CN117792428A - Spread spectrum signal carrier recovery method and related assembly - Google Patents
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Abstract
The invention relates to the technical field of wireless communication, and provides a spread spectrum signal carrier recovery method and related components, wherein the method comprises the following steps: firstly, carrying out rough frequency capturing on a tracked spread spectrum signal by utilizing FFT, carrying out frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal estimated by FFT, and enabling the signal with residual frequency deviation and phase deviation after compensation to enter a baseband phase-locked loop to carry out subsequent residual frequency tracking; and the tracked frequency is correspondingly divided to obtain a capture mark signal and a despreading signal of the spreading signal; and meanwhile, combining a control mechanism for controlling the compensation updating of the FFT by capturing the mark signal, and completing carrier recovery of spread spectrum weak signals in a high dynamic environment.
Description
Technical Field
The present invention relates to the field of wireless communications technologies, and in particular, to a method for recovering a spread spectrum signal carrier and related components.
Background
The direct sequence spread spectrum system is an information transmission system which uses a spread spectrum code sequence with high code rate to spread the frequency spectrum of a signal to be transmitted at a transmitting end, so that the signal to be transmitted becomes a broadband signal to be transmitted in a channel, and uses the same spread spectrum code sequence to despread at a receiving end, so that the spread spectrum signal is despread and the original signal is recovered. The system has the characteristics of low signal spectrum density and strong anti-interference and anti-fading capability, and is widely applied to the fields of military communication, satellite communication and the like. Carrier synchronization technology is one of the key technologies in this system. The receiving end captures and tracks the spreading code of the transmitting end and generates a spreading code phase completely consistent with the spreading code phase of the transmitting end so as to complete the despreading of the spread spectrum signal. Despreading of spread spectrum signals is often a coherent process, and the completion of the coherent process requires accurate carrier synchronization and recovery, so that the performance of the carrier synchronization technique directly affects the performance of the direct sequence spread spectrum system.
The carrier synchronization method commonly used at present is a carrier synchronization loop based on a phase-locked loop, which realizes the tracking of carrier signals by means of a phase discriminator, a numerical control oscillator and a loop filter, but under the environment of high dynamic state, larger Doppler frequency shift and lower signal to noise ratio, the fast frequency and phase locking and stable tracking are difficult to realize, which definitely limits the application environment of a direct-expansion system.
Disclosure of Invention
The invention provides a spread spectrum signal carrier recovery method and related components, which are used for solving the defect that a phase-locked loop is difficult to quickly lock frequency and phase in the environment with high dynamic state, larger Doppler frequency shift and lower signal-to-noise ratio in the prior art.
The invention provides a spread spectrum signal carrier recovery method, which comprises the following steps: performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal; performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a capture mark signal and a despread signal of the spread spectrum signal; the code element of the frequency compensated signal adopts a sectional accumulation mode in the baseband phase-locked loop; repeating the iterative execution of the frequency compensation step and the residual frequency step until the acquisition marker signal is an acquisition success signal and a despread signal corresponding to the acquisition success signal is used as a final carrier recovery signal under the condition that the acquisition marker signal is an acquisition failure signal; the acquisition failure signal is opposite to the acquisition success signal.
According to the method for recovering the carrier of the spread spectrum signal provided by the invention, before the spread spectrum signal is subjected to FFT, the method further comprises the following steps: and carrying out serial-parallel conversion on the spread spectrum signal to obtain parallel data for FFT conversion.
According to the method for recovering the carrier of the spread spectrum signal, the frequency compensation is carried out on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal, so as to obtain the frequency compensated signal, and the method comprises the following steps: performing spectrum accumulation on the spread spectrum signal to obtain a spectrum accumulation value; determining a first frequency control word corresponding to the first voltage-controlled oscillator according to the frequency spectrum accumulated value; determining a carrier complex signal of a first negative frequency according to the first frequency control word; multiplying the spread spectrum signal with the carrier complex signal of the first negative frequency to obtain the frequency compensated signal.
According to the method for recovering the carrier of the spread spectrum signal provided by the invention, the residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain the capture mark signal and a despread signal of the spread spectrum signal, and a code element of the frequency compensated signal adopts a sectional accumulation mode in the baseband phase-locked loop, and the method comprises the following steps: carrying out sectional accumulation processing on the code elements of the frequency compensated signal to obtain a sectional accumulated signal; phase discrimination is carried out on the signals after the sectional accumulation to obtain signals after phase discrimination; loop filtering is carried out on the phase-authenticated signal to obtain a filtered signal; determining a second frequency control word corresponding to a second voltage-controlled oscillator and a third frequency control word corresponding to a timer according to the filtered signal; determining a carrier complex signal of a second negative frequency according to the second frequency control word; dividing the frequency of the carrier complex signal with the second negative frequency to obtain a signal after frequency division; multiplying the frequency-divided signal with the frequency-compensated signal to obtain a despread signal of the spread spectrum signal; and determining the capture flag signal according to the third frequency control word.
According to the method for recovering the carrier of the spread spectrum signal, the determining the capture flag signal according to the third frequency control word includes: determining the variance of the timer in a preset time period according to the third frequency control word; when the variance in the preset time period is larger than a preset threshold value, the capture flag signal is the capture success signal; and when the variance in the preset time period is larger than a preset threshold value, the capture flag signal is the capture failure signal.
The invention also provides a spread spectrum signal carrier recovery system, which comprises: the FFT conversion module is used for carrying out FFT conversion on the tracked spread spectrum signal to obtain the frequency spectrum of the spread spectrum signal; the frequency compensation module is used for carrying out frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; the baseband phase-locked loop is used for carrying out residual frequency tracking and frequency division on the frequency compensated signal to obtain a capture mark signal and a despread signal of the spread spectrum signal; the code element of the frequency compensated signal adopts a sectional accumulation mode in the baseband phase-locked loop; the iteration module is used for repeatedly and iteratively executing the frequency compensation step and the residual frequency step under the condition that the capture mark signal is a capture failure signal until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
The invention also provides a spread spectrum signal carrier recovery system, which further comprises: and the serial-parallel conversion module is used for carrying out serial-parallel conversion on the spread spectrum signal to obtain parallel data for FFT conversion.
The invention also provides an electronic device comprising a memory, a processor and a computer program stored on the memory and operable on the processor, the processor implementing a spread spectrum signal carrier recovery method as described above when executing the program.
The invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, implements a spread spectrum signal carrier recovery method as described in any of the above.
The invention also provides a computer program product comprising a computer program which when executed by a processor implements a spread spectrum signal carrier recovery method as described in any one of the above.
The invention provides a spread spectrum signal carrier recovery method and related components, wherein the method comprises the following steps: firstly, carrying out rough frequency capturing on a tracked spread spectrum signal by utilizing FFT, carrying out frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal estimated by FFT, and enabling the signal with residual frequency deviation and phase deviation after compensation to enter a baseband phase-locked loop to carry out subsequent residual frequency tracking; and the tracked frequency is correspondingly divided to obtain a capture mark signal and a despreading signal of the spreading signal; and meanwhile, combining a control mechanism for controlling the compensation updating of the FFT by capturing the mark signal, and completing carrier recovery of spread spectrum weak signals in a high dynamic environment.
Drawings
In order to more clearly illustrate the invention or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of a method for recovering a carrier of a spread spectrum signal according to the present invention;
fig. 2 is a specific flow chart of a method for recovering a carrier of a spread spectrum signal according to the present invention;
fig. 3 is a schematic structural diagram of a carrier recovery system for spread spectrum signals according to the present invention;
FIG. 4 is a plot of FFT spectrum accumulation sum output;
FIG. 5 is a single FFT spectrum output plot;
FIG. 6 is a graph of baseband phase locked loop tracking residual frequency differences;
FIG. 7 is a graph of the residual frequency difference of a conventional phase-locked loop tracking;
fig. 8 is a schematic structural diagram of an electronic device provided by the present invention.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Considering that in a high dynamic environment, a spread spectrum signal often has larger doppler frequency offset, and the spread spectrum signal is also greatly interfered by external noise and is interfered by noise, a phase-locked loop often has difficulty in locking offset frequency and phase, even the locking can take a long time, and the phenomenon that the carrier frequency is unlocked due to larger frequency fluctuation is likely to occur.
Referring to fig. 1, fig. 1 is a flowchart of a method for recovering a spread spectrum signal carrier according to the present invention.
In order to solve the technical problems existing in the prior art, the invention provides a spread spectrum signal carrier recovery method, which comprises the following steps:
101: performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal;
102: performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal;
103: residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a despread signal of a capture mark signal and a spread spectrum signal; the code element of the signal after frequency compensation adopts a sectional accumulation mode in a baseband phase-locked loop;
104: under the condition that the capture mark signal is a capture failure signal, repeating the iterative execution of the frequency compensation step and the residual frequency step until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
Specifically, the invention is mainly a carrier synchronization part of a direct sequence spread spectrum system, and the input signal is a complex signal with large frequency offset which realizes the capture and tracking of spread spectrum codes and completes the corresponding point multiplication and despreading. Firstly, carrying out rough frequency capturing on a spread spectrum signal which is input into a phase-locked loop and is subjected to tracking, utilizing FFT (Fast Fourier Transformation, fast Fourier transform), carrying out frequency compensation on the spread spectrum signal according to the frequency corresponding to the peak value estimated by the FFT, and carrying out subsequent tracking on the residual frequency by entering the baseband phase-locked loop on the signal with residual frequency offset and phase offset after compensation; and the tracked frequency is correspondingly divided to obtain a capture mark signal and a despreading signal of the spreading signal; and meanwhile, combining a control mechanism for controlling the compensation updating of the FFT by capturing the mark signal, and completing carrier recovery of spread spectrum weak signals in a high dynamic environment.
In addition, the baseband phase-locked loop may include a phase detector, a loop filter, a voltage controlled oscillator, and a frequency division module, and the present invention is not particularly limited herein.
The capture process signal may be 0 and the capture success signal may be 1, and the present invention is not particularly limited herein.
Based on the above embodiments:
referring to fig. 2, fig. 2 is a specific flow chart of a method for recovering a spread spectrum signal carrier according to the present invention.
As a preferred embodiment, before performing FFT transformation on the spread spectrum signal, the method further includes: and carrying out serial-parallel conversion on the spread spectrum signals to obtain parallel data for FFT conversion.
Specifically, the despread complex signal is first passed through N 0 The parallel data is input into an FFT module to obtain N 0 The output spectrum of the points.
As a preferred embodiment, frequency compensating the spread spectrum signal according to the spectrum of the spread spectrum signal to obtain a frequency compensated signal, including: performing spectrum accumulation on the spread spectrum signal to obtain a spectrum accumulation value; determining a first frequency control word corresponding to the first voltage-controlled oscillator according to the frequency spectrum accumulated value; determining a carrier complex signal of a first negative frequency according to the first frequency control word; multiplying the spread spectrum signal with the carrier complex signal of the first negative frequency to obtain a frequency compensated signal.
Specifically, the output spectrum enters a spectrum accumulation module, and a waiting timing steady-state module inputs a capture flag signal and an accumulation zero clearing signal.
Deciding whether to output a spectrum value maximum selector (initial capture flag signal is capture process signal) according to the capture flag signal is capture process signal or capture success signal, inputting the spectrum value into the maximum selector by the capture flag signal is capture process signal, and resetting the accumulated number; the capture flag signal is a capture success signal, and the maximum selector does not update the input, maintaining the original input.
Maximum selector is based onInputting the corresponding frequency found by the spectral line, selecting corresponding frequency control word, and controlling the first voltage-controlled oscillator NCO 1 A corresponding carrier complex signal of a first negative frequency is generated.
Despread complex signal and NCO 1 Generating a corresponding complex carrier signal with a first negative frequency to perform complex multiplication, performing preliminary compensation on the larger frequency offset, adding the compensated complex signal with the residual frequency offset, and inputting the complex signal into a baseband phase-locked loop.
As a preferred embodiment, the residual frequency tracking and frequency division are performed on the frequency compensated signal by the baseband phase-locked loop to obtain a despread signal of the acquisition flag signal and the spread spectrum signal, and the symbol of the frequency compensated signal adopts a segment accumulation mode in the baseband phase-locked loop, which includes: carrying out sectional accumulation processing on code elements of the frequency compensated signal to obtain a sectional accumulated signal; phase discrimination is carried out on the signals after the sectional accumulation to obtain signals after the phase discrimination; loop filtering is carried out on the phase-authenticated signal to obtain a filtered signal; determining a second frequency control word corresponding to the second voltage-controlled oscillator and a third frequency control word corresponding to the timer according to the filtered signal; determining a carrier complex signal of a second negative frequency according to the second frequency control word; dividing the frequency of the carrier complex signal with the second negative frequency to obtain a signal after frequency division; multiplying the frequency-divided signal with the frequency-compensated signal to obtain a despread signal of the spread spectrum signal; the acquisition flag signal is determined based on the third frequency control word.
As a preferred embodiment, determining the acquisition flag signal based on the third frequency control word comprises: determining the variance of the timer in a preset time period according to the third frequency control word; when the variance in the preset time period is larger than a preset threshold value, the capture mark signal is a capture success signal; and when the variance in the preset time period is larger than the preset threshold value, the capture flag signal is a capture failure signal.
Specifically, within the baseband phase-locked loop, adjacent signals at one spreading chip are each K 0 The signals are accumulated in a group, and the accumulated signals (i.e. the signals after classification and accumulation) are input into the phase discriminator, so that the signal-to-noise ratio during phase discrimination can be improved, and noise interference can be reduced.
The output signal of the phase discriminator enters a loop filter, the loop filter filters out the corresponding noise, and the obtained phase discrimination result is sent into a second voltage-controlled oscillator NCO 2 The second voltage-controlled oscillator NCO 2 And obtaining a second frequency control word, and generating a corresponding carrier complex signal with a second negative frequency.
The carrier complex signal of the second negative frequency passes through K 0 The frequency-divided signal is multiplied by the frequency-compensated signal to compensate the residual phase, and a de-spread signal of the carrier is obtained.
Of course, in order to judge the tracking condition of the phase-locked loop, the loop filter also outputs a third frequency control word to the timer, which mainly calculates the latest delta T 0 (ΔT 0 Variance sigma in < T) time 2 When the timer reaches the time T, determining the delta T 0 Variance sigma over time period 2 Whether or not it is smaller than a set threshold value xi 1 And if the threshold value is smaller than the threshold value, the carrier acquisition is considered successful, the acquisition flag signal is marked as 1, if the threshold value is larger than the threshold value, the acquisition flag signal is marked as 0, the acquisition flag signal is sent to the frequency spectrum accumulation module, and the frequency compensation step and the residual frequency step are repeatedly and iteratively executed. The invention judges the phase-locked loop tracking condition by using a method for calculating the variance of the frequency control word, and controls a compensation updating control mechanism of the FFT by using the state tracking condition in combination with a timing method.
The timer may be a timed steady state determination module.
Referring to fig. 3, fig. 3 is a schematic structural diagram of a spread spectrum signal carrier recovery system according to the present invention.
The invention also provides a spread spectrum signal carrier recovery system, which comprises: the FFT conversion module is used for carrying out FFT conversion on the tracked spread spectrum signal to obtain the frequency spectrum of the spread spectrum signal; the frequency compensation module is used for carrying out frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; the baseband phase-locked loop is used for carrying out residual frequency tracking and frequency division on the frequency compensated signal to obtain a despread signal of the capture mark signal and the spread spectrum signal; the code element of the signal after frequency compensation adopts a sectional accumulation mode in a baseband phase-locked loop; the iteration module is used for repeatedly and iteratively executing the frequency compensation step and the residual frequency step under the condition that the capture mark signal is a capture failure signal until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
As a preferred embodiment, further comprising: and the serial-parallel conversion module is used for carrying out serial-parallel conversion on the spread spectrum signal to obtain parallel data for FFT conversion.
Compared with the traditional phase-locked loop, the carrier recovery method of the high-dynamic spread spectrum weak signal can still stably track and recover the carrier signal under the conditions of lower signal-to-noise ratio and larger Doppler frequency shift, correct frequency deviation and realize accurate and rapid carrier synchronization. The carrier recovery effect is described in comparison with the simulation result.
Referring to fig. 4, fig. 4 is a diagram of FFT spectrum accumulation and output.
Referring to fig. 5, fig. 5 is a single FFT spectrum output graph.
The simulation assumes that the spreading chip rate is 10Mchip/s, the information code uses QPSK modulation mode, the signal-to-noise ratio of the spreading chip is-2 dB, the Doppler frequency shift is 490KHz, the signal is subjected to FFT conversion once, the Doppler frequency shift is searched, the Doppler frequency shift is roughly compensated for 507.806KHz, and the residual frequency difference is 17.806KHz. The comparison effect of the accumulated spectrum and the single accumulation of the spread weak signal carrier recovery method can be known, the accumulated spectrum estimation is more accurate, and the noise is smaller.
Referring to fig. 6, fig. 6 is a diagram of a baseband pll tracking residual frequency difference.
Referring to fig. 7, fig. 7 is a diagram of a common pll tracking residual frequency difference.
And correcting by using a baseband phase-locked loop to obtain a tracking curve. Comparing the effect of a single common phase-locked loop, the frequency tracking effect of the segmented phase-locked loop is better.
For an introduction of a spread spectrum signal carrier recovery system provided by the present invention, refer to the above method embodiment, and the present invention is not repeated here.
Fig. 8 illustrates a physical structure diagram of an electronic device, as shown in fig. 8, which may include: a processor 801, a communication interface (Communications Interface) 802, a memory 803, and a communication bus 804, wherein the processor 801, the communication interface 802, and the memory 803 communicate with each other through the communication bus 804. The processor 801 may invoke logic instructions in the memory 803 to perform a spread spectrum signal carrier recovery method comprising: performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal; performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a despread signal of a capture mark signal and a spread spectrum signal; the code element of the signal after frequency compensation adopts a sectional accumulation mode in a baseband phase-locked loop; under the condition that the capture mark signal is a capture failure signal, repeating the iterative execution of the frequency compensation step and the residual frequency step until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
Further, the logic instructions in the memory 803 described above may be implemented in the form of software functional units and may be stored in a computer readable storage medium when sold or used as a stand alone product. Based on this understanding, the technical solution of the present invention may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution, in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.
In another aspect, the present invention also provides a computer program product, the computer program product including a computer program, the computer program being storable on a non-transitory computer readable storage medium, the computer program, when executed by a processor, being capable of executing the spread spectrum signal carrier recovery method provided by the above methods, the method comprising: performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal; performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a despread signal of a capture mark signal and a spread spectrum signal; the code element of the signal after frequency compensation adopts a sectional accumulation mode in a baseband phase-locked loop; under the condition that the capture mark signal is a capture failure signal, repeating the iterative execution of the frequency compensation step and the residual frequency step until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
In yet another aspect, the present invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, is implemented to perform a spread spectrum signal carrier recovery method provided by the above methods, the method comprising: performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal; performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal; residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a despread signal of a capture mark signal and a spread spectrum signal; the code element of the signal after frequency compensation adopts a sectional accumulation mode in a baseband phase-locked loop; under the condition that the capture mark signal is a capture failure signal, repeating the iterative execution of the frequency compensation step and the residual frequency step until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
The apparatus embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
From the above description of the embodiments, it will be apparent to those skilled in the art that the embodiments may be implemented by means of software plus necessary general hardware platforms, or of course may be implemented by means of hardware. Based on this understanding, the foregoing technical solution may be embodied essentially or in a part contributing to the prior art in the form of a software product, which may be stored in a computer readable storage medium, such as ROM/RAM, a magnetic disk, an optical disk, etc., including several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute the method described in the respective embodiments or some parts of the embodiments.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (10)
1. A method for carrier recovery of a spread spectrum signal, comprising:
performing FFT conversion on the tracked spread spectrum signal to obtain a frequency spectrum of the spread spectrum signal;
performing frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal;
residual frequency tracking and frequency division are carried out on the frequency compensated signal through a baseband phase-locked loop, so as to obtain a capture mark signal and a despread signal of the spread spectrum signal; the code element of the frequency compensated signal adopts a sectional accumulation mode in the baseband phase-locked loop;
repeating the iterative execution of the frequency compensation step and the residual frequency step until the acquisition marker signal is an acquisition success signal and a despread signal corresponding to the acquisition success signal is used as a final carrier recovery signal under the condition that the acquisition marker signal is an acquisition failure signal; the acquisition failure signal is opposite to the acquisition success signal.
2. The method for recovering a carrier of a spread spectrum signal according to claim 1, further comprising, before said FFT of the spread spectrum signal:
and carrying out serial-parallel conversion on the spread spectrum signal to obtain parallel data for FFT conversion.
3. The method for recovering a carrier of a spread spectrum signal according to claim 1, wherein said performing frequency compensation on said spread spectrum signal according to a spectrum of said spread spectrum signal to obtain a frequency compensated signal comprises:
performing spectrum accumulation on the spread spectrum signal to obtain a spectrum accumulation value;
determining a first frequency control word corresponding to the first voltage-controlled oscillator according to the frequency spectrum accumulated value;
determining a carrier complex signal of a first negative frequency according to the first frequency control word;
multiplying the spread spectrum signal with the carrier complex signal of the first negative frequency to obtain the frequency compensated signal.
4. A method for recovering a carrier of a spread spectrum signal according to any one of claims 1 to 3, wherein the residual frequency tracking and frequency division are performed on the frequency compensated signal by a baseband phase-locked loop to obtain the capture flag signal and a despread signal of the spread spectrum signal, and symbols of the frequency compensated signal are accumulated in a segment manner in the baseband phase-locked loop, including:
carrying out sectional accumulation processing on the code elements of the frequency compensated signal to obtain a sectional accumulated signal;
phase discrimination is carried out on the signals after the sectional accumulation to obtain signals after phase discrimination;
loop filtering is carried out on the phase-authenticated signal to obtain a filtered signal;
determining a second frequency control word corresponding to a second voltage-controlled oscillator and a third frequency control word corresponding to a timer according to the filtered signal;
determining a carrier complex signal of a second negative frequency according to the second frequency control word;
dividing the frequency of the carrier complex signal with the second negative frequency to obtain a signal after frequency division;
multiplying the frequency-divided signal with the frequency-compensated signal to obtain a despread signal of the spread spectrum signal;
and determining the capture flag signal according to the third frequency control word.
5. The method of spread spectrum signal carrier recovery as claimed in claim 4, wherein said determining the acquisition flag signal from the third frequency control word comprises:
determining the variance of the timer in a preset time period according to the third frequency control word;
when the variance in the preset time period is larger than a preset threshold value, the capture flag signal is the capture success signal;
and when the variance in the preset time period is larger than a preset threshold value, the capture flag signal is the capture failure signal.
6. A spread spectrum signal carrier recovery system, comprising:
the FFT conversion module is used for carrying out FFT conversion on the tracked spread spectrum signal to obtain the frequency spectrum of the spread spectrum signal;
the frequency compensation module is used for carrying out frequency compensation on the spread spectrum signal according to the frequency spectrum of the spread spectrum signal to obtain a frequency compensated signal;
the baseband phase-locked loop is used for carrying out residual frequency tracking and frequency division on the frequency compensated signal to obtain a capture mark signal and a despread signal of the spread spectrum signal; the code element of the frequency compensated signal adopts a sectional accumulation mode in the baseband phase-locked loop;
the iteration module is used for repeatedly and iteratively executing the frequency compensation step and the residual frequency step under the condition that the capture mark signal is a capture failure signal until the capture mark signal is a capture success signal, and taking a despread signal corresponding to the capture success signal as a final carrier recovery signal; the acquisition failure signal is opposite to the acquisition success signal.
7. The spread spectrum signal carrier recovery system as claimed in claim 6, further comprising:
and the serial-parallel conversion module is used for carrying out serial-parallel conversion on the spread spectrum signal to obtain parallel data for FFT conversion.
8. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor implements the spread spectrum signal carrier recovery method as claimed in any one of claims 1 to 5 when the program is executed by the processor.
9. A non-transitory computer readable storage medium having stored thereon a computer program, which when executed by a processor implements the spread spectrum signal carrier recovery method according to any one of claims 1 to 5.
10. A computer program product comprising a computer program which, when executed by a processor, implements the spread spectrum signal carrier recovery method as claimed in any one of claims 1 to 5.
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| CN202311524226.7A CN117792428B (en) | 2023-11-15 | 2023-11-15 | Spread spectrum signal carrier recovery method and related assembly |
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| CN202311524226.7A CN117792428B (en) | 2023-11-15 | 2023-11-15 | Spread spectrum signal carrier recovery method and related assembly |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108011653A (en) * | 2017-12-15 | 2018-05-08 | 北京卫星信息工程研究所 | Based on adaptive fast Acquisition tracking system and method |
| CN110071738A (en) * | 2019-04-28 | 2019-07-30 | 西安电子科技大学 | Spread-spectrum signal based on more pseudo-code branch receivers de-spreads tracking |
| CN113595586A (en) * | 2021-06-02 | 2021-11-02 | 西安电子科技大学 | Direct sequence spread spectrum signal capturing and tracking method based on MD-PMF-FFT |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108011653A (en) * | 2017-12-15 | 2018-05-08 | 北京卫星信息工程研究所 | Based on adaptive fast Acquisition tracking system and method |
| CN110071738A (en) * | 2019-04-28 | 2019-07-30 | 西安电子科技大学 | Spread-spectrum signal based on more pseudo-code branch receivers de-spreads tracking |
| CN113595586A (en) * | 2021-06-02 | 2021-11-02 | 西安电子科技大学 | Direct sequence spread spectrum signal capturing and tracking method based on MD-PMF-FFT |
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