CN109975829A - Variable bandwidth filtering multitone modulating, demodulation method and the system of satellite navigation communication - Google Patents

Abstract

The invention discloses a method and system for variable bandwidth filtering multi-tone modulation and demodulation for satellite navigation communication. The variable bandwidth filtering multi-tone modulation method for satellite navigation communication comprises: subjecting a navigation signal and a communication signal to variable bandwidth filtering multi-tone modulation. modulate to obtain a modulated signal transmitted in a multi-subband channel; send the modulated signal; the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication includes: receiving the modulated signal transmitted in the multi-subband channel; The modulated signal is jointly demodulated to obtain the communication signal and the navigation signal. The signal transmission scheme proposed by the present invention unifies the navigation channel and the communication channel through the specially designed variable-bandwidth filtering multi-tone modulation technology, and enables the navigation sub-channel and the communication sub-channel to coexist without changing the time-frequency domain structure. Thus, the spectrum utilization rate is improved, the signal rate of each carrier is reduced, and the cost and hardware complexity of each channel are reduced.

Description

Variable bandwidth filtering multi-tone modulation and demodulation method and system for satellite navigation communication

technical field

The present invention relates to the technical field of satellite communication, in particular to a method and system for variable bandwidth filtering multi-tone modulation and demodulation of satellite navigation communication.

Background technique

Satellite navigation and positioning technology is widely used today. The existing global satellite navigation systems include GPS (Global Positioning System) in the United States, Beidou in China, GLONASS (GLObal Navigation Satellite System) in Russia, and Galileo in Europe. The existing global satellite navigation systems such as GPS only have the ability to send navigation messages, but do not have the function of data communication. The satellite communication function in the existing navigation system has always been limited to short data communication, which can only meet the transmission of simple information. In addition, the communication system in the prior art is separated from the navigation system, and the fixed configuration of communication resources makes it impossible to improve the communication performance, and cannot solve the problems of insufficient communication channels and redundancy of the navigation channels, which become the bottleneck of satellite communication capability improvement. At the same time, the existing design idea of separation of navigation and communication makes the navigation signal not easy to be concealed and easily attacked.

The modulation method, channel arrangement method, demodulation method and other methods have also been studied initially when the Filtered Multitone Technology (FMT) is used for navigation. But traditional FMT and other navigation methods based on traditional multi-carrier modulation have a disadvantage, that is, their sub-band bandwidth is constant. Since the positioning accuracy of the FMT-based positioning depends on the subband bandwidth, the adjustment of the positioning accuracy of the FMT with the unified subband bandwidth is relatively limited. In addition, the sub-band width of FMT is closely related to its anti-Doppler capability and anti-delay capability. Therefore, the variable bandwidth FMT (VSB-FMT) technology is used in the navigation and communication integrated system, which can enable the system to be used in environments with various requirements such as positioning accuracy, anti-Doppler, and anti-delay, thereby improving system robustness.

How to combine the navigation and communication functions of satellites to achieve the optimal allocation of resources, and to achieve high-quality communication and navigation between satellites and the ground with low cost and hardware complexity has become an urgent problem to be solved at this stage.

SUMMARY OF THE INVENTION

In view of the shortcomings of the above-mentioned prior art, the object of the present invention is to provide a method and system for variable bandwidth filtering multi-tone modulation and demodulation of satellite navigation communication, which are used for combining satellite navigation and communication functions to realize resource optimization configuration, while improving transmission efficiency and spectrum utilization.

In order to achieve the above object and other related purposes, the present invention provides a bandwidth-variable filtering multi-tone modulation method for satellite navigation communication. Filtering the multi-tone modulation to obtain a modulated signal transmitted in a multi-subband channel; sending the modulated signal.

In an embodiment of the present invention, performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes modulating the navigation signal and the communication signal on several subbands with different bandwidths, so that the modulated signal is transmitted in multi-subband channels.

In an embodiment of the present invention, the multi-subband channel includes a navigation subchannel and a communication subchannel.

In an embodiment of the present invention, an implementation manner of performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes: performing the navigation sub-channel and the communication sub-channel on the navigation signal and the communication signal according to the navigation sub-channel and the communication sub-channel. Channels correspond to different spectrum allocation modes of the sub-bands to perform spectrum resource allocation to obtain a preliminary modulated signal; filter and shape the preliminary modulated signal to obtain a filtered signal; perform an inverse discrete Fourier transform on the filtered signal to obtain IFFT processing signal; performing parallel-serial transformation on the IFFT processing signal to obtain the modulated signal.

In an embodiment of the present invention, the navigation sub-channel includes an even number of navigation channels, each of which corresponds to a sub-band; the communication sub-channel includes several communication channels, each of which corresponds to one sub-band; the navigation signal is transmitted in the navigation sub-channel through the sub-band corresponding to the navigation channel; the communication signal is transmitted in the communication sub-channel through the sub-band corresponding to the communication channel.

Embodiments of the present invention also provide a method for variable bandwidth filtering multi-tone demodulation for satellite navigation communication, the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication comprising: receiving modulated signals transmitted in multi-subband channels; The modulated signal is jointly demodulated to obtain a communication signal and a navigation signal.

In an embodiment of the present invention, an implementation manner of jointly demodulating the modulated signal includes: sequentially performing serial-parallel transform, discrete Fourier transform, and matched filtering on the modulated signal to obtain the modulated signal. The original communication and navigation signals in the modulated signal.

In an embodiment of the present invention, the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication further includes: capturing, tracking and synchronizing navigation data in the navigation signal; parsing the navigation message according to the navigation data, Get the pseudorange information from the satellite to the ground.

Embodiments of the present invention also provide a bandwidth-variable filtering multi-tone modulation system for satellite navigation communication, including: a signal processing and sending module: used to perform variable-bandwidth filtering multi-tone modulation on a navigation signal and a communication signal to obtain multi-subband modulation The modulated signal is transmitted in the channel, and the modulated signal is transmitted.

Embodiments of the present invention also provide a variable bandwidth filtering multi-tone demodulation system for satellite navigation communication, including: a signal receiving and processing module: configured to receive a modulated signal transmitted in a multi-subband channel, and perform a modulation on the modulated signal. Joint demodulation to obtain communication signals and navigation signals.

As mentioned above, the variable bandwidth filtering multi-tone modulation and demodulation method and system for satellite navigation communication according to the present invention have the following beneficial effects:

The signal transmission scheme proposed by the present invention unifies the navigation channel and the communication channel through the specially designed variable-bandwidth filtering multi-tone modulation technology, and enables the navigation sub-channel and the communication sub-channel to coexist without changing the time-frequency domain structure. Therefore, the spectrum utilization rate is improved, the signal rate of each carrier is reduced, and the cost and hardware complexity of each channel are reduced. The anti-jamming performance of the satellite navigation communication system is improved.

Description of drawings

Fig. 1 is the VSB-FMT modulation block diagram of the navigation signal and the communication signal.

FIG. 2 is a block diagram of VSB-FMT demodulation of navigation signals and communication signals.

Figure 3 is a block diagram of navigation data processing.

FIG. 4 shows a spectrum allocation method of the navigation sub-channel and the communication sub-channel.

FIG. 5 is a block diagram of the implementation of the navigation signal correlation processing.

Detailed ways

The embodiments of the present invention are described below through specific specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other under the condition of no conflict.

It should be noted that the drawings provided in the following embodiments are only used to illustrate the basic concept of the present invention in a schematic way, so the drawings only show the components related to the present invention rather than the number, shape and number of components in actual implementation. For dimension drawing, the type, quantity and proportion of each component can be changed at will in actual implementation, and the component layout may also be more complicated.

This embodiment provides a bandwidth-variable filtering multi-tone modulation method for satellite navigation communication, and the variable-bandwidth filtering multi-tone modulation method for satellite navigation communication includes:

Perform variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain the modulated signal transmitted in the multi-subband channel;

The modulated signal is sent.

In this embodiment, the navigation signal and the communication signal are uniformly modulated by VSB-FMT (variable bandwidth filter multi-tone), and the VSB-FMT modulation process is shown in FIG. 1 .

In this embodiment, the variable bandwidth filtering multi-tone modulation of the navigation signal and the communication signal includes modulating the navigation signal and the communication signal to several subbands with different bandwidths, so that the modulated signal is in the multi-subband. transmission in the channel.

Wherein, the multi-subband channel includes a navigation subchannel and a communication subchannel.

Specifically, in this embodiment, an implementation manner of performing variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal includes:

Perform spectrum resource allocation on the navigation signal and the communication signal according to the spectrum allocation manners in which the navigation subchannel and the communication subchannel correspond to different subbands, to obtain a preliminary modulated signal;

Filtering and shaping the preliminary modulated signal to obtain a filtered signal;

Perform inverse discrete Fourier transform on the filtered signal to obtain an IFFT processed signal;

Perform parallel-serial conversion on the IFFT processed signal to obtain the modulated signal.

In this embodiment, the navigation sub-channel includes an even number of navigation channels, and each of the navigation channels corresponds to a sub-band; the communication sub-channel includes several communication channels, and each of the communication channels corresponds to a sub-band; The navigation signal is transmitted in the navigation sub-channel through the sub-band corresponding to the navigation channel; the communication signal is transmitted in the communication sub-channel through the sub-band corresponding to the communication channel.

The channel in this embodiment represents the frequency bandwidth occupied by signal transmission, wherein the navigation sub-channel corresponds to the frequency segment where the sub-band for transmitting the navigation signal is located, and the communication sub-channel corresponds to the frequency segment where the sub-band for transmitting the communication signal is located, as shown in FIG. 4 . Show.

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 that of single-carrier transmission, thereby effectively reducing the inter-symbol interference (ISI) caused by delay spreading. , Inter-symbol Interference), which greatly reduces the bit error rate, and also reduces the speed requirements and hardware complexity of data processing.

Varaible-Subband Filtered Multitone Modulation (VSB-FMT) is a carrier format used in next-generation communication systems. Its characteristic is that the sub-channel spectrum of the system does not overlap with each other, each sub-channel has a high spectrum constraint, and is not sensitive to the system frequency deviation. The non-overlapping sub-channel spectrum of the VSB-FMT system makes the Inter channel Interference (ICI, Inter channel Interference) in the received signal negligible, which enables the system to obtain good anti-ICI performance and facilitates spectrum management.

In terms of implementation structure, VSB-FMT can be efficiently implemented with Inverse Discrete Fourier Transform (IDFT, Inversed Discrete Fourier Transform) and Fourier Transform (DFT, Discrete Fourier Transform).

As shown in FIG. 1 , a matched filtering step is also included before the VSB-FMT modulation is performed, and the matched filtering in this embodiment is implemented by a square root raised cosine (SRRC) filter.

The filter design in this embodiment is very critical. In general, filters are traditionally required to meet the "perfect reconstruction" constraint to ensure that ISI in transmission does not affect performance. In this embodiment, a truncated filter is used to perform filtering and shaping to obtain a filtered signal. When multiple subbands are sent out through filters with the same frequency domain structure through the filter bank technology, the filter length can be effectively prevented from being limited by the frequency domain processing complexity, and the ISI in signal transmission will not affect the performance.

Further, a truncated root raised cosine Nyquist filter is used in this embodiment. Select T ₀ as the symbol period, then f ₀ =1/2T ₀ is the Nyquist frequency, and H(f) is the frequency response. Due to the properties of SRRC, if the receiving end needs to restore the frequency domain signal, the spectrum of one subband needs to include roll-off shaping. Taking the roll-off coefficient as ρ, the impulse response in the frequency domain is:

According to the properties of the SRRC filter, f ₁ =(1+ρ)f ₀ is the main lobe width in the frequency domain. In order to quantify the main lobe width, an appropriate sampling rate needs to be selected.

In a system, usually the sampling frequency _fs is first determined. Then, since f ₁ =(1+ρ)f ₀ , there is f _s /f ₀ =(1+ρ)f _s /f ₁ . By properly selecting integers M ₀ =f _s /f ₀ and M ₁ =f _s /f ₁ , the parameters of the entire system can be obtained. Among them, M ₀ is the number of sampling points in a symbol, and M ₁ is a mark related to the frequency domain of the filter. Its time domain filter is

g _SRRC (n)=ifft(H(f), lcd(M ₀ , M ₁ )), 0≤n<lcd(M ₀ , M ₁ );

This filter is the standard form of using a filter with a fixed bandwidth. Under VSB-FMT, assuming that there are subbands with a width of G group, the shaping filter is

where η _g is the variable bandwidth multiple, and there are k _g subbands in each group G. After decimation, its shaping filter main lobe width will be wider. In this embodiment, the navigation signal adopts SRRC+QPSK signal. Therefore, the navigation sub-signal can be expressed as:

in,

The navigation signal a(m) is the modulation signal, m is the symbol width of the navigation signal, c is the CDMA spreading code, the spreading code shown in Figure 1 is c ₁ (t), and T _c is the CDMA spreading code element width, where the spreading ratio is 2046, that is, there are 2046 symbols in each symbol, and g represents the SRRC filter. The k in the expression of the navigation sub-signal has two values, that is, it means that x(i) occupies two subbands at both ends of the frequency band as shown in FIG. 4 . In Figure 1, a _R (t) is the navigation signal.

In this embodiment, VSB-FMT modulation is performed on the communication sub-channel and the navigation sub-channel, and a _c (t) in FIG. 1 is a communication signal.

In the time domain, the communication signals a _c (t) are arranged and transmitted according to the rules shown in FIG. 4 .

In the frequency domain, the FMT sub-band of the communication signal can also be divided into several sub-bands according to the rules. Each communication sub-band can independently carry the same or different communication data channels. The communication sub-band is the minimum frequency domain resource that can be used.

When the integrated satellite navigation and communication system based on variable bandwidth filtering and multi-tone modulation is applied to data communication, the sub-band of the communication channel VSB-FMT data frame is allocated to each communication client. Each communication client generates a signal frame according to the pre-assigned subband, and the communication signal transmitted on each subband can be written as:

in, is the SRRC filter described above, k is the subband number occupied in the frequency domain, and i is the sample point label in the time domain.

The above is the processing and modulation process of the navigation signal and the communication signal.

This embodiment also provides a variable bandwidth filtering multi-tone demodulation method for satellite navigation communication, and the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication includes:

receiving a modulated signal transmitted in a multi-subband channel;

The modulated signal is jointly demodulated to obtain a communication signal and a navigation signal.

Specifically, in this embodiment, an implementation manner of jointly demodulating the modulated signal includes:

Serial-parallel transform, discrete Fourier transform and matched filtering are performed on the modulated signal in sequence to obtain the original communication signal and navigation signal in the modulated signal.

In this embodiment, the variable bandwidth filtering multi-tone demodulation method for satellite navigation communication further includes:

The navigation data in the navigation signal is captured, tracked, and synchronized; the navigation message is analyzed according to the navigation data, and the pseudo-range information from the satellite to the ground terminal is obtained.

After the communication client receives the modulated signal in the format shown in FIG. 4 , it first performs the VSB-FMT demodulation step shown in FIG. 2 on the modulated signal. First perform serial-to-parallel transformation, then perform Fourier transform (FFT), and finally perform matched filtering to obtain the original navigation signal and communication signal. 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 parsed.

The matched filter shown in Figure 3 is mainly designed to match the SRRC filter used in FMT modulation.

The acquisition step mainly includes a code correlation step and a Doppler detection step, as shown in Figure 3.

The tracking process mainly includes carrier tracking and C/A code tracking. The carrier tracking steps used in this embodiment are as follows.

When the navigation signal is correlated, input two symmetrical carriers (I and Q) as shown in Figure 5. The local reproduction signal of the in-phase branch (I) can be expressed as

Among them, An is the amplitude value, Δτ is the delay, f _{n is} the carrier frequency, is the estimated IF frequency. is the estimated carrier phase.

The locally reproduced signal of the quadrature branch (Q-way) can be expressed as

Then X(t) and and relevant to obtain

The third term in the formula is the code correlation peak, and finally the output of the phase-locked loop and the frequency-locked loop can be obtained according to the obtained correlation result, so as to obtain the accuracy that needs to be estimated. It can be seen that with the change of Δf, the width of the code correlation peak will change accordingly, thereby affecting the navigation accuracy. The accuracy of the code correlation peak can be obtained by referring to the prior art, and its theoretical accuracy can be obtained:

where T _s is the symbol time, f _sc is the subband width, T _c is the code time, and E _s /N ₀ represents the signal-to-noise ratio. It can be seen that adjusting T _s has a great influence on the positioning accuracy. With variable bandwidth settings, the ZZB theoretical circle can be flexibly adjusted. At the same time, signals with different bandwidths have different transmission characteristics. The sub-bandwidth signal has strong anti-Doppler ability and poor anti-multipath ability. The system can change the sub-band width according to the requirements, make tradeoffs in multiple dimensions such as positioning accuracy, signal-to-noise ratio, Doppler-multipath, etc., and obtain the best transmission scheme, which has more advantages than the traditional system that cannot change the sub-band width. degrees of freedom.

After the tracking process is completed and synchronization is further achieved, the navigation message can be parsed to obtain pseudo-range information from the satellite to the ground. After obtaining the pseudo-range information from multiple (four or more) satellites to the ground, we can solve the position coordinates of the ground to complete the positioning.

In order to correspondingly apply the above-mentioned variable bandwidth filtering multi-tone modulation method for satellite navigation communication, an embodiment of the present invention also provides a variable bandwidth filtering multi-tone modulation system for satellite navigation communication, including: a signal processing and sending module: used to convert the navigation signal Perform variable bandwidth filtering multi-tone modulation with the communication signal to obtain a modulated signal transmitted in a multi-subband channel, and transmit the modulated signal. The implementation principle of the signal processing and sending module is the same as the principle of the above-mentioned variable bandwidth filtering multi-tone modulation method for satellite navigation communication, and will not be repeated here.

In order to correspondingly apply the above-mentioned variable bandwidth filtering multi-tone demodulation method for satellite navigation communication, an embodiment of the present invention also provides a variable bandwidth filtering multi-tone demodulation system for satellite navigation communication, including: a signal receiving and processing module: for receiving The modulated signal transmitted in the multi-subband channel is jointly demodulated to obtain the communication signal and the navigation signal.

The implementation principle of the signal receiving and processing module is the same as the principle of the above-mentioned variable bandwidth filtering multi-tone demodulation method for satellite navigation communication, and will not be repeated here.

The above are only the preferred embodiments of the present invention. It should be pointed out that for those skilled in the art, without departing from the technical principles of the present invention, several improvements and modifications can be made. These improvements and modifications It should also be regarded as the protection scope of the present invention.

To sum up, this embodiment provides a variable bandwidth filtering multi-tone modulation and demodulation method and system for satellite navigation communication with variable bandwidth and relatively balanced navigation and communication performance, so that it can be applied to navigation system backup, emergency Communication, navigation signal assisted communication reception and other scenarios. The signal transmission scheme proposed in this embodiment unifies the navigation channel and the communication channel through the specially designed variable-bandwidth filtering multi-tone modulation technology, and enables the navigation sub-channel and the communication sub-channel to be able to communicate with each other without changing the time-frequency domain structure. Coexistence in a system improves spectrum utilization, reduces the signal rate of each carrier, reduces the cost and hardware complexity of each channel, and flexibly allocates the spectrum of navigation sub-channels and communication sub-channels to meet the needs of the system. A variety of requirements have improved the anti-interference performance of the system. At the same time, the invention supports the use of sub-carriers with different bandwidths for each carrier in an entire joint-modulated FMT, which can ensure that users with different accuracy requirements and different environments use sub-bands of different widths to serve users in the satellite, so that the satellite can serve more users in the scenario. The satellites in the system are usually used for data communication. Once other navigation satellites are attacked and cannot be used normally, the satellites act as backup satellites of the navigation satellites and play a navigation role by transmitting navigation signals. Moreover, since the satellite signal contains both communication signals and navigation signals, the navigation signals can be better concealed, making them less susceptible to interference. The present invention can expand the scope of application, and can be applied to single-carrier or multi-carrier transmission systems.

Therefore, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above-mentioned embodiments merely illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed in the present invention should still be covered by the claims of the present invention.

Claims (10)

1. a bandwidth-variable filtering multi-tone modulation method of satellite navigation communication, is characterized in that, the bandwidth-variable filtering multi-tone modulation method of described satellite navigation communication comprises: Perform variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal to obtain the modulated signal transmitted in the multi-subband channel; The modulated signal is sent. 2. The bandwidth-variable filtering multi-tone modulation method of satellite navigation communication according to claim 1, characterized in that, performing the variable-bandwidth filtering multi-tone modulation on the navigation signal and the communication signal comprises combining the navigation signal with the communication signal. The signal is modulated onto several subbands with different bandwidths, so that the modulated signal is transmitted in a multi-subband channel. 3 . The variable bandwidth filtering multi-tone modulation method for satellite navigation communication according to claim 2 , wherein the multi-subband channel includes a navigation subchannel and a communication subchannel. 4 . 4. the bandwidth-variable filtering multi-tone modulation method of satellite navigation communication according to claim 3, it is characterized in that, described a kind of realization mode that the navigation signal and the communication signal are carried out the bandwidth-variable filtering multi-tone modulation comprises: Perform spectrum resource allocation on the navigation signal and the communication signal according to the spectrum allocation manners in which the navigation subchannel and the communication subchannel correspond to different subbands, to obtain a preliminary modulated signal; Filtering and shaping the preliminary modulated signal to obtain a filtered signal; Perform inverse discrete Fourier transform on the filtered signal to obtain an IFFT processed signal; Perform parallel-serial conversion on the IFFT processed signal to obtain the modulated signal. 5. The variable bandwidth filtering multi-tone modulation method for satellite navigation communication according to claim 3, wherein the navigation sub-channel comprises an even number of navigation channels, each of which corresponds to a sub-band; the communication The sub-channel includes several communication channels, each of which corresponds to a sub-band; the navigation signal is transmitted in the navigation sub-channel through the sub-band corresponding to the navigation channel; the communication signal is transmitted through the communication channel The subband corresponding to the channel is transmitted in the communication subchannel. 6. A bandwidth-variable filtering multi-tone demodulation method for satellite navigation communication, characterized in that the bandwidth-variable filtering multi-tone demodulation method for satellite navigation communication comprises: receiving a modulated signal transmitted in a multi-subband channel; The modulated signal is jointly demodulated to obtain a communication signal and a navigation signal. 7. The variable-bandwidth filtering multi-tone demodulation method for satellite navigation communication according to claim 6, wherein the implementation of the joint demodulation on the modulated signal comprises: Serial-parallel transform, discrete Fourier transform and matched filtering are performed on the modulated signal in sequence to obtain the original communication signal and navigation signal in the modulated signal. 8. The variable bandwidth filtering multi-tone demodulation method of satellite navigation communication according to claim 6, wherein the variable bandwidth filtering multi-tone demodulation method of satellite navigation communication further comprises: Capturing, tracking and synchronizing navigation data in the navigation signal; The navigation message is parsed according to the navigation data, and the pseudo-range information from the satellite to the ground terminal is obtained. 9. A variable bandwidth filtering multi-tone modulation system of satellite navigation communication, characterized in that, comprising: Signal processing and sending module: used to perform variable bandwidth filtering multi-tone modulation on the navigation signal and the communication signal, obtain the modulated signal transmitted in the multi-subband channel, and send the modulated signal. 10. A variable bandwidth filtering multi-tone demodulation system for satellite navigation communication, characterized in that, comprising: Signal receiving and processing module: used to receive modulated signals transmitted in multi-subband channels, and jointly demodulate the modulated signals to obtain communication signals and navigation signals.