CN111884675A - Method and system for tracking multi-system phase hopping spread spectrum modulation signal - Google Patents

Abstract

The present invention provides a method and system for synchronizing a multi-ary phase hopping spread spectrum modulated signal, comprising: acquiring a phase hopping spread spectrum modulated signal sent by a sending end; The sequence is determined; the second multi-ary phase hopping sequence is generated by referring to the way that the transmitting end generates the first multi-ary phase hopping sequence, and it is mapped into a binary phase hopping sequence and a phase compensation sequence; Determine the method and phase compensation sequence to generate a local reference carrier with phase compensation function; the receiving end strips the carrier in the phase-hopping spread spectrum modulation signal based on the local reference carrier with phase compensation function and performs phase phasing on the complex pseudo-code sequence Compensation to obtain the real-number pseudo-code sequence and the data of the transmitting end; perform the correlation operation on the binary phase-hopping sequence, the real-number pseudo-code sequence and the data of the transmitting end, and obtain the data of the transmitting end by tracking. The invention provides a low-complexity multi-ary phase-hopping spread spectrum modulation signal tracking method.

Description

A tracking method and system for multi-ary phase hopping spread spectrum modulated signal

technical field

The invention belongs to the technical field of communication, and more particularly, relates to a tracking method and system for a multi-ary phase hopping spread spectrum modulation signal.

Background technique

The second stage of synchronization of the Global Navigation Satellite System (GNSS) receiver is tracking, which is performed on the basis of the acquired Doppler frequency and pseudocode phase estimates. During the tracking process, the carrier frequency and pseudocode phase of the local reference signal need to be highly synchronized with the received signal, so as to achieve the two purposes of measuring pseudorange and demodulating data. Tracking loops include carrier tracking loops and code tracking loops. The purpose of the carrier tracking loop is to strip the carrier from the received signal. The purpose of the code tracking loop is to strip pseudo-code and improve the signal-to-noise ratio of the navigation signal that would otherwise be buried in noise. The carrier tracking loop and the code tracking loop are closely combined to complete the signal tracking process together.

良好的自相关性能，

表示第k个码元的相位跳变偏移量。因此可以借助直接序列扩频导航信号的跟踪环路来设计跳相扩频导航信号的跟踪环路，只需要将其中的实数相关运算改为复数相关运算即可，复数相关运算可以依靠图1所示多进制跳相扩频调制信号的跟踪系统计算流程图，复数相关运算依赖图1中的相位补偿器完成。具体地，如图1所示，跟踪环路的输入为下变频之后的中频信号，中频信号首先与本地参考载波进行混频，以剥离信号中的载波，本地参考载波由载波NCO生成；然后，混频之后的信号与本地复现伪码进行复数相关运算，本地复现伪码由跳相序列发生器产生的跳相序列c_PH(k)通过查找相位补偿器中的跳相查找表得到，再经过相干积分和非相干累积操作之后，一方面可以剥离伪码以得到发送端的导航电文，另一方面通过码环鉴别器可以得到码跟踪误差；最后，根据载波环鉴别器输出的载波跟踪误差来调整本地参考载波频率，根据码跟踪误差来调整本地复现伪码相位，实现跟踪环路闭环反馈。这种跟踪算法采用了复数相关，而复数相关相对于实数相关来说需要更多乘法器和加法器，且所用乘法器的位宽较大，实现复杂度较高，因而导致了这种跟踪算法的实现复杂度较高。The receiver achieves signal tracking through the good autocorrelation performance of the navigation signal, that is, it relies on the equivalent pseudocode sequence

good autocorrelation performance,

Indicates the phase hopping offset of the k-th symbol. Therefore, the tracking loop of the phase-hopping spread-spectrum navigation signal can be designed with the help of the tracking loop of the direct-sequence spread-spectrum navigation signal. It is only necessary to change the real-number correlation operation to the complex-number correlation operation. Shown is the calculation flow chart of the tracking system of the multi-ary phase hopping spread spectrum modulation signal, and the complex correlation operation is completed by the phase compensator in Figure 1. Specifically, as shown in Figure 1, the input of the tracking loop is the intermediate frequency signal after down-conversion, the intermediate frequency signal is first mixed with the local reference carrier to strip the carrier in the signal, and the local reference carrier is generated by the carrier NCO; then, The signal after mixing is subjected to complex correlation operation with the local reproduction pseudo code, and the local reproduction pseudo code is obtained by looking up the phase hopping look-up table in the phase compensator by the phase hopping sequence c _PH (k) generated by the phase hopping sequence generator, After coherent integration and incoherent accumulation operations, on the one hand, the pseudocode can be stripped to obtain the navigation message of the sender, and on the other hand, the code tracking error can be obtained through the code loop discriminator; finally, the carrier tracking error output by the carrier loop discriminator can be obtained. To adjust the local reference carrier frequency, according to the code tracking error to adjust the local reproduction pseudo code phase, to achieve tracking loop closed-loop feedback. This tracking algorithm uses complex correlation, and complex correlation requires more multipliers and adders than real correlation, and the bit width of the multipliers used is large and the implementation complexity is high, which leads to this tracking algorithm. The implementation complexity is high.

SUMMARY OF THE INVENTION

In view of the defects of the prior art, the purpose of the present invention is to provide a tracking method and system for a multi-ary phase hopping spread spectrum modulated signal, aiming to solve the problem that the complex correlator structure in the tracking loop is complex and the bit width of the multiplier used is relatively large. This leads to the problem of high implementation complexity.

In order to achieve the above object, in the first aspect, the present invention provides a tracking method for a multi-ary phase hopping spread spectrum modulation signal, comprising the following steps:

The receiving end obtains the phase-hopping spread spectrum modulation signal sent by the transmitting end; the phase-hopping spread spectrum modulation signal includes a carrier wave, a complex pseudo-code sequence and data of the transmitting end; The phase hopping sequence is determined; wherein, the phase hopping sequence is a random sequence or a pseudo-random sequence, which is used to control the hopping offset of the phase;

The receiving end generates the second multi-ary phase hopping sequence by referring to the method in which the transmitting end generates the first multi-ary phase hopping sequence. Based on the coding rule between the multi-ary phase hopping sequence and the binary phase hopping sequence, the second The phase hopping sequence is mapped into a binary phase hopping sequence and a phase compensation sequence;

The receiving end generates a local reference carrier with a phase compensation function in combination with the determination method of the carrier in the phase-hopping spread spectrum modulation signal and the phase compensation sequence;

The receiving end strips the carrier in the phase-hopping spread spectrum modulation signal based on the local reference carrier with the phase compensation function and performs phase compensation on the complex pseudo-code sequence to obtain the real-number pseudo-code sequence and the transmitting end data;

The receiving end performs a correlation operation on the binary phase-hopping sequence, the real-number pseudocode sequence and the data of the transmitting end, and obtains the data of the transmitting end by tracking.

It can be understood that the complex number pseudo code sequence is a multi-ary sequence, and the real number pseudo code sequence is a binary sequence. After the phase compensation operation is performed on the complex pseudo-code sequence, the corresponding real-number pseudo-code sequence can be obtained.

It should be noted that "correlation" in related operations is the abbreviation for interrelatedness. The basic method of related operations is to first turn the thing under study into a signal, then compare the signals, and the mathematical formulas on which the comparison is based have a correlation coefficient. and related functions. Specifically, the correlation coefficient is a number that represents the similarity between two signals of equal length. Correlation functions are further divided into autocorrelation functions and cross-correlation functions. If the signals involved in the comparison are the same signal, the correlation function is called the autocorrelation function; if the signals involved in the comparison are different signals, the correlation function is called the cross-correlation function.

Specifically, the phase hopping sequence is used to control the hopping offset of the phase, which refers to the hopping offset of the phase of the control sequence symbol relative to the initial phase of the carrier.

In an optional embodiment, the second multi-ary system phase hopping sequence is c _PH (k); k represents the serial number of discrete symbols; subscript PH is the abbreviation of phase hopping (Phase Hopping);

Based on the coding rule between the multi-ary phase hopping sequence and the binary phase hopping sequence, map c _PH (k) into two sequences, the binary phase hopping sequence c ₁ (k) and the phase compensation sequence c ₂ (k);

c ₁ (k) is a binary sequence, and its level value is {-1,+1}; the specific value rules are as follows:

Among them, N represents the system of the multi-ary phase hopping sequence; the residual part c _Δ (k) of c _PH (k) in the mapping process is: c _Δ (k)=c _PH (k)%(N/2), Among them, % represents the remainder operation;

Among them, M represents the maximum value of the counter in the carrier digital oscillator.

In an optional embodiment, the phase compensation sequence c ₂ (k) is used as the increment sequence of the carrier digital oscillator, so as to obtain the local reference carrier with the phase compensation function.

In an optional embodiment, the receiving end generates a local reference carrier based on the count value of the carrier digital oscillator;

A value corresponding to the phase compensation sequence is added to the count value of the carrier digital oscillator on the basis of the current count, so that the local reference carrier generated by the carrier digital oscillator has a phase compensation function.

In an optional embodiment, the complex pseudo-code sequence is phase-compensated to obtain a real-number pseudo-code sequence, so that the corresponding poly-ary sequence is converted into a binary sequence, so as to simplify the complex-number correlation operation steps in the original signal tracking method to real numbers relevant steps;

By controlling the count of the carrier digital oscillator, the relevant parameters of the phase compensation operation for the complex pseudo-code sequence are pre-synchronized and loaded into the carrier stripping step, so as to avoid the need for a separate phase compensation operation after stripping the carrier. , to simplify the signal tracking steps.

In a second aspect, the present invention provides a tracking system for a multi-ary phase hopping spread spectrum modulation signal, characterized in that it includes:

The signal acquisition unit is used to acquire the phase-hopping spread spectrum modulation signal sent by the transmitting end; the phase-hopping spread spectrum modulation signal includes a carrier wave, a complex pseudo-code sequence and data of the transmitting end; the complex pseudo-code sequence is generated by the transmitting end. A multi-ary phase hopping sequence is determined; wherein, the phase hopping sequence is a random sequence or a pseudo-random sequence, which is used to control the hopping offset of the phase;

The sequence generation unit is configured to generate the second multi-ary phase hopping sequence with reference to the way in which the transmitting end generates the first multi-ary phase hopping sequence, and based on the coding rule between the multi-ary phase hopping sequence and the binary phase hopping sequence, the first multi-ary phase hopping sequence is generated. The binary phase hopping sequence is mapped into a binary phase hopping sequence and a phase compensation sequence;

a carrier generation unit, configured to generate a local reference carrier with a phase compensation function in combination with the determination method of the carrier in the phase-hopping spread spectrum modulation signal and the phase compensation sequence;

The phase compensation unit is used for stripping the carrier in the phase-hopping spread spectrum modulation signal based on the local reference carrier with the phase compensation function and performing phase compensation on the complex pseudo-code sequence to obtain a real-number pseudo-code sequence and transmitting end data;

A data tracking unit, configured to perform a correlation operation between the binary phase hopping sequence, the real-number pseudocode sequence and the data of the sender, and obtain the data of the sender by tracking.

其中，N表示多进制跳相序列的进制。映射过程中c_PH(k)的残留部分c_Δ(k)为：c_Δ(k)＝c_PH(k)％(N/2)，其中，％代表取余数运算；

其中，M代表载波数字振荡器中计数器的最大值。In an optional embodiment, the second multi-ary phase hopping sequence generated by the sequence generating unit is c _PH (k); k represents the serial number of discrete symbols; the subscript PH is the abbreviation of phase hopping; The coding rule between binary phase hopping sequence and binary phase hopping sequence, mapping c _PH (k) into binary phase hopping sequence c ₁ (k) and phase compensation sequence c ₂ (k) two sequences; c ₁ (k ) is a binary sequence, and its level value is {-1,+1}; the specific value rules are as follows:

Among them, N represents the base of the multi-ary phase hopping sequence. The residual part c _Δ (k) of c _PH (k) in the mapping process is: c _Δ (k)=c _PH (k)% (N/2), where % represents the remainder operation;

Among them, M represents the maximum value of the counter in the carrier digital oscillator.

In an optional embodiment, the carrier generation unit uses the phase compensation sequence c ₂ (k) as the increment sequence of the carrier digital oscillator, so as to obtain a local reference carrier with a phase compensation function.

In an optional embodiment, the carrier generation unit generates a local reference carrier based on the count value of the carrier digital oscillator; and increases the count value of the carrier digital oscillator on the basis of the current count by the phase compensation sequence corresponding to the value so that the local reference carrier generated by the carrier digital oscillator is phase compensated.

In an optional embodiment, the phase compensation unit obtains a real-numbered pseudo-code sequence after phase compensation of the complex-numbered pseudo-code sequence, so that the corresponding multi-ary sequence is converted into a binary sequence, so as to correlate the complex number in the original signal tracking method The operation steps are simplified to real number related steps;

By controlling the count of the carrier digital oscillator, the carrier generation unit pre-synchronously loads the relevant parameters of the phase compensation operation on the complex pseudocode sequence into the carrier stripping step, so as to avoid the need to separate the carrier stripping process after stripping the carrier. Perform phase compensation operations to simplify signal tracking steps.

In general, compared with the prior art, the above technical solutions conceived by the present invention have the following beneficial effects:

The present invention provides a method and system for tracking a multi-ary phase-hopping spread spectrum modulation signal. The real-number pseudo-code sequence is obtained by phase-compensating the complex pseudo-code sequence, so that the corresponding multi-ary sequence is converted into a binary sequence, so as to convert the original pseudo-code sequence into a binary sequence. The complex correlation operation steps in the signal tracking method are simplified to real correlation. Since the carrier loop has the function of adjusting the phase, this phase compensation operation can be accomplished with the help of the carrier loop. It only needs to introduce an additional adder in the carrier loop, and the implementation complexity is much lower than that of the complex correlator. At the same time, since the main autocorrelation peak of the real-number pseudo-code sequence is approximately the same as that of the complex-number pseudo-code sequence, the present invention can reduce the realization complexity of the tracking loop on the premise that the positioning accuracy is not lost.

Description of drawings

Fig. 1 is the tracking system flow chart of the existing multi-ary system phase hopping spread spectrum modulation signal;

Fig. 2 is the tracking method flow chart of the multi-system phase hopping spread spectrum modulation signal provided by the present invention;

Fig. 3 is the tracking loop flow chart of the multi-ary phase hopping spread spectrum modulation signal provided by the present invention;

和映射得到的二进制跳相序列c₁(k)的自相关函数主峰图；Fig. 4 is the equivalent pseudo-code sequence obtained by the simulation of the present invention

and the main peak map of the autocorrelation function of the binary phase-hopping sequence c ₁ (k) obtained by mapping;

5 is a comparison diagram of the simulation results of the code tracking accuracy of the PH-BPSK(1) signal by the tracking method 1 and the tracking method 2 provided by the present invention;

6 is a comparison diagram of the simulation results of the code tracking accuracy of the PH-BOCs (10,5) signal provided by the first tracking method and the second tracking method provided by the present invention;

Fig. 7 is a tracking method provided by the present invention and tracking method 2 to the code tracking accuracy simulation result comparison diagram of PH-BOCc (10,5) signal;

FIG. 8 is an architectural diagram of a tracking system for a multi-ary phase hopping spread spectrum modulation signal provided by the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The present invention provides a method for tracking a multi-ary phase hopping spread spectrum modulated signal, as shown in Figure 2, comprising the following steps:

S210, the receiving end acquires the phase-hopping spread spectrum modulation signal sent by the transmitting end; the phase-hopping spread spectrum modulation signal includes a carrier, a complex pseudo-code sequence, and data of the transmitting end; the complex pseudo-code sequence is generated by the transmitting end of the first The phase hopping sequence is determined by the system; wherein, the phase hopping sequence is a random sequence or a pseudo-random sequence, which is used to control the hopping offset of the phase;

S220, the receiving end generates a second multi-ary phase hopping sequence with reference to the manner in which the transmitting end generates the first multi-ary phase hopping sequence, and based on the coding rule between the multi-ary phase hopping sequence and the binary phase hopping sequence, converts the second multi-ary phase hopping sequence into the second multi-ary phase hopping sequence. The binary phase hopping sequence is mapped into a binary phase hopping sequence and a phase compensation sequence;

S230, the receiving end generates a local reference carrier with a phase compensation function in combination with the determination method of the carrier in the phase-hopping spread spectrum modulation signal and the phase compensation sequence;

S240, the receiving end strips the carrier in the phase-hopping spread spectrum modulation signal based on the local reference carrier with the phase compensation function, and performs phase compensation on the complex pseudo-code sequence to obtain a real-number pseudo-code sequence and data at the transmitting end ; Described real-number pseudo-code sequence is the complex-number pseudo-code sequence after phase compensation;

S250, the receiving end performs a correlation operation on the binary phase hopping sequence, the real-number pseudocode sequence, and the data of the transmitting end, and obtains the data of the transmitting end by tracking.

The present invention does not need to use a phase compensator for complex correlation by mapping a multi-ary sequence into a binary sequence, but only needs to use a simple real number correlator, which reduces the complexity of the tracking loop. In order not to lose the correlation performance of the signal, it is necessary to perform corresponding phase compensation on the received signal according to the mapping rule before correlation, and this phase compensation operation can be completed by a phase compensator. But to further reduce receiver complexity, this phase compensation operation can be implemented in a carrier digital oscillator (numerically controlled oscillator, NCO). Figure 3 shows a tracking loop based on carrier phase compensation assistance.

As shown in Figure 3, the received IF signal is first mixed with the local reference carrier to strip the carrier from the signal, which is generated by the carrier NCO; at the same time, phase compensation is performed based on the fact that the carrier loop can adjust the phase Operation, the phase compensation operation is performed depending on the phase compensation sequence c ₂ (k), and the phase compensation sequence can be obtained from the phase hopping sequence c _PH (k) by looking up the phase mapping table. Then, the signal after mixing and phase compensation is subjected to real number correlation operation with the binary pseudo code c ₁ (k) obtained by mapping, and the binary pseudo code can be obtained by looking up the phase mapping table from the phase hopping sequence c _PH (k), and then through coherent integration After the sum incoherent accumulation operation, on the one hand, the pseudocode can be stripped to obtain the data of the sender. For example, when the signal tracking method is applied to the field of navigation, the data of the sender can be a navigation message. On the other hand, the code tracking error can be obtained by the code loop discriminator. Finally, the local reference carrier frequency is adjusted according to the carrier tracking error output by the carrier loop discriminator, and the phase of the locally reproduced pseudo-code is adjusted according to the code tracking error to realize the closed-loop feedback of the tracking loop.

Further, i and q in FIG. 3 are the in-phase branch and quadrature branch signals after frequency mixing and carrier phase compensation, respectively, wherein the purpose of frequency mixing is to strip the carrier. i _E , i _P and i _L are respectively the leading, immediate and lagging branch signals after multiplication by the local pseudocode on the in-phase branch; _IE , _IP and _IL are the correlation summation with the local pseudo code on the in-phase branch respectively The leading, immediate and lagging branch signals after coherent integration; q _E , q _P and q _L are the leading, immediate and lagging branch signals after multiplication with the local pseudocode on the quadrature branch, respectively; _{Q E} , QP and _QL are the leading, immediate and lagging branch signals after correlation and coherent integration with the local pseudocode on the quadrature branch, respectively.

It can be seen from Fig. 3 that the phase hopping sequence c _PH (k) generated by the phase hopping sequence generator is mapped into two sequences c ₁ (k) and c ₂ (k) by looking up the phase mapping table. c ₁ (k) is a binary sequence, and its level value is {-1,+1}. Because the phase-hopping sequence is a pseudo-random sequence, the highest bit of the binary form of the phase-hopping sequence can be used to complete the mapping of the multi-ary sequence to the binary sequence. The rules are as follows:

Follow the above rules. Then the residual part of c _Δ (k) of c _PH (k) in the mapping process is:

c _Δ (k)=c _PH (k)% (N/2)

Among them, % represents the remainder operation.

进行因式分解：From the point of view of equivalent pseudocode, it is

Do the factorization:

进行因式分解后的公式和复数相关的定义，这种补偿就是使接收信号乘以

即可。这样接收信号中的等效多进制伪码序列就被转换成二进制伪码序列，在相关运算的时候只需要进行实数相关即可，即可以使用简单的乘法器来代替相位补偿器。Therefore, in order not to attenuate the correlation performance of the signal, it is necessary to perform some compensation on the received signal before correlation. According to the

The formula after factoring and the definition of complex number correlation, this compensation is to multiply the received signal by

That's it. In this way, the equivalent multi-ary pseudo-code sequence in the received signal is converted into a binary pseudo-code sequence, and only real number correlation is required in the correlation operation, that is, a simple multiplier can be used to replace the phase compensator.

To further simplify the tracking loop, phase compensation can be done based on the fact that the carrier NCO can adjust the phase. The carrier NCO can be regarded as a counter, and the local replica sine and cosine carriers can be generated by querying the look-up table according to the count value of the counter. When the counter overflows, it will be cleared, so one cycle of the carrier is equal to the time that the counter in the NCO counts from 0 to the maximum value, and the increment of each count of the counter is determined according to the output of the carrier loop filter, so the increment of the counter is adjusted. The carrier frequency can be adjusted. The phase compensation operation can be regarded as adding a value to the current count value of the counter, so another sequence c ₂ (k) output by the phase mapping table can be obtained as:

Among them, M represents the maximum value of the counter in the carrier NCO. Taking c ₂ (k) as the increment sequence of the carrier NCO, the phase compensation of the received signal is completed, and the following operations are consistent with the direct sequence spread spectrum navigation signal.

In a specific embodiment, the present invention simulates and analyzes the code tracking performance of the two designed tracking algorithms. The matching correlation-based tracking algorithm shown in FIG. 1 is called tracking method 1. The tracking algorithm based on carrier phase compensation assistance shown here is called tracking method two.

和由跳相序列c_PH(k)映射得到的二进制伪码序列c₁(k)的自相关性能。图4为其自相关函数的主峰。从图4可以看出，等效伪码和二进制伪码的自相关函数主峰几乎一致，而导航信号的定位精度主要由信号的自相关函数主峰决定，因此跟踪方法二是可行的，并且不会降低跳相扩频导航信号的定位精度。In order to verify the feasibility of tracking method 2, the equivalent pseudocode sequence is simulated first.

and the autocorrelation performance of the binary pseudocode sequence c ₁ (k) mapped from the phase-hopping sequence c _PH (k). Figure 4 shows the main peak of its autocorrelation function. It can be seen from Figure 4 that the main peaks of the autocorrelation function of the equivalent pseudocode and the binary pseudocode are almost the same, and the positioning accuracy of the navigation signal is mainly determined by the main peak of the autocorrelation function of the signal. Therefore, the second tracking method is feasible and will not Reduce the positioning accuracy of the phase-hopping spread spectrum navigation signal.

Fig. 5, Fig. 6 and Fig. 7 simulate the codes of three modulated signals, PH-BPSK(1), PH-BOCs(10,5) and PH-BOCc(10,5), for tracking method 1 and tracking method 2, respectively. tracking accuracy. These three modulation signals correspond to the commonly used BPSK(1), BOCs(10,5) and BOCc(10,5) signals, but the direct sequence spread spectrum modulation in the common signal modulation process is replaced by phase hopping. PH modulation. It can be seen from these three figures that the code tracking accuracy of tracking method 1 and tracking method 2 are comparable, and they are in good agreement with the theoretical values. caused by white noise.

It can be seen from the above simulation results that both the tracking method 1 and the tracking method 2 can effectively track the phase-hopping spread spectrum navigation signal, and have comparable code tracking performance. However, compared with the first tracking method, the second tracking method has lower hardware complexity when it is implemented. Table 1 lists the implementation complexity of the correlator portion of the two tracking loops. In terms of look-up table, a look-up table is needed in the phase compensator of tracking method 1 to complete the mapping between the phase hopping sequence and the equivalent pseudo-code sequence. Three phase compensators can share a look-up table; tracking method 2 requires a phase mapping The table completes the mapping of the phase hopping sequence to the binary pseudocode sequence and the phase compensation sequence. In terms of adders, there are 2 adders in each phase compensator. Tracking method 1 requires a total of 6 adders; tracking method 2 only needs 1 adder, which is used at the output of the carrier NCO to realize the receiving Phase compensation of the signal. In terms of multipliers, there are 4 multipliers in each phase compensator, and the tracking method requires a total of 12 multipliers; the second tracking method requires a total of 6 multipliers. Therefore, the tracking method 2 requires 5 adders and 6 multipliers in total less than the tracking method, the implementation structure is simpler, and the corresponding operation complexity is also lower. In addition, for the tracking method 1, the multiplier needs to realize the product of the front-end data stream and the multi-binary local pseudocode waveform, while the tracking method 2 only needs to realize the product of the front-end data stream and the binary local pseudocode waveform, and the complexity of multiplication is doubled. reduce. To sum up, the implementation complexity of tracking method 2 is significantly lower than that of method 1.

Table.1 Implementation complexity table of the correlator part of the two tracking methods

lookup table adder multiplier Tracking method one 1 6 12 Tracking method two 1 1 6

Specifically, the first tracking method is based on the perfect matching correlation principle. If the tracking loop is designed based on the perfect matching correlation principle, the loss of correlation performance will not be caused, and the best code tracking accuracy can theoretically be achieved. However, for the phase-hopping spread spectrum navigation signal, the complete matching correlation needs to be realized by complex correlation, and the realization complexity of complex correlation is relatively high.

Correspondingly, referring to the above Table 1, the implementation complexity of the tracking method (tracking method 2) provided by the present invention is lower than that of the tracking method 1, that is, the present invention can reduce the tracking algorithm compared with the prior art without reducing the tracking accuracy. complexity.

Fig. 8 is the tracking system architecture diagram of the multi-ary phase hopping spread spectrum modulation signal provided by the present invention, as shown in Fig. 8, this system comprises:

The signal acquisition unit 810 is used to acquire the phase-hopping spread spectrum modulation signal sent by the transmitting end; the phase-hopping spread spectrum modulation signal includes a carrier wave, a complex pseudo-code sequence and data of the transmitting end; the complex pseudo-code sequence is generated by the transmitting end. The first multi-ary phase hopping sequence is determined; wherein, the phase hopping sequence is a random sequence or a pseudo-random sequence, and is used to control the hopping offset of the phase;

The sequence generation unit 820 is configured to generate the second multi-ary phase hopping sequence with reference to the manner in which the transmitting end generates the first multi-ary phase hopping sequence, and based on the coding rule between the multi-ary phase hopping sequence and the binary phase hopping sequence, The second multi-ary phase hopping sequence is mapped into a binary phase hopping sequence and a phase compensation sequence;

a carrier generation unit 830, configured to generate a local reference carrier with a phase compensation function in combination with the determination method of the carrier in the phase-hopping spread spectrum modulation signal and the phase compensation sequence;

The phase compensation unit 840 is configured to strip the carrier in the phase-hopping spread spectrum modulation signal based on the local reference carrier with the phase compensation function and perform phase compensation on the complex pseudo-code sequence to obtain a real-number pseudo-code sequence and Sending end data; the real-number pseudo-code sequence is a complex-number pseudo-code sequence after phase compensation;

The data tracking unit 850 is configured to perform a correlation operation between the binary phase hopping sequence, the real-number pseudocode sequence and the data of the sender, and obtain the data of the sender by tracking.

It should be noted that, for the specific functions of each unit in FIG. 8 , reference may be made to the introduction in the foregoing method embodiments, and details are not described here.

Those skilled in the art can easily understand that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, etc., All should be included within the protection scope of the present invention.

Claims (10)

1. A method for tracking a multilevel phase-hopping spread spectrum modulation signal, comprising the steps of:

a receiving end acquires a phase hopping spread spectrum modulation signal sent by a sending end; the hopping spread spectrum modulation signal comprises a carrier, a complex pseudo code sequence and sending end data; the complex pseudo code sequence is determined by a first multilevel phase hopping sequence generated by a sending end; the hopping sequence is a random sequence or a pseudo-random sequence and is used for controlling the hopping offset of the phase;

the receiving end generates a second multi-system phase hopping sequence according to the mode that the transmitting end generates the first multi-system phase hopping sequence, and the second multi-system phase hopping sequence is mapped into a binary phase hopping sequence and a phase compensation sequence based on a coding rule between the multi-system phase hopping sequence and the binary phase hopping sequence;

the receiving end combines the carrier determining mode in the hopping phase spread spectrum modulation signal and the phase compensation sequence to generate a local reference carrier with a phase compensation function;

the receiving end strips the carrier in the phase hopping spread spectrum modulation signal based on a local reference carrier with a phase compensation function and performs phase compensation on the complex pseudo code sequence to obtain a real pseudo code sequence and sending end data;

and the receiving end performs related operation on the binary phase hopping sequence, the real pseudo code sequence and the sending end data, and tracks to obtain the sending end data.

2. The method of claim 1 wherein the second multilevel phase hopping spread spectrum modulation signal is c_PH(k) (ii) a k represents the number of discrete symbols; subscript PH is abbreviation of phase jump;

c is determined based on the coding rule between the multi-system phase hopping sequence and the binary phase hopping sequence_PH(k) Mapping to binary phase hopping sequence c₁(k) And phase compensation sequence c₂(k) Two sequences;

c₁(k) the method is a binary sequence, and the level value of the binary sequence is { -1, +1 }; the specific value rule is as follows:

wherein N represents the system of multi-system phase jump sequence, c in the mapping process_PH(k) Residual part c of_Δ(k) Comprises the following steps: c. C_Δ(k)＝c_PH(k) Percent (N/2), wherein,% represents the remainder calculation;

where M represents the maximum value of the counter in the carrier digital oscillator.

3. The method of claim 2, wherein the phase compensation sequence c is a phase compensation sequence₂(k) As an incremental sequence of carrier digital oscillators to obtain a local reference carrier with phase compensation function.

4. The method according to claim 3, wherein a receiving end generates a local reference carrier based on the count value of the carrier digital oscillator;

and increasing the count value of the carrier digital oscillator by a value corresponding to the phase compensation sequence on the basis of the current count so that the local reference carrier generated by the carrier digital oscillator has a phase compensation function.

5. The method according to any one of claims 1 to 4, wherein a real pseudo code sequence is obtained after phase compensation of a complex pseudo code sequence, so that the corresponding multilevel sequence is converted into a binary sequence, thereby simplifying the complex correlation operation step in the original signal tracking method to a real correlation operation step;

by controlling the counting of the carrier digital oscillator, the relevant parameters for carrying out the phase compensation operation on the complex pseudo code sequence are synchronously loaded in the carrier stripping step in advance, so that the operation of separately carrying out the phase compensation after the carrier is stripped is avoided, and the signal tracking step is simplified.

6. A system for tracking a multilevel phase hopped spread spectrum modulated signal, comprising:

the signal acquisition unit is used for acquiring a phase hopping spread spectrum modulation signal sent by a sending end; the hopping spread spectrum modulation signal comprises a carrier, a complex pseudo code sequence and sending end data; the complex pseudo code sequence is determined by a first multilevel phase hopping sequence generated by a sending end; the hopping sequence is a random sequence or a pseudo-random sequence and is used for controlling the hopping offset of the phase;

the sequence generating unit is used for generating a second multi-system phase hopping sequence according to the mode that the transmitting end generates the first multi-system phase hopping sequence, and mapping the second multi-system phase hopping sequence into a binary phase hopping sequence and a phase compensation sequence based on a coding rule between the multi-system phase hopping sequence and the binary phase hopping sequence;

the carrier generation unit is used for generating a local reference carrier with a phase compensation function by combining the determination mode of the carrier in the phase hopping spread spectrum modulation signal and the phase compensation sequence;

the phase compensation unit is used for stripping the carrier wave in the phase-hopping spread spectrum modulation signal based on a local reference carrier wave with a phase compensation function and performing phase compensation on the complex pseudo code sequence to obtain a real pseudo code sequence and sending end data;

and the data tracking unit is used for performing related operation on the binary phase hopping sequence, the real pseudo code sequence and the sending end data, and tracking to obtain the sending end data.

7. The tracking system for spread spectrum modulated multilevel phase hopping signal according to claim 6, wherein the second multilevel phase hopping sequence generated by said sequence generating unit is c_PH(k) (ii) a k represents a discrete symbolThe serial number of (2); subscript PH is abbreviation of phase jump; c is determined based on the coding rule between the multi-system phase hopping sequence and the binary phase hopping sequence_PH(k) Mapping to binary phase hopping sequence c₁(k) And phase compensation sequence c₂(k) Two sequences; c. C₁(k) The method is a binary sequence, and the level value of the binary sequence is { -1, +1 }; the specific value rule is as follows:

wherein N represents the system of multi-system phase jump sequence, c in the mapping process_PH(k) Residual part c of_Δ(k) Comprises the following steps: c. C_Δ(k)＝c_PH(k) Percent (N/2), wherein,% represents the remainder calculation;

where M represents the maximum value of the counter in the carrier digital oscillator.

8. The system for tracking a multilevel phase-hopped spread spectrum modulated signal of claim 7, wherein said carrier generation unit is configured to phase compensate sequence c₂(k) As an incremental sequence of carrier digital oscillators to obtain a local reference carrier with phase compensation function.

9. The tracking system for a multilevel phase-hopping spread spectrum modulation signal according to claim 8, wherein said carrier generation unit generates a local reference carrier based on a count value of said carrier digital oscillator; and increasing the count value of the carrier digital oscillator by a value corresponding to the phase compensation sequence on the basis of the current count so that the local reference carrier generated by the carrier digital oscillator has a phase compensation function.

10. The tracking system of the multilevel phase-hopping spread spectrum modulation signal according to any one of claims 6 to 9, wherein the phase compensation unit obtains a real number pseudo code sequence after performing phase compensation on the complex number pseudo code sequence, so that the corresponding multilevel sequence is converted into a binary sequence, thereby simplifying a complex number correlation operation step in an original signal tracking method into a real number correlation step;

the carrier generation unit synchronously loads relevant parameters for performing phase compensation operation on the complex pseudo code sequence into the carrier stripping step in advance through controlling the counting of the carrier digital oscillator, so that the operation of separately performing phase compensation after the carrier is stripped is avoided, and the signal tracking step is simplified.

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