Synchronization sequence generation and acquisition method based on dynamic double-slope linear frequency modulation signal

Abstract

The application provides a synchronization sequence generation and capture method based on dynamic double-slope linear frequency modulation signals. A sending end generates two linear frequency modulation signals with different sweep characteristics, and according to a pilot structure sequence, units of multiple linear frequency modulation signals are combined to form a pilot signal, the cumulative gain of the sequence is used to improve the detection performance in a low carrier-to-noise ratio environment, the synchronization performance is good, and the processing complexity of a subsequent receiving end is reduced. Meanwhile, the dynamic change of the sweep slope of the linear frequency modulation signal and the combination mode enhances the anti-interception capability of the pilot signal and improves the synchronization security. A receiving end based on the same pilot structure sequence extracts and combines the correlation values of the same linear frequency modulation signal in the received signal to obtain a combination gain. Because the slopes of the two linear frequency modulation signals are different, the responses to frequency offset are different, so that the receiving end overcomes the timing offset caused by the frequency offset, can calculate the timing and frequency offset according to the combination result, and realizes synchronization.

Description

Technical Field

[0001] This specification relates to the field of wireless communication technology, and in particular to a method for generating and capturing synchronization sequences based on dynamic dual-slope linear frequency modulated signals. Background Technology

[0002] Synchronization is a crucial component of mobile communication systems. Relying on synchronization to determine the Doppler frequency shift of signals is a key factor in ensuring correct signal reception and demodulation. In mobile communication systems, insufficient terminal clock stability and motion can lead to Doppler frequency shift. Traditional synchronization methods commonly use pseudo-random sequences (PN sequences) as training sequences. However, the performance of PN sequences is significantly affected by Doppler frequency shift, resulting in a significant attenuation of their correlation peaks. This forces the receiver to perform a two-dimensional search in both time and frequency dimensions, resulting in a huge computational burden and increased computational complexity. Especially when the carrier-to-noise ratio (CNR) at the receiver is low, further increasing processing complexity to improve synchronization performance. Summary of the Invention

[0003] To address the aforementioned technical problems, this specification provides the following technical solutions: In a first aspect, a method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal is provided, the method comprising: A first linear frequency modulated signal and a second linear frequency modulated signal are generated, and the first linear frequency modulated signal and the second linear frequency modulated signal have different sweep frequency characteristics; According to the preset first pilot structure sequence, multiple first linear frequency modulation signals and / or second linear frequency modulation signals are combined in the time domain to generate pilot signals for synchronization. The pilot signal is sent to the receiving end for signal reception. The receiving end processes the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. Based on a preset second pilot structure sequence, the correlation results of the first linear frequency modulated signal in the first correlation result sequence are merged to obtain a first merged result, and the correlation results of the second linear frequency modulated signal in the second correlation result sequence are merged to obtain a second merged result. The second pilot structure sequence is identical to the first pilot structure sequence. Synchronization is achieved based on the first merged result and the second merged result.

[0004] In some embodiments, the sweep slope of the first linear frequency modulated signal and the sweep slope of the second linear frequency modulated signal are dynamically changed with time or frame number.

[0005] In some embodiments, the first pilot structure sequence changes dynamically over time or frame number.

[0006] Secondly, a method for capturing a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal is provided, the method comprising: The receiver receives a signal, which is a first linear frequency modulated (LFM) signal and a second LFM signal generated by the transmitter. The first LFM signal and the second LFM signal have different frequency sweep characteristics. According to a preset first pilot structure sequence, multiple first LFM signals and / or second LFM signals are combined in the time domain to generate a pilot signal for synchronization. The pilot signal is processed by a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. According to the preset second pilot structure sequence, the correlation results of the first linear frequency modulated signal in the first correlation result sequence are merged to obtain a first merged result, and the correlation results of the second linear frequency modulated signal in the second correlation result sequence are merged to obtain a second merged result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence; Synchronization is completed based on the first and second merge results.

[0007] In some embodiments, the second pilot structure sequence is dynamically changed over time or frame number.

[0008] In some embodiments, the second pilot structure sequence is the same as the first pilot structure sequence and is implemented in at least one of the following ways: The transmitting end and the receiving end of the receiving signal are mapped and selected according to the same time and according to the configuration parameters.

[0009] In some embodiments, the step of completing the synchronization based on the first merging result and the second merging result includes: Determine the first peak position of the first merged result and the second peak position of the second merged result; Based on the first peak position, the second peak position, and the sweep slope of the first and second linear frequency modulated signals, the timing estimate and frequency offset estimate are determined to complete the synchronization.

[0010] In some embodiments, before determining the timing estimate and frequency offset estimate based on the first peak position, the second peak position, and the sweep slope of the first linear frequency modulated signal and the second linear frequency modulated signal, the method further includes: Determine whether the peak value / peak-to-average power ratio of the first merged result exceeds a first threshold, and determine whether the peak value / peak-to-average power ratio of the second merged result exceeds a second threshold; If both judgment results are yes, it is determined that the signal used for synchronization has been received, and the timing estimate and frequency offset estimate are determined based on the first peak position, the second peak position, and the sweep slope of the first linear frequency modulation signal and the second linear frequency modulation signal.

[0011] In some embodiments, the merging method includes coherent merging or incoherent merging.

[0012] Thirdly, a synchronization sequence generation device based on a dynamic dual-slope linear frequency modulated signal is provided, the device comprising: A linear frequency modulation (LFM) signal generation module is used to generate a first LFM signal and a second LFM signal, wherein the first LFM signal and the second LFM signal have different sweep frequency characteristics. The pilot framing module is used to combine multiple first linear frequency modulation signals and / or second linear frequency modulation signals in the time domain according to a preset first pilot structure sequence to generate pilot signals for synchronization. A signal transmitting module is used to transmit the pilot signal to the receiving end.

[0013] Fourthly, a synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated signal is provided, the device comprising: A signal receiving module is used to receive signals; The matched filtering module is used to process the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence; The merging module is used to merge the correlation results of the first linear frequency modulated signal in the first correlation result sequence according to a preset second pilot structure sequence to obtain a first merging result, and to merge the correlation results of the second linear frequency modulated signal in the second correlation result sequence to obtain a second merging result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence; The synchronization module is used to complete the synchronization based on the first merging result and the second merging result.

[0014] Fifthly, a synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal is provided, the system comprising: A synchronization sequence generation device based on a dynamic dual-slope linear frequency modulated (LFM) signal is used to generate a first LFM signal and a second LFM signal, which have different sweep frequency characteristics; and according to a preset first pilot structure sequence, multiple first LFM signals and / or second LFM signals are combined in the time domain to generate a pilot signal for synchronization; and the pilot signal is sent to a receiving end. A synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated (LFM) signal is used to receive the signal, process the pilot signal using a first matched filter corresponding to the first LFM signal and a second matched filter corresponding to the second LFM signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence; and according to a preset second pilot structure sequence, merge the correlation results of the first LFM signal in the first correlation result sequence to obtain a first merged result, and merge the correlation results of the second LFM signal in the second correlation result sequence to obtain a second merged result; wherein the second pilot structure sequence is the same as the first pilot structure sequence; and complete synchronization based on the first merged result and the second merged result.

[0015] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of this specification. For those skilled in the art, other drawings can be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of a synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal, as provided in this specification. Figure 2 This is a flowchart illustrating a method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal, as provided in this specification. Figure 3 This is a waveform diagram of a single first linear frequency modulated signal in the first frame provided in this specification; Figure 4 This is a waveform diagram of a single second linear frequency modulated signal in the first frame provided in this specification; Figure 5 This is a schematic diagram showing the frequency change of the pilot signal in the first frame provided in this specification over time; Figure 6This is a flowchart illustrating a synchronization sequence acquisition method based on a dynamic dual-slope linear frequency modulated signal provided in this specification. Figure 7 This is a schematic diagram of the output of the first frame merging process provided in this manual; Figure 8 This is a schematic diagram showing the frequency change of the pilot signal in the second frame provided in this specification over time; Figure 9 This is a schematic diagram of the output of the second frame merging process provided in this manual. Detailed Implementation

[0018] This specification describes several technical solutions with different concepts. Each concept has one or more embodiments, and different concepts can be combined to form more embodiments. Those skilled in the art, after reading this specification, can combine different concepts to obtain new technical solutions, and these new technical solutions should also fall within the scope of this specification.

[0019] The technical solutions of these different concepts will be introduced in turn below. Some concepts may appear in multiple technical solutions of different concepts. For these concepts, this article will explain them when they first appear and will not repeat them in the following text.

[0020] Synchronization is a crucial component of mobile communication systems. Relying on synchronization to time and determine the Doppler frequency offset of the signal is a key factor in ensuring correct signal reception and demodulation. Specifically, the core function of synchronization is to achieve time alignment and frequency calibration: on the one hand, through timing synchronization, the receiver can accurately capture the start time of the signal, determine the correspondence between the symbol period and the sampling clock, and avoid inter-symbol interference caused by time offset; on the other hand, through frequency synchronization, the receiver can detect and compensate for the Doppler frequency offset generated during signal transmission, ensuring that the carrier frequency remains consistent with the local oscillator frequency, eliminating the impact of frequency offset on signal demodulation. In short, synchronization is the bridge connecting the transmitter and receiver, and a prerequisite for all subsequent communication processes such as signal demodulation and data decoding.

[0021] However, in mobile communication systems, insufficient terminal clock stability and motion can cause significant Doppler frequency offset. The greater the Doppler frequency offset, the more severe the interference with synchronization.

[0022] To address the aforementioned issues, traditional synchronization methods commonly employ pseudo-random sequences (PN sequences) as training sequences. However, a problem arises: the synchronization performance of PN sequences is extremely sensitive to Doppler frequency offset. When a significant Doppler frequency offset exists, the frequency of the received signal deviates from the frequency of the local PN sequence, leading to a significant attenuation of the correlation peak and drastically reducing synchronization accuracy. To obtain reliable synchronization results, the receiver must employ a two-dimensional time-frequency search strategy. This search method not only consumes substantial computational resources, significantly increasing the receiver's computational complexity, but also prolongs synchronization time, impacting real-time communication performance. Therefore, reducing the computational complexity of the synchronization process and improving synchronization performance remains a challenging problem.

[0023] Linear frequency modulated (LFM) signals exhibit strong resistance to frequency offset, effectively reducing the impact of frequency offset on synchronization results. Furthermore, due to the time-frequency coupling characteristics of LFM signals, two-dimensional time-frequency searches can be transformed into one-dimensional searches, thereby reducing computational complexity. Therefore, LFM signals are widely used in LoRa IoT communication systems and terrestrial radar systems, and have broad application prospects in satellite communication where Doppler frequency offset exists.

[0024] However, in harsh communication environments with low carrier-to-noise ratios, achieving reliable synchronization using only one or two linear frequency modulated (LFM) signals necessitates increasing the length of the LFM signals to improve synchronization performance. However, longer signals require more computation and resources for processing and demodulation, further increasing processing complexity. Therefore, the key is to utilize LFM signals to reduce the computational complexity of the synchronization process and improve synchronization performance.

[0025] To address the aforementioned technical issues, this specification provides a synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal.

[0026] Figure 1 This is a schematic diagram of a synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal, as provided in this specification.

[0027] The synchronization sequence generation and capture system includes a synchronization sequence generation device and a synchronization sequence capture device.

[0028] The synchronization sequence generation device is used to generate a first linear frequency modulation (LFM) signal and a second LFM signal, the first LFM signal and the second LFM signal having different frequency sweep characteristics; and according to a preset first pilot structure sequence, to combine multiple first LFM signals and / or second LFM signals in the time domain to generate a pilot signal for synchronization; and to send the pilot signal to the receiving end. A synchronization sequence acquisition device is used to receive signals and process the pilot signals using a first matched filter corresponding to the first linear frequency modulated (LFM) signal and a second matched filter corresponding to the second LFM signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. Based on a preset second pilot structure sequence, the device merges the correlation results of the first LFM signal in the first correlation result sequence to obtain a first merged result, and merges the correlation results of the second LFM signal in the second correlation result sequence to obtain a second merged result. The second pilot structure sequence is identical to the first pilot structure sequence. Synchronization is completed based on the first merged result and the second merged result.

[0029] The synchronization sequence generator acts as the transmitter, generating two linear frequency modulated (LFM) signals with different sweep characteristics. The LFM signals possess excellent pulse compression characteristics and strong resistance to frequency deviation. Then, based on the pilot structure sequence, multiple LFM signal units are combined to form a pilot signal, also known as a "synchronization sequence." This pilot signal / synchronization sequence represents the known signal used to achieve timing and frequency synchronization between the receiver and transmitter. The cumulative gain of the sequence enhances detection performance in low carrier-to-noise ratio (CNR) environments, achieving an effect comparable to a very long LFM signal, resulting in good synchronization performance. More importantly, in the subsequent processing of the pilot signal at the receiver, multiple short signals are generally more flexible and less complex than processing a single extremely long signal. This improves synchronization performance while avoiding the processing delays and inefficiencies associated with using extremely long signals. Furthermore, the sweep slope and combination of the first and second LFM signals can be dynamically changed, enhancing the pilot signal's resistance to interception and improving synchronization security, resulting in a significant improvement in synchronization performance under conditions of large frequency deviation and low CNR.

[0030] Meanwhile, the synchronization sequence acquisition device acts as the receiver. When processing the signal, the receiver locally generates a pilot structure sequence with the same structure as the synchronization sequence. Based on this pilot structure sequence, it extracts and combines the correlation values ​​of the same linear frequency modulated (LFM) signal in the received signal. This is equivalent to concentrating the energy of the entire sequence onto a single point to obtain a combining gain, greatly improving the output signal-to-noise ratio (SNR), thus enabling signal detection even in low carrier-to-noise ratio (CNR) environments. Because the slopes of the first and second LFM signals are different, their responses to frequency offset differ, allowing the receiver to overcome the timing offset caused by the frequency offset and calculate both the timing and frequency offset.

[0031] Furthermore, the sweep slopes of the first and second linear frequency modulated signals are dynamically changing with time or frame number. And / or the first pilot structure sequence is dynamically changing with time or frame number. And / or the second pilot structure sequence is dynamically changing with time or frame number.

[0032] The dynamic linear frequency modulation signal and pilot structure sequence mean that the synchronization signal used in each communication is dynamically changing. The dynamically changing slope and combination method enhance the anti-interception capability of the pilot signal and improve synchronization security. The synchronization performance is significantly improved under conditions of large frequency deviation and low carrier-to-noise ratio.

[0033] The synchronization sequence generation and acquisition system in this embodiment generates a special synchronization sequence composed of linear frequency modulation signals with different sweep frequency characteristics, and acquires and processes it at the receiving end. Ultimately, it achieves high-precision, low-complexity, and high-security timing and frequency offset estimation, thereby completing synchronization. It is suitable for communication scenarios with large frequency offset and low carrier-to-noise ratio.

[0034] This specification also provides a method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal, which is applied to the synchronization sequence generation device in the above-mentioned synchronization sequence generation and capture system.

[0035] Figure 2 This is a flowchart illustrating a method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal, as provided in this specification.

[0036] The method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal includes: Step 102: Generate a first linear frequency modulation signal and a second linear frequency modulation signal, wherein the first linear frequency modulation signal and the second linear frequency modulation signal have different sweep frequency characteristics.

[0037] The linear frequency modulated (LFM) signal described in this article refers to a signal whose frequency varies with time. This type of signal has excellent anti-interference and anti-attenuation characteristics. Its time difference and frequency difference are interchangeable; a signal that is time-delayed and frequency-shifted will still produce a peak output after matched filtering, only its position will be different. This characteristic allows the receiver to transform the time-consuming two-dimensional time-frequency search into a more efficient one-dimensional time search, significantly reducing computational complexity.

[0038] In some embodiments, the first linear frequency modulated signal and the second linear frequency modulated signal have different sweep frequency characteristics.

[0039] The dual-slope structure formed by the first and second linear frequency modulated signals can generate two correlation peaks at different positions, enabling the receiver to overcome the timing offset caused by frequency deviation and calculate the timing and frequency offset.

[0040] In some embodiments, the sweep slope of the first linear frequency modulated signal and the sweep slope of the second linear frequency modulated signal are dynamically changed with time or frame number.

[0041] In traditional synchronization methods, the spectral characteristics of linear frequency modulated (LFM) signals are quite obvious. Using a fixed set of symmetrical LFM signal patterns makes them easy to intercept, resulting in insufficient security. Therefore, this embodiment uses a dynamically generated LFM signal with a dynamic sweep slope, meaning that the synchronization signal used in each communication is dynamically changing, thereby improving the anti-interception capability of the synchronization signal and enhancing synchronization security.

[0042] Specifically, during system design, a finite discrete set of frequency sweep slopes is pre-defined based on the operating scenario of the communication system. , .

[0043] The transmitting end provides two sweep slope values ​​for each frame. , ,and The sweep slope value is taken from a discrete set. The selection is made from the pool. The selection methods include, but are not limited to, selecting in a specific order or selecting randomly.

[0044] For example, the first frame is selected .

[0045] Next, by controlling the initial frequency and sweep slope parameters of the control signal, a linear frequency modulation signal whose frequency changes linearly with time is generated; wherein, the sweep slope is a non-zero value, the sign of which determines the frequency scanning direction, and the magnitude of its absolute value determines the rate of frequency change per unit time.

[0046] For example, the value is determined based on the sweep slope. , Two basic first linear frequency modulated signals are generated respectively. Second linear frequency modulation signal .

[0047] The expression for the first linear frequency modulated signal is shown below: Among them, the instantaneous frequency of the linear frequency modulated signal It changes linearly over time. The duration of a linear frequency modulated signal. The starting frequency of the first linear frequency modulated signal is 1. Phase in the expression Differentiation yields the instantaneous frequency as: K 1 represents the sweep slope of the first linear frequency modulated signal, which determines the speed and direction of frequency change.

[0048] in, K1>0: The frequency increases linearly with time (upmodulation). K 1<0: The frequency decreases linearly with time (down-modulation), and the magnitude of |K1| determines the bandwidth of the frequency sweep B = |K1| * T.

[0049] The expression for the second linear frequency modulated signal is shown below: in, The duration of a linear frequency modulated signal. This is the starting frequency of the second linear frequency modulated signal. j It is the imaginary unit.

[0050] and Values ​​are determined by the sweep slope. , Sure, and The methods for determining this include, but are not limited to, and For a fixed value, or .

[0051] For example, suppose the Doppler frequency shift at the transmitting and receiving ends is... The transmission start time is 0.5ms, and the duration of a linear frequency modulated signal is set to... .

[0052] Reference Figure 3 The real and imaginary waveforms of a single first linear frequency modulated signal in the first frame are as follows: Figure 3 As shown.

[0053] Reference Figure 4 The real and imaginary waveforms of a single second linear frequency modulated signal in the first frame are as follows: Figure 4 As shown.

[0054] Step 104: According to the preset first pilot structure sequence, combine multiple first linear frequency modulation signals and / or second linear frequency modulation signals in the time domain to generate pilot signals for synchronization.

[0055] The first pilot structure sequence determines and The arrangement order (e.g., [0,0,1,0,...]). Used to combine multiple short, fundamental linear frequency modulated signals. and They are combined into a long, complex synchronization sequence (i.e., pilot signal) to improve performance and security.

[0056] In some embodiments, the pilot structure sequence is configured as a binary control sequence. This is achieved by generating a binary first pilot structure sequence. The generated first and second linear frequency modulated signals are multiplexed in the time domain to form a complete pilot signal. This represents the number of linear frequency modulated signals in the pilot signal. Indicates the first pilot signal The first position is the linear frequency modulation signal. Indicates the first pilot signal The position represents the second linear frequency modulation signal.

[0057] In this embodiment, the binary first pilot structure sequence Generated by a linear congruential generator (LCG). Assume the number of linear frequency modulated signals in the pilot is... The LCG parameters a=3, c=16, and m=17 are fixed. Based on the local time, initial seeds are generated using seed1=15 and seed2=16 respectively. Values ​​are iteratively generated according to the calculation rule (a×current seed+c) % m, and then the binary bits (0 or 1) are obtained by taking the modulo of 2. Finally, the first pilot structure sequence of the first frame is generated. .

[0058] In some embodiments, the first pilot structure sequence changes dynamically over time or frame number.

[0059] The dynamic linear frequency modulation signal and pilot structure sequence mean that the synchronization signal used in each communication is dynamically changing, with non-fixed spectral characteristics that are difficult to identify and detect, thus enhancing the anti-interception capability of the pilot signal. Simultaneously, because the key / rules (i.e., sweep slope, synchronization signal) of the next communication cannot be predicted, it is impossible to generate effective false signals for interference or deception, improving synchronization security and significantly enhancing synchronization performance under conditions of large frequency offset and low carrier-to-noise ratio.

[0060] Next, based on the first pilot structure sequence, multiple first linear frequency modulated (LFM) signals and / or second LFM signals are combined in the time domain. The values ​​at each position in the first pilot structure sequence determine whether the corresponding position is a first LFM signal or a second LFM signal. For example, the first pilot structure sequence generated in the first frame is... If the first element is 0, then the first position of the pilot signal is the first linear frequency modulation signal; if the second element is 0, then the second position of the pilot signal is the first linear frequency modulation signal; if the third element is 1, then the third position of the pilot signal is the second linear frequency modulation signal, and so on, until the complete synchronization sequence is obtained.

[0061] As an example, based on the pilot structure sequence A pilot signal is generated using a first linear frequency modulated (LFM) signal and a second LFM signal. The pilot signal can be represented as: Where m represents time, through Decision in m Which linear frequency modulated signal should be placed in each time slot? This refers to the basic signal x 1 ( t Delay on the timeline m T seconds. This ensures that each basic signal occupies its own unique, non-overlapping time period, allowing it to be processed separately at the receiving end.

[0062] Reference Figure 5 The frequency of the pilot signal in the first frame changes over time as follows: Figure 5 As shown.

[0063] Figure 5 In the diagram, the frequency variation of the pilot signal over time is represented by multiple line segments. The downward-sloping line segments correspond to the first linear frequency modulated signal, and their slope... The upward-sloping line segment corresponds to the second linear frequency modulated signal, and its slope is... The pilot structure is composed of the following sequence: first linear frequency modulated (LFM) signal, first LFM signal, second LFM signal, first LFM signal, second LFM signal, first LFM signal, second LFM signal, second LFM signal, second LFM signal. This sequence is the same as the pilot structure sequence generated in the first frame. Correspondingly.

[0064] In some embodiments, the pilot signal is a baseband signal, which can be transmitted after shaping filtering and up-conversion. It should be noted that the pilot signal can also be called a synchronization sequence or synchronization signal, etc., all referring to known signals used to achieve timing and frequency synchronization between the receiving end and the transmitting end.

[0065] Step 106: The pilot signal is sent to the receiving end for signal reception. The receiving end processes the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. Based on a preset second pilot structure sequence, the correlation results of the first linear frequency modulated signal in the first correlation result sequence are merged to obtain a first merged result. The correlation results of the second linear frequency modulated signal in the second correlation result sequence are merged to obtain a second merged result. The second pilot structure sequence is identical to the first pilot structure sequence. Synchronization is then achieved based on the first merged result and the second merged result.

[0066] The transmitting end sends the generated pilot signal to the synchronization sequence acquisition device, which acts as the receiving end. The pilot signal is identified by the synchronization sequence acquisition method based on dynamic dual-slope linear frequency modulation signal, and the synchronization information is obtained.

[0067] This specification provides a method for generating synchronization sequences based on dynamic dual-slope linear frequency modulated (LFM) signals. On one hand, by generating and combining LFM signals with different sweep characteristics, the pilot signals exhibit non-fixed and diverse frequency variation patterns in the time domain. This design makes the pilot signals, compared to synchronization sequences composed of single-mode LFM signals, possess stronger uniqueness and lower regularity, thereby effectively reducing the probability of being identified and intercepted by non-target receivers during transmission and improving the security of the synchronization process.

[0068] On the other hand, this generation method uses a pre-defined first pilot structure sequence to deterministically combine linear frequency modulated signals with different sweep characteristics in the time domain. This lays the signal foundation for the receiver to transform the originally high-complexity two-dimensional time-frequency search into a low-complexity one-dimensional correlation processing for a fixed sequence. In other words, it creates the preconditions for significantly reducing the computational complexity of the receiver, thereby significantly reducing the overall computational burden of the synchronization process at the system level.

[0069] This specification also provides a synchronization sequence acquisition method based on a dynamic dual-slope linear frequency modulated signal, which is applied to the synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated signal in the above-mentioned synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal.

[0070] Figure 6 This is a flowchart illustrating a synchronization sequence acquisition method based on a dynamic dual-slope linear frequency modulated signal, as provided in this specification. The synchronization sequence acquisition method based on the dynamic dual-slope linear frequency modulated signal includes: Step 202: Receive signals, wherein the signals are a first linear frequency modulated (LFM) signal and a second linear frequency modulated (LFM) signal generated by the transmitting end, the first LFM signal and the second LFM signal having different frequency sweep characteristics; and according to a preset first pilot structure sequence, combine multiple first LFM signals and / or second LFM signals in the time domain to generate a pilot signal for synchronization.

[0071] In some embodiments, the signal received by the receiver is a signal that has been shaped, filtered, and down-converted to baseband.

[0072] The receiver does not know exactly when the pilot signal arrives, nor how much the frequency has shifted due to the Doppler effect. Its task is to locate the pilot signal and interpret the synchronization information.

[0073] The synchronization information includes timing offset and carrier frequency offset information, also known as timing estimate and frequency offset estimate.

[0074] The receiving end has the exact same rules as the sending end, and these rules include a set of slopes. When generating a linear frequency modulated signal, select K 1. K 2. The pilot structure sequence is generated according to the rules (such as calculation based on system time, frame number, or using the same random number seed). a(m) The rules.

[0075] Therefore, by independently calculating the same sweep slope and pilot structure sequence as the transmitter at the receiver, these parameters are used to match the received signal. A significant correlation peak is only generated when the signal is a pilot signal emitted by the transmitter. This correlation peak corresponds to the moment when the input signal aligns with a known signal, providing a basis for subsequent synchronization. Simultaneously, the shared rules between the receiver and transmitter are agreed upon by both parties, eliminating the need for information exchanged through the channel, thus achieving effective anti-interception and improving synchronization security.

[0076] The specific process is as follows: First, the receiver, following the same rules as the transmitter, provides two sweep slope values ​​for each frame. , ,and The sweep slope takes values ​​from a finite discrete set. The selection is made from the available options. Selection methods include, but are not limited to, selecting in a specific order or selecting randomly.

[0077] In this case, the sweep slope value given by the receiving end for each frame is the same as the sweep slope value given by the transmitting end, that is, the sweep slope value is... , Thus, the receiving end captures signals with the same sweep slope value based on the sweep slope value.

[0078] Methods to ensure that the sweep slope value given by the receiver in each frame is the same as that given by the transmitter include, but are not limited to, mapping selection based on time at both ends, and mapping selection based on manually configured parameters at both ends. For example, the transmitter and receiver may use receiver sweep slope selectors with the same structure, and select based on the time mapping provided by the GNSS. Since the time provided by the GNSS at both ends is the same, the same sweep slope value can be obtained. , The same , .

[0079] For example, the first frame is selected .

[0080] Next, the value is obtained using the locally known sweep slope. , Generate the first linear frequency modulated signal The corresponding first matched filter and the second linear frequency modulated signal The corresponding second matched filter.

[0081] Step 204: The pilot signal is processed using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal to obtain a first correlation result sequence and a second correlation result sequence.

[0082] The received signal is subjected to matched filtering using a first matched filter and a second matched filter.

[0083] In some embodiments, the method for generating a matched filter based on the sweep slope value is as follows: based on the sweep slope value... , Generate the first linear frequency modulated signal Second linear frequency modulation signal According to matched filter theory, the unit impulse response of a matched filter is... , , where * denotes complex conjugate. Let the input of the matched filter be... The output after passing through two matched filters is the first correlation result sequence. Second related result sequence This output is used for subsequent merging processing.

[0084] Step 206: According to the preset second pilot structure sequence, merge the correlation results of the first linear frequency modulated signal in the first correlation result sequence to obtain a first merge result, and merge the correlation results of the second linear frequency modulated signal in the second correlation result sequence to obtain a second merge result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence.

[0085] Based on the same pilot structure sequence generation rules as the transmitter, a binary second pilot structure sequence is generated for the receiver. This is used to determine the positions of the first and second linear frequency modulated (LFM) signals within the pilot signal. For example, the pilot structure sequence generated in the first frame is... . Indicates the first pilot signal The first position is the linear frequency modulation signal. Indicates the first pilot signal The position represents the second linear frequency modulation signal.

[0086] In some embodiments, the second pilot structure sequence is dynamically changed over time or frame number.

[0087] The second pilot structure sequence generated by the receiver in each frame is the same as the first pilot structure sequence generated by the transmitter in each frame, that is, = .

[0088] The second pilot structure sequence is the same as the first pilot structure sequence and is implemented in at least one of the following ways: The transmitting end and the receiving end of the receiving signal are mapped and selected according to the same time and according to the configuration parameters.

[0089] For example, methods for obtaining synchronized time include, but are not limited to, using GNSS time synchronization and two calibrated and synchronized timers. Alternatively, if both the transmitting and receiving ends are manually configured with the same parameters by agreement, the time can be selected based on this parameter mapping.

[0090] The receiving end uses the second pilot structure sequence The correlation results from the matched filter at the receiving end are combined. Based on the position of the first linear frequency modulated (LFM) signal in the pilot, the correlation results of all first LFM signals are combined. Similarly, based on the position of the second LFM signal in the pilot, the correlation results of all second LFM signals are combined. This yields a combining gain, improving synchronization detection performance, especially in low signal-to-noise ratio environments.

[0091] It should be noted that the correlation result of the linear frequency modulated (LFM) signal can be understood as the energy or retrieval result output by the LFM signal after passing through the matched filter. Therefore, by superimposing the correlation results of the first LFM signal, which are scattered throughout the sequence, according to the second pilot structure sequence, and similarly superimposing the correlation results of the second LFM signal, it is equivalent to concentrating the energy of the entire sequence onto a single point, greatly improving the output signal-to-noise ratio (SNR), thus enabling signal detection even in low carrier-to-noise ratio environments.

[0092] As an example, the methods of merging include, but are not limited to, coherent merging and incoherent merging.

[0093] Coherent combining: This method considers phase information when combining signals and has the best performance, but it is sensitive to frequency offset.

[0094] Incoherent combining: only the amplitude (energy) of the signal is combined, ignoring the phase. It has strong resistance to frequency deviation but slightly loses performance.

[0095] When using this method, select the appropriate merging method based on actual needs. For example, in scenarios with low carrier-to-noise ratio and large frequency offset, incoherent merging is selected. Then, according to the position of the first linear frequency modulated (LFM) signal in the pilot, the correlation results of all the first LFM signals are incoherently merged to obtain the first merged result. Similarly, according to the position of the second LFM signal in the pilot, the correlation results of all the second LFM signals are incoherently merged to obtain the second merged result. For example... Figure 7 As shown, Figure 7 This is the result of merging the first frame.

[0096] Step 208: Synchronize based on the first merge result and the second merge result.

[0097] In some embodiments, the step of completing the synchronization based on the first merging result and the second merging result includes: Determine the first peak position of the first merged result and the second peak position of the second merged result; Based on the first peak position, the second peak position, and the sweep slope of the first and second linear frequency modulated signals, the timing estimate and frequency offset estimate are determined to complete the synchronization.

[0098] When the received signal is perfectly aligned / matched with the local reference signal at the receiver (i.e., the signal of the matched filter), the correlation operation outputs a very sharp peak. The position (time point) of this peak indicates the timing estimate at the receiver, thus completing time synchronization. Therefore, based on the first combining result of the first linear frequency modulated signal and the second combining result of the second linear frequency modulated signal, the peak position in the first combining result and the second combining result is found, and the position of the peak provides the timing information. Simultaneously, using... and The difference in sweep slope can be used to derive a formula to calculate the frequency offset estimate from information such as peak values.

[0099] Since the receiving end obtains the curves of the first and second combined results through matched filtering and combining, as shown... Figure 7 As shown in the figure, this curve may contain multiple peaks, but not all peaks are the desired synchronization signal; they may be random fluctuations caused by noise. Therefore, it is necessary to determine whether the synchronization signal has arrived or to find the true synchronization signal peak before synchronization.

[0100] Only pilot signals used for synchronization transmitted by the transmitter will produce significant correlation peaks in the merged results. The correlation peak information can then be used to determine whether a synchronization signal has arrived, i.e., whether the currently received information is a pilot signal. If a synchronization signal arrives, timing and frequency offset estimates are calculated. If no synchronization signal arrives, timing and frequency offset estimates are not calculated.

[0101] In some embodiments, before determining the timing estimate and frequency offset estimate based on the first peak position, the second peak position, and the sweep slope of the first linear frequency modulated signal and the second linear frequency modulated signal, the method further includes: Determine whether the peak value / peak-to-average power ratio of the first merged result exceeds a first threshold, and determine whether the peak value / peak-to-average power ratio of the second merged result exceeds a second threshold; If both judgment results are yes, it is determined that the signal used for synchronization has been received, and the timing estimate and frequency offset estimate are determined based on the first peak position, the second peak position, and the sweep slope of the first linear frequency modulation signal and the second linear frequency modulation signal.

[0102] As an example, the detection quantities used for the decision include, but are not limited to, peak value and peak-to-average ratio (PAR), where PAR = peak value / average value.

[0103] Calculate the peak-to-average power ratio (PAPR) of the correlation values ​​of the first and second linear frequency modulated (LFM) signals, and apply threshold decisions for each signal, using the same threshold for both. (For example, the first and second thresholds are the same.)

[0104] It should be noted that peak value or peak-to-average ratio (PAPR) can be used for judgment. This involves determining whether the PAPR of the first merged result exceeds a first threshold, and whether the PAPR of the second merged result exceeds a second threshold. Alternatively, both peak value and PAPR can be used. In this case, both the peak value and PAPR of the first and second linear frequency modulated (LFM) signals must meet certain conditions before a synchronization signal is finally determined to have arrived. If only one signal has a PAPR exceeding the threshold, while the other does not, it is determined that no synchronization signal has been detected.

[0105] Once it is determined that the pilot signal used for synchronization has been captured, i.e. synchronization has been achieved, the timing estimate and frequency offset estimate are calculated.

[0106] Based on the sweep slope value given by the receiver, the second pilot structure sequence given by the receiver, and the peak position in the combined result of the first and second linear frequency modulated signals, the timing and frequency offset are calculated.

[0107] For example, in the first frame, the peak position of the linear frequency modulated signal is... = 0.52ms, the peak position of the second linear frequency modulated signal is = 0.48ms.

[0108] Timely estimate .

[0109] Frequency offset estimate .

[0110] Synchronization prepares for the correct reception and demodulation of subsequent data payload signals. During the synchronization phase, the processed signal is a known, specific pilot signal / synchronization sequence. In the data reception phase, the processed signal is an unknown data signal carrying user information. Therefore, based on the timing and frequency offset estimates calculated during synchronization, the receiver configuration is adjusted. For example, the receiver may adjust its sampling clock or determine an optimal sampling time to achieve timing synchronization. Furthermore, based on the frequency offset estimate, the spectrum of the received data signal can be adjusted to counteract the frequency offset and achieve carrier synchronization.

[0111] In some embodiments, the synchronization process of the signal in the second frame is demonstrated based on the above-described synchronization sequence generation and capture method based on dynamic dual-slope linear frequency modulated signals.

[0112] The specific process is as follows: First, the transmitting end provides two sweep slope values ​​for each frame. , ,and The sweep slope takes values ​​from a finite discrete set. Selected from the options.

[0113] Second frame selection .

[0114] Next, the positions of the first and second linear frequency modulated signals in the pilot are determined by a binary first pilot structure sequence.

[0115] The first pilot structure sequence generated in the second frame is: .

[0116] Based on the first pilot structure sequence, a second frame pilot signal is generated using a first linear frequency modulated signal and a second linear frequency modulated signal.

[0117] The frequency of the pilot signal in the second frame changes over time as follows: Figure 8 As shown.

[0118] Figure 8 In the second frame, the frequency change of the pilot signal over time is represented by multiple line segments. The upward-sloping line segments correspond to the first linear frequency modulated signal, and their slope... The downward-sloping line segment corresponds to the second linear frequency modulated signal, and its slope is... The pilot structure is composed of the following sequence: second linear frequency modulated (LFM) signal, first LFM signal, second LFM signal, second LFM signal, first LFM signal, first LFM signal, second LFM signal, first LFM signal. This sequence is the same as the pilot structure sequence generated in the second frame. Correspondingly.

[0119] Subsequently, the second frame of pilot signal is sent to the receiving end.

[0120] The receiver provides two sweep slope values ​​for each frame. , ,and The sweep slope takes values ​​from a finite discrete set. The sweep slope value given by the receiver for each frame is the same as the sweep slope value given by the transmitter.

[0121] Second frame selection .

[0122] Based on the given two sweep slope values , The matched filter that generates the first linear frequency modulated signal and the matched filter that generates the second linear frequency modulated signal are used to perform matched filtering on the received signal.

[0123] Next, a binary second pilot structure sequence determines the positions of the first and second linear frequency modulated (LFM) signals in the pilot for the second frame. The second pilot structure sequence generated by the receiver for each frame is the same as the first pilot structure sequence generated by the transmitter for each frame.

[0124] The second pilot structure sequence generated in the second frame is as follows: .

[0125] Then, according to the second pilot structure sequence at the receiving end. The relevant results given after matched filtering at the receiving end are merged. For example... Figure 9 As shown, Figure 9 This is the output of the merged processing for the second frame.

[0126] The result determines whether the synchronization signal has arrived; if it has, synchronization is achieved. This process is essentially the same as the processing of the first frame pilot signal in the aforementioned embodiment, and will not be described again here.

[0127] Finally, based on the first and second merging results, the timing estimate and frequency offset estimate are calculated.

[0128] In the second frame, the peak position of the linear frequency modulated signal one is... = 0.475ms, the peak position of the second linear frequency modulated signal is = 0.6ms.

[0129] Timing estimation .

[0130] Frequency offset estimation .

[0131] Therefore, it can be concluded that the signals of the second frame and the first frame are dynamically changing, regardless of the preset set. How to choose in _ , Regardless of the type of pilot structure sequence generated a(m) The synchronization sequence generation and acquisition system functioned correctly. Successful synchronization of signals with different parameters across multiple frames was achieved, indicating that both timing and frequency offset estimations matched the settings.

[0132] This specification provides a method for obtaining a synchronization sequence. On the one hand, by utilizing the same prior knowledge as when combining signals at the transmitting end, the receiving end can accurately gather all relevant peaks of the same linear frequency modulated signal that are dispersed in the time domain, thereby accumulating processing gain and significantly improving the detection probability and anti-interference capability of weak synchronization signals in low signal-to-noise ratio environments.

[0133] On the other hand, by using a second pilot structure sequence that is identical to the first pilot structure sequence of the transmitting end as a reference for processing the received signal, the receiving end can maximize the processing gain of the long sequence through a deterministic and low-complexity merging operation without blind search, which significantly improves the processing efficiency and reliability of the synchronization process.

[0134] Reference Figure 1 This specification also discloses a synchronization sequence generation device based on a dynamic dual-slope linear frequency modulated signal, the device comprising: A linear frequency modulation (LFM) signal generation module is used to generate a first LFM signal and a second LFM signal, wherein the first LFM signal and the second LFM signal have different sweep frequency characteristics. The pilot framing module is used to combine multiple first linear frequency modulation signals and / or second linear frequency modulation signals in the time domain according to a preset first pilot structure sequence to generate pilot signals for synchronization. A signal transmitting module is used to transmit the pilot signal to the receiving end.

[0135] The device further includes: The sweep slope selector module is used to determine the different sweep characteristics of the first linear frequency modulation signal and the second linear frequency modulation signal.

[0136] The device further includes: The pilot structure sequence generation module is used to determine the preset first pilot structure sequence.

[0137] The device is used to implement the synchronization sequence generation method based on dynamic dual-slope linear frequency modulation signal as described above.

[0138] Reference Figure 1This specification also discloses a synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated signal, the device comprising: A signal receiving module is used to receive signals, which are a first linear frequency modulated (LFM) signal and a second LFM signal generated by the transmitting end. The first LFM signal and the second LFM signal have different frequency sweep characteristics. According to a preset first pilot structure sequence, multiple first LFM signals and / or second LFM signals are combined in the time domain to generate a pilot signal for synchronization. The matched filtering module is used to process the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence; The merging module is used to merge the correlation results of the first linear frequency modulated signal in the first correlation result sequence according to a preset second pilot structure sequence to obtain a first merging result, and to merge the correlation results of the second linear frequency modulated signal in the second correlation result sequence to obtain a second merging result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence; The synchronization module is used to complete the synchronization based on the first merging result and the second merging result. The synchronization module can also be called the timing and frequency offset calculation module.

[0139] The device further includes: The sweep slope selector module is used to determine the first matched filter corresponding to the first linear frequency modulated signal and the second matched filter corresponding to the second linear frequency modulated signal.

[0140] The device further includes: The decision module is used to determine whether the peak value / peak-to-average power ratio of the first merged result exceeds a first threshold, and whether the peak value / peak-to-average power ratio of the second merged result exceeds a second threshold; if both determinations are yes, it is determined that the signal for synchronization has been received, and synchronization is completed based on the first merged result and the second merged result.

[0141] The device is used to implement the synchronous sequence acquisition method based on dynamic dual-slope linear frequency modulation signal as described above.

[0142] Furthermore, although the operations of the methods disclosed herein are described in a specific order in the accompanying drawings, this does not require or imply that these operations must be performed in that specific order, or that all of the operations shown must be performed to achieve the desired result. Additionally or alternatively, certain steps may be omitted, multiple steps may be combined into one step, and / or one step may be broken down into multiple steps.

[0143] While the spirit and principles of this disclosure have been described with reference to several specific embodiments, it should be understood that this disclosure is not limited to the disclosed specific embodiments, and the division of aspects does not imply that features in these aspects cannot be combined for benefit; such division is merely for convenience of expression. This disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A method for generating a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal, characterized in that, The method includes: A first linear frequency modulated signal and a second linear frequency modulated signal are generated, and the first linear frequency modulated signal and the second linear frequency modulated signal have different sweep frequency characteristics; According to the preset first pilot structure sequence, multiple first linear frequency modulation signals and second linear frequency modulation signals are combined in the time domain to generate pilot signals for synchronization. The pilot signal is sent to the receiving end for signal reception. The receiving end processes the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. Based on a preset second pilot structure sequence, the correlation results of the first linear frequency modulated signal in the first correlation result sequence are merged to obtain a first merged result, and the correlation results of the second linear frequency modulated signal in the second correlation result sequence are merged to obtain a second merged result. The second pilot structure sequence is identical to the first pilot structure sequence. Synchronization is achieved based on the first merged result and the second merged result.

2. The method as described in claim 1, characterized in that, The sweep slopes of the first and second linear frequency modulated signals are dynamically changed with time or frame number; and / or, The first pilot structure sequence changes dynamically with time or frame number.

3. A method for acquiring a synchronization sequence based on a dynamic dual-slope linear frequency modulated signal, characterized in that, The method includes: The received signal is a first linear frequency modulated (LFM) signal and a second LFM signal generated by the transmitting end. The first LFM signal and the second LFM signal have different frequency sweep characteristics. According to a preset first pilot structure sequence, multiple first LFM signals and second LFM signals are combined in the time domain to generate a pilot signal for synchronization. The pilot signal is processed by a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. According to the preset second pilot structure sequence, the correlation results of the first linear frequency modulated signal in the first correlation result sequence are merged to obtain a first merged result, and the correlation results of the second linear frequency modulated signal in the second correlation result sequence are merged to obtain a second merged result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence; Synchronization is completed based on the first and second merge results.

4. The method as described in claim 3, characterized in that, The second pilot structure sequence is dynamically changing with time or frame number; and / or, The second pilot structure sequence is the same as the first pilot structure sequence and is implemented in at least one of the following ways: The transmitting end and the receiving end of the receiving signal are mapped and selected according to the same time and according to the configuration parameters.

5. The method as described in claim 3, characterized in that, The step of synchronizing based on the first merging result and the second merging result includes: Determine the first peak position of the first merged result and the second peak position of the second merged result; Based on the first peak position, the second peak position, and the sweep slope of the first and second linear frequency modulated signals, the timing estimate and frequency offset estimate are determined to complete the synchronization.

6. The method as described in claim 5, characterized in that, Before determining the timing estimate and frequency offset estimate based on the first peak position, the second peak position, and the sweep slope of the first and second linear frequency modulated signals, the method further includes: Determine whether the peak value / peak-to-average power ratio of the first merged result exceeds a first threshold, and determine whether the peak value / peak-to-average power ratio of the second merged result exceeds a second threshold; If both judgment results are yes, it is determined that the signal used for synchronization has been received, and the timing estimate and frequency offset estimate are determined based on the first peak position, the second peak position, and the sweep slope of the first linear frequency modulation signal and the second linear frequency modulation signal.

7. The method as described in claim 3, characterized in that, The merging methods include coherent merging or incoherent merging.

8. A synchronization sequence generation device based on a dynamic dual-slope linear frequency modulated signal, characterized in that, The device includes: A linear frequency modulation (LFM) signal generation module is used to generate a first LFM signal and a second LFM signal, wherein the first LFM signal and the second LFM signal have different sweep frequency characteristics. The pilot framing module is used to combine multiple first linear frequency modulation signals and second linear frequency modulation signals in the time domain according to a preset first pilot structure sequence to generate pilot signals for synchronization. The signal transmitting module is used to transmit the pilot signal to the receiving end for the receiving end to receive the signal. It processes the pilot signal using a first matched filter corresponding to the first linear frequency modulated (LFM) signal and a second matched filter corresponding to the second LFM signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence. Based on a preset second pilot structure sequence, it merges the correlation results of the first LFM signal in the first correlation result sequence to obtain a first merged result, and merges the correlation results of the second LFM signal in the second correlation result sequence to obtain a second merged result. The second pilot structure sequence is the same as the first pilot structure sequence. Synchronization is achieved based on the first merged result and the second merged result.

9. A synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated signal, characterized in that, The device includes: The signal receiving module is used to receive signals, which are a first linear frequency modulated (LFM) signal and a second LFM signal generated by the transmitting end. The first LFM signal and the second LFM signal have different frequency sweep characteristics. According to a preset first pilot structure sequence, multiple first LFM signals and second LFM signals are combined in the time domain to generate a pilot signal for synchronization. The matched filtering module is used to process the pilot signal using a first matched filter corresponding to the first linear frequency modulated signal and a second matched filter corresponding to the second linear frequency modulated signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence; The merging module is used to merge the correlation results of the first linear frequency modulated signal in the first correlation result sequence according to a preset second pilot structure sequence to obtain a first merging result, and to merge the correlation results of the second linear frequency modulated signal in the second correlation result sequence to obtain a second merging result; wherein, the second pilot structure sequence is the same as the first pilot structure sequence; The synchronization module is used to complete the synchronization based on the first merging result and the second merging result.

10. A synchronization sequence generation and acquisition system based on a dynamic dual-slope linear frequency modulated signal, characterized in that, The system includes: A synchronization sequence generation device based on a dynamic dual-slope linear frequency modulated (LFM) signal is used to generate a first LFM signal and a second LFM signal, which have different sweep frequency characteristics; and according to a preset first pilot structure sequence, multiple first LFM signals and second LFM signals are combined in the time domain to generate a pilot signal for synchronization; and the pilot signal is sent to a receiving end. A synchronization sequence acquisition device based on a dynamic dual-slope linear frequency modulated (LFM) signal is used to receive the signal, process the pilot signal using a first matched filter corresponding to the first LFM signal and a second matched filter corresponding to the second LFM signal, respectively, to obtain a first correlation result sequence and a second correlation result sequence; and according to a preset second pilot structure sequence, merge the correlation results of the first LFM signal in the first correlation result sequence to obtain a first merged result, and merge the correlation results of the second LFM signal in the second correlation result sequence to obtain a second merged result; wherein the second pilot structure sequence is the same as the first pilot structure sequence; and complete synchronization based on the first merged result and the second merged result.

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