A new route guidance integrated signal acquisition method and device

Abstract

The embodiment of the application provides a novel route guidance integrated signal capturing method and device, relates to the positioning and communication technical field, and the method comprises the following steps: designing a symbol timing and carrier frequency synchronization algorithm based on a preamble sequence, eliminating the carrier frequency offset and the symbol timing offset, designing a threshold adaptive algorithm, calculating the statistical characteristics of noise and interference in real time, the threshold adaptive algorithm calculating a suitable capturing threshold in real time, a parallel code phase search algorithm, adjusting the phase of a local pseudo code generator, performing a frequency domain correlation on the received signal, judging in combination with the threshold provided by the threshold adaptive algorithm, calculating the code phase, and the scheme provided by the embodiment of the application can improve the precision and efficiency of signal capturing and enhance the anti-interference capability of the system.

Description

Technical Field

[0001] This invention belongs to the field of positioning and communication technology, specifically relating to a novel integrated navigation and communication signal acquisition method and device. Technical Background

[0002] In modern aviation, airway communication and navigation systems are crucial components for ensuring flight safety and efficiency. Currently, various aviation communication and navigation signals have been proposed, such as VHF communication signals, L-DACS communication signals, GPS navigation signals, and DME ranging signals. However, civil aviation suffers from a shortage of frequency resources, mutual interference between communication, surveillance, and navigation signals, low ranging accuracy, and difficulty in simultaneously guaranteeing signal measurability, robustness, accuracy, and real-time performance. To address these issues and meet the strategic need for highly integrated, high-integrity, and highly scalable integrated civil aviation airway navigation and communication services, an integrated navigation and communication architecture and electromagnetic compatibility technology system for the civil aviation land-based navigation frequency band was designed, achieving co-frequency reuse of communication and positioning signals.

[0003] Acquiring the new integrated airway communication and navigation signal presents challenges. Existing acquisition methods are susceptible to interference in complex electromagnetic environments, leading to decreased reliability and accuracy. During airway navigation, the high-speed dynamic changes of the aircraft relative to ground base stations cause Doppler frequency shifts in the received signal. Under the new airway navigation signal system, the signal receiver may experience symbol timing deviations, causing phase distortion and inter-stationary signal interference (ISI). In the airway navigation environment, the near-field effect is significant, with near-field base station signals severely impacting the acquisition of far-field base station signals. Compared to traditional positioning signals, the new integrated airway communication and navigation signal features intermittent multi-carrier spectrum. Existing acquisition methods are unsuitable for acquiring this signal. Summary of the Invention

[0004] The purpose of this invention is to provide a novel integrated navigation and communication signal acquisition method and device, which improves the accuracy and efficiency of signal acquisition, enhances the anti-interference capability of the system, and is suitable for various complex electromagnetic environments.

[0005] In a first aspect, embodiments of the present invention provide a novel integrated airway communication and navigation signal acquisition method, the method comprising:

[0006] A new preamble sequence is designed to improve its autocorrelation properties and provide more reliable synchronization information in noisy and interference environments. A synchronization algorithm is then developed based on the designed preamble sequence to achieve synchronization of the positioning signal at the receiver, eliminating carrier frequency offset and symbol timing offset.

[0007] The designed preamble-based synchronization algorithm initially determines the approximate frequency offset of the signal, guiding subsequent symbol timing deviation estimation and fine frequency offset estimation. The correlation between the received signal and the locally generated reference signal is calculated to determine the symbol timing deviation. Finally, a precise frequency offset estimate is performed.

[0008] A threshold adaptive algorithm is designed to calculate the appropriate acquisition threshold in real time by calculating the statistical characteristics of noise and interference, thereby improving the reliability of signal acquisition.

[0009] The synchronized signal and the locally generated pseudo-code signal are frequency domain transformed, their correlation is calculated, the phase of the local pseudo-code generator is adjusted, and the correlation results of the local pseudo-code under different phases are obtained. Combined with adaptive threshold detection of correlation peaks, the pseudo-code phase of the received signal is determined. After confirmation of acquisition, the system enters tracking mode.

[0010] In one embodiment of the present invention, a new preamble sequence is designed to have better autocorrelation characteristics, providing more reliable synchronization information in noisy and interference environments. A synchronization algorithm is designed based on the designed preamble sequence to achieve synchronization of the positioning signal at the receiving end, eliminating carrier frequency offset and symbol timing offset, including:

[0011] The length and structure of the preamble sequence are optimized, and a new preamble sequence structure is generated based on the m-sequence, giving it better autocorrelation and cross-correlation properties to adapt to different channel environments and noise interference levels. The synchronization algorithm introduces a multi-level synchronization detection mechanism, gradually obtaining precise carrier frequency offset and symbol timing offset from coarse to fine through multiple detections and verifications of the synchronization signal, thus improving the reliability and accuracy of synchronization. The synchronization algorithm design includes methods for calculating the correlation function, signal matching techniques, and filtering design.

[0012] In one embodiment of the present invention, the approximate frequency offset of the signal is initially determined using the designed preamble-based synchronization algorithm, guiding subsequent symbol timing deviation estimation and fine frequency offset estimation. The correlation between the received signal and the locally generated reference signal is calculated to determine the symbol timing deviation. Finally, a precise frequency offset estimation is performed, including:

[0013] First, the integer carrier frequency offset of the received signal is calculated and compensated using the proposed synchronization algorithm based on the preamble sequence. Then, the symbol timing offset of the received signal is calculated and compensated. Finally, fine frequency offset estimation and compensation are performed to achieve synchronization of the received signal and eliminate carrier frequency offset and symbol timing offset.

[0014] In one embodiment of the present invention, the threshold adaptive algorithm is designed to improve the reliability of signal acquisition by calculating the statistical characteristics of noise and interference in real time.

[0015] Design an adaptive threshold adjustment algorithm to dynamically adjust the capture threshold based on changes in signal quality.

[0016] In one embodiment of the present invention, the process of performing frequency domain transformation on the synchronized signal and the locally generated pseudo-code signal, calculating their correlation, adjusting the phase of the local pseudo-code generator to obtain the correlation results of the local pseudo-code under different phases, combining adaptive threshold detection of correlation peaks to determine the pseudo-code phase of the received signal, and confirming acquisition, the system enters the tracking mode, including:

[0017] The synchronized received signal and the locally generated pseudocode signal are frequency domain transformed, and after frequency domain conjugate multiplication, IFFT is performed and modulus is taken. The phase of the local pseudocode generator is adjusted, the peak value of the correlation result is detected, and compared with the threshold calculated by the threshold adaptive algorithm. After confirmation of acquisition, the code phase of the corresponding local code is output.

[0018] Secondly, embodiments of the present invention provide a novel integrated airway communication and navigation signal acquisition device, the device comprising:

[0019] Synchronization module: Used to determine and compensate for signal symbol timing deviation and carrier frequency offset, so as to achieve signal synchronization.

[0020] Threshold adaptive module: used to determine the acquisition threshold based on real-time calculated noise and interference characteristics, thereby improving the reliability of signal acquisition.

[0021] Parallel code phase search module: Adjusts the phase of the local pseudocode generator, performs frequency domain correlation with the received signal, and calculates the code phase by combining the threshold provided by the threshold adaptive module.

[0022] In one embodiment of the present invention, the position synchronization module is specifically used for:

[0023] Multi-level synchronization detection can include two stages: coarse synchronization and fine synchronization, progressively improving synchronization accuracy. This module can accurately determine the time deviation between the symbol start time in the received signal and the locally generated reference signal, and perform corresponding time offset compensation on the received signal to achieve symbol-level synchronization. Frequency offset estimation can determine and compensate for the difference between the carrier frequency of the received signal and the local reference frequency, ensuring frequency consistency between the received signal and the local reference signal.

[0024] In one embodiment of the present invention, the threshold adaptive module is specifically used for:

[0025] The threshold adjustment mechanism adjusts the threshold value according to the intensity and characteristics of noise and interference, ensuring that the most suitable threshold value can be used in different environments, thereby improving the reliability and accuracy of signal acquisition.

[0026] In one embodiment of the present invention, the parallel code phase search module is specifically used for:

[0027] The received signals are processed in parallel and matched with local pseudocode signals with different phase offsets, thereby accelerating the pseudocode phase search process. By comparing the correlation results under different phase offsets, the phase offset corresponding to the correlation peak is determined, i.e., the pseudocode phase of the received signal. The optimal phase offset is output as the final code phase result for subsequent signal tracking and demodulation.

[0028] Beneficial effects of the embodiments of the present invention:

[0029] This invention provides a novel integrated communication and navigation signal acquisition method and apparatus for air routes. Based on a proposed preamble sequence, a positioning signal synchronization algorithm is proposed, and an adaptive threshold technique is designed. A parallel code phase search module accelerates the pseudo-code phase search process, improving the system's processing speed and efficiency, and achieving signal synchronization and acquisition. This provides a reliable method for acquiring integrated communication and navigation signals for novel air routes. Compared with related technologies, this invention improves the accuracy and efficiency of signal acquisition, enhances the system's anti-interference capability, and is suitable for various complex electromagnetic environments. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0031] Figure 1 A flowchart illustrating a novel integrated airway communication and navigation signal acquisition method provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the signal synchronization algorithm based on a preamble sequence provided in an embodiment of the present invention;

[0033] Figure 3 This is a schematic diagram of the threshold adaptive adjustment algorithm provided in an embodiment of the present invention.

[0034] Figure 4 This is a schematic diagram of the structure of parallel code phase search provided in an embodiment of the present invention.

[0035] Figure 5 This is a schematic diagram of a novel integrated airway communication and navigation signal acquisition device provided in an embodiment of the present invention. Detailed Implementation Plan

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0037] Existing acquisition methods are susceptible to interference in complex electromagnetic environments, leading to decreased reliability and accuracy in signal acquisition. In en-route navigation, the high-speed dynamic changes of the aircraft relative to ground base stations cause Doppler frequency shifts in the received signal. Under the new en-route navigation signal system, the signal receiver may experience symbol timing deviations, causing phase distortion and ISI (Intermittent Signal Interference). In en-route navigation environments, the near-field effect is significant; near-field base station signals severely impact the acquisition of far-field base station signals. Compared to traditional positioning signals, the new integrated en-route communication and navigation signal features spectral discontinuities and multi-carrier characteristics. Existing acquisition methods are not suitable for acquiring this signal.

[0038] To address the aforementioned problems, embodiments of the present invention provide a novel integrated airway communication and navigation signal acquisition method and apparatus, which will be described in detail below.

[0039] First, a novel integrated airway communication and navigation signal acquisition method provided by an embodiment of the present invention will be described.

[0040] See Figure 1 This is a flowchart illustrating a novel integrated navigation and communication signal acquisition method provided by an embodiment of the present invention. The method is applied to an electronic device with computing capabilities. For example, the method is applied to a computer. The method includes the following steps S101 to S104.

[0041] Step S101: Design a new preamble sequence with better autocorrelation characteristics to provide more reliable synchronization information in noisy and interference environments. Based on the designed preamble sequence, design a synchronization algorithm to achieve synchronization of the positioning signal at the receiver, eliminating carrier frequency offset and symbol timing offset.

[0042] Training sequence structure T = [CDC * D * ], where C represents the symbol sequence C(n) = D(N / 4-n) obtained by IFFT transformation of an m-sequence of length N / 4. The timing synchronization algorithm based on the training sequence is expressed as:

[0043]

[0044] The obtained d corresponds to the middle position of the training sequence (excluding the cyclic prefix).

[0045] Step S102: Using the designed preamble-based synchronization algorithm, the approximate frequency offset of the signal is initially determined to guide subsequent symbol timing deviation estimation and fine frequency offset estimation. The correlation between the received signal and the locally generated reference signal is calculated to determine the symbol timing deviation. Finally, the frequency offset is precisely estimated.

[0046] Specifically, such as Figure 2 First, by analyzing the preamble sequence of the received signal, the approximate frequency offset of the signal is obtained and compensated for. Based on this, the symbol timing deviation is estimated using the proposed algorithm. Finally, the frequency offset is precisely estimated to facilitate subsequent signal processing.

[0047] Step S103: Design a threshold adaptive algorithm. By calculating the statistical characteristics of noise and interference in real time, the threshold adaptive algorithm calculates a suitable acquisition threshold in real time, thereby improving the reliability of signal acquisition.

[0048] Specifically, such as Figure 3 Based on the intensity and characteristics of noise and interference, the most suitable threshold value can be used in different environments. A signal-to-noise ratio estimator is constructed, and the corresponding capture threshold is calculated.

[0049] Step S104: Perform frequency domain transformation on the synchronized signal and the locally generated pseudocode signal, calculate the correlation between the two, adjust the phase of the local pseudocode generator, obtain the correlation results of the local pseudocode under different phases, combine the adaptive threshold detection of correlation peaks, determine the pseudocode phase of the received signal, and after confirming the acquisition, the system enters the tracking mode.

[0050] Specifically, such as Figure 4 The synchronized signal and the locally generated pseudocode signal are frequency-domain transformed, and their correlation is calculated. The phase of the local pseudocode generator is adjusted to obtain the correlation results of the local pseudocode at different phases. Then, the pseudocode phase of the received signal is determined by combining adaptive threshold detection of correlation peaks. Once acquisition is confirmed, the system enters tracking mode to facilitate subsequent signal processing.

[0051] Corresponding to the aforementioned novel integrated airway communication and navigation signal acquisition method, this embodiment of the invention also provides a novel integrated airway communication and navigation signal acquisition device.

[0052] See Figure 5 This is a schematic diagram of a novel integrated navigation and communication signal acquisition device provided in an embodiment of the present invention. The device is applied to electronic devices with computing capabilities and includes:

[0053] Synchronization module 501: Used to determine and compensate for the symbol timing deviation and carrier frequency offset of the signal, so as to realize the synchronization of the signal.

[0054] Acquisition threshold adaptive module 502: used to determine the acquisition threshold based on real-time calculated noise and interference characteristics, thereby improving the reliability of signal acquisition.

[0055] Parallel code phase search module 503: Adjusts the phase of the local pseudocode generator, performs frequency domain correlation with the received signal, and calculates the code phase by combining the threshold provided by the threshold adaptive module.

[0056] In one embodiment of the present invention, the position synchronization module 501 is specifically used for:

[0057] Multi-level synchronization detection can include two stages: coarse synchronization and fine synchronization, progressively improving synchronization accuracy. This module can accurately determine the time deviation between the symbol start time in the received signal and the locally generated reference signal, and perform corresponding time offset compensation on the received signal to achieve symbol-level synchronization. Frequency offset estimation can determine and compensate for the difference between the carrier frequency of the received signal and the local reference frequency, ensuring frequency consistency between the received signal and the local reference signal.

[0058] In one embodiment of the present invention, the threshold adaptive module 502 is specifically used for:

[0059] The threshold adjustment mechanism adjusts the threshold value according to the intensity and characteristics of noise and interference, ensuring that the most suitable threshold value can be used in different environments, thereby improving the reliability and accuracy of signal acquisition.

[0060] In one embodiment of the present invention, the parallel code phase search module 503 is specifically used for:

[0061] The received signals are processed in parallel and matched with local pseudocode signals with different phase offsets, thereby accelerating the pseudocode phase search process. By comparing the correlation results under different phase offsets, the phase offset corresponding to the correlation peak is determined, i.e., the pseudocode phase of the received signal. The optimal phase offset is output as the final code phase result for subsequent signal tracking and demodulation.

Claims

1. A novel integrated airway communication and navigation signal acquisition method, characterized in that, The method includes: A new preamble sequence is designed to improve its autocorrelation properties and provide more reliable synchronization information in noisy and interference environments. A synchronization algorithm is then developed based on the designed preamble sequence to achieve synchronization of the positioning signal at the receiver, eliminating carrier frequency offset and symbol timing offset. The designed preamble-based synchronization algorithm initially determines the approximate frequency offset of the signal, guiding subsequent symbol timing deviation estimation and fine frequency offset estimation. The correlation between the received signal and the locally generated reference signal is calculated to determine the symbol timing deviation. Finally, a precise frequency offset estimate is performed. A threshold adaptive algorithm based on signal-to-noise ratio is designed. By calculating the statistical characteristics of noise and interference in real time, the threshold adaptive algorithm calculates an appropriate acquisition threshold in real time, thereby improving the reliability of signal acquisition. The synchronized signal and the locally generated pseudo-code signal are frequency domain transformed, their correlation is calculated, the phase of the local pseudo-code generator is adjusted, and the correlation results of the local pseudo-code under different phases are obtained. Combined with adaptive threshold detection of correlation peaks, the pseudo-code phase of the received signal is determined. After confirmation of acquisition, the system enters tracking mode.

2. The method according to claim 1, characterized in that, The design introduces a novel preamble sequence with improved autocorrelation characteristics, providing more reliable synchronization information in noisy and interference environments. Based on the designed preamble sequence, a synchronization algorithm is designed to achieve synchronization of the positioning signal at the receiver, eliminating carrier frequency offset and symbol timing offset, including: The length and structure of the preamble sequence are optimized, and a new preamble sequence structure is generated based on the m-sequence, giving it better autocorrelation and cross-correlation properties to adapt to different channel environments and noise interference levels. The synchronization algorithm introduces a multi-level synchronization detection mechanism, gradually obtaining precise carrier frequency offset and symbol timing offset from coarse to fine through multiple detections and verifications of the synchronization signal, thus improving the reliability and accuracy of synchronization. The synchronization algorithm design includes methods for calculating the correlation function, signal matching techniques, and filtering design.

3. The method according to claim 1, characterized in that, The preamble-based synchronization algorithm preliminarily determines the approximate frequency offset of the signal, guiding subsequent symbol timing deviation estimation and fine frequency offset estimation. The correlation between the received signal and the locally generated reference signal is calculated to determine the symbol timing deviation. Finally, a precise frequency offset estimation is performed, including: First, the integer carrier frequency offset of the received signal is calculated and compensated using the proposed synchronization algorithm based on the preamble sequence. Then, the symbol timing offset of the received signal is calculated and compensated. Finally, fine frequency offset estimation and compensation are performed to achieve synchronization of the received signal and eliminate carrier frequency offset and symbol timing offset.

4. The method according to claim 1, characterized in that, The design is based on a threshold adaptive algorithm for signal-to-noise ratio (SNR). By calculating the statistical characteristics of noise and interference in real time, the threshold adaptive algorithm calculates a suitable acquisition threshold in real time, improving the reliability of signal acquisition. This includes: Design an adaptive threshold adjustment algorithm to dynamically adjust the capture threshold based on changes in signal quality.

5. The method according to claim 1, characterized in that, The process involves performing a frequency domain transformation on the synchronized signal and the locally generated pseudo-code signal, calculating their correlation, adjusting the phase of the local pseudo-code generator, obtaining the correlation results of the local pseudo-code under different phases, and combining this with adaptive threshold detection of correlation peaks to determine the pseudo-code phase of the received signal. After confirming acquisition, the system enters tracking mode, including: The synchronized received signal and the locally generated pseudocode signal are frequency domain transformed, and after frequency domain conjugate multiplication, IFFT is performed and modulus is taken. The phase of the local pseudocode generator is adjusted, the peak value of the correlation result is detected, and compared with the threshold calculated by the threshold adaptive algorithm. After confirmation of acquisition, the code phase of the corresponding local code is output.

6. A novel integrated airway communication and navigation signal acquisition device, characterized in that, The device includes: Synchronization module: Used to determine and compensate for signal symbol timing deviation and carrier frequency offset, so as to achieve signal synchronization. Threshold adaptive module: used to determine the acquisition threshold based on real-time calculated noise and interference characteristics, thereby improving the reliability of signal acquisition. Parallel code phase search module: Adjusts the phase of the local pseudocode generator, performs frequency domain correlation with the received signal, and calculates the code phase by combining the threshold provided by the threshold adaptive module.

7. The apparatus according to claim 6, characterized in that, The synchronization module is specifically used for: Multi-level synchronization detection can include two stages: coarse synchronization and fine synchronization, progressively improving synchronization accuracy. This module can accurately determine the time deviation between the symbol start time in the received signal and the locally generated reference signal, and perform corresponding time offset compensation on the received signal to achieve symbol-level synchronization. Frequency offset estimation can determine and compensate for the difference between the carrier frequency of the received signal and the local reference frequency, ensuring frequency consistency between the received signal and the local reference signal.

8. The apparatus according to claim 6, characterized in that, The threshold adaptive module is specifically used for: The threshold adjustment mechanism adjusts the threshold value according to the intensity and characteristics of noise and interference, ensuring that the most suitable threshold value can be used in different environments, thereby improving the reliability and accuracy of signal acquisition.

9. The apparatus according to claim 6, characterized in that, The parallel code phase search module is specifically used for: The received signals are processed in parallel and matched with local pseudocode signals with different phase offsets, thereby accelerating the pseudocode phase search process. By comparing the correlation results under different phase offsets, the phase offset corresponding to the correlation peak is determined, i.e., the pseudocode phase of the received signal. The optimal phase offset is output as the final code phase result for subsequent signal tracking and demodulation.

Images