CN109975829A - Variable bandwidth filtering multitone modulating, demodulation method and the system of satellite navigation communication - Google Patents
Variable bandwidth filtering multitone modulating, demodulation method and the system of satellite navigation communication Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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- G—PHYSICS
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- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
- G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
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Abstract
The invention discloses variable bandwidth filtering multitone modulating, demodulation method and the systems of a kind of satellite navigation communication, the variable bandwidth filtering multitone modulating method of the satellite navigation communication includes: that navigation signal and signal of communication are carried out variable bandwidth filtering multitone modulating, obtains the modulated signal transmitted in multi-subband channel；Send the modulated signal；The variable bandwidth filtering multitone demodulation method of the satellite navigation communication includes: the modulated signal for receiving and transmitting in multi-subband channel；Joint demodulation is carried out to the modulated signal, obtains signal of communication and navigation signal.Signal transmission plan proposed by the present invention passes through specially designed variable bandwidth filtering multitone modulating technology, navigation channels and communication channel are unified, navigation subchannel and communications sub-channel is set to coexist under the premise of not changing time-frequency domain structure, to improve the availability of frequency spectrum, the signal rate per road-load wave is reduced, so that the cost on every road and hardware complexity are all reduced.
Description
Technical Field
The invention relates to the technical field of satellite communication, in particular to a method and a system for modulating and demodulating variable bandwidth filtering multitone of satellite navigation communication.
Background
The satellite navigation Positioning technology is widely applied nowadays, and the existing global satellite navigation systems include the gps (global Positioning system) in the united states, the beidou in china, the glonass (global navigation satellite system) in russia, and the Galileo system in europe. However, the existing global navigation satellite system such as GPS only has the capability of sending navigation messages, and does not have the function of data communication. The satellite communication function in the existing navigation system is limited to short data communication, and only simple information transmission can be satisfied. In addition, the communication system and the navigation system in the prior art are separated, and the communication performance cannot be improved all the time due to the fixed configuration of communication resources, and the problems of insufficient communication channels, redundant navigation channels and the like cannot be solved, so that the bottleneck of improving the satellite communication capacity is formed. Meanwhile, the existing design idea of separating navigation communication causes that navigation signals are not easy to conceal and are easy to attack.
When the filtering multi-tone technology (FMT) is used for navigation, methods such as a modulation mode, a channel arrangement mode, a demodulation mode and the like are also preliminarily researched. However, the conventional FMT and other navigation methods based on the conventional multi-carrier modulation have a disadvantage that the subband bandwidth width is constant. Since the positioning accuracy of FMT-based positioning depends on the sub-band bandwidth, the positioning accuracy adjustment of FMT with uniform sub-band bandwidth is relatively limited. In addition, the sub-band width of the FMT is closely related to the doppler and delay resistance thereof. Therefore, the variable bandwidth FMT (VSB-FMT) technology is used for the navigation communication integrated system, so that the system can be used in the environment with various requirements on positioning accuracy, Doppler resistance, time delay resistance and the like, and the robustness of the system is improved.
How to combine the navigation and communication functions of the satellite to realize the optimal configuration of resources and realize high-quality communication and navigation between the satellite and the ground with lower cost and hardware complexity becomes a problem to be solved urgently at the present stage.
Disclosure of Invention
In view of the above-mentioned shortcomings of the prior art, the present invention provides a method and system for modulating and demodulating variable bandwidth filtering multi-tone for satellite navigation communication, which is used to combine the navigation and communication functions of the satellite to realize the optimal configuration of resources, and simultaneously improve the transmission efficiency and the spectrum utilization rate.
In order to achieve the above and other related objects, the present invention provides a method for modulating a variable bandwidth filtering multi-tone for satellite navigation communication, comprising: carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel; and transmitting the modulation signal.
In an embodiment of the present invention, the performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes modulating the navigation signal and the communication signal onto a plurality of subbands with different bandwidths, so that the modulated signal is transmitted in a multi-subband channel.
In an embodiment of the present invention, the multi-subband channels include a navigation subchannel and a communication subchannel.
In an embodiment of the present invention, an implementation manner of the variable bandwidth filtering multi-tone modulation of the navigation signal and the communication signal includes: performing spectrum resource allocation on the navigation signal and the communication signal according to spectrum allocation modes of different sub-bands corresponding to the navigation sub-channel and the communication sub-channel to obtain a primary modulation signal; filtering and shaping the preliminary modulation signal to obtain a filtering processing signal; performing inverse discrete Fourier transform on the filtered signals to obtain IFFT processed signals; and performing parallel-to-serial conversion on the IFFT processing signal to obtain the modulation signal.
In an embodiment of the present invention, the navigation sub-channels include an even number of navigation channels, and each navigation channel corresponds to one sub-band; the communication sub-channels comprise a plurality of communication channels, and each communication channel corresponds to one sub-band; the navigation signal is transmitted in a navigation sub-channel through the sub-band corresponding to the navigation channel; and the communication signal is transmitted in a communication sub-channel through the sub-band corresponding to the communication channel.
The embodiment of the invention also provides a bandwidth-variable filtering multi-tone demodulation method for satellite navigation communication, which comprises the following steps: receiving a modulated signal transmitted in a multi-subband channel; and carrying out joint demodulation on the modulation signals to obtain communication signals and navigation signals.
In an embodiment of the present invention, an implementation manner of the joint demodulation of the modulated signals includes: and sequentially performing serial-parallel transformation, discrete Fourier transformation and matched filtering on the modulation signal to obtain an original communication signal and a navigation signal in the modulation signal.
In an embodiment of the present invention, the method for multi-tone demodulation with variable bandwidth filtering for satellite navigation communication further includes: acquiring, tracking and synchronizing navigation data in the navigation signal; and analyzing the navigation message according to the navigation data to acquire pseudo-range information from the satellite to the ground terminal.
The embodiment of the invention also provides a bandwidth-variable filtering multi-tone modulation system for satellite navigation communication, which comprises: the signal processing and transmitting module: the system is used for carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel and sending the modulation signal.
The embodiment of the invention also provides a bandwidth-variable filtering multi-tone demodulation system for satellite navigation communication, which comprises: the signal receiving and processing module: the method is used for receiving the modulation signals transmitted in the multi-subband channel, and performing joint demodulation on the modulation signals to acquire communication signals and navigation signals.
As described above, the method and system for modulating and demodulating the variable bandwidth filtering multi-tone of the satellite navigation communication according to the present invention have the following advantages:
the signal transmission scheme provided by the invention unifies the navigation channel and the communication channel through a specially designed variable bandwidth filtering multi-tone modulation technology, so that the navigation sub-channel and the communication sub-channel can coexist on the premise of not changing a time-frequency domain structure, the frequency spectrum utilization rate is improved, the signal rate of each path of carrier wave is reduced, the cost and the hardware complexity of each path are reduced, the frequency spectrums of the navigation sub-channel and the communication sub-channel are flexibly distributed to meet various requirements of a satellite navigation communication system, and the anti-interference performance of the satellite navigation communication system is improved.
Drawings
FIG. 1 is a block diagram of VSB-FMT modulation of a navigation signal and a communication signal.
Fig. 2 is a block diagram of VSB-FMT demodulation of a navigation signal and a communication signal.
FIG. 3 is a navigation data processing block diagram.
Fig. 4 shows a spectrum allocation of the navigation sub-channel and the communication sub-channel.
FIG. 5 is a block diagram of a navigation signal correlation process implementation.
Detailed Description
The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It is to be noted that the features in the following embodiments and examples may be combined with each other without conflict.
It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention, and the components related to the present invention are only shown in the drawings rather than drawn according to the number, shape and size of the components in actual implementation, and the type, quantity and proportion of the components in actual implementation may be changed freely, and the layout of the components may be more complicated.
The embodiment provides a method for modulating variable bandwidth filtering multi-tone of satellite navigation communication, which includes:
carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel;
and transmitting the modulation signal.
The navigation signal and the communication signal are uniformly modulated by VSB-FMT (variable bandwidth filtered multitone) in the embodiment, and the VSB-FMT modulation process is shown in FIG. 1.
In this embodiment, the performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes modulating the navigation signal and the communication signal onto a plurality of subbands with different bandwidths, so that the modulated signal is transmitted in a plurality of subband channels.
Wherein the multi-subband channel comprises a navigation subchannel and a communication subchannel.
Specifically, in this embodiment, one implementation manner of performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes:
performing spectrum resource allocation on the navigation signal and the communication signal according to spectrum allocation modes of different sub-bands corresponding to the navigation sub-channel and the communication sub-channel to obtain a primary modulation signal;
filtering and shaping the preliminary modulation signal to obtain a filtering processing signal;
performing inverse discrete Fourier transform on the filtered signals to obtain IFFT processed signals;
and performing parallel-to-serial conversion on the IFFT processing signal to obtain the modulation signal.
In this embodiment, the navigation sub-channels include an even number of navigation channels, and each navigation channel corresponds to one sub-band; the communication sub-channels comprise a plurality of communication channels, and each communication channel corresponds to one sub-band; the navigation signal is transmitted in a navigation sub-channel through the sub-band corresponding to the navigation channel; and the communication signal is transmitted in a communication sub-channel through the sub-band corresponding to the communication channel.
In this embodiment, the channel represents a frequency bandwidth occupied by signal transmission, where a navigation sub-channel corresponds to a frequency segment where a sub-band for transmitting a navigation signal is located, and a communication sub-channel corresponds to a frequency segment where a sub-band for transmitting a communication signal is located, as shown in fig. 4.
The multi-carrier modulation technology is to transmit data in parallel on M sub-channels, so that the symbol duration in each sub-channel is extended to M times of that of single carrier transmission, thereby effectively reducing Inter-symbol Interference (ISI) caused by delay spread, greatly reducing the error rate, and simultaneously reducing the speed requirement of data processing and the hardware complexity.
Variable bandwidth Filtered multitone modulation (VSB-FMT, variable-bandwidth-Filtered multitone modulation) is a carrier format applied to next generation communication systems. The method is characterized in that the frequency spectrums of the sub-channels of the system are not overlapped, and each sub-channel has high frequency spectrum constraint and is insensitive to the frequency deviation of the system. The sub-channel frequency spectrums which are not overlapped with each other in the VSB-FMT system enable Inter-channel Interference (ICI) in a received signal to be negligible, so that the system obtains good ICI resistance performance and facilitates the management of the frequency spectrums.
In terms of implementation structure, VSB-FMT can be efficiently implemented using Inverse Discrete Fourier Transform (IDFT) and Fourier Transform (DFT).
As shown in fig. 1, before VSB-FMT modulation, a matched filtering step is further included, and the matched filtering of the present embodiment is implemented by a Square Root Raised Cosine (SRRC) filter.
The filter design in this embodiment is very critical. In general, filters traditionally need to meet the "perfect reconstruction" constraint to ensure that ISI in the transmission does not affect performance. In this embodiment, a truncated filter is used to perform filtering and shaping, so as to obtain a filtering processing signal. When a plurality of sub-bands are sent out through filters with the same frequency domain structure by using a filter bank technology, the limitation of the filter length by the frequency domain processing complexity can be effectively avoided, and the ISI in signal transmission can not influence the performance.
Further, the present embodiment employs a truncated root raised cosine nyquist filter. Selecting T0Is the symbol period, then f0＝1/2T0At the Nyquist frequency, H (f) is the frequency response. Due to the SRRC property, if the receiving end needs to recover the frequency domain signal, the spectrum of one sub-band needs to include roll-off shaping. Taking the roll-off coefficient as rho, the frequency domain impact response is:
f is derived from the SRRC filter properties1＝(1+ρ)f0For the frequency domain main lobe width, a proper sampling rate needs to be selected to quantify the main lobe width.
In a system, the sampling frequency f is usuallysIs first determined. Then, due to f1＝(1+ρ)f0Then there is fs/f0＝(1+ρ)fs/f1. By choosing the integer M appropriately0＝fs/f0，M1＝fs/f1The parameters of the whole system can be obtained. Wherein M is0Is the number of sampling points within a symbol, M1Is a flag associated with the filter frequency domain. With a time domain filter of
gSRRC(n)＝ifft(H(f),lcd(M0,M1)),0≤n<lcd(M0,M1)；
The filter is a standard form of filter used at a fixed bandwidth. Under VSB-FMT, assuming there are sub-bands of G groups width, the shaping filter is as
η thereingFor variable bandwidth factor, there is k in each group GgAnd (4) sub-bands. After decimation, its shaped filter main lobe width will be wider. In the present embodiment, the navigation signal employs SRRC + QPSK signal. Thus, the navigation sub-signal may be represented as:
wherein,
the pilot signal a (m) is a modulation signal, m is the symbol width of the pilot signal, c is the CDMA spreading code, and the spreading code shown in FIG. 1 is c1(t)，TcFor CDMA spreading code symbol width with a spreading ratio of 2046, i.e., 2046 symbols in each symbol, g denotes an SRRC filter. K in the navigation sub-signal expression has two values, i.e. x (i) represents that two sub-bands at two ends of the frequency band are occupied as shown in fig. 4. A in FIG. 1RAnd (t) is a navigation signal.
The present embodiment performs VSB-FMT modulation on the communication sub-channel and the navigation sub-channel, a in FIG. 1cAnd (t) is a communication signal.
In the time domain, the communication signal ac(t) arranging and transmitting according to the rule as shown in FIG. 4.
In the frequency domain, the FMT sub-band of the communication signal may be further divided into a plurality of sub-bands according to rules, each communication sub-band may independently carry the same or different communication data channels, and the communication sub-band is the smallest frequency domain resource that can be used.
When the integrated satellite navigation communication system based on the variable bandwidth filtering multi-tone modulation is applied to data communication, the sub-band of the VSB-FMT data frame of the communication channel is distributed to each communication client. Each communication client performs signal frame generation according to the pre-allocated sub-bands, and the communication signal transmitted on each sub-band can be written as:
wherein,for the above described SRRC filter, k is the subband number occupied by the frequency domain, and i is the time domain sampling point index.
The above is the processing and modulation process of the navigation signal and the communication signal.
The embodiment also provides a method for demodulating the variable bandwidth filtering multi-tone of the satellite navigation communication, which comprises the following steps:
receiving a modulated signal transmitted in a multi-subband channel;
and carrying out joint demodulation on the modulation signals to obtain communication signals and navigation signals.
Specifically, in this embodiment, one implementation manner of jointly demodulating the modulated signals includes:
and sequentially performing serial-parallel transformation, discrete Fourier transformation and matched filtering on the modulation signal to obtain an original communication signal and a navigation signal in the modulation signal.
In this embodiment, the method for multi-tone demodulation with variable bandwidth filtering for satellite navigation communication further includes:
acquiring, tracking and synchronizing navigation data in the navigation signal; and analyzing the navigation message according to the navigation data to acquire pseudo-range information from the satellite to the ground terminal.
After the communication client receives the modulated signal in the format shown in fig. 4, the modulated signal is first subjected to the VSB-FMT demodulation step shown in fig. 2. The method comprises the steps of performing serial-to-parallel conversion, performing Fourier transform (FFT), and performing matched filtering to obtain an original navigation signal and a communication signal. And after the navigation signal is obtained, the operation steps of capturing, tracking and synchronizing the navigation data in the navigation signal are further carried out, and then the navigation message is analyzed.
The matched filtering as shown in fig. 3 is primarily a filter designed to match the SRRC filter used in FMT modulation.
Wherein the acquisition step mainly comprises a code correlation step and a doppler detection step, as shown in fig. 3.
The tracking process mainly comprises carrier tracking and C/A code tracking. The following is a carrier tracking procedure used in this embodiment.
When the pilot signal is correlated, two symmetrical carriers (I path and Q path) are input as shown in fig. 5, and the local reproduction signal of the in-phase branch (I path) can be represented as
Wherein A isnIs an amplitude value, Δ τ is a time delay, fnIs the carrier frequency and is,is the estimated intermediate frequency.Is the estimated phase of the carrier.
The locally reproduced signal of the quadrature branch (Q-way) can be represented as
Then X (t) is respectively reacted withAndcan be correlated to obtain
And finally, obtaining the output of the phase-locked loop and the frequency-locked loop according to the obtained correlation result so as to obtain the precision required to be estimated. It can be seen that as Δ f changes, the width of the code correlation peak changes correspondingly, and thus the navigation accuracy is affected. The precision of the code correlation peak refers to the prior art, and the theoretical precision can be obtained, namely:
wherein T issIs the symbol time, fscIs the sub-band width, TcIs code time, Es/N0Representing the signal-to-noise ratio. It can be seen that T is adjustedsThe influence on the positioning accuracy is very large. The ZZB theoretical bound can be flexibly adjusted by setting variable bandwidth. Meanwhile, the transmission characteristics of signals with different bandwidths are different. The sub-bandwidth signal has strong Doppler resistance and poor multipath resistance. The system can change the width of the sub-band according to the requirement, compromises are carried out on multiple dimensions such as positioning precision, signal-to-noise ratio, Doppler, multipath and the like, the best transmission scheme is obtained, and the system has more freedom degrees compared with the traditional system which can not change the width of the sub-band.
After the tracking process is completed and synchronization is further realized, the navigation message can be analyzed, and pseudo-range information from the satellite to the ground terminal is obtained. After pseudo-range information from a plurality of (four or more) satellites to the ground terminal is obtained, the position coordinates of the ground terminal can be solved, and positioning is completed.
In order to correspondingly apply the variable bandwidth filtering multi-tone modulation method for satellite navigation communication, an embodiment of the present invention further provides a variable bandwidth filtering multi-tone modulation system for satellite navigation communication, including: the signal processing and transmitting module: the system is used for carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel and sending the modulation signal. The implementation principle of the signal processing and transmitting module is the same as that of the above-mentioned variable bandwidth filtering multi-tone method of satellite navigation communication, and is not described herein again.
In order to correspondingly apply the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication, an embodiment of the present invention further provides a variable bandwidth filtering multi-tone demodulation system for satellite navigation communication, including: the signal receiving and processing module: the method is used for receiving the modulation signals transmitted in the multi-subband channel, and performing joint demodulation on the modulation signals to acquire communication signals and navigation signals.
The implementation principle of the signal receiving and processing module is the same as that of the above-mentioned variable bandwidth filtering multi-tone demodulation method for satellite navigation communication, and is not described herein again.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
In summary, the present embodiment provides a variable bandwidth filtering multi-tone modulation and demodulation method and system for satellite navigation communication with variable bandwidth and balanced navigation and communication performance, so that the method and system can be applied to scenarios such as navigation system backup, emergency communication, navigation signal assisted communication reception, and the like. The signal transmission scheme provided by the embodiment unifies the navigation channel and the communication channel through a specially designed variable bandwidth filtering multi-tone modulation technology, and enables the navigation sub-channel and the communication sub-channel to coexist in one system on the premise of not changing a time-frequency domain structure, so that the frequency spectrum utilization rate is improved, the signal rate of each path of carrier is reduced, the cost and the hardware complexity of each path are reduced, the frequency spectrums of the navigation sub-channel and the communication sub-channel are flexibly distributed to meet various requirements of the system, and the anti-interference performance of the system is improved. Meanwhile, the invention supports that each carrier in the whole combined modulation FMT uses the sub-carriers with different bandwidths, and can ensure that the satellite can service users with different precision requirements and different environments by using sub-bands with different widths, thereby ensuring that the satellite can service the users in more scenes. The satellite in the system is used for data communication at ordinary times, and once other navigation satellites are attacked and cannot be used normally, the satellite is used as a standby satellite of the navigation satellite and plays a navigation role by transmitting a navigation signal. And because the satellite signal contains both the communication signal and the navigation signal, the navigation signal can be well concealed, so that the navigation signal is not easily interfered. The invention can expand the application range and can be applied to single carrier or multi-carrier transmission systems.
Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.
The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.
Claims (10)
1. A method for modulating a variable bandwidth filtering multi-tone of satellite navigation communication is characterized in that the method for modulating the variable bandwidth filtering multi-tone of the satellite navigation communication comprises the following steps:
carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel;
and transmitting the modulation signal.
2. The method of claim 1, wherein the variable bandwidth filtering multi-tone modulating the navigation signal with the communication signal comprises modulating the navigation signal and the communication signal onto subbands having different bandwidths, such that the modulated signal is transmitted in a plurality of subband channels.
3. The method of claim 2, wherein the multi-subband channels comprise navigation subchannels and communication subchannels.
4. The method of claim 3, wherein one implementation of the variable bandwidth filtered multitone modulation of the navigation signal and the communication signal comprises:
performing spectrum resource allocation on the navigation signal and the communication signal according to spectrum allocation modes of different sub-bands corresponding to the navigation sub-channel and the communication sub-channel to obtain a primary modulation signal;
filtering and shaping the preliminary modulation signal to obtain a filtering processing signal;
performing inverse discrete Fourier transform on the filtered signals to obtain IFFT processed signals;
and performing parallel-to-serial conversion on the IFFT processing signal to obtain the modulation signal.
5. The method of claim 3, wherein the navigation sub-channels comprise an even number of navigation channels, each navigation channel corresponding to a sub-band; the communication sub-channels comprise a plurality of communication channels, and each communication channel corresponds to one sub-band; the navigation signal is transmitted in a navigation sub-channel through the sub-band corresponding to the navigation channel; and the communication signal is transmitted in a communication sub-channel through the sub-band corresponding to the communication channel.
6. A method for multi-tone demodulation with variable bandwidth filtering for satellite navigation communication is characterized in that the method for multi-tone demodulation with variable bandwidth filtering for satellite navigation communication comprises the following steps:
receiving a modulated signal transmitted in a multi-subband channel;
and carrying out joint demodulation on the modulation signals to obtain communication signals and navigation signals.
7. The method of claim 6, wherein the jointly demodulating the modulated signals comprises:
and sequentially performing serial-parallel transformation, discrete Fourier transformation and matched filtering on the modulation signal to obtain an original communication signal and a navigation signal in the modulation signal.
8. The method of claim 6, further comprising:
acquiring, tracking and synchronizing navigation data in the navigation signal;
and analyzing the navigation message according to the navigation data to acquire pseudo-range information from the satellite to the ground terminal.
9. A variable bandwidth filtered multitone modulation system for satellite navigation communications, comprising:
the signal processing and transmitting module: the system is used for carrying out variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain a modulation signal transmitted in a multi-subband channel and sending the modulation signal.
10. A variable bandwidth filtered multitone demodulation system for satellite navigation communications, comprising:
the signal receiving and processing module: the method is used for receiving the modulation signals transmitted in the multi-subband channel, and performing joint demodulation on the modulation signals to acquire communication signals and navigation signals.
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| CN111641445A (en) * | 2020-04-17 | 2020-09-08 | 中国人民解放军军事科学院国防科技创新研究院 | Satellite communication and navigation integrated processing system and method |
| CN112578411A (en) * | 2020-11-06 | 2021-03-30 | 中国科学院国家空间科学中心 | Method and system for capturing weak BDS-3B 1C baseband signals |
| CN112737997A (en) * | 2020-12-25 | 2021-04-30 | 上海微波技术研究所（中国电子科技集团公司第五十研究所） | Navigation communication integrated signal waveform construction method and system based on FH-OFDM |
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