阅读说明：本技术 一种卫星信号载波同步方法及系统 (Satellite signal carrier synchronization method and system ) 是由 徐劲松 李延龄 王贝贝 邹文萱 冯子涵 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种卫星信号载波同步方法及系统,所述方法包括如下步骤:对接收到的载波信号进行混频滤波,得到采样信号；基于采样信号计算得到其同相分量和正交分量；基于所述两个分量捕获载波频偏并补偿,实现载波第一次同步；利用双层锁相环对载波信号混频滤波,第一次提取载波频率和相位信息,通过上述信息对载波频偏和相位偏差进行第一次补偿,得到第一次补偿后的载波信号；利用双层锁相环对载波信号混频滤波,第二次提取载波频率和相位信息,通过上述信息对载波频偏和相位偏差进行第二次补偿,得到第二次补偿后的载波信号,完成对载波信号的相位跟踪,实现载波第二次同步。(The invention discloses a satellite signal carrier synchronization method and a system, wherein the method comprises the following steps of carrying out frequency mixing filtering on a received carrier signal to obtain a sampling signal; calculating an in-phase component and a quadrature component of the sampling signal based on the sampling signal; capturing carrier frequency offset and compensating based on the two components to realize first carrier synchronization; the carrier signal is subjected to frequency mixing filtering by using a double-layer phase-locked loop, carrier frequency and phase information is extracted for the first time, and the carrier frequency deviation and the phase deviation are subjected to first compensation through the information to obtain a carrier signal subjected to the first compensation; and performing frequency mixing filtering on the carrier signal by using a double-layer phase-locked loop, extracting carrier frequency and phase information for the second time, performing second compensation on the carrier frequency deviation and the phase deviation through the information to obtain a carrier signal after the second compensation, completing phase tracking on the carrier signal, and realizing the second synchronization of the carrier.)

1. A satellite signal carrier synchronization method, comprising the steps of:

carrying out frequency mixing filtering on the received carrier signal to obtain a sampling signal;

calculating an in-phase component and a quadrature component of the sampling signal based on the sampling signal;

capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating to realize first carrier synchronization;

performing frequency mixing filtering on the carrier signal subjected to the first synchronization by using a pre-designed double-layer phase-locked loop, extracting carrier frequency and phase information of the carrier signal subjected to the frequency mixing filtering for the first time, and performing first compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the first compensation;

performing frequency mixing filtering on the carrier signal subjected to the first compensation by using a pre-designed double-layer phase-locked loop, extracting carrier frequency and phase information of the carrier signal subjected to the first compensation and frequency mixing filtering for the second time, and performing second compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the second compensation;

and finishing the phase tracking of the carrier signal according to the carrier signal after the first compensation and the second compensation, and realizing the second synchronization of the carrier.

2. The satellite signal carrier synchronization method according to claim 1, wherein the in-phase component and the quadrature component of the sampling signal are calculated by:

wherein I (k) is an in-phase component, Q (k) is a quadrature component, r (k) is a sampled signal, n_I(k) Is the in-phase component of noise, n_Q(k) Is the quadrature component of the noise and is,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal.

3. The method of claim 1, wherein the carrier frequency offset in the sampled signal is captured by:

where f (k) is the carrier frequency offset, I (k) is the in-phase component, Q (k) is the quadrature component,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal,is the phase difference between the phase of the carrier signal after mixing and the initial phase;

and compensating carrier frequency offset in the sampling signal through the DDS.

4. The method of claim 1, wherein the double-layer phase-locked loop filters the carrier signal by mixing twice through a down-converter and a matched filter.

5. The method of claim 1, wherein the carrier frequency and phase information of the filtered carrier signal is extracted for the first time and the second time by:

the carrier signal prior information is obtained by utilizing the known code sequence to carry out inverse modulation, and the carrier frequency and the phase information of the carrier signal are obtained by carrying out integral accumulation and zero clearing on the prior information.

6. The method of claim 1, wherein the first and second compensations for carrier frequency offset and phase offset are performed by:

and the carrier frequency and the phase information of the carrier signal are utilized to realize the first compensation and the second compensation of the carrier frequency difference and the phase deviation through DDS and filtering.

7. A satellite signal carrier synchronization system is characterized by comprising a down converter, a matched filter, a frequency locking ring and a double-layer phase locking ring;

down converter and matched filter: the device is used for carrying out frequency mixing filtering on the received carrier signal to obtain a sampling signal;

frequency locking ring: the carrier frequency offset compensation circuit is used for calculating to obtain an in-phase component and an orthogonal component of a sampling signal based on the sampling signal, capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating to realize first-time carrier synchronization;

double-layer phase-locked loop: the carrier frequency offset compensation device is used for carrying out frequency mixing filtering on the carrier signals subjected to the first synchronization, extracting carrier frequency and phase information of the carrier signals subjected to the frequency mixing filtering for the first time, and carrying out first compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain carrier signals subjected to the first compensation;

carrying out frequency mixing filtering on the carrier signal subjected to the first compensation, extracting carrier frequency and phase information of the carrier signal subjected to the first compensation and frequency mixing filtering for the second time, and carrying out second compensation on carrier frequency deviation and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the second compensation;

and finishing the phase tracking of the carrier signal according to the carrier signal after the first compensation and the second compensation, and realizing the second synchronization of the carrier.

Technical Field

The invention relates to a satellite signal carrier synchronization method and a satellite signal carrier synchronization system, and relates to the fields of satellite navigation, satellite communication, wireless communication application and the like.

Background

In recent years, high dynamics is ubiquitous in satellite communication, aerospace measurement and control and navigation systems. In a satellite communication system, with the rapid development of satellite communication technology, mobile communication between constellations and between satellites and between grounds, which are composed of space vehicles (communication satellites, navigation satellites, deep space probes and the like), is receiving more and more attention from people; due to the high-speed motion of the satellite constellation relative to the ground and the high-speed motion between the constellations, the two receiving and transmitting parties are under the high-dynamic communication condition, the time domain shows serious time selective fading, and the frequency domain shows that the signal has large Doppler frequency offset and high-order Doppler frequency offset change rate.

In the field of satellite navigation, the application of a medium-low dynamic receiver in the civil field is quite wide, such as vehicle and ship navigation; however, the high dynamic receiver has less domestic research, and the high dynamic navigation system plays a significant role in improving military capability; therefore, research into signal reception techniques in low signal-to-noise ratio, high dynamic environments has become urgent.

In a high dynamic application environment, high-speed relative motion between two communication parties often introduces larger Doppler frequency offset and high-order change rate thereof on a carrier frequency of a signal received by a receiver; in order to adapt to a high dynamic environment, the loop bandwidth of the carrier tracking loop of the medium-low dynamic receiver must be widened to acquire and track the doppler frequency offset and the change rate thereof of the received signal, however, the increase of the loop bandwidth tends to cause the reduction of the carrier tracking accuracy, and especially when the tracking loop is in a low signal-to-noise ratio communication environment, the introduction of noise may even cause the loss of lock of the carrier tracking loop.

Two major technical difficulties mainly exist in carrier synchronization under a high dynamic environment; one is that the absolute frequency offset is large, and in a high dynamic environment, because a communication carrier often has a very high motion speed, a very large doppler frequency offset is generated at a communication receiving end, which brings a serious challenge to the design of a receiver. The occurrence of large frequency offset forces the receiver to have to relax the front-end bandwidth so as to enable the useful signal to completely enter the post-stage signal processing module; however, a large amount of out-of-band noise is inevitably introduced while the bandwidth is amplified, so that the input signal-to-noise ratio of the receiver is remarkably reduced, and great challenges are brought to subsequent synchronization and demodulation modules; meanwhile, in the acquisition module, a larger frequency offset range also means a larger frequency search interval, and the search interval is too large, which may cause practical engineering problems such as lack of hardware resources of the receiver.

Another technical difficulty in high dynamic environments is the existence of a large frequency change rate; in an actual space, the relative motion speed of a communication carrier is often changed drastically, so that the corresponding doppler frequency offset also fluctuates drastically, that is, a large frequency change rate exists; compared with frequency deviation, the influence of a higher frequency change rate on a communication system is stronger; the method not only needs a receiver synchronization module to give a relatively accurate estimation value during acquisition, but also requires a carrier tracking system to have extremely high dynamic tracking capability, and can give an accurate estimation value in real time under the condition of rapid change of carrier frequency and phase, thereby bringing a severe test to the acquisition and tracking modules in carrier synchronization.

Disclosure of Invention

The invention aims to provide a satellite signal carrier synchronization method and a satellite signal carrier synchronization system, which can realize accurate capture and tracking of a carrier of a satellite signal and complete second synchronization of the carrier signal in a high-dynamic and large-frequency-offset environment.

The invention is realized by the following technical scheme:

in a first aspect, a satellite signal carrier synchronization method is provided, including the following steps:

carrying out frequency mixing filtering on the received carrier signal to obtain a sampling signal;

calculating an in-phase component and a quadrature component of the sampling signal based on the sampling signal;

capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating to realize first carrier synchronization;

performing frequency mixing filtering on the carrier signal subjected to the first synchronization by using a pre-designed double-layer phase-locked loop, extracting carrier frequency and phase information of the carrier signal subjected to the frequency mixing filtering for the first time, and performing first compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the first compensation;

performing frequency mixing filtering on the carrier signal subjected to the first compensation by using a pre-designed double-layer phase-locked loop, extracting carrier frequency and phase information of the carrier signal subjected to the first compensation and frequency mixing filtering for the second time, and performing second compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the second compensation;

and finishing the phase tracking of the carrier signal according to the carrier signal after the first compensation and the second compensation, and realizing the second synchronization of the carrier.

With reference to the first aspect, further, the in-phase component and the quadrature component of the sampled signal are calculated by:

wherein I (k) is an in-phase component, Q (k) is a quadrature component, r (k) is a sampled signal, n_I(k) Is the in-phase component of noise, n_Q(k) Is the quadrature component of the noise and is,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal.

With reference to the first aspect, further, the carrier frequency offset in the sampled signal is captured by:

where f (k) is the carrier frequency offset, I (k) is the in-phase componentAnd Q (k) is the quadrature component,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal,is the phase difference between the phase of the carrier signal after mixing and the initial phase;

and compensating carrier frequency offset in the sampling signal through the DDS.

With reference to the first aspect, further, the two frequency mixing filtering of the carrier signal by the double-layer phase-locked loop are performed by the down converter and the matched filter.

With reference to the first aspect, further, the carrier frequency and phase information of the filtered carrier signal are extracted for the first time and the second time by the following methods:

the carrier signal prior information is obtained by utilizing the known code sequence to carry out inverse modulation, and the carrier frequency and the phase information of the carrier signal are obtained by carrying out integral accumulation and zero clearing on the prior information.

With reference to the first aspect, further, the first compensation and the second compensation for the carrier frequency offset and the phase deviation are implemented by the following methods:

and the carrier frequency and the phase information of the carrier signal are utilized to realize the first compensation and the second compensation of the carrier frequency difference and the phase deviation through DDS and filtering.

In a second aspect, the invention further provides a satellite signal carrier synchronization system, which comprises a down converter, a matched filter, a frequency locking ring and a double-layer phase locking ring;

down converter and matched filter: the device is used for carrying out frequency mixing filtering on the received carrier signal to obtain a sampling signal;

frequency locking ring: the carrier frequency offset compensation circuit is used for calculating to obtain an in-phase component and an orthogonal component of a sampling signal based on the sampling signal, capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating to realize first-time carrier synchronization;

double-layer phase-locked loop: the carrier frequency offset compensation device is used for carrying out frequency mixing filtering on the carrier signals subjected to the first synchronization, extracting carrier frequency and phase information of the carrier signals subjected to the frequency mixing filtering for the first time, and carrying out first compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain carrier signals subjected to the first compensation;

carrying out frequency mixing filtering on the carrier signal subjected to the first compensation, extracting carrier frequency and phase information of the carrier signal subjected to the first compensation and frequency mixing filtering for the second time, and carrying out second compensation on carrier frequency deviation and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the second compensation;

and finishing the phase tracking of the carrier signal according to the carrier signal after the first compensation and the second compensation, and realizing the second synchronization of the carrier.

Compared with the prior art, the invention has the following beneficial effects:

the invention provides a satellite signal carrier synchronization method and a satellite signal carrier synchronization system, which are characterized in that frequency mixing filtering is carried out on a received carrier signal to obtain a sampling signal, a pre-designed frequency locking ring captures carrier frequency offset in the sampling signal and compensates the carrier frequency offset to realize first-time carrier synchronization; the method comprises the steps that a pre-designed double-layer phase-locked loop preliminarily filters a carrier signal, carrier frequency and phase information of the carrier signal are extracted for the first time, first compensation is conducted on carrier frequency deviation and phase deviation according to the carrier frequency and phase deviation to obtain the carrier signal after the first compensation, the carrier signal is filtered again, the carrier frequency and phase information of the carrier signal are accurate, second compensation is conducted on the carrier frequency deviation and the phase deviation according to the carrier frequency deviation and the phase deviation to obtain the carrier signal after the second compensation, phase tracking of the carrier signal is completed, and second synchronization of the carrier is achieved;

the invention provides a satellite signal carrier synchronization method and a satellite signal carrier synchronization system, and provides a carrier synchronization algorithm combining a frequency locking ring and a double-layer phase-locked loop, wherein the improved frequency locking ring is used for capturing larger carrier frequency deviation and compensating to realize the first synchronization of a carrier.

Drawings

In order to more clearly illustrate the technical solution of the embodiment of the present invention, the drawings needed to be used in the embodiment of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a structural diagram of a satellite signal carrier synchronization system according to an embodiment of the present invention;

fig. 2 is a flowchart illustrating a first carrier synchronization process in a satellite signal carrier synchronization method according to an embodiment of the present invention;

fig. 3 is a flowchart illustrating a second carrier synchronization processing in a satellite signal carrier synchronization method according to an embodiment of the present invention;

fig. 4 is a diagram of open loop test data of a frequency locking loop in a satellite signal carrier synchronization method according to an embodiment of the present invention;

fig. 5 is a performance diagram of a phase-locked loop in an acquisition state in a satellite signal carrier synchronization method according to an embodiment of the present invention.

Detailed Description

The invention is further described below with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Example one

With reference to fig. 1, fig. 2, and fig. 3, the method for synchronizing a satellite signal carrier provided by the present invention includes the following steps:

carrying out frequency mixing filtering on the received carrier signal to obtain a sampling signal:

the invention provides a satellite signal carrier synchronization method, which adopts a down converter and a matched filter to carry out frequency mixing filtering on a received carrier signal; after the carrier signal passes through the down converter, the mixed signal is lower than the original signal, the carrier frequency in the carrier signal is reduced, the carrier signal has the maximum signal-to-noise ratio after passing through the matched filter, the noise in the carrier signal is reduced, and the sampling signal is obtained.

Calculating an in-phase component and a quadrature component of the sampling signal based on the sampling signal:

according to the satellite signal carrier synchronization method, after the sampling signal is obtained, the sampling signal is calculated, and the in-phase component and the quadrature component of the sampling signal are obtained.

The in-phase component and the quadrature component of the sampling signal are calculated by the following method:

wherein I (k) is an in-phase component, Q (k) is a quadrature component, r (k) is a sampled signal, n_I(k) Is the in-phase component of noise, n_Q(k) Is the quadrature component of the noise and is,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal.

And capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating to realize the first time synchronization of the carrier:

the invention provides a satellite signal carrier synchronization method, which comprises the steps of calculating an in-phase component and an orthogonal component of a sampling signal, and capturing carrier frequency offset in the sampling signal through a frequency discriminator based on the in-phase component and the orthogonal component of the sampling signal.

The carrier frequency offset is captured by the following method:

where f (k) is the carrier frequency offset, I (k) is the in-phase component, Q (k) is the quadrature component,is the phase of the local oscillator mixed with the received carrier signal,. DELTA.f (k) is the frequency estimation residual, t_k-1Is the starting point in time of the day,is the initial phase of the received carrier signal,is the phase difference between the phase of the carrier signal after mixing and the initial phase; and each symbol in the formula is independent of the data symbol variation and only varies with the frequency offset, x (k) is the denominator in the above formula in fig. 2, and y (k) is the numerator in the above formula.

After carrier frequency offset in the sampling signal is obtained through calculation, the carrier frequency offset in the sampling signal is compensated through a DDS; the satellite signal carrier synchronization method provided by the invention utilizes the improved frequency locking ring to capture larger carrier frequency offset and compensate to realize the first carrier synchronization.

Filtering the carrier signal after the first synchronization by utilizing a pre-designed double-layer phase-locked loop, extracting carrier frequency and phase information of the filtered carrier signal for the first time, and performing first compensation on carrier frequency offset and phase deviation through the carrier frequency and phase information to obtain the carrier signal after the first compensation:

the satellite signal carrier synchronization method provided by the invention adopts a double-layer phase-locked loop structure, the phase-locked loop 1(PLL1) is used for carrying out phase locking on a carrier signal so as to obtain the frequency information of the carrier signal, and the carrier signal is subjected to reverse rotation by utilizing the frequency information obtained by the PLL1, so that the newly obtained carrier signal only has a small frequency difference, and the first compensation of the carrier signal is realized.

The specific processing flow of the first compensation of the PLL1 on the carrier signal is as follows:

carrying out frequency mixing filtering on the carrier signal, reducing noise in the carrier signal and obtaining the carrier signal with the maximum signal-to-noise ratio;

in the PLL1, inverse modulation is carried out by utilizing a known code sequence (UW) to acquire the prior information of a carrier signal;

integrating, accumulating and clearing the prior information of the carrier signal through a low-pass filter to obtain carrier frequency and phase information of the carrier signal;

and the carrier frequency and phase information acquired from the PLL1 are utilized to realize the first compensation of the carrier frequency offset and the phase offset of the carrier signal through the DDS and the loop filter.

The pre-designed double-layer phase-locked loop is utilized to carry out frequency mixing filtering on the carrier signal after the first compensation, the carrier frequency and the phase information of the carrier signal after the first compensation and the frequency mixing filtering are extracted for the second time, and the carrier frequency deviation and the phase deviation are compensated for the second time through the carrier frequency and the phase information, so that the carrier signal after the second compensation is obtained:

the satellite signal carrier synchronization method provided by the invention adopts a double-layer phase-locked loop structure, after the carrier signal is compensated for the first time through the PLL1, the carrier signal is subjected to low-delay filtering by using the phase-locked loop 2(PLL2), and the carrier signal is compensated for the second time until a loop is locked.

The specific processing flow of the second compensation of the PLL2 on the carrier signal is as follows:

carrying out frequency mixing filtering on the carrier signal after the first compensation, reducing noise in the carrier signal and obtaining the carrier signal with the maximum signal-to-noise ratio;

in the PLL2, inverse modulation is carried out by utilizing a known code sequence (UW) to obtain the prior information of the carrier signal after first compensation and frequency mixing filtering;

integrating, accumulating and clearing the prior information of the carrier signal through a low-pass filter to obtain carrier frequency and phase information of the carrier signal;

and the carrier frequency and phase information acquired from the PLL2 are utilized to realize the second compensation of the carrier frequency offset and the phase offset of the carrier signal through the DDS and the loop filter.

According to the carrier signals after the first compensation and the second compensation, the phase tracking of the carrier signals is completed, and the second synchronization of the carrier is realized:

after the carrier signal is compensated for the first time by the PLL1 and the carrier signal is compensated for the second time by the PLL2, the phase tracking of the carrier signal is completed according to the carrier signal after the first compensation and the second compensation, and the second synchronization of the carrier is realized.

The invention provides a satellite signal carrier synchronization method, and provides a carrier synchronization algorithm combining a frequency locking ring and a double-layer phase-locked loop, wherein the improved frequency locking ring is used for capturing larger carrier frequency deviation and compensating to realize the first synchronization of a carrier.

Example two

In order to verify the feasibility of the carrier synchronization method designed in the present invention and analyze the feasibility of the time service signal link without affecting the communication performance of the satellite, a description is given to a satellite signal carrier synchronization method provided in the present invention by taking the high-speed aircraft communication reception in a certain satellite communication system as an example, with reference to fig. 4 and 5.

Doppler frequency f of received carrier signal_d(t) can be expressed as:

in the above equation, the first term f on the right side of the equation_d(t₀) Representing a constant Doppler frequency of the received carrier signal, which corresponds to the relative radial velocity of motion between the satellite and the receiverDegree, coefficient f 'of the remaining two terms on the right side of the equation'_d(t₀) And f'_d(t₀) Respectively, representing first and second order rates of change of the doppler frequency of the received carrier signal, respectively corresponding to the acceleration and jerk of the relative radial motion between the satellite and the receiver.

Assuming a Doppler shift of 4.4kHz (about 929Hz for GPS) and a Doppler frequency change rate of 40 Hz/s.

Firstly, setting a frequency locking loop parameter, and setting an initial frequency difference: f. of_d(t₀)＝4.4KHz，f’_d(t₀)＝40Hz/s，f”_d(t₀)＝0，Eb/n0＝-3dB。

An open loop test of the Frequency Locked Loop (FLL) is performed, and a lock detection indication signal can be detected after 50000 measurement samples (50000/16 3125 symbols 0.35 ms). As shown in fig. 4.

Designing and verifying a phase-locked loop (PLL), wherein a loop filter in the PLL is to adopt a second-order loop, and a transfer function F(s) of the loop filter can be expressed as follows:

for convenience of representation, letThe parameter values of three branches of the loop filter can be obtained as follows:

in the above formula, b is a real-valued coefficient of a real-valued pole, where b is 1; k is the gain of the PLL, K is 1; xi is a damping coefficient and is taken as 0.707; omega_nIn order to have an undamped oscillation frequency,B_Lis the loop bandwidth.

According to the above design parameters, simulation experiment verification is performed, and fig. 5 shows the loop tracking performance (with large phase deviation) in the capture state.

EXAMPLE III

The satellite signal carrier synchronization system provided by the invention adopts the satellite signal carrier synchronization method described in the first embodiment.

The invention provides a satellite signal carrier synchronization system, which comprises a down converter and a matched filter, wherein the down converter and the matched filter are used for carrying out frequency mixing filtering on a received carrier signal to obtain a sampling signal; after the carrier signal passes through the down converter, the mixed signal is lower than the original signal, the carrier frequency in the carrier signal is reduced, the carrier signal has the maximum signal-to-noise ratio after passing through the matched filter, the noise in the carrier signal is reduced, and the sampling signal is obtained.

The invention provides a satellite signal carrier synchronization system, which also comprises a frequency locking ring, a frequency acquisition unit and a frequency control unit, wherein the frequency locking ring is used for obtaining an in-phase component and an orthogonal component of a sampling signal based on calculation of the sampling signal, capturing carrier frequency offset in the sampling signal based on the in-phase component and the orthogonal component and compensating the carrier frequency offset to realize first carrier synchronization; the method is used for carrying out first synchronization on the sampling signals after frequency mixing filtering, and the first synchronization is realized by capturing larger carrier frequency offset and compensating by using an improved frequency locking loop.

The invention provides a satellite signal carrier synchronization system, which also comprises a double-layer phase-locked loop, a first-time synchronization module and a second-time synchronization module, wherein the double-layer phase-locked loop is used for filtering a carrier signal after first synchronization, extracting carrier frequency and phase information of the filtered carrier signal for the first time, and performing first compensation on carrier frequency deviation and phase deviation through the carrier frequency and phase information to obtain a carrier signal after the first compensation; and carrying out frequency mixing filtering on the carrier signal subjected to the first compensation, extracting carrier frequency and phase information of the carrier signal subjected to the first compensation and frequency mixing filtering for the second time, and carrying out second compensation on carrier frequency deviation and phase deviation through the carrier frequency and phase information to obtain a carrier signal subjected to the second compensation.

The double-layer phase-locked loop is used for carrying out secondary synchronization on a sampling signal after primary synchronization, and comprises a phase-locked loop 1(PLL1) and a phase-locked loop 2(PLL2), wherein the phase-locked loop 1(PLL1) is used for extracting carrier frequency and phase information of a carrier signal for the first time, and carrying out primary compensation on carrier frequency deviation and phase deviation, the phase-locked loop 2(PLL2) is used for extracting carrier frequency and phase information of the carrier signal for the second time, and carrying out secondary compensation on the carrier frequency deviation and the phase deviation, and phase tracking is carried out by utilizing the double-layer phase-locked loop.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.