Adaptive anti-interference forwarding type navigation signal generation method and system

Abstract

The application discloses a kind of self-adapting anti-interference's forwarding formula navigation signal generation method and system, belong to navigation signal processing technical field.The method includes: using all airspace array antenna receives multi-system satellite navigation mixed signal and pre-processes to obtain multiple digital baseband signals;Real-time high-precision attitude determination and analysis ephemeris, based on antenna attitude points to target satellite;The amplitude and phase of multiple digital baseband signals are jointly closed-loop calibrated with time delay;Based on calibrated signal, antenna attitude and satellite position, the optimal weight is calculated by multi-stage weight generation logic;Optimal weight is used to adaptively beamforming, separate multiple independent satellite signals;After transmission link transmission to signal generation end, transmit after regulating time delay, doppler and power.The system includes antenna host and signal generation device, and the two are connected by transmission link.The application realizes unknown code type satellite signal single separation, all airspace dynamic tracking etc., compatible with ordinary and accurate deception forwarding, and has strong anti-interference ability.

Description

Technical Field

[0001] This invention relates to the field of satellite navigation signal processing technology, and more specifically, to a method and system for generating adaptive, interference-resistant, repeater-type navigation signals. Background Technology

[0002] Satellite navigation signal relay equipment is mainly used in areas where satellite signals are obstructed, such as indoors, underground, tunnels, and enclosed cabins. It receives clear navigation signals from outdoors, processes and amplifies them, and then relays them to the obstructed area to ensure the normal positioning calculation of the terminal navigation equipment. Based on this, relay-based navigation spoofing jamming technology precisely controls parameters such as the delay, Doppler shift, and transmission power of the original satellite signal, causing the target receiver to calculate incorrect position, velocity, or time information. This technology can be applied in special fields such as national defense and security.

[0003] Currently, for military codes and encrypted navigation signals, due to the unknown pseudocode patterns and undisclosed signal characteristics, it is impossible to effectively separate single satellite signals through code division multiple access. The industry usually relies on large-aperture directional antennas for coarse spatial separation, which has technical limitations such as high hardware costs, large size, difficulty in synchronization, and slow beam switching.

[0004] Existing satellite navigation signal relay equipment generally suffers from the following technical defects: First, insufficient anti-interference capability. Traditional relay equipment often uses a single antenna to receive mixed signals, making it susceptible to interference in complex electromagnetic environments. Furthermore, the lack of effective isolation between the transmitting and receiving antennas allows transmitted signals to couple back to the receiver, creating transmission-reception interference. Second, low pointing accuracy. The lack of a real-time attitude measurement mechanism prevents precise pointing of the target satellite based on antenna attitude. Even with array antennas, there is a lack of beam pointing control schemes linked to attitude measurement. Third, poor multi-channel signal consistency. The different channels of an array antenna exhibit amplitude and phase errors and inconsistent time delays due to hardware differences. Existing solutions lack a real-time closed-loop calibration process, leading to reduced beamforming accuracy. Fourth, limited signal separation capability. Conventional relay equipment cannot effectively separate the pure signal of a single satellite from the mixed signal, making subsequent parameter adjustments difficult to implement precisely for individual satellites. This limits the flexibility of deception and interference and the availability of the relayed signal.

[0005] Therefore, a new navigation signal generation and forwarding technology is needed to address the shortcomings of the existing technologies, achieve independent separation of satellite signals with unknown codes, real-time consistency calibration of multiple channels, effective isolation of transmitted and received signals, and balance dynamic tracking performance with hardware cost, thereby improving the system's anti-interference capability and engineering applicability. Summary of the Invention

[0006] The present invention aims to overcome the above-mentioned shortcomings of the prior art and provide an adaptive anti-interference forwarding navigation signal generation method and system, which solves the technical problems of weak anti-interference ability, low pointing accuracy, poor multi-channel consistency and limited signal separation ability in the prior art, and realizes accurate separation of unknown code satellite signals, independent control of multiple parameters and dynamic tracking in the entire airspace.

[0007] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows: As a first aspect of the present invention, an adaptive anti-interference transponder navigation signal generation method is provided, comprising the following steps: receiving mixed signals from multiple satellite navigation systems using a full-space array antenna, and obtaining multiple digital baseband signals through preprocessing; performing real-time high-precision attitude measurement, analyzing ephemeris to determine satellite positions, and forming a pointing direction for the target satellite based on the antenna attitude; performing joint closed-loop calibration of amplitude, phase, and time delay on the multiple digital baseband signals to generate calibrated signals; calculating optimal weights through multi-level weight generation logic based on the calibrated signals, antenna attitude, and satellite position information; using the optimal weights for adaptive beamforming, forming an enhanced beam in the direction of the target satellite and a suppressed beam in the direction of non-target satellites and interference, separating multiple independent satellite signals; transmitting the multiple independent satellite signals to the signal generation end through a transmission link, and then combining or transmitting them individually after time delay, Doppler, and power modulation.

[0008] As a second aspect of the present invention, an adaptive anti-interference repeater navigation signal generation system is provided, comprising an antenna host and a signal generation device, which are connected via a transmission link. The antenna host includes: a full-space array antenna for receiving mixed signals from multiple satellite navigation systems; a multi-channel preprocessing module for preprocessing the received signals to obtain multiple digital baseband signals; an attitude measurement module for performing real-time high-precision attitude measurement, analyzing ephemeris to determine satellite positions, and forming a pointing direction for the target satellite based on the antenna attitude; an amplitude, phase, and time delay calibration module for performing joint closed-loop calibration of the amplitude, phase, and time delay of the multiple digital baseband signals to generate calibrated signals; a weight calculation module for calculating optimal weights based on the calibrated signals, antenna attitude, and satellite position information through multi-level weight generation logic; and a beamforming module for adaptive beamforming using the optimal weights, forming an enhanced beam in the direction of the target satellite and a suppressed beam in the direction of non-target satellites and interference, thus separating multiple independent satellite signals. The signal generation device includes: a multi-channel parallel independent processing channel for receiving the multi-channel independent satellite signals respectively; a parameter control module for independently controlling the time delay, Doppler, and power of each signal; and a signal transmission module for combining or transmitting the controlled signals individually.

[0009] Compared with the prior art, the technical solution of the present invention can achieve at least the following technical effects: First, by employing a full-space array antenna combined with real-time high-precision attitude measurement, the system can autonomously analyze ephemeris and accurately point to the target satellite based on the antenna attitude without relying on a large-aperture directional antenna. It can stably receive satellite signals in dynamic environments (such as vehicle-mounted or airborne carriers in motion) and provide a reliable angle reference for subsequent beamforming, thus solving the technical problems of low pointing accuracy and lack of real-time attitude measurement mechanism in traditional solutions.

[0010] Secondly, by performing joint closed-loop calibration of amplitude, phase, and time delay on multiple digital baseband signals, it is possible to compensate in real time for amplitude and phase inconsistencies and group delay deviations caused by hardware differences, temperature drift, and device aging in each channel, ensuring high synchronization of multi-channel signals, laying a solid data foundation for high-precision beamforming, and improving the problems of poor multi-channel consistency and low beamforming accuracy of existing array antennas.

[0011] Third, based on the calibrated signal, antenna attitude and satellite position information, the optimal weight is calculated through multi-level weight generation logic, and the optimal weight is used for adaptive beamforming. This can form an enhanced beam in the direction of the target satellite and effectively suppress non-target satellites and interference directions, thereby separating multiple independent satellite signals from the mixed signal. This solves the problem that traditional relay equipment has limited signal separation capability and cannot accurately control a single satellite, and can achieve effective separation of encrypted signals with unknown code patterns.

[0012] Fourth, the separated independent satellite signals are transmitted to the signal generation end via a transmission link. At the signal generation end, each signal is independently delayed, Doppler, and power regulated before being combined or transmitted individually. This achieves physical isolation between the receiver and transmitter, avoiding transmission and reception interference and system self-oscillation caused by transmitted signal coupling feedback. On the other hand, it allows the parameters of each satellite signal to be adjusted independently and precisely, meeting the differentiated needs of ordinary navigation forwarding and precise spoofing forwarding, and adapting to the working thresholds of different types of receivers, thus improving the system's flexibility and applicability.

[0013] In summary, the technical solution provided by this invention is superior to existing technologies in terms of anti-interference capability, pointing accuracy, signal separation purity, transmission and reception isolation effect, and parameter adjustment flexibility. It can solve many technical defects of existing forwarding navigation signal generation equipment and has high engineering practicality and promotion value. Attached Figure Description

[0014] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1A flowchart illustrating an adaptive anti-interference forwarding navigation signal generation method provided in an embodiment of the present invention; Figure 2 A schematic diagram of an adaptive anti-interference forwarding navigation signal generation system provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the structure of the full-space array antenna in an embodiment of the present invention. Detailed Implementation

[0015] The technical solutions in the embodiments of the present invention will now be clearly and completely described with reference to the accompanying drawings. The described embodiments are only a part of the implementation of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0016] In practical engineering applications, satellite navigation signal relay equipment is typically deployed in areas where satellite signals are obstructed, such as indoors, underground, tunnels, and enclosed cabins. Its basic workflow is as follows: a receiving antenna is erected in an open outdoor area to acquire mixed signals from multiple satellite navigation systems. After processing such as filtering, amplification, delay, or parameter tampering, the signals are relayed to the obstructed area via a transmitting antenna to ensure the positioning calculation of the terminal equipment or to achieve directional deception interference. During this process, the receiving end faces interference from a complex electromagnetic environment. There are inherent inconsistencies in amplitude, phase, and time delay between multi-channel hardware, and signal coupling feedback can easily occur between the transmitting and receiving antennas. Furthermore, for military-coded and encrypted navigation signals, due to the unknown pseudo-code pattern, code division multiple access (CDMA) cannot be used to separate individual satellite signals. Relying on large-aperture directional antennas for spatial separation leads to increased hardware costs and tracking blind spots.

[0017] To address the aforementioned technological limitations, this invention proposes a holistic design approach: physically separating the signal receiver and transmitter and connecting them via a transmission link to eliminate transmit-receive coupling interference; employing a full-space array antenna with a real-time attitude measurement module at the receiver to achieve self-sensing of antenna attitude and precise pointing to the target satellite; utilizing a closed-loop calibration mechanism with a built-in standard source to compensate for amplitude, phase, and time delay differences between multiple channels in real time; furthermore, employing multi-level weight generation logic and adaptive beamforming technology to separate multiple independent satellite signals from the mixed signal; finally, independently adjusting the time delay, Doppler, and power of each signal at the transmitter to meet different needs of ordinary relaying or precise spoofing relaying. The entire scheme aims to achieve synchronous separation, dynamic tracking, and flexible control of multiple satellite signals without relying on large-aperture directional antennas or prior knowledge of known pseudocodes.

[0018] The specific embodiments of the present invention will be described in detail below.

[0019] Example 1: An Adaptive Anti-interference Transponder Navigation Signal Generation Method This invention provides an adaptive, anti-interference, forwarding navigation signal generation method. See also... Figure 1 The method includes the following steps: S1: A full-space array antenna is used to receive mixed signals from multiple satellite navigation systems, and multiple digital baseband signals are obtained after preprocessing.

[0020] At the receiving end, a full-space array antenna is deployed. This array antenna consists of multiple array elements arranged in a preset spatial layout, which has full-space coverage capability. It can simultaneously receive satellite navigation signals from different directions, effectively covering a wide airspace including low elevation angles, without the need to deploy multiple independent directional antennas.

[0021] After receiving mixed signals from multiple satellite navigation systems such as BDS, GPS, GLONASS, and GALILEO, the array antenna outputs signals from each element into their respective receiving channels. These channels then undergo preprocessing operations, including low-noise amplification, bandpass filtering, quadrature down-conversion, and digital noise reduction. Bandpass filtering suppresses out-of-band interference to prevent it from infiltrating subsequent processing stages. Quadrature down-conversion converts the radio frequency signal to a zero-IF or low-IF digital baseband signal to meet the requirements of subsequent digital signal processing. Digital noise reduction further filters out noise components from the baseband signal, improving signal quality. After preprocessing, multiple synchronized digital baseband signals are output.

[0022] By employing a full-space array antenna, simultaneous reception of signals from multiple satellites can be achieved, effectively avoiding the problems of complex hardware structure and difficulty in signal synchronization caused by multiple independent directional antennas. This provides sufficient spatial freedom for subsequent multi-satellite signal separation and reduces system hardware costs and debugging difficulty.

[0023] S2: Perform real-time high-precision attitude measurement, analyze ephemeris to determine satellite position, and form a pointing direction for the target satellite based on antenna attitude.

[0024] An attitude measurement module is configured at the receiving end. This module receives navigation satellite signals or uses a built-in attitude sensor to collect and calculate the attitude information of the antenna carrier in real time, including heading angle, pitch angle and roll angle, to ensure the real-time and accuracy of the attitude information.

[0025] Simultaneously, the attitude measurement module analyzes satellite ephemeris data and calculates the spatial coordinates of each navigation satellite at the current moment by combining ephemeris parameters. By fusing the acquired antenna attitude information with the satellite spatial position information, the azimuth and elevation angles from the array antenna to each target satellite can be accurately determined, forming a reliable beam pointing basis and providing an angle reference for subsequent adaptive beamforming.

[0026] The attitude measurement process operates continuously at a preset high frequency, enabling real-time tracking of the antenna carrier's attitude changes and timely updates to the beam pointing information. By combining real-time high-precision attitude measurement with satellite ephemeris analysis, the system can autonomously obtain the precise direction of the target satellite without relying on externally provided pointing information or performing complex airspace searches, significantly improving the system's autonomy and response speed.

[0027] S3: Perform joint closed-loop calibration of amplitude, phase and time delay on the multi-channel digital baseband signals to generate calibrated signals.

[0028] This step involves performing a combined amplitude, phase, and time delay closed-loop calibration on the multiple digital baseband signals output from step S1 to eliminate signal distortion caused by hardware differences between the multiple channels, ensure the consistency of signals in each channel, and provide a high-quality signal foundation for subsequent beamforming.

[0029] The joint closed-loop calibration runs repeatedly at a preset cycle, adapting to changes in ambient temperature and hardware drift, ensuring the stability of calibration accuracy. It specifically consists of two parts: amplitude and phase calibration, and time delay calibration. Amplitude and phase calibration: The system uses an internally generated reference signal or an externally injected calibration signal, which is sequentially sent to each receiving channel through the RF switch network. The amplitude and phase differences between the output signals of each channel and the reference signal are compared to calculate the amplitude and phase errors of each channel, generate corresponding complex correction weights, and superimpose these correction weights into the signal paths of each channel in real time to compensate for the amplitude and phase inconsistencies between channels. Delay calibration: The system detects and measures the signal transmission delay difference between each receiving channel, and performs hierarchical compensation through adjustable delay lines or digital delay filters. First, the large fixed delay difference is compensated by the adjustable true delay line in the analog domain, and then the residual micro-delay difference is corrected by the fractional delay filter in the digital domain, so that the signals of each channel are accurately aligned in time.

[0030] Since multi-channel hardware has unavoidable factors such as manufacturing tolerances and temperature drift, if amplitude, phase and time delay calibration is not performed, it will lead to problems such as pointing deviation and signal gain reduction in subsequent beamforming. Therefore, this step is an important foundation for ensuring the accuracy of array signal processing.

[0031] S4: Based on the calibrated signal, antenna attitude and satellite position information, calculate the optimal weight through multi-level weight generation logic.

[0032] This step is based on the calibrated signal obtained in step S3 and the antenna attitude and satellite position information obtained in step S2. It uses multi-level weight generation logic to calculate the optimal beamforming weights that are adapted to the current signal environment, taking into account both efficient processing of known signals and adaptive capability for unknown signals.

[0033] The multi-level weight generation logic is specifically divided into three levels, which can be flexibly combined or used individually according to the actual signal type and application scenario: Level 1: Basic weight generation. By utilizing the phase relationship of the signals received by each array element, preliminary beam pointing weights are quickly formed to achieve preliminary alignment of the target satellite direction. The second level is iterative optimization. The basic weights are used as initial values. Based on preset optimization criteria (such as minimizing the error between the output signal and the desired signal and maximizing the output signal-to-interference-plus-noise ratio), the weights are iteratively updated until they converge to the optimal solution that meets the preset accuracy requirements. Level 3: Blind adaptive processing. For satellite signals with undisclosed pseudocodes and unknown signal structures (such as military code signals), a blind beamforming algorithm based on the statistical characteristics of the signal itself is adopted. Without obtaining detailed code information of the signal, the weights can be adaptively adjusted to achieve signal separation.

[0034] This multi-level weight generation logic can quickly obtain high-quality optimal weights under different signal conditions, which not only ensures efficient processing of known code signals, but also improves the system's adaptability to unknown code signals and enhances the system's versatility.

[0035] S5: Adaptive beamforming is performed using the optimal weights to form an enhanced beam in the direction of the target satellite and a suppressed beam in the direction of non-target satellites and interference, thereby separating multiple independent satellite signals.

[0036] This step uses the optimal weights calculated in step S4 to perform adaptive beamforming processing on the calibrated signal output in step S3. Through spatial weighted synthesis, the target satellite signal is enhanced and interference is suppressed, and multiple independent satellite signals are separated.

[0037] Specifically, each calibrated digital baseband signal is multiplied by its corresponding complex weight, and then summed to obtain the beam output signal. For the direction of the target satellite to be received, the signals in that direction are superimposed in phase by setting the weights to form an enhanced beam and improve the strength of the target signal. For the directions of non-target satellites and interference signals, the signals in those directions are mutually canceled or significantly attenuated by adjusting the weights to form deep suppression, effectively suppressing interference and unwanted signals.

[0038] By simultaneously generating multiple independent beams, each aligned with a target satellite, multiple independent satellite signals can be separated from the mixed navigation signals of multiple systems. Each signal corresponds to the pure navigation information of a single satellite. This adaptive beamforming process achieves spatial filtering without despreading or decoding the signal, making it particularly suitable for separating military code signals with unknown pseudocodes, thus improving the system's anti-interference capability and signal separation purity.

[0039] S6: The multiple independent satellite signals are transmitted to the signal generation end through the transmission link, and after time delay, Doppler and power regulation, they are combined or transmitted and output as a single channel.

[0040] This step involves transmitting the multiple independent satellite signals obtained in step S5 to the signal generation end via a preset transmission link. The transmission link preferentially uses wired transmission methods (such as cables or optical fibers) to ensure signal fidelity and real-time performance during long-distance transmission, while also achieving physical isolation between the receiving and transmitting ends, reducing electromagnetic coupling interference from the transmitted signal to the receiving end, and improving system stability.

[0041] At the signal generation end, an independent processing channel is configured for each independent satellite signal to perform time delay adjustment, Doppler frequency compensation, and transmit power control respectively: Delay control: Adjusting the signal propagation delay, thereby affecting the distance measurement value calculated by the receiver for positioning, to adapt to the needs of different application scenarios; Doppler compensation: simulates or corrects frequency shifts caused by satellite motion or carrier motion, ensuring that the signal frequency matches the receiver's reception range; Power control: Adjusts the transmitted signal strength so that the power of the signal when it reaches the target receiver is within the dynamic range of normal receiver operation, avoiding the effect of excessively strong or weak signals on the reception.

[0042] After the satellite signals have been adjusted, they can be combined and transmitted by a single antenna, or they can be transmitted independently by their respective antennas. Through the adjustment of these parameters, the system can flexibly switch between two operating modes: normal navigation signal relay and precise deception jamming, thus improving the system's applicability.

[0043] In some implementations, the specific method for real-time high-precision attitude measurement is further defined. This real-time high-precision attitude measurement is achieved collaboratively by three navigation antennas and two receiving antennas. The system determines the spatial position of each satellite by analyzing the satellite ephemeris, and simultaneously measures the antenna's own attitude (including heading angle, pitch angle, and roll angle). Based on the geometric relationship between the antenna attitude and the satellite position, a direction pointing to the target satellite is generated, providing a precise direction reference for subsequent adaptive beamforming.

[0044] The three navigation antennas are fixedly mounted on the carrier in a preset geometric layout, preferably arranged in a right-angled triangle, with the spacing between each navigation antenna being a known fixed value. The core function of these three navigation antennas is to receive satellite navigation signals. By measuring the time difference or carrier phase difference of the signal from the same satellite arriving at the three navigation antennas, and combining this with the preset antenna geometric layout parameters, the azimuth and elevation information of the antenna array are calculated, thereby determining the carrier's attitude angles (heading angle, pitch angle, and roll angle).

[0045] The core function of the two receiving antennas is to receive satellite signals and analyze ephemeris data to obtain the orbital parameters and spatial positions of each satellite, providing a satellite position reference for attitude calculation and target pointing generation. It is worth noting that the five antennas (three navigation antennas + two receiving antennas) can share the same RF front-end and baseband processing channel. Time-division multiplexing or frequency-division multiplexing can be used to distinguish the signal sources of different antennas, effectively simplifying the system structure and reducing hardware costs.

[0046] From a functional perspective, the specific geometric layout of the three navigation antennas enables the system to perform self-attitude measurement without relying on external sensors (such as inertial navigation systems or electronic compasses), thereby improving the system's independence and reliability. The two receiving antennas provide redundancy for ephemeris analysis, effectively improving the accuracy and stability of ephemeris analysis and avoiding ephemeris analysis failure caused by abnormal signals received by a single antenna.

[0047] The satellite signals received by the two receiving antennas are processed through down-conversion and demodulation to extract ephemeris parameters from the navigation message. These ephemeris parameters include, but are not limited to, the satellite's orbital elements and time correction factors. The system uses standard algorithms (such as Kepler orbit extrapolation) to calculate the instantaneous spatial position of each satellite in the geocentric-ground-fixed coordinate system based on these ephemeris parameters. Since the ephemeris data is updated every few hours, the ephemeris analysis process does not need to meet high real-time requirements, but it must ensure the stability of satellite signal reception and the accuracy of navigation message decoding. The obtained satellite spatial positions serve as the core input data for subsequent target pointing calculations.

[0048] The antenna attitude is obtained through differential carrier phase measurement of three navigation antennas. The specific implementation process is as follows: the carrier phase difference of the same satellite signal arriving at the three navigation antennas is measured, and combined with the preset geometric baseline vector between the antennas, the azimuth and elevation angles of the antenna array are calculated by the attitude calculation algorithm; then, through coordinate transformation, the antenna array attitude is converted into the heading angle, elevation angle and roll angle of the carrier relative to the local horizontal coordinate system, thus completing the accurate measurement of the antenna attitude.

[0049] After obtaining the antenna attitude, the satellite's spatial position obtained from ephemeris analysis and the antenna's own installation position on the carrier (with known fixed parameters) are combined to calculate the unit vector pointing from the antenna to the satellite through geometric relationships. This unit vector is first expressed in the antenna body coordinate system, and then transformed to the local horizontal coordinate system based on the measured antenna attitude, ultimately obtaining the azimuth and elevation angles of the target satellite. This pointing information is directly used for the steering vector calculation in the adaptive beamforming process, ensuring accurate beam pointing to the target satellite.

[0050] This implementation utilizes a combination of three navigation antennas and two receiving antennas, enabling the system to achieve real-time, high-precision attitude measurement without relying on external attitude measurement equipment, effectively reducing system hardware costs and structural complexity. The attitude measurement method based on carrier phase difference measurement achieves an accuracy better than 0.5°, fully meeting the pointing accuracy requirements of satellite tracking. By analyzing ephemeris data to obtain the satellite position and combining it with antenna attitude to generate target pointing, the system eliminates the need for coarse spatial search or complex direction-finding iteration calculations, significantly improving system response speed.

[0051] Furthermore, this attitude measurement scheme exhibits excellent adaptability. Independent of satellite signal coding patterns, it is also applicable to military code signals with unknown coding patterns. The core reason is that the attitude measurement process utilizes only the carrier phase information of the satellite signal, without relying on the parsing of pseudocode content. The entire attitude measurement process operates continuously at a frequency of no less than 10Hz, enabling real-time tracking of the carrier's attitude changes. This provides a reliable guarantee for stable beam pointing in dynamic environments (such as carrier movement and attitude adjustments), ensuring stable system operation in complex electromagnetic environments.

[0052] In some implementations, the joint closed-loop calibration of amplitude, phase, and time delay is further defined. This joint closed-loop calibration runs in real time at a set period and specifically includes two parts: amplitude and phase calibration and time delay calibration. Through the synergistic effect of the two calibrations, the amplitude and phase inconsistencies and time delay deviations between the receiving channels are compensated, providing a high-quality synchronization signal foundation for subsequent adaptive beamforming. This is a key support for the high-precision signal separation achieved in this invention. Specifically, amplitude and phase calibration uses a built-in standard source to generate a reference signal, which is then injected into each receiving channel sequentially. The amplitude and phase differences between the output of each channel and the reference signal are compared to generate correction weights to compensate for the amplitude and phase inconsistencies between the channels. Time delay calibration uses a combination of analog domain compensation and digital domain correction to compensate for the group time delay deviation between the channels, ensuring that the signals of each channel remain synchronized.

[0053] The antenna host integrates a standard calibration source to generate a reference signal with known amplitude and phase. This reference signal can be a continuous wave or a modulated signal, and its operating frequency covers the navigation signal band, ensuring that the calibration signal matches the actual received navigation signal frequency band and guaranteeing calibration accuracy. The system sequentially sends the reference signal to the input terminals of each receiving channel via an RF switch network. These input terminals can be optionally located before or after the low-noise amplifier, allowing for flexible adjustment based on the actual system layout.

[0054] At the output of each receiving channel, the digital baseband signal, after amplification, filtering, and down-conversion, is acquired. This digital baseband signal is then compared with the ideal amplitude and phase of a reference signal. Signal processing algorithms are used to calculate the amplitude and phase errors of each channel relative to the reference channel. Based on these calculated amplitude and phase errors, a set of complex correction weights is generated, with each receiving channel corresponding to a unique complex correction weight. These weights are stored in real-time in the system storage module and are subsequently applied during beamforming weight calculations to achieve real-time compensation for channel amplitude-phase inconsistencies.

[0055] Due to temperature drift and aging characteristics of system hardware (including but not limited to amplifiers, mixers, filters, ADCs, etc.), the amplitude and phase errors of each channel will change slowly over time. Therefore, the amplitude and phase calibration needs to be repeated at a set period to achieve closed-loop real-time tracking. The set period is preferably 1 millisecond to 1 second and can be flexibly adjusted according to actual system requirements. This embodiment achieves amplitude and phase calibration through a built-in standard source, eliminating the need for additional external calibration equipment. This simplifies the system operation process, ensures the repeatability and stability of the calibration process, and reduces system maintenance costs.

[0056] The delay calibration compensates for the inconsistency in group delay between receiving channels. This group delay difference mainly originates from hardware factors such as differences in RF cable length, filter phase characteristics, and ADC sampling clock deviation. The specific implementation process of delay calibration is as follows: First, by measuring the response signals of each receiving channel to the same test pulse or broadband signal, the relative delay difference between channels is obtained based on the time difference of the response signals. Then, a combination of analog domain compensation and digital domain correction is used to perform layered compensation of the relative delay difference.

[0057] The analog domain compensation is implemented using an adjustable true delay line, which is preferably placed after the low-noise amplifier and before the down-conversion, to coarsely compensate for the large fixed delay differences between channels. The adjustable true delay line can be a microstrip line switching array or a voltage-controlled delay chip, with a step accuracy reaching sub-nanosecond levels, meeting the accuracy requirements of coarse compensation. Digital domain correction is implemented in the baseband digital signal processing section, using a fractional delay filter (such as a Farrow structure) to finely adjust the delay of the sampled digital baseband signal, compensating for the remaining delay difference less than one sampling period.

[0058] The time delay calibration method, which combines analog domain compensation with digital domain correction, fully utilizes the large dynamic range advantage of analog compensation to efficiently compensate for large fixed time delay differences, while leveraging the high precision advantage of digital compensation to accurately correct minute residual time delay differences. Ultimately, this keeps the group time delay difference between receiving channels within the nanosecond range. Consistent with amplitude and phase calibration, time delay calibration also runs in real-time at a set period to address delay drift caused by environmental factors such as temperature changes, ensuring the continuity and accuracy of the time delay calibration.

[0059] This implementation uses amplitude and phase calibration with a built-in standard source to enable the system to detect and compensate for amplitude and phase inconsistencies in each receiving channel in real time. After calibration, the residual amplitude error is less than 0.1dB and the residual phase error is less than 0.5°, which significantly improves the pointing accuracy and signal gain of beamforming. Through time delay calibration combining analog and digital domains, the group time delay difference between channels is controlled within 1 nanosecond. For broadband navigation signals (such as GPS L1 C / A code, with a bandwidth of about 2MHz and a chip width of about 500ns), this calibration accuracy is sufficient to ensure time delay alignment during signal coherent synthesis and avoid time delay deviations affecting the signal synthesis effect.

[0060] The amplitude, phase, and time delay joint closed-loop calibration operates automatically at a set period without manual intervention. It adapts to the effects of temperature changes and device aging, effectively ensuring the stability and reliability of the array system during long-term operation. This calibration mechanism provides a high-quality synchronization signal foundation for subsequent adaptive beamforming, significantly improving the signal separation accuracy of the system in complex electromagnetic environments, and further guaranteeing the stability and reliability of target satellite signal reception.

[0061] In some implementations, the multi-level weight generation logic is further defined. This multi-level weight generation logic includes three levels: generating initial coherent composite weights based on the phase relationship of the signals received by each array element; iteratively optimizing the weights using a dual-objective optimization approach that combines minimum mean square error criterion and correlation maximization; and for signals with unknown code patterns, using a blind beamforming algorithm based on the signal's own characteristics to assist in optimizing the weights, so as to generate the final optimal weights.

[0062] Generation of initial coherent synthesis weights. Given the approximate orientation of the target satellite, a set of initial weights is first generated using the array geometry and the target satellite's steering vector. Specifically, a reference element is selected (e.g., an element located at the array center or boundary), and the spatial phase difference between each element and the reference element is calculated. This phase difference is determined by the element position and the signal incident direction, and is expressed as equation (1): (1) In equation (1), Indicates the phase difference of array elements; Indicates the signal wavelength; This represents the position vector of an array element relative to a reference array element; A unit vector representing the direction of the target satellite; This represents the vector dot product operation.

[0063] The initial coherent synthesis weights are taken as the complex conjugate of the phase differences of each array element, and their expression is shown in equation (2): (2) In equation (2), Indicates the initial coherent synthesis weights; Represents the imaginary unit; Indicates exponentiation; Consistent with the definition in equation (1).

[0064] In this way, when the signals of each array element are multiplied by their corresponding initial weights, the signals from the direction of the target satellite will be superimposed in phase, forming a preliminary beam pointing. This initial weight does not require iterative calculation, has a small computational load, and can quickly provide a usable beam during system startup or beam switching.

[0065] Dual-objective optimization iteration. The initial coherent synthesis weights are based solely on geometric relationships, without considering interference and noise in the actual received signal. To further improve the signal-to-interference-plus-noise ratio (SINR) of the output signal, a dual-objective optimization of minimum mean square error (MSE) and correlation maximization is used to iteratively update the weights. The minimum mean square error (MSE) criterion minimizes the mean square error between the beam output signal and the desired signal, which can be a locally reproduced reference signal (for a known code signal) or a reference waveform obtained through other means. The correlation maximization criterion maximizes the correlation between the output signal and the desired signal, which is equivalent to maximizing the power of the desired signal in the output signal. The two criteria can be mathematically unified by constructing a comprehensive cost function, such as equation (3): (3) In equation (3), Represents the comprehensive cost function; Represents a weight vector; Represents the expectation operator; Represents the weight vector The conjugate transpose of; Represents the received signal vector; Indicates the desired signal; Indicates the desired signal The conjugate transpose of; This represents the balance coefficient, used to balance the weights of the two terms in the cost function; This represents the absolute value operator.

[0066] The weights are iteratively updated using gradient descent or recursive least squares algorithms, with a convergence threshold set (e.g., the change in weights is less than...). (The iteration stops when the time is reached). After several iterations, the weights converge to the optimal solution. This bi-objective optimization maintains the waveform fidelity of the desired signal while suppressing interference, avoiding the signal distortion problem that may be caused by a single criterion.

[0067] Blind beamforming algorithm-assisted optimization. For military codes or encrypted navigation signals with unknown pseudocode patterns, a local copy of the desired signal cannot be obtained, so the above dual-objective optimization cannot be directly applied. In this case, a blind beamforming algorithm based on the characteristics of the signal itself is used to assist in optimizing the weights. Commonly used blind algorithms include constant modulus algorithm, cyclic stationary algorithm, or subspace method. Taking constant modulus algorithm as an example, navigation satellite signals (especially modulated spread spectrum signals) have the characteristic of approximately constant envelope. The objective function of constant modulus algorithm is shown in equation (4): (4) In equation (4), Represent the objective function of the constant modulus algorithm; Represents a weight vector; Represents the expectation operator; Represents the weight vector The conjugate transpose of; Represents the received signal vector; Represents the absolute value operator; This represents the squaring operation.

[0068] By minimizing the objective function of the constant-mode algorithm, the amplitude fluctuation of the beam output signal can be effectively reduced, enabling the beam to accurately point to a signal source with constant envelope characteristics, thereby separating the target satellite signal from the mixed signal. The constant-mode blind beamforming algorithm does not rely on any prior knowledge of the signal (including signal code, amplitude, phase, etc.), but only utilizes the statistical characteristics of the signal itself to adaptively adjust the beamforming weights and achieve the separation of the target signal.

[0069] This blind beamforming algorithm can be used in conjunction with the aforementioned initial coherent synthesis weights. Specifically, the initial coherent synthesis weights are used as the initial values ​​for blind adaptive processing iterations. Based on these initial values, blind adaptive iterative calculations are performed, ultimately outputting the optimal weights for signals with unknown code patterns (such as military encrypted signals), thereby improving the separation accuracy and stability of signals with unknown code patterns. For civilian navigation signals with known code patterns, the blind beamforming algorithm can also be used as an auxiliary optimization method to further adjust the weight parameters, improve the robustness of the weights, and ensure the stability of beam performance under complex interference environments.

[0070] In this implementation, the three-level weight generation logic has a clear division of labor and works in concert to achieve efficient processing of different signal types and optimal weight generation. The specific functions are as follows: The first-level initial coherent synthesis weights utilize geometric information such as array element positions and signal incident directions to quickly establish beam pointing without complex iterative calculations, effectively ensuring the system's real-time response capability and guaranteeing that the beam can be quickly aligned with the target satellite. The second-level dual-target optimization iteration, based on the initial weights, further suppresses interference signals and noise components through iterative calculations, significantly improving the signal-to-interference-plus-noise ratio and waveform fidelity of the beam output signal, providing a guarantee for the accurate separation of target signals. The third-level blind beamforming algorithm provides a technical path for the separation of unknown code signals without prior knowledge, enabling the invention to simultaneously process known civilian code signals and unknown military code signals, effectively overcoming the technical limitation of traditional relay equipment being unable to separate encrypted signals.

[0071] The three-level weight generation logic can be flexibly combined and used according to the type of actual received signal (known code pattern / unknown code pattern) and signal environment (interference intensity, noise level), and can achieve the optimal balance between computational efficiency, iterative convergence speed and signal separation accuracy, adapting to different engineering application scenarios.

[0072] Experimental verification shows that the multi-level weight generation logic adopted in this implementation has a weight update delay of less than 10 milliseconds, which can meet the application requirements of millisecond-level beam switching in the system. At the same time, it can achieve near-theoretical optimal beam performance in different signal environments (including strong interference, low signal-to-interference-plus-noise ratio, mixed code patterns, etc.), ensuring stable separation and high-quality output of target satellite signals.

[0073] In some implementations, the method for calculating the optimal weights of the unknown code signal is further defined. These optimal weights are generated using the minimum variance distortion-free response criterion and calculated using the inverse of the signal covariance matrix and the target satellite steering vector.

[0074] The minimum variance distortionless response criterion requires that the beam response be kept at unity gain (distortionless) in the direction of the desired signal (i.e. the direction of the target satellite) while minimizing the beam output power (variance), thereby achieving the purpose of suppressing interference and noise.

[0075] Mathematically, this criterion can be formulated as an optimization problem under the following constraints: Minimize output power .

[0076] in, Represents a weight vector; Represents the weight vector The conjugate transpose of; The steering vector representing the direction of the target satellite. , These are the elevation and azimuth angles, respectively, in the direction of the target satellite; Represents the expectation operator; Represents the received signal vector; Represents the absolute value operator; This represents the covariance matrix of the received signal.

[0077] The analytical solution to the above optimization problem is shown in equation (5): (5) In equation (5), This represents the optimized weight vector. Represents the covariance matrix of the received signal The inverse matrix; for abbreviation; Indicates the guide vector The conjugate transpose of .

[0078] This optimal solution enables the beam to adaptively form nulls in the direction of interference while maintaining a constant desired signal gain, thereby maximizing the output signal-to-interference-plus-noise ratio.

[0079] Obtaining the signal covariance matrix. Covariance matrix. By receiving signal vector The time average estimate is obtained. In practical systems, the data acquisition... Individual elements The digital baseband signals at consecutive sampling times constitute a data matrix. The estimation formula for the covariance matrix is ​​shown in equation (6): (6) In equation (6), Represents the covariance matrix The estimated value; Indicates the number of consecutive sampling moments; Indicates the sampling time index; Indicates the first The column vector of received signals at each sampling time has a dimension of ( (Number of array elements) Represents the column vector of received signals The conjugate transpose of .

[0080] To adapt to time-varying environments (such as satellite motion and interference changes), the covariance matrix... Regular updates are required, typically using a sliding window or exponentially weighted average to ensure both estimation accuracy and real-time performance.

[0081] covariance matrix The dimension is equal to the number of array elements. Its inverse operation has a complexity of approximately (in (This represents the order of complexity). For With a typical configuration, modern digital signal processors can easily complete this inversion calculation in milliseconds.

[0082] Generation of the target satellite's guidance vector. Guiding vector. Used to describe the direction The phase difference caused by a unit amplitude plane wave on each array element, its i.e. The elements are shown in equation (7): (7) In equation (7), Indicates the guide vector The One element; Represents the imaginary unit ( ); Indicates the wavelength of the navigation signal; Indicates the first The coordinates of each array element in the array coordinate system; Indicates the azimuth angle of the target satellite; Indicates the elevation angle of the target satellite; This indicates an exponential operation. The azimuth angle of the target satellite is also included. and pitch angle The information is provided by the attitude measurement module based on the antenna attitude and ephemeris analysis results.

[0083] For a full-space dome array, the coordinates of each element are known, and the steering vector can be calculated and stored in real time. To reduce computational load, the steering vectors on grids at different angles can also be pre-calculated and quickly obtained through table lookup and interpolation.

[0084] Obtain the covariance matrix estimate and guide vector Next, calculate the estimated value of the covariance matrix. The inverse matrix is ​​then used to calculate the optimal weight vector according to equation (8): (8) In equation (8), Represents the optimal weight vector; This represents the estimated value of the covariance matrix; Represents the estimated value of the covariance matrix The inverse matrix; Indicates the guide vector; Indicates the guide vector The conjugate transpose of .

[0085] The above optimal weight vector The constraints must be met, and the beam output power must be minimized. In practical engineering implementation, to avoid numerical instability during matrix inversion, numerically stable algorithms such as QR decomposition or Cholesky decomposition can be used to ensure the reliability of the calculation results.

[0086] Calculated optimal weights It can be directly applied to adaptive beamforming. In this implementation, the minimum variance distortionless response (MVDR) criterion is used to calculate the optimal weight. This criterion can adaptively form a deep null in the direction of the interference signal while ensuring that the signal passes through the target satellite direction without distortion, thereby significantly improving the output signal-to-interference-plus-noise ratio.

[0087] Compared to traditional coherent combining and beamforming methods based solely on the steering vector, the core advantage of the MVDR criterion lies in its full utilization of the statistical properties of the received signal (i.e., the covariance matrix). It can dynamically adjust the weights according to the actual interference environment. Its anti-interference ability is superior.

[0088] Specifically, the MVDR criterion used in this implementation can obtain the globally optimal weights analytically without iteration. The calculation process is simple, the convergence speed is fast, and it is applicable to array antennas of any geometry. Furthermore, this criterion is independent of the signal code pattern; regardless of whether the target signal has a known or unknown code pattern, it can be determined through the steering vector. With covariance matrix The optimal weights are calculated, and the fit is extremely strong.

[0089] In actual testing, the MVDR criterion of this implementation method was used for beamforming, which can achieve a null depth of more than 30dB in the direction of interference signals. At the same time, the gain in the direction of the target satellite is proportional to the number of array antenna elements, which effectively improves the working stability of the system in complex electromagnetic environments and is significantly better than traditional beamforming methods.

[0090] In some embodiments, the method of this invention further includes a full-space dynamic closed-loop tracking step. This step achieves accurate dynamic tracking of moving satellites by real-time monitoring of satellite azimuth changes, triggering weight updates, setting speed to switch beam pointing, and combining angle tracking technology to correct beam pointing, thereby ensuring stable reception of target satellite signals.

[0091] During normal system operation, the attitude measurement module continuously analyzes satellite ephemeris at a preset high frequency and calculates the instantaneous azimuth and elevation angles of each target satellite in real time. The preset high frequency is preferably between 10Hz and 50Hz to ensure timely capture of subtle changes in satellite position. The satellite angle information output by the attitude measurement module is sent to the beam control unit, which compares this instantaneous angle information with the satellite angle value stored at the previous moment to obtain the satellite angle offset Δθ.

[0092] It should be noted that satellite motion in orbit is regular and gradually changing, with its angular change rate typically less than 0.1° / s; however, when the carrier (such as a vehicle-mounted or airborne carrier) undergoes rapid attitude changes, the angular offset of the satellite relative to the antenna will increase significantly. The real-time monitoring process of this implementation method can comprehensively capture all factors that cause changes in the satellite's relative orientation, including both the satellite's own in-orbit motion and the antenna attitude changes caused by the carrier's motion, ensuring comprehensiveness and timeliness of tracking and aiming.

[0093] The beam control unit presets an angular offset trigger threshold (e.g., 0.2°). When the angular offset Δθ of a target satellite is detected to reach this threshold, the system determines that the current beam pointing has deviated from the target satellite and immediately initiates the weight update process. The trigger threshold can be flexibly set according to the actual tracking accuracy requirements and beamwidth: if the threshold is set too small, it will lead to frequent weight updates, increasing the system's computational burden and affecting the system's real-time performance; if the threshold is set too large, it will cause beam tracking lag, resulting in a decrease in the target satellite's signal reception gain and affecting signal quality.

[0094] After the weight update process is initiated, the system recalculates the steering vector of the target satellite's orientation based on the newly detected instantaneous azimuth and elevation angles. Simultaneously, combining the covariance matrix of the currently received signal, it regenerates the optimal weights adapted to the current satellite orientation according to the Minimum Variance Distortionless Response (MVDR) criterion. This weight update process is completed in a digital signal processor (DSP), ensuring that the weight update delay does not exceed 10 milliseconds, guaranteeing the real-time performance of the tracking and aiming.

[0095] After the weights are updated, the system loads the newly generated optimal weights into the beamformer, enabling rapid switching of beam pointing. Since weight loading is a purely digital operation, the beam pointing switching speed is theoretically limited only by the update rate of the digital circuit. In practical engineering applications, the beam pointing switching speed can reach the millisecond level, far superior to the second-level response speed of traditional mechanical turntables, and can quickly adapt to the dynamic changes of satellites and carriers.

[0096] To achieve smooth beam pointing switching and avoid output signal jitter caused by abrupt weight changes, this implementation adopts a progressive weight update strategy. That is, within several sampling periods, the weights are linearly transitioned from the old weights to the new weights, ensuring the continuity and stability of the output signal. The beam switching speed (i.e., the speed at which the beam pointing actually changes after weight loading) can be flexibly set, and its value must balance switching response time and signal quality, typically controlled between 5ms and 20ms to adapt to the needs of different dynamic scenarios.

[0097] It should be noted that relying solely on satellite angle offset to trigger weight updates constitutes open-loop control. This method is susceptible to beam pointing residuals due to factors such as satellite ephemeris errors and attitude measurement errors, which can affect tracking accuracy. Therefore, this implementation introduces angle tracking technology to perform closed-loop correction of the beam pointing, further improving tracking accuracy.

[0098] The basic principle of angle tracking technology is as follows: a beamformer simultaneously generates a sum beam and a difference beam. The sum beam is weighted and synthesized from all array elements and is primarily used to receive signals from the target satellite. The difference beam is generated by dividing the array antenna into two half-arrays (either left and right or top and bottom), calculating the amplitude or phase difference between the output signals of the two half-arrays, and then extracting the angle error signal. This angle error signal is proportional to the deviation angle between the beam pointing direction and the true direction of the satellite, accurately reflecting the degree of beam pointing offset.

[0099] After the extracted angle error signal is processed by loop filtering, a beam pointing correction value is generated. This correction value is then superimposed on the angle value of the steering vector, and the corrected optimal weights are recalculated. Through the above closed-loop iterative process, the angle error signal gradually approaches zero, and the beam pointing is precisely corrected to the true direction of the satellite, achieving precise alignment between the beam and the satellite. Angle tracking technology can effectively compensate for minor pointing deviations caused by satellite ephemeris errors, attitude measurement errors, or weight calculation errors, enabling beam pointing accuracy to reach the sub-beamwidth level.

[0100] The full-space dynamic closed-loop tracking process of this embodiment organically integrates the angle monitoring, weight update, beam pointing switching, and angle tracking correction of the attitude measurement module to form a complete closed-loop control system. It has the following technical advantages: real-time monitoring of satellite azimuth changes and setting reasonable trigger thresholds can avoid unnecessary weight updates and effectively save system computing resources while ensuring tracking accuracy; millisecond-level beam switching speed can quickly adapt to dynamic application scenarios with rapid changes in satellite motion and carrier attitude; the introduction of angle tracking technology further eliminates beam pointing residuals, ensuring that the beam is always accurately aligned with the target satellite and avoiding signal reception quality degradation caused by pointing deviation.

[0101] The entire tracking and aiming process is fully automated and requires no manual intervention. It can continuously lock onto moving target satellites and supports synchronous tracking of multiple targets across the entire airspace, significantly improving the system's stability and reliability in dynamic environments and providing a stable beam pointing foundation for subsequent signal separation and forwarding.

[0102] In some implementations, the transmission link is further defined as follows: the transmission link adopts optical fiber transmission, and its transmission rate is adapted to the real-time transmission requirements of multiple independent satellite signals. It can realize physical isolation between the signal receiving end and the transmitting end, fundamentally solve the problem of transmission-receiver coupling interference, and provide a key engineering foundation for the transmission-receiver separation system architecture.

[0103] Specifically, a fiber optic cable is used to establish a connection between the antenna host (receiver) and the signal generation device (transmitter) to achieve long-distance, high-quality signal transmission. The specific implementation process of fiber optic transmission is as follows: one end of the fiber is connected to the electro-optic conversion module in the antenna host, which converts the digital baseband signal obtained from the receiver into an optical signal; the other end of the fiber is connected to the photoelectric conversion module in the signal generation device, which restores the transmitted optical signal to a digital baseband electrical signal, ensuring the fidelity of signal transmission.

[0104] Single-mode fiber is preferred for the optical fiber, as it offers advantages such as low transmission loss and high bandwidth, making it suitable for long-distance transmission from several meters to several kilometers and meeting the requirements of various engineering deployment scenarios. Two implementation schemes can be adopted for the connection: Scheme 1 uses a pair of optical fibers to transmit downlink signals (satellite signals from the receiver to the transmitter) and uplink signals (control signals or status feedback signals from the transmitter to the receiver) respectively; Scheme 2 uses single-fiber bidirectional technology, achieving bidirectional transmission of downlink and uplink signals through a single optical fiber, effectively reducing fiber usage and simplifying cabling.

[0105] The fiber optic interface uses industry-standard fiber optic connectors, such as FC, SC, or LC type connectors. These standard connectors are highly versatile, reliable, and facilitate on-site cabling, equipment debugging, and subsequent maintenance, thereby improving the system's engineering applicability.

[0106] To further explain the fiber optic transmission rate and related parameters based on signal transmission requirements: The multiple independent satellite signals separated at the receiver are all digital baseband signals. The sampling rate of each signal is consistent with the sampling rate at the receiver, typically not less than 100MHz, and the quantization bits are not less than 16 bits. Based on this, the raw data rate of each digital baseband signal is not less than 1.6Gbps. If we consider parallel transmission of multiple signals (e.g., M=8 parallel transmission channels), the total signal data rate can reach over 12.8Gbps.

[0107] To reduce the bandwidth requirements of fiber optic transmission and optimize transmission efficiency, multiple digital baseband signals can be time-division multiplexed or parallel encoded at the antenna host end, merging multiple parallel data streams into a single high-speed data stream before transmission over the fiber optic cable. The transmission rate of the fiber optic cable is determined by the specifications of the selected optical module; for example, 10Gbps, 25Gbps, or higher-specification SFP+ optical modules can be used. For typical application scenarios (parallel transmission channels M≤8, sampling rate 100MHz, quantization bits 16-bit), a 10Gbps optical module and corresponding fiber optic cable are sufficient to meet the real-time transmission requirements of multiple signals.

[0108] The delay in fiber optic transmission consists of three main parts: electro-optical conversion delay, fiber optic propagation delay (propagation speed is about 5ns / m), and photoelectric conversion delay. The total transmission delay after these three are added together is usually less than 1 microsecond. This delay is much smaller than the chip width of the navigation signal (such as the GPS L1 C / A chip width of about 500ns), and will not affect the real-time performance of the signal, ensuring the accuracy of subsequent signal modulation and transmission.

[0109] The core advantage of optical fiber transmission lies in its excellent physical isolation characteristics and anti-interference ability: optical fiber transmits information in the form of optical signals. Its transmission medium is glass fiber, which is non-conductive and does not radiate electromagnetic waves. Therefore, the high-power radio frequency signal generated at the transmitting end cannot be fed back to the receiving end through optical fiber coupling, completely cutting off the transmission and reception coupling path.

[0110] In contrast, in traditional cable transmission, high-power signals from the transmitting end are easily coupled to the receiving end through the cable shielding layer or spatial radiation, causing transmission-receiver interference. In severe cases, this can even lead to system self-oscillation, affecting the normal operation of the receiver. Furthermore, fiber optic transmission allows for the long-distance separation of the antenna host and signal generation equipment (e.g., the antenna host is installed outdoors, and the signal generation equipment is installed indoors), further improving spatial isolation. Actual measurement data shows that with fiber optic transmission, the system's transmission-receiver isolation can reach over 60dB, far superior to traditional cable transmission methods.

[0111] Meanwhile, fiber optic transmission also has additional advantages such as resistance to electromagnetic interference, lightning protection, light weight, and convenient wiring. It is suitable for complex electromagnetic environments and outdoor deployment scenarios, and can be widely used in various engineering application scenarios such as vehicle-mounted, ship-mounted, and fixed stations.

[0112] This implementation uses optical fiber as the transmission link. Its high bandwidth ensures real-time, lossless transmission of multiple independent satellite signals, avoiding signal distortion caused by data compression or downsampling and guaranteeing signal quality. Its physical isolation characteristics fundamentally solve the technical problem of transmitted signal coupling feedback to the receiver in traditional repeater equipment, eliminating the risk of system self-oscillation and enabling the receiver to operate stably in a high-gain state. Its advantages such as anti-electromagnetic interference and lightning protection further improve the system's reliability in complex electromagnetic environments.

[0113] Furthermore, signal transmission can be achieved between the antenna host and the signal generation device with only one or two optical fibers. The on-site wiring is simple and the equipment deployment is flexible, which effectively reduces the system deployment cost and maintenance difficulty. It provides a reliable engineering implementation basis for the system architecture of transmitting and receiving separation, and further enhances the engineering applicability and promotion value of the present invention.

[0114] Example 2: An Adaptive Anti-interference Transponder Navigation Signal Generation System This invention provides an adaptive anti-interference forwarding navigation signal generation system, such as... Figure 2 As shown, the system includes an antenna host 100 and a signal generation device 200, which are connected via a transmission link. The antenna host 100 is used to receive, preprocess, calibrate, calculate weights, and beamform mixed signals from multiple satellite navigation systems, separating them into multiple independent satellite signals. The signal generation device 200 is used to adjust the parameters and transmit the separated independent satellite signals via radio frequency. The specific structure is as follows: The antenna host 100 includes a full-space array antenna 11, a multi-channel preprocessing module 12, an attitude measurement module 13, an amplitude and phase delay calibration module 14, a weight calculation module 15, and a beamforming module 16. These modules work together to complete signal reception and separation processing, with the following specific functions: Full-space array antenna 11: Used to receive mixed signals from multiple satellite navigation systems. This antenna is composed of multiple array elements arranged in a preset spatial layout. It can cover the entire airspace from azimuth angle 0° to 360° and elevation angle 0° to 90°. It can simultaneously receive satellite navigation signals from multiple systems such as BDS, GPS, GLONASS, and GALILEO from different directions. It eliminates the need to deploy multiple directional antennas, reducing the complexity of system hardware.

[0115] Multi-channel preprocessing module 12: It is connected to the output terminals of each element of the full-space array antenna 11 in a one-to-one correspondence. It is used to perform preprocessing operations such as low-noise amplification, bandpass filtering, quadrature downconversion and digital noise reduction on the satellite signals received by each element in sequence, suppress interference and noise, convert the radio frequency signal into a multi-channel digital baseband signal adapted to subsequent digital processing, and output it to the amplitude and phase delay calibration module 14.

[0116] Attitude Measurement Module 13: This module is used to achieve real-time high-precision attitude measurement. It can receive navigation satellite signals or use built-in attitude sensors to collect and calculate the attitude information (including heading angle, pitch angle, and roll angle) of the antenna carrier in real time. Simultaneously, it analyzes satellite ephemeris data to obtain the instantaneous spatial position of each satellite. Based on the geometric relationship between the antenna attitude and the satellite spatial position, it calculates the direction information pointing to each target satellite. The output of the attitude measurement module 13 is connected to the weight calculation module 15, providing a precise angle reference for weight calculation.

[0117] Amplitude and phase delay calibration module 14: This module performs joint closed-loop calibration of amplitude, phase, and delay of the multiple digital baseband signals output from the multi-channel preprocessing module 12, eliminating signal distortion caused by hardware differences between the multiple channels and ensuring the consistency of the signals in each channel. Specifically, the amplitude and phase calibration section uses an internally generated reference signal to compare the differences between the output signals of each channel and the reference signal, generating correction weights to compensate for amplitude and phase inconsistencies between channels. The delay calibration section uses a combination of analog domain compensation and digital domain correction to compensate for group delay deviations between channels, ensuring time synchronization of the signals in each channel. The amplitude and phase delay calibration module 14 operates in real-time at a set period, and its calibrated multiple digital baseband signals are sent to the weight calculation module 15 and the beamforming module 16, respectively.

[0118] Weight calculation module 15: Based on the calibrated signal output by amplitude and phase delay calibration module 14, and the antenna attitude and satellite position information provided by attitude measurement module 13, the optimal weight vector is calculated through multi-level weight generation logic. This multi-level weight generation logic specifically includes three levels of processing: First level, based on the phase relationship of the received signals of each array element, initial coherent synthesis weights are generated to quickly establish beam pointing; Second level, a dual-objective optimization strategy of minimum mean square error criterion and correlation maximization is adopted to iteratively optimize the initial weights and improve weight performance; Third level, for unknown code signals (such as military encrypted signals), a blind beamforming algorithm based on the characteristics of the signal itself is used for auxiliary optimization to achieve signal separation without prior knowledge.

[0119] Beamforming module 16: Connected to weight calculation module 15 and amplitude / phase delay calibration module 14 respectively, it uses the optimal weights output by weight calculation module 15 to perform spatial weighted synthesis of the calibrated multi-channel digital baseband signals output by amplitude / phase delay calibration module 14. Through weight adjustment, coherent superposition of signals from each array element is achieved in the direction of the target satellite to form an enhanced beam and improve the target signal strength; in the direction of non-target satellites and interference signals, it adaptively forms depth-suppressed nulls to suppress interference and unwanted signals. Beamforming module 16 can simultaneously output multiple independent satellite signals, each signal corresponding to one target satellite, achieving synchronous separation of multi-satellite signals.

[0120] The antenna host 100 and the signal generation device 200 are connected by a transmission link. This transmission link is used not only to transmit multiple independent satellite signals output by the beamforming module 16 to the signal generation device 200 in real time, but also to achieve physical isolation between the signal receiving end (antenna host 100) and the transmitting end (signal generation device 200) to avoid transmission and reception coupling interference.

[0121] The signal generation device 200 includes multiple parallel independent processing channels 21, a parameter control module 22, and a signal transmission module 23. These modules work together to complete signal parameter control and radio frequency transmission. Their specific functions are as follows: Multiple parallel independent processing channels 21: These channels are used to receive independent satellite signals from the transmission link. The number of these channels corresponds one-to-one with the number of independent satellite signals output by the beamforming module 16. Each channel is dedicated to receiving and initially processing one satellite signal. The channels are physically independent and do not interfere with each other, ensuring independent control of the single satellite signal. The output of the multiple parallel independent processing channels 21 is connected to the parameter control module 22.

[0122] Parameter control module 22: Connected to the multi-channel parallel independent processing channel 21, it is used to independently control the time delay, Doppler, and power of each independent satellite signal, so that the output signal is adapted to the operating threshold of different types of receivers. Specifically, time delay control is used to change the signal propagation delay to adapt to deception positioning or ordinary forwarding requirements; Doppler compensation is used to correct frequency offsets caused by satellite motion or carrier motion to ensure signal frequency matching; power control is used to adjust the transmitted signal strength to ensure that the signal is within the normal operating dynamic range when it reaches the target receiver. The output of parameter control module 22 is connected to signal transmission module 23.

[0123] Signal transmission module 23: It is used to convert the various regulated signals output by parameter control module 22 into radio frequency signals for combined or single-channel transmission output. This module includes a digital-to-analog converter, an up-converter, a power amplifier and a transmitting antenna. It supports two working modes: continuous forwarding and pulse forwarding, and can flexibly adapt to the needs of different application scenarios.

[0124] The system of this invention, through the split architecture of the antenna host 100 and the signal generation device 200, achieves physical separation and functional decoupling of reception and transmission, effectively avoiding transmission-receiver coupling interference; the full-space array antenna 11, in conjunction with the attitude measurement module 13, can autonomously acquire satellite orientation and antenna attitude in dynamic environments without external reference; the amplitude and phase delay calibration module 14 eliminates the hardware differences of multiple channels, laying the foundation for high-precision beamforming; the weight calculation module 15 and the beamforming module 16 work together, through multi-level weight generation logic and adaptive beamforming, to enhance the target signal while effectively suppressing interference, achieving separation of signals from multiple independent satellites; the transmission link ensures lossless real-time transmission of signals while providing high transmission-receiver isolation; the signal generation device 200's multi-channel parallel independent processing channel 21, parameter adjustment module 22, and signal transmission module 23 enable independent and precise adjustment of the delay, Doppler, and power of each satellite signal, adapting to both ordinary receivers and anti-interference receivers. Overall, the system effectively solves technical problems such as interference suppression, multi-channel consistency calibration, unknown code pattern signal separation, transmit / receive coupling isolation, and independent control of multiple parameters in complex electromagnetic environments without relying on large-aperture directional antennas or prior knowledge of known pseudocodes. It features high integration, low cost, and strong engineering practicality.

[0125] In some embodiments, the structure of the all-space array antenna 11 is further defined, such as... Figure 3 As shown, the all-space array antenna 11 consists of an upper hemispherical surface 111 and a lower cylinder 112, with their axes coinciding to form a stable integrated structure. The cylinder 112 serves as the supporting structure for the entire antenna, without housing any antenna array elements 114. Its upper end is fixedly connected to the bottom edge of the hemisphere 111. The cylinder is hollow inside, housing the RF cables, power divider network, calibration circuitry, and necessary shielding and heat dissipation components, effectively protecting internal components and preventing external interference. The bottom of the cylinder 112 has a mounting flange, facilitating the fixing of the entire antenna to a carrier (such as a vehicle-mounted or ship-mounted carrier) or tripod, improving deployment flexibility. The cylinder 112 and hemisphere 111 achieve functional decoupling; the cylinder 112 focuses on mechanical support and internal wiring, while the hemisphere 111 focuses on electromagnetic wave reception, simplifying the antenna's manufacturing, assembly, and maintenance processes.

[0126] Hemispherical 111: Made of metal or composite material, its outer or inner surface is used to mount antenna array elements 114. The curvature design of the hemispherical 111 ensures that the antenna can cover the entire airspace from azimuth 0° to 360° and elevation 0° to 90°, eliminating the low elevation gain drop or dead zone problems common in planar arrays. Multiple spherically distributed subarrays 113 are arranged on the hemispherical 111. Each subarray 113 is evenly distributed along the hemispherical 111 or at an optimized angle, specifically using a latitude and longitude division method: divided into 2 to 3 layers along the latitude direction, and each layer evenly divided into 4 to 6 subarrays 113 along the longitude direction. The normal direction of each subarray 113 points to the outer normal of the sphere, naturally covering different zenith and azimuth angles, ensuring uniformity of signal reception across the entire airspace. Appropriate gaps are left between the subarrays 113 to reduce electromagnetic coupling between them and improve signal reception quality. Due to the curvature characteristics of the hemisphere 111, the local coordinate systems of each subarray 113 are different, but each subarray 113 itself maintains planar characteristics, which facilitates the implementation of beamforming algorithms.

[0127] Within each subarray 113, antenna elements 114 are uniformly arranged in a rectangular grid: within the local plane of the subarray 113, antenna elements 114 are arranged at equal intervals along two orthogonal directions (e.g., the x and y directions), forming a regular grid of M rows × N columns. The row spacing is equal to the column spacing, and each is set to half the wavelength of the navigation signal (e.g., for the GPS L1 band, the half wavelength is approximately 95 mm). All adjacent elements 114 are spaced at the same intervals, and each element 114 has the same radiation characteristics. This regular arrangement simplifies the beamforming algorithm of the subarray 113, allowing beam scanning to be achieved using standard digital phase shifting. The number of elements 114 within each subarray 113 is determined based on the required signal gain and beamwidth, with typical configurations being 4×4, 6×6, or 8×8.

[0128] To achieve high-performance beamforming across the entire array, a collaborative control method combining true time delay weighting between subarrays and phase-shift weighting within subarrays is adopted, as detailed below: True delay weighting between subarrays 113: Due to the large spatial distance between subarrays 113 (typically tens of centimeters), the time difference in signal arrival at different subarrays 113 cannot be ignored, especially for broadband navigation signals (bandwidth from several MHz to tens of MHz), where the delay difference can lead to beam dispersion. Therefore, a true delay weighting method is adopted between subarrays 113. Through adjustable delay lines or digital fractional delay filters, the propagation delay between subarrays 113 is accurately compensated, ensuring that signals from the same direction achieve time alignment at the output of each subarray 113, thus guaranteeing the fidelity of broadband signal transmission.

[0129] Phase-shift weighting within subarray 113: Due to the small spacing (on the order of half a wavelength) between the array elements 114 within subarray 113, the maximum time delay difference of the signal arriving at each array element 114 is much smaller than the chip width of the navigation signal. Therefore, beam pointing control can be achieved by using phase-shift weighting. Phase-shift weighting rapidly adjusts the beam pointing by multiplying the received signal of each array element 114 by a complex phase factor. The response speed can reach the millisecond level, and the computational load is small, enabling fast electronic scanning of the beam.

[0130] The two weighting methods described above work together: phase-shifting weighting within subarray 113 handles rapid electronic scanning of the beam, while true-delay weighting between subarrays 113 handles consistency compensation for the broadband signal, jointly achieving high-performance beamforming across the entire array. Simultaneously, each subarray 113 can independently form one or more sub-beams. The outputs of each subarray 113 are aligned and merged after true-delay weighting to form a complete beam. Since the weighting of each subarray 113 can be set independently, the entire array can simultaneously generate multiple independent beams, each with an independent direction. The number of beams is limited by the array's degrees of freedom (total number of array elements minus the number of constraints), typically reaching a total number of array elements minus 2. In practice, the system assigns a beam to each satellite based on the satellite positions provided by the attitude measurement module 13. The beams work in parallel without interference, and beam switching is achieved by updating the weights, eliminating the need for mechanical rotation and improving system response speed.

[0131] The full-space array antenna 11 of this embodiment achieves full-space coverage without blind spots through the combination structure of hemispherical 111 and cylindrical 112, while providing a stable mechanical foundation. The spherical distribution of subarrays 113 on the hemispherical 111 avoids the delay and blind spots of mechanical scanning. The uniform rectangular grid arrangement of array elements 114 within the subarrays 113 simplifies the implementation of the beamforming algorithm. The division of labor between true time delay weighting and within-subarray phase shift weighting balances the requirements of broadband signal fidelity and fast electronic beam scanning. A single array can simultaneously generate multiple independent beams, replacing the traditional scheme of multiple large-aperture directional antennas in parallel, significantly reducing hardware costs and equipment size. It can be flexibly deployed in various scenarios such as vehicle-mounted, portable, and fixed installations, and has good engineering practicality.

[0132] In some implementations, the amplitude and phase delay calibration module 14 is further defined. See also Figure 2 The amplitude and phase delay calibration module 14 integrates a standard source, an amplitude and phase calibration unit, and a delay compensation unit. Each unit has a clear division of labor and works in concert to achieve high-precision calibration of multi-channel signals, as detailed below: The standard source generates a reference signal with known amplitude and phase. This reference signal's frequency covers all navigation signal bands (e.g., GPS L1, L2 and BDS B1, B2), and the waveform can be either continuous wave or wideband modulated signal to meet the needs of different calibration scenarios. The output of the standard source is connected to the input of each receiving channel via an RF switch network (typically located after the low-noise amplifier and before the downconverter). During the calibration cycle, the reference signal is sequentially injected into each receiving channel as a reference for amplitude and phase calibration. The standard source internally uses a high-stability crystal oscillator as its time base, whose long-term amplitude and phase stability is superior to the rate of change of channel errors, ensuring the accuracy and repeatability of calibration. The activation and deactivation of the standard source are uniformly scheduled by the system controller. It is automatically activated during the calibration cycle and remains in standby mode under normal conditions to reduce system power consumption.

[0133] The amplitude and phase calibration unit is responsible for comparing the amplitude and phase differences between the output signals of each receiving channel and the reference signal, and generating corresponding correction weights. When the reference signal from the standard source is injected into a receiving channel, the signal output by that channel (the digital baseband signal after amplification, filtering, down-conversion, and analog-to-digital conversion) is sent to the amplitude and phase calibration unit. Simultaneously, the amplitude and phase calibration unit receives a copy of the reference signal (or an ideal reference signal) from the standard source and calculates the amplitude and phase errors of that channel relative to the reference channel through correlation calculations or direct comparisons. The amplitude error is obtained by comparing the root mean square values ​​of the signals, and the phase error is obtained by calculating the peak phase of the cross-correlation between the two signals. The amplitude and phase calibration unit converts the calculated amplitude and phase errors into complex correction weights, stores them in the calibration register, and adds them to the weights of subsequent beamforming in real time to compensate for the channel amplitude and phase inconsistencies. After the correction weights of all receiving channels have been calculated, one amplitude and phase calibration process is completed. The amplitude and phase calibration unit repeats the above calibration process at a set period (e.g., 1 millisecond to 1 second) to achieve closed-loop tracking of amplitude and phase errors, adapting to error drift caused by changes in ambient temperature and device aging.

[0134] The delay compensation unit is responsible for compensating for the group delay deviation between each receiving channel, ensuring time synchronization of signals from each channel. Its specific implementation process is as follows: First, a broadband test pulse or pseudo-random sequence generated by a standard source is injected into each receiving channel. The delay compensation unit measures the delay difference of each channel relative to the reference channel using cross-correlation peak detection or carrier phase slope method, achieving sub-nanosecond accuracy. After obtaining the delay difference, the delay compensation unit employs a two-stage compensation mechanism to achieve precise delay compensation: the first stage is coarse compensation in the analog domain, which compensates for larger fixed delay differences by adjusting adjustable true delay lines (such as microstrip line switching arrays or voltage-controlled delay chips), with compensation steps ranging from 0.1 nanoseconds to 1 nanosecond; the second stage is fine correction in the digital domain, which uses fractional delay filters (such as Farrow structures) to finely adjust the delay of the sampled digital baseband signal, compensating for the remaining delay difference less than one sampling period. The delay compensation unit coordinates the two-stage compensation mechanism to ultimately control the group delay difference between each receiving channel within 1 nanosecond, meeting the requirements for coherent synthesis of broadband navigation signals. Similar to the time delay calibration unit, the time delay compensation unit also operates in real time at a set cycle to cope with time delay changes caused by temperature drift and device aging, ensuring the stability of calibration accuracy.

[0135] The amplitude and phase delay calibration module 14 in this embodiment achieves real-time closed-loop calibration of multi-channel amplitude, phase and delay through the coordinated work of the standard source, amplitude and phase calibration unit and delay compensation unit. It has high calibration accuracy and controllable period, providing a high-quality synchronization signal foundation for subsequent beamforming.

[0136] In some implementations, the multi-channel parallel independent processing channel 21 corresponds one-to-one with the multiple independent satellite signals output by the beamforming module 16, enabling independent reception, processing, and parameter adjustment of single-satellite signals, as detailed below: The number of parallel independent processing channels 21 is exactly the same as the number of independent satellite signals output by the beamforming module 16. Each processing channel is dedicated to processing one satellite signal. The channels are physically independent of each other, and each channel has its own dedicated buffer, data path, and parameter register, eliminating resource contention and parameter coupling issues. This one-to-one hardware mapping relationship is established through system initialization configuration: the m-th output of the beamforming module 16 is directly connected to the input of the m-th processing channel 21 of the signal generation device 200 via a transmission link, ensuring the accuracy and real-time performance of signal transmission.

[0137] Since each processing channel corresponds to a different satellite, their signal characteristics (such as pseudocode type, Doppler shift, and signal-to-interference-plus-noise ratio) may differ. The one-to-one correspondence structure allows each processing channel to have its delay, Doppler, and power parameters set independently without interference. Within each processing channel 21, the parameter control module 22 (or the channel's built-in control submodule) independently adjusts the delay, Doppler, and power of the satellite signal according to instructions issued by the system: delay control is achieved through a digital delay line, and the adjustment range and accuracy are set independently according to the satellite's deception positioning or normal relay requirements; Doppler compensation generates an offset frequency through a digitally controlled oscillator, which is calculated independently for the satellite's motion speed and the target deception speed; power control adjusts the signal amplitude through a digital multiplier to ensure that the power of the signal reaching the target receiver is within the receiver's normal operating threshold range.

[0138] The advantage of this independent processing structure is that the system can simultaneously configure differentiated parameters for different satellite signals. For example, it can perform deception interference on a satellite signal (set a large time delay and a specific Doppler frequency shift) and perform normal navigation forwarding on another satellite signal (set zero time delay and no Doppler compensation). This flexibility is something that a shared processing channel scheme cannot achieve, significantly improving the system's adaptability and the stealth of deception interference.

[0139] The structure of the multi-channel parallel independent processing channel 21 in this embodiment, which corresponds one-to-one with multiple independent satellite signals, enables independent processing and parameter control of single satellite signals. It avoids resource competition and parameter coupling caused by channel reuse, improves the system's flexibility and differentiated adaptability, and can simultaneously meet the needs of ordinary navigation forwarding and precise deception forwarding.

[0140] It should be noted that the system embodiments of the present invention are based on the same inventive concept as the aforementioned method embodiments. Each functional module and each functional unit in the system corresponds one-to-one with each step in the aforementioned method embodiments, and is used to execute the aforementioned adaptive anti-interference forwarding navigation signal generation method. The specific implementation methods of each functional module and each functional unit can be found in the detailed description of the corresponding steps in the aforementioned method embodiments, and will not be repeated here.

[0141] In summary, the adaptive anti-interference forwarding navigation signal generation method and system provided by the embodiments of the present invention can function independently or work together to achieve multiple technical advantages, effectively solving many defects of traditional forwarding navigation signal generation technology. The specific beneficial effects are as follows: 1) Full-space array antenna and real-time high-precision attitude measurement work together to achieve precise autonomous pointing of the target satellite: This invention uses a full-space array antenna combined with a real-time high-precision attitude measurement module, enabling the system to autonomously analyze satellite ephemeris and accurately determine the target satellite's pointing based on the antenna attitude (heading angle, pitch angle, roll angle) without relying on a large-aperture directional antenna. This combination of technologies effectively solves the technical problems of low pointing accuracy and lack of real-time attitude measurement mechanism in traditional solutions, ensuring that the system can stably receive satellite signals in dynamic environments (such as vehicle-mounted or airborne carrier movements). It also provides a reliable angle reference for subsequent adaptive beamforming, reducing hardware costs while ensuring satellite tracking performance, achieving an optimal balance between hardware cost and tracking performance.

[0142] 2) Combined Amplitude, Phase, and Delay Closed-Loop Calibration to Ensure Synchronization and Consistency of Multi-Channel Signals: This invention performs combined amplitude, phase, and delay calibration on multiple digital baseband signals using an amplitude, phase, and delay calibration module. It utilizes a built-in standard source to compensate for amplitude and phase inconsistencies in each receiving channel in real time. Simultaneously, it employs a combination of coarse compensation in the analog domain and fine correction in the digital domain to eliminate group delay deviations between channels. After calibration, the residual amplitude error between channels can be controlled within 0.1dB, the residual phase error within 0.5°, and the group delay difference within 1ns. This effectively eliminates the adverse effects of differences in multi-channel hardware (amplifiers, mixers, filters, etc.) on beamforming accuracy, ensuring high synchronization of multiple signals and laying a solid data foundation for subsequent high-gain, low-sidelobe beamforming.

[0143] 3) Multi-level weight generation logic, balancing efficient processing of known code signals with separation of unknown code signals: Based on calibrated signal, antenna attitude, and satellite position information, this invention calculates optimal weights through a three-level weight generation logic: The first level provides an initial coherent synthesis weight as the starting point for rapid convergence in weight iteration, ensuring the system's real-time response capability; the second level employs a dual-objective optimization approach of minimum mean square error criterion and correlation maximization to further suppress interference and noise, improving weight performance; the third level introduces a blind beamforming algorithm for unknown code signals (such as military encrypted codes), enabling weight optimization without prior signal knowledge. This three-level logic works collaboratively, resulting in a weight update delay of less than 10 milliseconds. This ensures efficient processing of civilian known code signals while effectively separating encrypted signals such as military codes, overcoming the technical bottleneck of traditional relay equipment's inability to separate unknown code signals and expanding the system's applicability.

[0144] 4) MVDR Criterion Optimizes Weights, Enhancing Anti-interference Capability in Complex Electromagnetic Environments: This invention employs the Minimum Variance Distortionless Response (MVDR) criterion to calculate optimal weights. Weights are generated through operations on the inverse of the signal covariance matrix and the target satellite steering vector. This allows for adaptive null formation with a depth of at least 30dB in the direction of interfering signals, while ensuring distortion-free passage of the signal in the target satellite's direction. This feature enables the beamformer to dynamically adjust the weights according to the actual electromagnetic environment, achieving an output signal-to-interference-plus-noise ratio gain of up to [insert value here]. (where N is the number of array antenna elements), which significantly improves the system's anti-interference capability and weak signal reception capability in complex electromagnetic environments, ensuring stable reception of target satellite signals.

[0145] 5) Full-space dynamic closed-loop tracking for precise tracking of moving satellites: This invention establishes a full-space dynamic closed-loop tracking mechanism. The attitude measurement module monitors satellite azimuth changes in real time. When the satellite's angular deviation reaches a preset trigger condition, a weight update process is rapidly initiated, and beam pointing switching is completed at millisecond speeds. Simultaneously, angle tracking technology is introduced. By generating sum and difference beams, angle error signals are extracted and corrected in a closed loop, achieving precise beam pointing calibration. This feature enables the system to continuously lock onto moving satellites, with tracking angular velocities exceeding 5° / s. This effectively avoids signal loss due to satellite in-orbit motion or carrier attitude changes, achieving full-space multi-target synchronous dynamic tracking and improving system stability in dynamic environments.

[0146] 6) Fiber optic transmission link for physical isolation and high-reliability transmission: This invention uses fiber optic cable as the transmission link, with a transmission rate of no less than 10Gbps, which can meet the real-time, lossless transmission requirements of multiple independent satellite signals. Simultaneously, the fiber optic transmission medium is glass fiber, which is non-conductive and does not radiate electromagnetic waves, achieving physical isolation between the receiving end (antenna host) and the transmitting end (signal generation equipment). This results in a transmit-receive isolation of over 60dB, completely eliminating system self-oscillation and performance degradation caused by high-power RF signal coupling feedback from the transmitting end to the receiving end. Furthermore, fiber optic transmission has advantages such as resistance to electromagnetic interference and lightning strike protection, further enhancing the system's reliability in harsh electromagnetic environments.

[0147] 7) Multi-channel parallel independent processing enables fine-grained control and multi-mode adaptation of single-satellite signals: This invention sets up multiple parallel independent processing channels at the signal generation end. Each channel corresponds one-to-one with the separated independent satellite signals, allowing independent time delay, Doppler, and power control for each satellite signal. Specifically, the time delay control range is 0–250ms with a control accuracy ≤1ns; the Doppler compensation range is ±500kHz with a compensation accuracy ≤1Hz; power control is adjusted through a quantization formula to adapt the transmitted signal to different operating thresholds of ordinary receivers (-60dBm to -90dBm) and anti-jamming receivers (≤-100dBm), ensuring that the signal-to-interference-plus-noise ratio at the receiving end is not lower than -30dB. This feature enables independent and fine-grained adjustment of single-satellite signal parameters, while supporting both ordinary navigation signal forwarding and precise deception jamming modes, significantly improving the system's flexibility and the stealth of deception jamming.

[0148] 8) Optimized All-Space Array Antenna Structure, Reducing Hardware Cost and Size: The all-space array antenna of this invention adopts a structure combining an upper hemisphere and a lower cylinder. The cylinder serves as a supporting structure and does not house any antenna elements; its interior is used to accommodate cables, calibration circuits, and other components. Multiple spherically distributed subarrays are arranged on the hemisphere. The antenna elements within each subarray are evenly arranged in a rectangular grid. Time delay compensation is performed between subarrays using true time delay weighting, and phase control is performed within subarrays using phase shift weighting. This structure allows a single array to cover the entire airspace from azimuth 0° to 360° and elevation 0° to 90°, avoiding the problems of high hardware cost, large size, and synchronization difficulties caused by parallel connection of multiple large-aperture directional antennas in traditional methods. At the same time, the coordinated control of true time delay and phase shift ensures the transmission fidelity of broadband navigation signals and the speed of beam scanning. Compared with traditional solutions, hardware costs are reduced by more than 65%, equipment size is reduced by 70%, and the flexibility of system deployment is improved.

[0149] 9) Optimized calibration and processing mechanisms to improve system automation and stability: The amplitude and phase delay calibration module of this invention has a built-in standard source, amplitude and phase calibration unit and delay compensation unit, which can operate in real time in closed loop with a period of no more than 1ms. The calibration process is fully automatic and requires no manual intervention, ensuring the stability of the system in long-term operation. Multiple parallel independent processing channels correspond one-to-one with independent satellite signals, realizing independent parameter control of single satellite signals. This allows the delay, Doppler and power of each satellite signal to be configured independently as needed, providing flexible and accurate hardware support for complex application scenarios such as multi-target deception and interference.

[0150] In summary, through the independent action and synergistic cooperation of the aforementioned technical features, this invention effectively solves the technical problems of traditional repeater-type navigation signal generation systems, such as weak interference suppression, poor multi-channel consistency, inability to separate unknown code signals, severe transmit-receive coupling interference, high hardware cost, and insufficient dynamic tracking performance, without relying on large-aperture directional antennas or prior knowledge of known pseudocodes. It significantly improves the system's anti-interference capability, pointing accuracy, signal separation purity, operational stability, and engineering applicability, and can be widely applied to various scenarios such as ordinary navigation signal repeater and precise deception interference.

[0151] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. An adaptive anti-interference forwarding navigation signal generation method, characterized in that, Includes the following steps: A full-space array antenna is used to receive mixed signals from multiple satellite navigation systems, and multiple digital baseband signals are obtained after preprocessing. Perform real-time high-precision attitude measurement, analyze ephemeris to determine satellite position, and form a pointing direction for the target satellite based on antenna attitude; The amplitude, phase, and time delay of the multi-channel digital baseband signals are jointly calibrated in a closed loop to generate calibrated signals. Based on the calibrated signal, antenna attitude, and satellite position information, the optimal weight is calculated through multi-level weight generation logic. Adaptive beamforming is performed using the optimal weights to form an enhanced beam in the direction of the target satellite and a suppressed beam in the direction of non-target satellites and interference, thereby separating multiple independent satellite signals. The multiple independent satellite signals are transmitted to the signal generation end via a transmission link, and after time delay, Doppler, and power regulation, they are combined or transmitted individually.

2. The method according to claim 1, characterized in that, The real-time high-precision attitude measurement is achieved through three navigation antennas and two receiving antennas. The satellite position is determined by analyzing the ephemeris and the target satellite pointing is generated based on the antenna attitude.

3. The method according to claim 1, characterized in that, The joint closed-loop calibration of amplitude, phase, and time delay is performed in real time at a set period, specifically including: Amplitude and phase calibration: A reference signal is generated using a built-in standard source, the differences between channels are compared and correction weights are generated to compensate for the amplitude and phase inconsistencies between channels; Delay calibration: A combination of analog domain compensation and digital domain correction is used to compensate for the group delay deviation between channels, so that the signals of each channel remain synchronized.

4. The method according to claim 1, characterized in that, The multi-level weight generation logic includes: Initial coherent synthesis weights are generated based on the phase relationship of the signals received by each array element; The weights are iteratively optimized using a dual-objective optimization approach that combines the minimum mean square error criterion with the maximization of correlation. For signals with unknown code patterns, a blind beamforming algorithm based on the signal's own characteristics is used to assist in optimizing the weights in order to generate the final optimal weights.

5. The method according to claim 4, characterized in that, The step of using a blind beamforming algorithm based on the signal's own characteristics to assist in optimizing the weights, in order to generate the final optimal weights, includes: The optimal weights are generated by using the minimum variance distortion-free response criterion and the inverse of the signal covariance matrix and the target satellite steering vector.

6. The method according to claim 1, characterized in that, It also includes a full-space dynamic closed-loop tracking and aiming step: real-time monitoring of satellite azimuth changes, triggering weight updates when the satellite angle deviation reaches the triggering condition, switching beam pointing at a set speed, and using angle tracking technology to correct beam pointing.

7. The method according to claim 1, characterized in that, The transmission link is an optical fiber, whose transmission rate meets the real-time transmission requirements of multiple independent satellite signals, and achieves physical isolation between the signal receiving end and the transmitting end.

8. An adaptive anti-interference relay-type navigation signal generation system, characterized in that, It includes an antenna host and a signal generation device, which are connected via a transmission link; The antenna host includes: A full-space array antenna for receiving mixed signals from multiple satellite navigation systems; A multi-channel preprocessing module is used to preprocess the received signal to obtain multiple digital baseband signals; The attitude measurement module is used to perform real-time high-precision attitude measurement, analyze ephemeris to determine the satellite position, and form a pointing direction for the target satellite based on the antenna attitude; The amplitude and phase delay calibration module is used to perform joint closed-loop calibration of amplitude, phase and delay on the multi-channel digital baseband signals to generate calibrated signals. The weight calculation module is used to calculate the optimal weight based on the calibrated signal, antenna attitude and satellite position information through multi-level weight generation logic; The beamforming module is used to perform adaptive beamforming using the optimal weights, forming an enhanced beam in the direction of the target satellite and a suppressed beam in the direction of non-target satellites and interference, thereby separating multiple independent satellite signals. The signal generation device includes: Multiple parallel independent processing channels are used to receive the multiple independent satellite signals respectively; The parameter control module is used to independently control the time delay, Doppler, and power of each signal. The signal transmission module is used to combine or transmit the regulated signals individually.

9. The system according to claim 8, characterized in that, The full-space array antenna consists of an upper hemisphere and a lower cylinder. The cylinder serves as a support structure without antenna elements, while the hemisphere has multiple subarrays arranged in a spherical pattern. The elements within each subarray are evenly arranged in a rectangular grid. Time delay compensation is performed between subarrays using true time delay weighting, and phase control is performed within each subarray using phase shift weighting to simultaneously generate multiple independent beams.

10. The system according to claim 8, characterized in that, The amplitude and phase delay calibration module includes a standard source, an amplitude and phase calibration unit, and a delay compensation unit; the multi-channel parallel independent processing channel corresponds one-to-one with multiple independent satellite signals, realizing independent reception, processing, and parameter control of single-satellite signals.

Images