume that navigator fix information can transmit is limited, for improving the precision of navigator fix, need to make the position in source and pseudo range measurement obtain more accurate, need to consider that associated arguments has more, more accurate correction means and revise data, need to adopt the error correction parameter of the better VEC of performance, transmission practical requirement for this reason.
The navigation association multiplexed signals and the intelligent despread-and-demodulation method that the present invention proposes a kind of band sharing, concrete steps are as follows:
Step 1, generation, by parasitic signal text and parasitic navigation time service text, comprise following three parts:
1, utilizing existing ripe application apparatus to generate by parasitic signal text, can be the signal of broadcast singal, ground cellular mobile communication signal, satellite communication signal or other types;
2, location and the time service function of utilizing high accuracy navigation Timing Receiver, obtain information source three-dimensional location coordinates information and temporal information, and it is carried out to framing and process generation location stamp text;
3, generate pseudorandom code word, can select the spread spectrum code word of Gold code, Walsh code, chaos sequence or other types;
The Coordinated Universal Time(UTC) that the generation of above text is provided by high accuracy navigation Timing Receiver and pulse per second (PPS), as time reference, are carried out sequencing control by pulse per second (PPS).
Step 2, to being modulated by parasitic signal and parasitic signal, be modulated to intermediate frequency or radio frequency band:
1,, to being modulated by parasitic signal text, modulation system is according to its original system signal system;
2, location stamp text and pseudorandom code word are carried out to XOR, complete band spectrum modulation, then carry out digital to analog conversion by direct sequence synthesis chip, generate intermediate frequency or radiofrequency signal.
Step 3, parasitic signal is carried out to power control, make its power not affect by parasitic signal and normally work.
Step 4, to being closed road by parasitic signal and parasitic signal, process, make the two shared frequency range and channel, generate the pervasive association navigator fix signal existing with multiplexed signals form.
Multiplexed signals behind step 5, involutory road carries out up-conversion, is converted into by the radio frequency band of parasitic signal.
Step 6, the multiplexed signals after up-conversion is carried out to filtering, power amplification, pass through antenna transmission.
Step 7, by antenna reception multiplexed signals, and amplify, filtering processes.
Step 8, to amplifying, filtered multiplexed signals carries out down-conversion, is converted into intermediate frequency or zero intermediate frequency.
Step 9, the multiplexed signals after down-conversion is carried out to shunt, and process respectively.
Step 10, Yi road wherein, by being carried out demodulation by the signal system of parasitic signal, is demodulated to text.
Step 11, another road signal is carried out to SHL intelligence despread-and-demodulation, is specifically divided into following steps:
1, first by buffer, the signal after modulus sampling is kept in to processing by time span;
2, the parasitic text demodulating is modulated according to parasitic signal system, generated original parasitic signal;
3, the parasitic signal regenerating is carried out to inversion operation by inverter, for example, 4 bits represent that decimal number 5 is 0101, and negate is-5, and the complement of two's two's complement is expressed as 1011; 4 bits represent that decimal number-4 are 1100, and negate is 4, and binary system is 0100, carries out 180 degree phase overturns, generate inversion signal, are further:
(1) make the temporary signal of modulus sampling of inversion signal and equal time length carry out sum operation by adder, thereby this is just equivalent to superpose, anti-phase parasitic signal has been removed background noise, remaining parasitic location stamp signal,
(2) to having removed the location stamp signal of background noise, carry out spread spectrum demodulation, obtain navigator fix information.
The location stamp signal by parasitic signal and parasitism of step 12, normal demodulation carries out corresponding further processing separately, is independent of each other.
The navigation association multiplexed signals and the intelligent despread-and-demodulation device that the invention allows for a kind of band sharing, described device is by forming with lower module:
1, parasitic signal generation module, can be broadcast singal exciter, ground cellular mobile communication base band, satellite communication base band or other digital basebands, and described parasitic signal generation module comprises following submodule:
(1) parasitic text generation module, according to the frame format generating digital information of parasitic signal and export parasitic text modulation module to;
(2) parasitic text modulation module, carries out digital to analog conversion according to the signal system of parasitic signal, is modulated to intermediate frequency or radio frequency.
2, location stamp signal generator module, described location stamp signal generator module comprises following submodule:
(1) high accuracy navigation time service module, can be the Big Dipper (GPS) single mode or bimodulus time service module, locating information, time service information is provided, and exports locating information generation module to.Time service module also produces pulse per second (PPS) triggering signal simultaneously, is connected to parasitic text generation module and locating information generation module, as the triggering signal of sequencing control;
(2) locating information generation module, the locating information that time service module is provided and time service information carry out framing processing;
(3) pseudorandom number generation module, storage generates through the filtered code word of pulse-shaping (Gold code, Walsh code or Constructing Chaotic Code);
(4) band spectrum modulation module, locating information generation module and pseudorandom number generation module export the Frame of generation and code word to band spectrum modulation module and carry out XOR, complete band spectrum modulation.
3, intermediate frequency or radio frequency close road module, the signal that parasitic signal generation module and location stamp signal generator module generate exports to and closes road module and close road and process, before radio frequency closes Hai Xuhe road, road module, add up-converter module in this way, the signal that parasitic signal generation module and location stamp signal generator module generate exports first respectively up-converter module to and carries out up-conversion:
(1) up-converter module, closes road module output multiplexed signals to up-converter module, and up-conversion, to the frequency range of parasitic signal, exports radiofrequency emitting module to;
(2) radiofrequency emitting module, is divided into two submodules of power amplifier and antenna, and power amplifier module, carries out power amplification to radiofrequency signal, exports Anneta module to; Anneta module, goes out radiofrequency signal by channels transmit.
4, Receiver Module, is divided into two submodules of Anneta module and low noise amplifier, i.e. Anneta module, and the signal on receive channel, exports low noise amplifier module to; Low noise amplifier module, carries out power amplification to received signal, exports down conversion module to.
5, down conversion module, downconverts to intermediate frequency or zero intermediate frequency by radiofrequency signal, exports splitter (if information source end is to close road at radio frequency, first entering again down conversion module by splitter) to.
6, intermediate frequency or radio frequency shunt module, be divided into two-way by intermediate frequency (zero intermediate frequency) signal or radiofrequency signal after down-conversion, exports respectively parasitic signal receiver module and location stamp signal Despread and demodulator to.
7, parasitic signal receiver module, is divided into two submodules of modulus sampling module and parasitic signal demodulation module:
(1) modulus sampling module, carries out modulus sampling to signal, exports parasitic signal demodulation module to;
(2), parasitic signal demodulation module, parasitic signal is carried out to demodulation, export the parasitic signal modulation module in back end processing module and SHL intelligence Despread and demodulator to.
8, SHL intelligence Despread and demodulator, is divided into modulus sampling module, memory module, parasitic modulation module, background noise removal module and five submodules of spread spectrum demodulation module:
(1) modulus sampling module, carries out modulus sampling to signal, exports memory module to;
(2) memory module, temporary modulus sampled data, exports background noise to and removes module;
(3) parasitic signal modulation module, modulates generation parasitic signal again according to the system of parasitic signal, exports background noise to and removes module;
(4) background noise is removed module, and the data-conversion that parasitic signal modulation module is produced and the data of memory module are added, and remove background noise, export spread spectrum demodulation module to;
(5) spread spectrum demodulation module, carries out despread-and-demodulation to removing background noise signal afterwards, exports rear module to and carries out further application processing.
The present invention has following beneficial effect:
1. the present invention proposes association navigator fix signal on communication broadcast channel and realizes the method for pseudo range measurement and location, has utilized pseudo noise code spread spectrum, makes up the situation of the navigator fix signal low-power parasitism of association with spreading gain.Under not affecting by the prerequisite of parasitic communication broadcast signal, with the navigator fix signal of association, just can realize and survey pseudorange and location.The navigator fix signal of the association of Pseudo Code Spread Spectrum, has disguise and anti-interference.
2. intelligent despread-and-demodulation method can be forced down the signal background noise level containing the mixed signal of the navigator fix signal of association, while making the navigator fix signal of association colonize in communication broadcast channel, be not subject to the restriction of the demodulation threshold under traditional concept, the navigator fix signal of accomplishing association to be demodulated is buried when communication broadcast signal background is following, still can realize demodulating and decoding; Intelligence despread-and-demodulation method can make the navigator fix signal power level value of association very low, still can normal transmission and demodulation.Intelligence despread-and-demodulation method can also be relaxed by the requirement of parasitic communication channel bandwidth, therefore the method for the invention can realize generalization, shown in table 1 specific as follows.
Table 1: the level range that allows the navigator fix signal parasitism of association
3. the navigator fix signal parasitism of association is divided into two kinds to the mode on communication broadcast signal: a kind of is with signal generation module, to generate separately the navigator fix signal of association, and the navigator fix signal of association be modulated to the same frequency range of communication broadcast signal on launch, when two homogenous frequency signals transmit in space, aliasing is synthetic; Another kind be after each automodulation up-conversion of two kinds of signals at radio-frequency head synthesis mode, synthetic after again through power amplification, from antenna toward spatial emission.Above-mentioned synthetic method only need be improved on a small quantity to former communication broadcast equipment and system, and operation is used application easily.
4. the method for the invention and device not only can improve the performance of outdoor positioning system and terminal for outdoor positioning, improve positioning precision; Equally also can meet the location navigation under indoor complex environment for indoor positioning, thereby provide feasible method and apparatus for realizing indoor and outdoor seamless navigation location.
Accompanying drawing explanation
Fig. 1 is navigator fix signal parasitism and the SHL intelligence despread-and-demodulation method workflow schematic diagram that the present invention realizes association;
Fig. 2 is the navigator fix association multiplexed signals of band sharing of the present invention and the intelligent despread-and-demodulation apparatus structure schematic diagram that can filter association signal;
Fig. 3 is that high-precision GNSS of the present invention (Big Dipper or GPS) Timing Receiver forms schematic diagram;
Fig. 4 is that background noise remover of the present invention forms schematic diagram;
Fig. 5 is that extended frequency demodulator of the present invention forms schematic diagram;
Fig. 6 is CMMB broadcast singal frame structure schematic diagram of the present invention;
Fig. 7 is that spread-spectrum signal of the present invention forms structural representation;
Fig. 8 is full frame stack spread-spectrum signal schematic diagram of the present invention;
Fig. 9 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 10 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 11 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 12 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 13 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 14 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 15 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end;
Figure 16 is the comparison schematic diagram of making an uproar in correlation of the present invention and the end.
Embodiment
Below in conjunction with Figure of description 1-16, introduce the embodiment of navigation association multiplexed signals and intelligent despread-and-demodulation method and the device of band sharing of the present invention.
Embodiment 1
Pervasive association navigator fix signal system embodiment based on CMMB broadcast singal system:
As shown in Figure 6, pilot frame is 1 frame per second to CMMB broadcast singal frame structure schematic diagram, and every frame is divided into 40 time slots, and the duration of each time slot is 25ms, comprises beacon message and 53 OFDM symbols of business datum part of frame head part.Beacon signal structure subframe wherein is also shown in Fig. 6, and beacon signal structure subframe comprises sender unit identification (TxID) and two sections of identical synchronizing signals.
The association navigator fix signal structure of spread spectrum as shown in Figure 7, is comprised of locating information and spreading code.Locating information comprises three-dimensional location coordinates information and the temporal information in source, and information code generates location time service spread-spectrum signal through spreading code band spectrum modulation.Wherein three-dimensional location coordinates information can be longitude, latitude, the elevation information under certain coordinate system, or the coordinate under any self-defined coordinate system.Coordinate information can be demarcated in advance, or surveys high means Real-time Obtaining by GPS, baroceptor.Temporal information comprises the UTC time, or gps time, clock correcting information etc.
Owing to need to the normal reception of CMMB broadcast singal not being formed to parasitic framing signal under the prerequisite of disturbing, designed full frame stack parasitic method: full frame stack location spread-spectrum signal on broadcast singal frame structure, as shown in Figure 8.Association navigator fix spread-spectrum signal level is than the low 20dB of CMMB signal, but spreading code code length is that 511 Gold code spreading gains are 10*log10 (511)=27.08dB, can guarantee slightly the catching of spread-spectrum signal, essence is caught and trace demodulation.In try net, through on probation, experimental results show that association signal can catch, follow the tracks of, can measure pseudorange value, for location.
As shown in Figure 1, concrete implementation step is as follows:
1, the CMMB broadcast singal multiplexer in Fig. 2 produces CMMB text coding.
2, the CMMB exciter in Fig. 2 carries out OFDM modulation generation CMMB signal.
3, in Fig. 2, there is high accuracy Timing Receiver generation information source three-dimensional location coordinates information and the temporal information that function is tamed in satellite navigation (Big Dipper or GPS).Timing Receiver as shown in Figure 3, comprises high-precision GNSS (based on the Big Dipper or GPS) Timing Receiver, atomic clock module and clock correction correcting module.GNSS Timing Receiver provides coordinate information, Coordinated Universal Time(UTC) (UTC) and pulse per second (PPS) (1PPS).Because GNSS time service long-term stability is better, short-term stability is poor, better there is long-term skew in atomic clock module short-term stability, therefore taking to tame principle proofreaies and correct atomic clock module, in conjunction with the long steady good and short steady good advantage of atomic clock module of GNSS time service, export high-precision 1PPS, for the CMMB exciter in Fig. 2 and locating information maker provide unified time reference.
4, the pseudorandom number generation device of pseudo noise code in Fig. 2 produces.Pseudorandom number generation device is one group of hardware ROM, and the code word of generation (Gold code, Walsh code or Constructing Chaotic Code) is stored in ROM after pulse-shaping filtering, during use, under code clock drives, reads.
5, by locating information and pseudo noise code, the NOR gate circuit in Fig. 2 is done XOR.
6, through synthetic (DDS) chip of direct sequence, carry out BPSK modulation and DA conversion again, generate location stamp signal.
7, two paths of signals is closed to road by the mixer in Fig. 2 and process, location stamp signal is with form and the stack of CMMB signal of parasitic signal.
8, involutory road signal carries out up-conversion by the upconverter in Fig. 2, is converted to radio frequency band.
9, again radiofrequency signal is passed through to the power amplifier power amplification in Fig. 2.
10, pass through antenna transmission.
In above step, the high accuracy Timing Receiver in the Fig. 2 relating to, CMMB broadcast singal multiplexer, CMMB modulator, DDS chip, mixer, upconverter, power amplifier and transmitting antenna are existing matured product, can directly adopt.Locating information maker, pseudorandom number generation device and NOR gate circuit can be generated by single-chip microcomputer, DSP and FPGA.
The method of the invention and install anti-interference degree analyzing:
The navigator fix spread-spectrum signal of association in full frame stacked system is continuous, is conducive to follow the tracks of, and is conducive to carry out long-time integration processing.The time that full frame stacked system can be done correlation intergal computing is 250 times of left and right (25ms/100 μ s) of segmented mode, and spreading gain has improved 10*log10 (250)=24dB.Full frame stacked system complexity is minimum.
Invention can generally be applicable to other communication and broadcast singal, and the level of parasitic signal and power should appropriately adjust according to the level of original signal structure and power condition.
Example 2
At transmitting terminal, generate on the basis of pervasive association navigator fix signal, receiving terminal takes the SHL intelligence demodulation techniques that signal system adapts therewith to carry out reception & disposal, and as shown in Figure 1, concrete implementation step is as follows:
1, by the reception antenna in Fig. 2, receive signal;
2, by low noise playback amplifier, signal is amplified;
3, after down-conversion, be transformed into intermediate-freuqncy signal;
4, make intermediate-freuqncy signal be divided into two-way by splitter;
5, two paths of signals is carried out to analog-to-digital conversion by modulus sampling A/D chip;
6, demodulation is carried out in normal OFDM mode in a road wherein;
7, decoding output CMMB text;
8, by the background noise remover in Fig. 2, denoising is carried out in another road, by the mode of the anti-phase CMMB signal that superposes, remove CMMB signal, obtain parasitic signal.The composition of background noise remover as shown in Figure 4, first the signal after modulus being sampled by buffer is kept in processing by regular hour length, text after CMMB demodulation is re-started to OFDM according to CMMB agreement by CMMB exciter to be modulated, signal after modulation is passed through to inverter inversion operation, for example: 4 bits represent that decimal number 5 is 0101, negate is-5, and the complement of two's two's complement is expressed as 1011; 4 bits represent that decimal number-4 are 1100, negate is 4, binary system is 0100, carry out 180 degree phase overturns, generate anti-phase CMMB signal, by adder, carry out sum operation with the temporary signal of AD sampling of equal time length again, thereby this CMMB signal that is just equivalent to superpose anti-phase has been removed background noise, remaining parasitic location stamp signal;
9, parasitic location stamp signal is carried out to despreading demodulation processing by extended frequency demodulator in Fig. 2, obtain locating information.The composition of extended frequency demodulator as shown in Figure 5, first carries out code phase by matched filter and slightly catches, and makes initial code phase positions synchronization accuracy <1/2 chip.By carrier loop and code ring, the frequency of carrier wave and code and phase place are carried out to essence tracking again, by the parasitic location of code ring demodulation output stamp text;
10, location stamp decoded message output.
In above step, the reception antenna relating in Fig. 2, low noise amplifier, low-converter, splitter, modulus sampling A/D chip are all chosen as existing matured product, can directly use.CMMB demodulator in Fig. 4 and CMMB exciter are also existing matured product, and remainder can be realized by FPGA hardware circuit.Extended frequency demodulator in Fig. 5 may be selected to the ripe Big Dipper/GPS receiver module or realizes based on FPGA and dsp chip.
Pervasive association navigator fix signal and the emulation of intelligent modulation demodulation techniques:
1. homology produces single carrier communication signal and association navigator fix signal, and this two classes signal is repeatedly mixed, after mixed changing, divides again two-way to carry out being decoded by the despread-and-demodulation of parasitic navigator fix signal, can realize the normal reception to parasitic signal.Constantly reduce the level of parasitic signal, while seeing last losing lock, spurious signal level is with respect to by the size of spurious signal level.Thereby the critical level that can reflect parasitic signal despread-and-demodulation.If communication broadcast signal adopts modulated spread spectrum signal, modulation system is BPSK, and carrier frequency is 20M; Association navigator fix signal adopts the C/A coded signal of GPS, and information data rate is 50bps, and spread-spectrum code rate is 1.023Mchip/s.
In mixed signal, add white Gaussian noise, make signal to noise ratio E/N
ofor 10dB.
(1) when association navigator fix signal is than the low 20dB of communication broadcast signal, mixed signal (signal of communication+location stamp signal+noise) is done relevant (referring to Fig. 9) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 10.5.
(2) when association navigator fix signal is than the low 30dB of communication broadcast signal, mixed signal (signal of communication+location stamp signal+noise) is done relevant (referring to Figure 10) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 5.9.
(3) when association navigator fix signal is than the low 40dB of communication broadcast signal, mixed signal (communication broadcast signal+association navigator fix signal+noise) is done relevant (referring to Figure 11) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 2.3.
(4) when association navigator fix signal is than the low 45dB of communication broadcast signal, mixed signal (communication broadcast signal+association navigator fix signal+noise) is done relevant (referring to Figure 12) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 1.2.Now peak value and secondary lobe can not obviously be distinguished.
(5) in the situation that above-mentioned steps can not have been carried out normal reception, adopt intelligent demodulation techniques, realize the raising of parasitic signal reception level.After success, progressively reduce the power level of parasitic signal, until can not normally receive time.Simulation result demonstrates when association navigator fix signal is during than the low 45dB of signal of communication level, and autocorrelation peak and maximum side petal are almost equal, can not normally receive.In mixed signal, add anti-phase communication or broadcast singal, time delay 1/10 femtosecond (fs), then to C/A code do relevant, obtain be correlated with after signal distribution plots as follows:
When location is stabbed signal than the low 45dB of signal of communication level, mixed signal (signal of communication+location stamp signal+noise) is done relevant (referring to Figure 13) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 1.75.
Association navigator fix signal is lower when more than signal of communication, and relevant peaks peak value and secondary lobe can not obviously be distinguished.
2. in mixed signal, add white Gaussian noise, establish signal to noise ratio E/N
ofor 20dB:
(1) when association navigator fix signal is than the low 45dB of communication broadcast signal, (do not add inversion signal), mixed signal (signal of communication+location stamp signal+noise) is done relevant (referring to Figure 14) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 1.5.
(2) when association navigator fix signal is than the low 50dB of signal of communication (adding inversion signal), mixed signal (communication or broadcast singal+association navigator fix signal+noise) is done relevant (referring to Figure 15) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 2.8.
(3) when association navigator fix signal is than the low 55dB of communication broadcast signal (adding inversion signal), mixed signal (communication broadcast signal+association navigator fix signal+noise) is done relevant (referring to Figure 16) to C/A code, and the mean value that obtains the ratio of auto-correlation peak-peak/maximum side petal is about 1.8.
Result: signal to noise ratio E/N
oduring for 10dB, intelligent demodulation ability can be improved 5dB; Signal to noise ratio E/N
ofor 20dB, intelligent demodulation ability can be improved 10dB.
The invention is not restricted to above-mentioned execution mode, those skilled in the art make to any apparent improvement of above-mentioned execution mode or change, can not exceed the protection range of design of the present invention and claims.
Claims (5)
1. the navigation association multiplexed signals of band sharing and an intelligent despread-and-demodulation method, concrete steps are as follows:
Step 1, generation are by parasitic signal text and parasitic navigation time service text;
Step 2, to being modulated by parasitic signal and parasitic signal, be modulated to intermediate frequency or radio frequency band;
Step 3, parasitic signal is carried out to power control, make its power not affect by parasitic signal and normally work;
Step 4, to being closed road by parasitic signal and parasitic signal, process, make the two shared frequency range and channel, generate the pervasive association navigator fix signal existing with multiplexed signals form;
Multiplexed signals behind step 5, involutory road carries out up-conversion, is converted into by the radio frequency band of parasitic signal;
Step 6, the multiplexed signals after up-conversion is carried out to filtering, power amplification, pass through antenna transmission;
Step 7, by antenna reception multiplexed signals, and amplify, filtering processes;
Step 8, to amplifying, filtered multiplexed signals carries out down-conversion, is converted into intermediate frequency or zero intermediate frequency;
Step 9, the multiplexed signals after down-conversion is carried out to shunt, and process respectively;
Step 10, Yi road wherein, by being carried out demodulation by the signal system of parasitic signal, is demodulated to text;
Step 11, another road signal is carried out to SHL intelligence despread-and-demodulation, first the signal after modulus being sampled by buffer is kept in processing by time span, then the parasitic text demodulating is modulated according to parasitic signal system, generate original parasitic signal, again the parasitic signal regenerating is carried out to inversion operation by inverter, generate inversion signal;
The location stamp signal by parasitic signal and parasitism of step 12, normal demodulation carries out corresponding further processing separately.
2. according to the navigation association multiplexed signals of band sharing described in claim 1 and intelligent despread-and-demodulation method, it is characterized in that, generate described in step 1 by parasitic signal text and parasitic navigation time service text and can be:
2.1 generations can be broadcast singal, ground cellular mobile communication signal, satellite communication signal by parasitic signal text,
2.2 utilize location and the time service function of high accuracy navigation Timing Receiver, obtain information source three-dimensional location coordinates information and temporal information, and it are carried out to framing and process generation location stamp text,
2.3 generate pseudorandom code word, can select the spread spectrum code word of Gold code, Walsh code, chaos sequence or other types; The Coordinated Universal Time(UTC) that the generation of described text is provided by high accuracy navigation Timing Receiver and pulse per second (PPS), as time reference, are carried out sequencing control by pulse per second (PPS).
3. according to the navigation association multiplexed signals of band sharing described in claim 1 and intelligent despread-and-demodulation method, it is characterized in that, to being modulated by parasitic signal and parasitic signal, be modulated in the following manner intermediate frequency or radio frequency band described in step 2:
By parasitic signal text, modulated for 3.1 pairs, modulation system is according to its original system signal system,
3.2 carry out XOR by location stamp text and pseudorandom code word, complete band spectrum modulation, then carry out digital to analog conversion by direct sequence synthesis chip, generate intermediate frequency or radiofrequency signal.
4. according to the navigation association multiplexed signals of band sharing described in claim 1 and intelligent despread-and-demodulation method, it is characterized in that, in step 11, the inversion signal of generation is further:
4.1 make the temporary signal of modulus sampling of inversion signal and equal time length carry out sum operation by adder, thereby sum operation has been equivalent to superpose, anti-phase parasitic signal has been removed background noise, remaining parasitic location stamp signal,
4.2 pairs of location stamp signals of having removed background noise carry out spread spectrum demodulation, obtain navigator fix information.
5. the navigation association multiplexed signals of band sharing and an intelligent despread-and-demodulation device, is characterized in that described intelligent despread-and-demodulation device is by forming with lower module:
(1) parasitic signal generation module, can be broadcast singal exciter, ground cellular mobile communication base band, satellite communication base band or other digital basebands, and described parasitic signal generation module comprises following submodule:
1) parasitic text generation module, according to the frame format generating digital information of parasitic signal and export parasitic text modulation module to,
2) parasitic text modulation module, carries out digital to analog conversion according to the signal system of parasitic signal, is modulated to intermediate frequency or radio frequency;
(2) location stamp signal generator module, described location stamp signal generator module comprises following submodule: high accuracy navigation time service module, described high accuracy navigation time service module can be the Big Dipper (GPS) single mode or bimodulus time service module, locating information is provided, time service information also exports locating information generation module to, described time service module also produces pulse per second (PPS) triggering signal simultaneously, be connected to parasitic text generation module and locating information generation module, triggering signal as sequencing control, the locating information that locating information generation module provides time service module and time service information carry out framing processing, pseudorandom number generation module stores generates through the filtered code word of pulse-shaping, band spectrum modulation module, locating information generation module and pseudorandom number generation module export the Frame of generation and code word to band spectrum modulation module and carry out XOR, complete band spectrum modulation,
(3) intermediate frequency or radio frequency close road module, described in the signal that parasitic signal generation module and location stamp signal generator module generate exports to, close road module and close road processing, before closing Hai Xuhe road, road module, radio frequency adds frequency-variable module in this way, the signal that parasitic signal generation module and location stamp signal generator module generate exports first respectively up-converter module to and carries out up-conversion, the described road module output multiplexed signals that closes is to up-converter module, described up-conversion is to the frequency range of parasitic signal, export radiofrequency emitting module to, described radiofrequency emitting module comprises power amplifier module and Anneta module, described power amplifier module and Anneta module are gone out radiofrequency signal by channels transmit,
(4) Receiver Module comprises: Anneta module and low noise amplifier submodule, signal on described Anneta module receive channel, export low noise amplifier module to, described low noise amplifier module carries out power amplification to received signal, exports down conversion module to;
(5) down conversion module, downconverts to intermediate frequency or zero intermediate frequency by radiofrequency signal, exports splitter to;
(6) intermediate frequency or radio frequency shunt module, be divided into two-way by intermediate-freuqncy signal or radiofrequency signal after down-conversion, exports respectively parasitic signal receiver module and location stamp signal Despread and demodulator to;
(7) parasitic signal receiver module comprises: modulus sampling module and parasitic signal demodulation module, wherein modulus sampling module carries out modulus sampling to signal, export parasitic signal demodulation module to, described parasitic signal demodulation module carries out demodulation to parasitic signal, exports the parasitic signal modulation module in back end processing module and SHL intelligence Despread and demodulator to;
(8) SHL intelligence Despread and demodulator comprises following submodule: modulus sampling module, memory module, parasitic modulation module, background noise is removed module and spread spectrum demodulation module, described modulus sampling module carries out modulus sampling to signal, export memory module to, described memory module is kept in modulus sampled data, export background noise to and remove module, described parasitic signal modulation module is modulated generation parasitic signal again according to the system of parasitic signal, export background noise to and remove module, described background noise is removed module the data of the data-conversion of parasitic signal modulation module generation and memory module is added, remove background noise, export spread spectrum demodulation module to, described spread spectrum demodulation module, to removing background noise signal afterwards, carry out despread-and-demodulation, export rear module to and carry out further application processing.
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