Interoperable moon satellite navigation signal flexible broadcasting method

Abstract

The application provides a compatible and interoperable lunar satellite navigation signal flexible broadcasting method, which realizes interoperability by setting the working frequency band and center frequency point of the lunar navigation signal to be the same as the navigation signal of LunaNet and adopting direct sequence spread spectrum modulation, realizes compatibility by controlling the signal broadcasting power range, adopts high-flexible non-distortion navigation signal multi-frequency and multi-component multiplexing technology, aggregates multiple lunar navigation signal components into a composite signal without distortion for broadcasting, adopts digital pre-distortion technology to compensate for the non-ideal characteristics of the transmission link after signal multiplexing and before frequency up-conversion, perceives interference and / or deception through the receiver, makes decisions and generates adjustment instructions according to the perception information through the ground station, and adjusts the power and / or signal system of the navigation signal through the satellite in response to the adjustment instructions, so as to realize flexible broadcasting. In this way, the application realizes low-distortion, low-complexity, high-efficiency and high-flexibility flexible broadcasting of the lunar satellite navigation signal.

Description

Technical Field

[0001] This invention relates to the field of lunar satellite navigation technology, and more specifically to a compatible and interoperable method for flexible broadcasting of lunar satellite navigation signals. Background Technology

[0002] Currently, many countries have launched lunar space navigation service system construction plans and jointly broadcast Augmented Forward Signal (AFS) in accordance with the lunar augmented navigation service standard defined by the LunaNet interoperability specification, providing positioning, navigation and timing services similar to those of the Global Navigation Satellite System for lunar and lunar orbiting space users. The AFS signal is transmitted in the S-band of 2483.5MHz to 2500MHz, with a center frequency of 2492.028MHz. The AFS signal includes two signal components: the AFS-I data signal of modulated message information located in the in-phase branch and the AFS-Q pilot signal of unmodulated data located in the quadrature branch. The two signal components are transmitted with equal power. Both AFS-I and AFS-Q adopt direct sequence spread spectrum modulation. The modulation method of AFS-I is BPSK (1), and the modulation method of AFS-Q is BPSK (5).

[0003] Existing lunar satellite navigation signal broadcasting methods mostly employ fixed signal systems, resulting in low flexibility and a lack of consideration for countermeasures against spoofing and interference. Furthermore, current methods do not address the issue of distortion and deviation suppression in lunar satellite navigation signals. To address these problems and the need for more comprehensive utilization of lunar space navigation service resources, it is necessary to propose a low-distortion, low-complexity, high-efficiency, and highly flexible elastic broadcasting method for lunar navigation signals that is compatible and interoperable with LunaNet's AFS signal. This method would enable flexible responses to interference and spoofing and provide greater flexibility for future incremental development. Summary of the Invention

[0004] The purpose of this invention is to overcome the problems of insufficient flexibility, lack of consideration for signal distortion and deviation suppression, and insufficient anti-interference and anti-spoofing capabilities in existing lunar satellite navigation signal broadcasting methods. It proposes a flexible broadcasting method for lunar satellite navigation signals that is compatible and interoperable with existing lunar satellite navigation systems, characterized by low distortion, low complexity, high efficiency, and high flexibility. While achieving good compatibility and interoperability, it improves flexibility, signal quality, and the ability to cope with interference and spoofing.

[0005] Against the backdrop of the internationally pioneering joint planning of the LunaNet lunar navigation system, this invention proposes a signal broadcasting method that is compatible and interoperable with it. This method facilitates the low-cost use of LunaNet navigation service resources by the receivers of this system, and enables international cooperative users to receive the lunar navigation signals of this system at low cost, thereby enhancing the comprehensive lunar space navigation service capabilities.

[0006] To provide diverse lunar navigation services, lunar navigation signals consist of multiple signal components, and the signal modulation methods may include BPSK, BOC, QMBOC, CBOC, TMBOC, AltBOC, and others. Allocating a separate RF transmission link for each signal component would result in unacceptable payload complexity. Therefore, this invention proposes a baseband navigation signal generation method that combines highly flexible, distortion-free multi-frequency, multi-component signal multiplexing with digital predistortion, adaptable to various modulation methods. Different signal components are aggregated and predistorted before being broadcast using the same RF transmission link, saving payload resources and solving the signal distortion problem caused by the non-ideal characteristics of the broadcast link. The multi-frequency, multi-component signal multiplexing technology proposed in this invention has high flexibility and versatility, providing a technical foundation for flexible signal broadcasting.

[0007] Lunar navigation signals are easily affected by interference and deception due to their low landing power and transparent signal structure. Therefore, this invention proposes a method for flexibly adjusting the power and signal structure of navigation signals in interference and deception environments, enabling a resilient response to interference and deception.

[0008] To achieve the above-mentioned technical effects, the present invention provides a compatible and interoperable method for elastically broadcasting lunar satellite navigation signals, comprising the following steps: The operating frequency band and center frequency of the lunar navigation signal are set to be the same as those of the LunaNet navigation signal. Direct sequence spread spectrum modulation is adopted, and the receiving power range of the lunar navigation signal is determined. By employing a highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology based on infinite norm minimization, multiple lunar navigation signal components are aggregated into a composite signal without distortion and broadcast through the same transmission link, which saves payload resources and supports flexible adjustment of the signal system. After signal multiplexing and before up-conversion, digital predistortion technology is used to compensate for the non-ideal characteristics of the transmission link in order to suppress navigation signal distortion deviation. The receiver detects interference and / or spoofing and transmits the detected information to the ground station; the ground station makes decisions based on the detected information and generates adjustment instructions to be transmitted to the satellite; the satellite responds to the adjustment instructions to adjust the power and / or signal mode of the navigation signal to achieve flexible broadcasting.

[0009] Optionally, determining the receiving power range of the lunar navigation signal specifically includes: Calculate the normalized power spectral density of the lunar navigation signal of the current system, and preset the receiving power range of the lunar navigation signal; Calculate the maximum interference power and normalized power spectral density of the lunar navigation signal from other systems, and combine the bilateral receiving bandwidth and white noise power spectral density of the current system receiver with the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receiver of this system can tolerate. Then, use the equivalent carrier-to-noise ratio formula to determine the minimum received power of the lunar navigation signal. Calculate the minimum received power and normalized power spectral density of lunar navigation signals from other systems, and combine the bilateral receiving bandwidth, white noise power spectral density of receivers from other systems, the coverage multiple of the signal of this system, and the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receivers from other systems can tolerate, and use the equivalent carrier-to-noise ratio formula to determine the maximum received power of the lunar navigation signal of the current system. Based on the minimum and maximum received power, the range of received power that meets the compatibility requirements is obtained.

[0010] Optionally, the adoption of a highly flexible, distortion-free navigation signal multi-frequency multi-component multiplexing technology based on infinite norm minimization, which aggregates multiple lunar navigation signal components into a single composite signal without distortion and broadcasts it through the same transmission link, specifically includes: The signal component identification and structured decomposition steps treat signals with different pseudo-random codes as different signal components, and represent each navigation signal component to be broadcast as the product of a bipolar pseudo-random signal and a stepped subcarrier; wherein, the bipolar pseudo-random signal is determined by the product of the pseudo-code sequence, data and the second-level code, and the stepped subcarrier is the product of the modulation subcarrier and the frequency shift subcarrier; The vectorization representation step involves constructing a pseudo-random signal matrix from all values ​​of the bipolar pseudo-random signal and a subcarrier matrix from all values ​​of the stepped subcarrier; and then combining the column vectors of the pseudo-random signal matrix with the corresponding column vectors of the subcarrier matrix through the Kronecker product operation to generate a matrix representing the complete signal components. The auxiliary signal matrix construction steps involve introducing an auxiliary signal matrix, which is constructed by concatenating the following matrices column-wise: a subcarrier orthogonal complement auxiliary matrix, an intermodulation term auxiliary matrix, and a DC component auxiliary matrix. The subcarrier orthogonal complement auxiliary matrix is ​​constructed by concatenating the Kronecker product of the pseudo-random signal vectors of each signal component and the orthogonal complement matrices of the subcarrier vectors of each signal component. The intermodulation term auxiliary matrix is ​​constructed by the Kronecker product of the intermodulation term matrix and the identity matrix; the intermodulation term matrix is ​​a matrix composed of all intermodulation term vectors of orders 2 to N of the bipolar pseudo-random signal vectors. The DC component auxiliary matrix is ​​constructed by the Kronecker product of all-1 basis vectors and the identity matrix. The solution steps are optimized. Based on the power ratio and phase relationship of each signal component, the linear combination coefficients of the useful signal are determined. With the goal of minimizing the infinite norm of the composite signal vector, the linear combination coefficients of the useful signal and the auxiliary signal are optimized to obtain the linear combination coefficient vector of the auxiliary signal that minimizes the peak power of the composite signal. The composite signal generation step involves calculating the vectorized representation of the composite signal using the linear combination coefficients of the useful signal and the optimized linear combination coefficients of the auxiliary signal, and generating the composite signal using a lookup table based on the value combination of the pseudo-random signal and the value combination of the subcarrier.

[0011] Optionally, the method of employing navigation signal multi-frequency multi-component multiplexing technology to aggregate multiple navigation signal components with different pseudo-random codes and / or different modulation schemes into a composite signal for broadcasting through the same transmission link also includes a distortion-free processing step. Based on the zero-crossing point deviation of the S-curve at different correlation intervals when the composite signal is correlated with different signal components, it is determined whether there is correlation function distortion. If distortion exists, the subcarrier orthogonal complement auxiliary matrix and the DC component auxiliary matrix that cause distortion are removed from the auxiliary signal matrix, and only the intermodulation term auxiliary matrix is ​​retained. The linear combination coefficients of the auxiliary signals are then resolved to generate a distortion-free composite signal.

[0012] Optionally, in the optimization solution step, the optimization solution for the linear combination coefficients of the auxiliary signals, with the objective of minimizing the infinity norm of the composite signal vector, to obtain the linear combination coefficient vector of the auxiliary signals that minimizes the peak power of the composite signal, specifically involves: make Let be the linear combination coefficient vector of the useful signal, where and These are the transmit power and initial phase of the i-th navigation signal component, respectively; Auxiliary signal linear combination coefficient vector Calculated based on the following formula: ; in, A matrix representing the complete signal components, The auxiliary signal matrix, The linear combination coefficient vector of the auxiliary signal; Using the linear combination coefficient vector of auxiliary signals The vectorized representation of a composite signal is calculated as follows: .

[0013] Optionally, if distortion exists, the subcarrier orthogonal complement auxiliary matrix and the DC component auxiliary matrix that cause distortion are removed from the auxiliary signal matrix, and only the intermodulation term auxiliary matrix is ​​retained. The linear combination coefficients of the auxiliary signals are then re-solved to generate a distortion-free composite signal. Specifically: make This represents the linear combination coefficient vector of the auxiliary signal after distortion removal, with dimension . ,in N The number of signal components. L Let be the row number of the subcarrier matrix; This is the auxiliary matrix for the intermodulation term; The linear combination coefficient vector of the auxiliary signal that minimizes peak power and is distortion-free is obtained by solving the following optimization problem. : ; Using the linear combination coefficient vector of the auxiliary signal The vectorized representation of a distortion-free composite signal is calculated as follows: .

[0014] Optionally, in the signal component identification and structured decomposition step, the bipolar pseudo-random signal Represented as: ; in, Let i be the pseudocode sequence of the i-th signal. The product of the data and the secondary code. For pseudocode width, The duration is A rectangular pulse; The frequency shift subcarrier Represented as: ; in, Let be the difference between the center frequency of the i-th navigation signal component and the center frequency of the composite signal. , The duration of each step. The duration is rectangular pulse, It is the imaginary unit.

[0015] Optionally, the digital predistortion technology is implemented through a cascaded digital predistortion module, the digital predistortion module comprising: The output multiplexer non-ideal characteristic compensation module is used to compensate for the non-ideal amplitude-frequency and phase-frequency characteristics of the output multiplexer in the transmission link; A high-power amplifier non-ideal characteristic compensation module is used to compensate for the nonlinear distortion and memory effect of the high-power amplifier in the transmission link; The filter non-ideal characteristic compensation module is used to compensate for the non-ideal amplitude-frequency and phase-frequency characteristics of the filter in the transmission link.

[0016] Optionally, the step of sensing interference and / or spoofing through a receiver and transmitting the sensing information to a ground station; the ground station making decisions based on the sensing information and generating adjustment commands for uploading to the satellite; and the satellite responding to the adjustment commands to adjust the power and / or signal mode of the navigation signal to achieve flexible broadcasting, specifically including: The receiver determines whether there is interference and / or deception, and transmits the information on whether there is interference, the frequency band of interference, and whether there is deception to the ground station. The ground station makes a comprehensive decision based on the feedback information from the receiver, generates an adjustment command that includes power adjustment parameters and / or signal system adjustment parameters, and uploads the adjustment command to the satellite; The satellite increases the overall broadcast power of the lunar navigation signal according to the power adjustment parameters in the adjustment instruction; and / or shuts down some signal components or reduces the power of some signal components, allocating power to key signal components; wherein, the shutdown of signal components and the adjustment of power allocation are achieved through the navigation signal multi-frequency multi-component multiplexing technology; The satellite determines whether it needs to change the frequency and / or modulation method of each navigation signal component according to the signal system adjustment parameters in the adjustment instruction. If so, it adjusts the frequency and / or modulation method of each navigation signal component through the navigation signal multi-frequency multi-component multiplexing technology to avoid interference frequency bands. The satellite determines whether it needs to change the spreading code and message of the navigation signal component to counter deception based on the signal system adjustment parameters in the adjustment instruction. If so, it replaces the spreading code and message of the navigation signal component according to the signal system adjustment parameters.

[0017] Optionally, the equivalent carrier-to-noise ratio formula is: ; in, This refers to the received power of the signal. The power spectral density of white noise. The normalized power spectral density of the signal. The received power of the interference signal. The normalized power spectral density of the interference signal, This refers to the bilateral receiving bandwidth of the receiver; When determining the minimum received power The received power of the lunar navigation signal of the current system. The normalized power spectral density of the lunar navigation signal of the current system. The maximum interference power received from other lunar navigation signals. Normalized power spectral density of received lunar navigation signal interference from other systems; When determining the maximum received power This is the minimum receiving power for lunar navigation signals from other systems. For the normalized power spectral density of lunar navigation signals from other systems, This represents the total interference power of the current system's lunar navigation signals received by other systems. This represents the normalized power spectral density of the lunar navigation signal in the current system.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) Compared with lunar navigation signals that do not have compatibility and interoperability, this invention makes it easier for the receiver of this system to use the resources of other lunar navigation systems at low cost, and also enables international cooperative users to receive the lunar navigation signals of this system at low cost, which is conducive to improving the comprehensive lunar space navigation service capability.

[0019] (2) The highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology proposed in this invention reduces the peak power of the signal without introducing additional distortion, and does not impose additional constraints on the number of navigation signal components, the power ratio and phase relationship of the signal components, the modulation method of the signal components, or the frequency distribution of the signal components. It can realize the elastic broadcasting of lunar navigation signals with low distortion, low complexity, high efficiency, and high flexibility.

[0020] (3) The present invention proposes a navigation signal distortion deviation suppression technology based on digital predistortion, which can effectively suppress signal distortion and reduce the SCB characteristics of lunar navigation signals from about 1ns to about 0.3ns.

[0021] (4) The flexible broadcasting method with adjustable power and signal system proposed in this invention can improve the system’s ability to cope with interference and deception compared with existing methods. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 This is a flowchart illustrating the steps of the compatible and interoperable lunar satellite navigation signal elastic broadcasting method provided in an embodiment of the present invention; Figure 2 The flowchart below shows a specific step in determining the receiving power range of the lunar navigation signal using the flexible broadcasting method for compatible and interoperable lunar satellite navigation signals provided in an embodiment of the present invention. Figure 3 The flowchart below shows the flexible broadcasting process of the compatible and interoperable lunar satellite navigation signal flexible broadcasting method provided in an embodiment of the present invention, which allows for flexible adjustment of power and signal system. Figure 4 A flowchart illustrating the specific implementation of the compatible and interoperable lunar satellite navigation signal elastic broadcasting method provided in an embodiment of the present invention for determining the lunar navigation signal power range of the system; Figure 5 A flowchart illustrating the highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology of the compatible and interoperable lunar satellite navigation signal elastic broadcasting method provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the navigation signal generation and broadcasting link of the compatible and interoperable lunar satellite navigation signal elastic broadcasting method described in this invention; Figure 7 This is a schematic diagram illustrating the principle of the navigation signal distortion deviation suppression technology based on digital predistortion in the flexible broadcasting method of compatible and interoperable lunar satellite navigation signals described in this invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0025] It should be noted that references to "an embodiment," "embodiment," "example embodiment," etc., in this specification refer to the described embodiment including specific features, structures, or characteristics, but not every embodiment must include these specific features, structures, or characteristics. Furthermore, such expressions do not refer to the same embodiment. Moreover, when describing specific features, structures, or characteristics in conjunction with embodiments, whether or not explicitly described, it is indicated that incorporating such features, structures, or characteristics into other embodiments is within the knowledge of those skilled in the art.

[0026] Furthermore, certain terms are used in the specification and subsequent claims to refer to specific components or parts. Those skilled in the art will understand that manufacturers may use different names or terms to refer to the same component or part. This specification and subsequent claims do not distinguish components or parts by differences in name, but rather by differences in function. The terms "comprising" and "including" used throughout the specification and subsequent claims are open-ended and should be interpreted as "including but not limited to." Additionally, the term "connection" here includes any direct and indirect electrical connection means. Indirect electrical connection means include connections made through other means.

[0027] This invention provides a compatible and interoperable method for the flexible broadcasting of lunar satellite navigation signals. This method mainly includes the following four technical points: 1. Navigation signal design compatible and interoperable with LunaNet; 2. Highly flexible and distortion-free multi-frequency multi-component multiplexing technology for navigation signals; 3. Navigation signal distortion and deviation suppression technology based on digital predistortion; 4. A flexible broadcasting method with adjustable power and signal system. Through the coordinated operation of these four technical points, low-distortion, low-complexity, high-efficiency, and highly flexible flexible broadcasting of lunar satellite navigation signals is achieved.

[0028] Figure 1 This invention illustrates a method for flexible broadcasting of compatible and interoperable lunar satellite navigation signals according to an embodiment of the present invention, comprising the following steps: S101: Set the operating frequency band and center frequency of the lunar navigation signal to be the same as those of the LunaNet navigation signal, and use direct sequence spread spectrum modulation to achieve interoperability; and determine the receiving power range of the lunar navigation signal to achieve compatibility; S102: It adopts a highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology based on infinite norm minimization, which aggregates multiple lunar navigation signal components into a composite signal without distortion and broadcasts it through the same transmission link, saving payload resources and supporting flexible adjustment of the signal system. S103: After signal multiplexing and before up-conversion, digital predistortion technology is used to compensate for the non-ideal characteristics of the transmission link in order to suppress navigation signal distortion deviation; S104: The receiver detects interference and / or spoofing and transmits the detected information to the ground station; the ground station makes a decision based on the detected information and generates an adjustment command to be transmitted to the satellite; the satellite responds to the adjustment command to adjust the power and / or signal mode of the navigation signal to achieve flexible broadcasting.

[0029] Step S101 describes the design of navigation signals compatible and interoperable with LunaNet in this embodiment. Compatibility means that using multiple satellite navigation systems, individually or in combination, will not cause unacceptable interference or harm the operation and service of other individual satellite navigation systems. Interoperability means that by integrating multiple systems, better service can be obtained at the user level than by using a single system, without imposing additional burden on the user.

[0030] To facilitate interoperability, this embodiment sets the conventional broadcast frequency band and center frequency of the lunar navigation signal to be the same as those of the LunaNet navigation signal. Specifically, the operating frequency band of the navigation signal is 2483.5MHz to 2500MHz, and the center frequency is 2492.028MHz. The navigation signal uses direct sequence spread spectrum modulation, and the modulation method can be various forms such as BPSK, BOC, QMBOC, CBOC, TMBOC, and AltBOC. The number of signal components and the phase of the signal components can be arbitrarily set.

[0031] To meet compatibility requirements, the power range of the lunar navigation signal needs to be constrained. If the power of the lunar navigation signal broadcast by this system is too weak, it is easily interfered with by signals broadcast by other systems; if the power of the lunar navigation signal broadcast by this system is too strong, it will interfere with the receivers of other systems. Therefore, this embodiment proposes a method for reasonably determining the power range of the lunar navigation signal.

[0032] See Figure 2 and Figure 4 In this embodiment, step S101, determining the receiving power range of the lunar navigation signal, specifically includes: S11: Calculate the normalized power spectral density of the lunar navigation signal of the current system and preset the receiving power range of the lunar navigation signal.

[0033] S12: Calculate the maximum interference power and normalized power spectral density of the lunar navigation signal from other systems, and combine the bilateral receiving bandwidth and white noise power spectral density of the current system receiver with the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receiver of this system can tolerate, and determine the minimum received power of the lunar navigation signal using the equivalent carrier-to-noise ratio formula.

[0034] S13: Calculate the minimum received power and normalized power spectral density of lunar navigation signals from other systems, and combine the bilateral receiving bandwidth and white noise power spectral density of receivers from other systems with the coverage multiple of the signal of this system, as well as the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receivers from other systems can tolerate, and use the equivalent carrier-to-noise ratio formula to determine the maximum received power of the lunar navigation signal of the current system.

[0035] S14: Based on the minimum and maximum received power, obtain the received power range that meets the compatibility requirements.

[0036] The equivalent carrier-to-noise ratio formula used in steps S12 and S13 of this embodiment is: ; in, This refers to the received power of the signal. The power spectral density of white noise. The normalized power spectral density of the signal. The received power of the interference signal. The normalized power spectral density of the interference signal, This refers to the bilateral receiving bandwidth of the receiver; When determining the minimum received power The received power of the lunar navigation signal of the current system. The normalized power spectral density of the lunar navigation signal of the current system. The maximum interference power received from other lunar navigation signals. Normalized power spectral density of received lunar navigation signal interference from other systems; When determining the maximum received power This is the minimum receiving power for lunar navigation signals from other systems. For the normalized power spectral density of lunar navigation signals from other systems, This represents the total interference power of the current system's lunar navigation signals received by other systems. This represents the normalized power spectral density of the lunar navigation signal in the current system.

[0037] To more clearly illustrate the above process for determining the power range, Figure 4The complete flow of the lunar navigation signal power range of this system is further illustrated in flowchart form. See also... Figure 4 The steps on the left side of the flowchart are used to determine the minimum received power of the lunar navigation signal for this system, while the steps on the right side are used to determine the maximum received power of the lunar navigation signal for this system. Specifically: Step 1: Calculate the normalized power spectral density of the lunar navigation signal of this system.

[0038] Step 2: Preset the receiving power range of the lunar navigation signal of this system.

[0039] Step 3a: Calculate the maximum interference power and normalized power spectral density of the received lunar signals from other systems on the signal of this system.

[0040] Step 4a: Determine the bilateral receiving bandwidth and white noise power spectral density of the navigation signal receiver in this system.

[0041] Step 5a: Calculate the equivalent carrier-to-noise ratio (CNR) of the lunar navigation signal under different receiving powers using the equivalent carrier-to-noise ratio formula. The equivalent carrier-to-noise ratio formula is shown above; where, This represents the received power of the lunar navigation signal for this system. This represents the normalized power spectral density of the lunar navigation signal for this system. The power spectral density of white noise. For the receiver's bilateral receiving bandwidth, The maximum interference power of lunar signals from other systems on this system's signal. This represents the normalized power spectral density of interference from lunar signals received from other systems on the signal of this system.

[0042] Step 6a: Determine the received power P1 of the lunar navigation signal of this system corresponding to the lowest equivalent carrier-to-noise ratio that the lunar navigation signal receiver of this system can tolerate.

[0043] Step 3b: Calculate the minimum received power and normalized power spectral density of lunar navigation signals from other systems.

[0044] Step 4b: Determine the bilateral receiving bandwidth and white noise power spectral density of the navigation signal receivers of other systems.

[0045] Step 5b: Determine the coverage depth of the lunar navigation signal of this system.

[0046] Step 6b: Calculate the equivalent carrier-to-noise ratio (CNR) of other lunar navigation signals under different received powers using the above equivalent carrier-to-noise ratio formula. Unlike step 5a, here... It is the minimum receiving power for lunar navigation signals from other systems. It is the normalized power spectral density of lunar navigation signals from other systems. It is the white noise power spectral density of other system navigation signal receivers. It is the bilateral receiving bandwidth of navigation signal receivers in other systems. It is the total interference power of the signals from this system received by lunar navigation signal receivers from other systems. It is the normalized power spectral density of the lunar navigation signal of this system.

[0047] Step 7b: Determine the landing power P2 of the lunar navigation signal of this system corresponding to the lowest equivalent carrier-to-noise ratio that other systems' lunar navigation signal receivers can tolerate.

[0048] Step 8: Based on the calculation results of Step 6a and Step 7b, obtain the receiving power range [P1, P2] of the lunar navigation signal of this system that meets the compatibility requirements.

[0049] Step S102 is the highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology used in this embodiment. Due to the limited payload resources, it is difficult to allocate a separate radio frequency broadcast link for each lunar navigation signal component. Therefore, multiplexing technology is required to aggregate signal components of several adjacent frequency points in the same frequency band before broadcasting.

[0050] The baseband composite signal after polymerization It usually has the following form ; in It is the duration of each step. yes Within the time period The value of . In the formula The definition is as follows ; A composite signal is obtained from several signal components. The process is called multiplexing. The main problem solved by highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology is ensuring the quality of the generated composite signal. It has low peak power and does not introduce additional distortion. In addition, the multiplexing technology needs to be highly flexible, that is, it should not impose additional restrictions on the number of signal components, the spread spectrum modulation method of the signal components, the power ratio of the signal components, the phase relationship of the signal components, etc.

[0051] In an optional implementation, step S102 specifically includes the following sub-steps: The signal component identification and structured decomposition steps treat signals with different pseudo-random codes as different signal components. Each navigation signal component to be broadcast is represented as the product of a bipolar pseudo-random signal and a stepped subcarrier. The bipolar pseudo-random signal is determined by the product of the pseudo-code sequence, data, and a second-level code. The stepped subcarrier is the product of a modulation subcarrier and a frequency-shifting subcarrier. Specifically, the bipolar pseudo-random signal... Represented as: ; in, Let i be the pseudocode sequence of the i-th signal. The product of the data and the secondary code. For pseudocode width, The duration is A rectangular pulse; The frequency shift subcarrier Represented as: ; in, Let be the difference between the center frequency of the i-th navigation signal component and the center frequency of the composite signal. , The duration of each step. The duration is rectangular pulse, It is the imaginary unit.

[0052] The vectorization representation step involves constructing a pseudo-random signal matrix from all values ​​of the bipolar pseudo-random signal and a subcarrier matrix from all values ​​of the stepped subcarrier; and then combining the column vectors of the pseudo-random signal matrix with the corresponding column vectors of the subcarrier matrix through the Kronecker product operation to generate a matrix representing the complete signal components. The auxiliary signal matrix construction steps involve introducing an auxiliary signal matrix, which is constructed by concatenating the following matrices column-wise: a subcarrier orthogonal complement auxiliary matrix, an intermodulation term auxiliary matrix, and a DC component auxiliary matrix. The subcarrier orthogonal complement auxiliary matrix is ​​constructed by concatenating the Kronecker product of the pseudo-random signal vectors of each signal component and the orthogonal complement matrices of the subcarrier vectors of each signal component. The intermodulation term auxiliary matrix is ​​constructed by the Kronecker product of the intermodulation term matrix and the identity matrix; the intermodulation term matrix is ​​a matrix composed of all intermodulation term vectors of orders 2 to N of the bipolar pseudo-random signal vectors. The DC component auxiliary matrix is ​​constructed by the Kronecker product of all-1 basis vectors and the identity matrix. The optimization solution process involves determining the linear combination coefficients of the useful signal based on the power ratio and phase relationship of each signal component. With the goal of minimizing the infinity norm of the composite signal vector, the linear combination coefficients of the auxiliary signal are optimized to obtain the auxiliary signal linear combination coefficient vector that minimizes the peak power of the composite signal. Specifically: make Let be the linear combination coefficient vector of the useful signal, where and These are the transmit power and initial phase of the i-th navigation signal component, respectively; Auxiliary signal linear combination coefficient vector Calculated based on the following formula: ; in, A matrix representing the complete signal components, The auxiliary signal matrix, The linear combination coefficient vector of the auxiliary signal; Using the linear combination coefficient vector of auxiliary signals The vectorized representation of a composite signal is calculated as follows: .

[0053] The composite signal generation step involves calculating the vectorized representation of the composite signal using the linear combination coefficients of the useful signal and the optimized linear combination coefficients of the auxiliary signal, and generating the composite signal using a lookup table based on the value combination of the pseudo-random signal and the value combination of the subcarrier.

[0054] Furthermore, step S102 also includes a distortion-free processing step: Based on the zero-crossing point deviation of the S-curve at different correlation intervals when the composite signal is correlated with different signal components, it is determined whether there is correlation function distortion. If distortion exists, the subcarrier orthogonal complement auxiliary matrix and the DC component auxiliary matrix that cause distortion are removed from the auxiliary signal matrix, retaining only the intermodulation term auxiliary matrix. The linear combination coefficients of the auxiliary signals are then resolved to generate a distortion-free composite signal. Specifically: make This represents the linear combination coefficient vector of the auxiliary signal after distortion removal, with dimension . ,in N The number of signal components. L Let be the row number of the subcarrier matrix; This is the auxiliary matrix for the intermodulation term; The linear combination coefficient vector of the auxiliary signal that minimizes peak power and is distortion-free is obtained by solving the following optimization problem. : ; Using the linear combination coefficient vector of the auxiliary signal The vectorized representation of a distortion-free composite signal is calculated as follows: .

[0055] Figure 5 The main steps of the highly flexible and distortion-free navigation signal multi-frequency multi-component multiplexing technology are shown below, and each step will be explained in detail below.

[0056] Step 1: Signal component identification and structured decomposition.

[0057] Signals with different pseudo-random codes are treated as different signal components. Assume the navigation signal to be broadcast contains... N The signal component, the first Road navigation signal components It can be structurally decomposed into bipolar pseudo-random signals. and stepped subcarrier The product of the two. A stepped subcarrier is a modulated subcarrier. and frequency shifting subcarrier The product of.

[0058] ; In the above formula, A bipolar pseudo-random signal without a subcarrier can be represented as: ; in, They represent the first The pseudocode sequence of the signal, the product of data and secondary code, the pseudocode width, and the duration are: A rectangular pulse.

[0059] This refers to the subcarrier corresponding to the modulation scheme. For example, if the signal components are modulated using BPSK, It is always 1. If the signal uses sinusoidal BOC modulation, ,in It is a symbolic function. It is the frequency of the subcarrier used in BOC modulation.

[0060] A stepped frequency shift subcarrier is used for continuous sinusoidal subcarriers. Equivalent substitution. Among them It is the first The difference between the center frequency of the navigation signal component and the center frequency of the composite signal.

[0061] It can be represented as: ; in .because It is the first The subcarrier period of the road navigation signal, which means that one subcarrier period is decomposed into part.

[0062] Step 2: Vectorization representation of bipolar pseudo-random signals.

[0063] It can be verified. Total This embodiment uses all possible values ​​of the pseudo-random signal matrix as its representation. S OK. S The dimension is ,make S The k Behavior k -1 in bipolar binary form. For example, when N When =3, S The specific values ​​are as follows: ; The pseudo-random signal matrix S The Listing , It is a pseudo-random signal In vector form.

[0064] Step 3: Vectorization representation of stepped subcarriers.

[0065] make Its value has only a finite number of possible values. In this embodiment, all possible values ​​are taken as the subcarrier matrix. E The rows. In principle, the matrix E Only vectors are needed All the different possible values, i.e. E There are no duplicate rows in the matrix. E Include L If it is done, then E The dimension is .Will E The List as , It is the first Subcarrier of each signal component In vector form.

[0066] Step 4: Vectorization of complete signal components.

[0067] make Then its vector form can be expressed as: ; in This is the Kronecker product. Therefore, N The vector of each signal component constitutes dimensional matrix ; Step 5: Construct the auxiliary signal matrix.

[0068] To achieve higher amplification efficiency, an auxiliary signal needs to be introduced to give the composite signal a lower peak power. This step presents the method for constructing the auxiliary signal matrix as follows: The signal vector Intermodulation term denoted as ,in This indicates that vectors are multiplied element by element. Representation matrix S The List, It is the index value of the signal participating in the intermodulation operation. Intermodulation term Corresponding to actual signal Simulation experiments show that... Compared with the original navigation signal They exhibit good cross-correlation properties. The second-order cross-modulation terms, third-order cross-modulation terms, ..., N Composed of intermodulation terms A 3D matrix is ​​denoted as V Furthermore, to construct a complete orthogonal basis, it is necessary to introduce elements whose elements are all 1. basis vectors of dimension This vector corresponds to the DC component.

[0069] Will The orthogonal complement space corresponding to A 3D matrix is ​​denoted as .make Then it is easy to verify. column vectors and Orthogonal. Let I express L An identity matrix of order 1 can be proven to be... and column vectors and column vectors and They are orthogonal to each other. Therefore... It can be defined as: ; Step 6: Optimize the linear combination coefficients of the auxiliary signals to reduce the peak power of the composite signal.

[0070] make , These are the linear combination coefficients of the signal vectors, where , They are the first The transmit power and initial phase of the road navigation signal components. Let The vector representing the linear combination coefficients of the auxiliary signals, with dimension . By solving the optimization problem shown in the following equation, the linear combination coefficient vector of the auxiliary signal that minimizes the peak power can be obtained. .

[0071] ; Step 7: Generate a composite signal.

[0072] Using the results obtained in step 6 Calculate the vectorized representation of a composite signal: ; When generating specific composite signals, a two-dimensional lookup table, as shown in Table 1, can be used. The values ​​of the composite signal are determined by the pseudo-random signal. The combination of values ​​and the combination of subcarrier values Determined jointly. (In Table 1) Represents the subcarrier matrix E The OK.

[0073] Table 1:

[0074] Step 8: Assess whether there is signal distortion.

[0075] Correlate different signal components with the composite signal generated in step 7, calculate the zero-crossing deviation of the S-curve under different correlation intervals, and evaluate whether the correlation function has been distorted. If the correlation function does not have significant distortion, use the lookup table obtained in step 7 to generate the composite signal. If the correlation function has significant distortion, proceed to step 9.

[0076] Step 9: Remove vectors in the auxiliary signal matrix that may cause distortion, and solve the peak power optimization problem again.

[0077] make The vector represents the linear combination coefficients of the distortion-removing auxiliary signal, with dimension . By solving the optimization problem shown in the following equation, the linear combination coefficient vector of the auxiliary signal that minimizes the peak power can be obtained. .

[0078] ; Step 10: Generate a distortion-free composite signal.

[0079] Using the results obtained in step 9 Calculate the vectorized representation of a composite signal. ; Similar to step 7, the composite signal is generated using a two-dimensional lookup table as shown in Table 1.

[0080] The link for generating and broadcasting navigation signals, such as Figure 6 As shown, filters, output multiplexers, and high-power amplifiers in the transmit link are the main components causing signal distortion. Filters and output multiplexers change the frequency characteristics of the signal; non-ideal amplitude-frequency and phase-frequency characteristics can cause amplitude distortion and phase shift within the signal band. In particular, non-constant group delay characteristics can cause significant signal distortion. High-power amplifiers introduce nonlinear distortion and memory effects, resulting in signal quality degradation.

[0081] This embodiment employs digital predistortion technology to compensate for the non-ideal characteristics of the transmission link, thereby suppressing navigation signal distortion deviations. Digital predistortion is performed after signal multiplexing and before up-conversion.

[0082] like Figure 7 As shown, the digital predistortion module consists of three main cascaded parts: (1) Output multiplexer non-ideal characteristic compensation module, which completes the compensation of the non-ideal amplitude-frequency characteristics and phase-frequency characteristics of the output multiplexer in the transmission link, so that the group delay after cascade is as constant as possible and the amplitude-frequency response curve fluctuates within a reasonable range.

[0083] (2) High-power amplifier non-ideal characteristic compensation module, which compensates for nonlinear distortion and memory effect of high-power amplifier. This module can adopt a variety of compensation methods such as memory polynomial and neural network.

[0084] (3) Filter non-ideal characteristic compensation module, which completes the compensation of the non-ideal amplitude-frequency characteristics and phase-frequency characteristics of the filter in the transmission link, so that the group delay after cascade is as constant as possible and the amplitude-frequency response curve fluctuates within a reasonable range.

[0085] By using the cascaded digital predistortion modules described above, signal distortion can be effectively suppressed, reducing the SCB characteristics of the lunar navigation signal from about 1ns to about 0.3ns.

[0086] Lunar navigation signals are easily affected by interference and deception due to their low landing power and transparent signal structure. This embodiment proposes a method for flexibly adjusting the power and signal structure of navigation signals in interference and deception environments, enabling a resilient response to interference and deception.

[0087] See Figure 3 In an optional implementation, step S104 specifically includes: S21: The receiver determines whether there is interference and / or spoofing, and transmits the information on whether there is interference, the frequency band of interference, and whether there is spoofing to the ground station.

[0088] S22: The ground station makes a comprehensive decision based on the feedback information from the receiver, generates an adjustment command that includes power adjustment parameters and / or signal system adjustment parameters, and uploads the adjustment command to the satellite.

[0089] S23: The satellite increases the overall broadcast power of the lunar navigation signal according to the power adjustment parameters in the adjustment instruction; and / or, shuts down some signal components or reduces the power of some signal components, and allocates the power to key signal components; wherein, the shutdown of signal components and the adjustment of power ratio are achieved through the navigation signal multi-frequency multi-component multiplexing technology.

[0090] S24: The satellite determines whether it is necessary to change the frequency and / or modulation method of each navigation signal component according to the signal system adjustment parameters in the adjustment instruction. If so, the frequency and / or modulation method of each navigation signal component is adjusted by the navigation signal multi-frequency multi-component multiplexing technology to avoid interference frequency bands.

[0091] S25: The satellite determines, based on the signal system adjustment parameters in the adjustment instruction, whether it needs to change the spreading code and message of the navigation signal components to counter deception. If so, it replaces the spreading code and message of the navigation signal components according to the signal system adjustment parameters. Furthermore, the receiver correspondingly abandons receiving the original lunar navigation signal and instead receives the new lunar navigation signal.

[0092] In summary, this invention provides a compatible and interoperable flexible broadcasting method for lunar satellite navigation signals. Interoperability is achieved by setting the lunar navigation signal's operating frequency band and center frequency to be consistent with LunaNet and employing direct sequence spread spectrum modulation. The equivalent carrier-to-noise ratio (CNR) formula is used to determine the receiving power range that meets compatibility requirements. A highly flexible, distortion-free navigation signal multi-frequency multi-component multiplexing technique is employed to aggregate multiple signal components into a single composite signal, achieving high-efficiency broadcasting while ensuring low peak power and distortion-free operation. A cascaded digital predistortion module is introduced after multiplexing and before up-conversion to compensate for the non-ideal characteristics of the output multiplexer, high-power amplifier, and filter, reducing the signal distortion (SCB) index from approximately 1 ns to approximately 0.3 ns. Simultaneously, a closed-loop flexible adjustment mechanism of "receiver perception—ground decision-making—satellite execution" is constructed, flexibly responding to interference and deception environments by dynamically adjusting signal power, component frequencies, and changing spreading codes and messages. The synergistic effect of these techniques achieves a flexible broadcasting effect for lunar satellite navigation signals with low distortion, low complexity, high efficiency, and high flexibility.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0094] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A compatible and interoperable method for flexible broadcasting of lunar satellite navigation signals, characterized in that, Including the following steps: The operating frequency band and center frequency of the lunar navigation signal are set to be the same as those of LunaNet's navigation signal. Direct sequence spread spectrum modulation is used to achieve interoperability, and the receiving power range of the lunar navigation signal is determined to achieve compatibility. A highly flexible, distortion-free navigation signal multi-frequency multi-component multiplexing technology based on infinite norm minimization is adopted to aggregate multiple lunar navigation signal components into a composite signal without distortion and broadcast it through the same transmission link. After signal multiplexing and before up-conversion, digital predistortion technology is used to compensate for the non-ideal characteristics of the transmission link in order to suppress navigation signal distortion deviation. The receiver detects interference and / or spoofing and transmits the detected information to the ground station; the ground station makes decisions based on the detected information and generates adjustment instructions to be transmitted to the satellite; the satellite responds to the adjustment instructions to adjust the power and / or signal mode of the navigation signal to achieve flexible broadcasting.

2. The method according to claim 1, characterized in that, Determining the received power range of the lunar navigation signal specifically includes: Calculate the normalized power spectral density of the lunar navigation signal of the current system, and preset the receiving power range of the lunar navigation signal; Calculate the maximum interference power and normalized power spectral density of the lunar navigation signal from other systems, and combine the bilateral receiving bandwidth and white noise power spectral density of the current system receiver with the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receiver of this system can tolerate. Then, use the equivalent carrier-to-noise ratio formula to determine the minimum received power of the lunar navigation signal. Calculate the minimum received power and normalized power spectral density of lunar navigation signals from other systems, and combine the bilateral receiving bandwidth, white noise power spectral density of receivers from other systems, the coverage multiple of the signal of this system, and the minimum equivalent carrier-to-noise ratio that the lunar navigation signal receivers from other systems can tolerate, and use the equivalent carrier-to-noise ratio formula to determine the maximum received power of the lunar navigation signal of the current system. Based on the minimum and maximum received power, the range of received power that meets the compatibility requirements is obtained.

3. The method according to claim 1, characterized in that, The aforementioned highly flexible, distortion-free navigation signal multi-frequency multi-component multiplexing technology based on infinite norm minimization aggregates multiple lunar navigation signal components into a single composite signal without distortion and broadcasts it through the same transmission link. Specifically, it includes: The signal component identification and structured decomposition steps treat signals with different pseudo-random codes as different signal components, and represent each navigation signal component to be broadcast as the product of a bipolar pseudo-random signal and a stepped subcarrier; wherein, the bipolar pseudo-random signal is determined by the product of the pseudo-code sequence, data and the second-level code, and the stepped subcarrier is the product of the modulation subcarrier and the frequency shift subcarrier; The vectorization representation step involves constructing a pseudo-random signal matrix from all values ​​of the bipolar pseudo-random signal and a subcarrier matrix from all values ​​of the stepped subcarrier; and then combining the column vectors of the pseudo-random signal matrix with the corresponding column vectors of the subcarrier matrix through the Kronecker product operation to generate a matrix representing the complete signal components. The auxiliary signal matrix construction steps involve introducing an auxiliary signal matrix, which is constructed by concatenating the following matrices column-wise: a subcarrier orthogonal complement auxiliary matrix, an intermodulation term auxiliary matrix, and a DC component auxiliary matrix. The subcarrier orthogonal complement auxiliary matrix is ​​constructed by concatenating the Kronecker product of the pseudo-random signal vectors of each signal component and the orthogonal complement matrices of the subcarrier vectors of each signal component. The intermodulation term auxiliary matrix is ​​constructed by the Kronecker product of the intermodulation term matrix and the identity matrix; the intermodulation term matrix is ​​a matrix composed of all intermodulation term vectors of orders 2 to N of the bipolar pseudo-random signal vectors. The DC component auxiliary matrix is ​​constructed by the Kronecker product of all-1 basis vectors and the identity matrix. The solution steps are optimized by determining the linear combination coefficients of the useful signal based on the power ratio and phase relationship of each signal component. With the goal of minimizing the infinite norm of the composite signal vector, the linear combination coefficients of the auxiliary signal are optimized to obtain the linear combination coefficient vector of the auxiliary signal that minimizes the peak power of the composite signal. The composite signal generation step involves calculating the vectorized representation of the composite signal using the linear combination coefficients of the useful signal and the optimized linear combination coefficients of the auxiliary signal, and generating the composite signal using a lookup table based on the value combination of the pseudo-random signal and the value combination of the subcarrier.

4. The method according to claim 3, characterized in that, The method employs navigation signal multi-frequency multi-component multiplexing technology to aggregate multiple navigation signal components with different pseudo-random codes and / or different modulation schemes into a composite signal for broadcasting through the same transmission link. It also includes a distortion-free processing step. Based on the zero-crossing point deviation of the S-curve at different correlation intervals when the composite signal is correlated with different signal components, it is determined whether there is correlation function distortion. If distortion exists, the subcarrier orthogonal complement auxiliary matrix and the DC component auxiliary matrix that cause distortion are removed from the auxiliary signal matrix, and only the intermodulation term auxiliary matrix is ​​retained. The linear combination coefficients of the auxiliary signals are then resolved to generate a distortion-free composite signal.

5. The method according to claim 3, characterized in that, In the optimization solution step, the optimization solution is performed on the linear combination coefficients of the auxiliary signals with the objective of minimizing the infinity norm of the composite signal vector, to obtain the linear combination coefficient vector of the auxiliary signals that minimizes the peak power of the composite signal. Specifically: make Let be the linear combination coefficient vector of the useful signal, where and These are the transmit power and initial phase of the i-th navigation signal component, respectively; Auxiliary signal linear combination coefficient vector Calculated based on the following formula: ; in, A matrix representing the complete signal components, The auxiliary signal matrix, The linear combination coefficient vector of the auxiliary signal; Using the linear combination coefficient vector of auxiliary signals The vectorized representation of a composite signal is calculated as follows: .

6. The method according to claim 4, characterized in that, If distortion exists, the subcarrier orthogonal complement auxiliary matrix and the DC component auxiliary matrix that cause distortion are removed from the auxiliary signal matrix, and only the intermodulation term auxiliary matrix is ​​retained. The linear combination coefficients of the auxiliary signals are then resolved to generate a distortion-free composite signal. Specifically: make This represents the linear combination coefficient vector of the auxiliary signal after distortion removal, with dimension . ,in N The number of signal components. L Let be the row number of the subcarrier matrix; This is the auxiliary matrix for the intermodulation term; The linear combination coefficient vector of the auxiliary signal that minimizes peak power and is distortion-free is obtained by solving the following optimization problem. : ； Using the linear combination coefficient vector of the auxiliary signal The vectorized representation of a distortion-free composite signal is calculated as follows: .

7. The method according to claim 3, characterized in that, In the signal component identification and structured decomposition steps, the bipolar pseudo-random signal Represented as: ； in, Let i be the pseudocode sequence of the i-th signal. The product of the data and the secondary code. For pseudocode width, The duration is A rectangular pulse; The frequency shift subcarrier Represented as: ； in, Let be the difference between the center frequency of the i-th navigation signal component and the center frequency of the composite signal. , The duration of each step. The duration is rectangular pulse, It is the imaginary unit.

8. The method according to claim 1, characterized in that, The digital predistortion technology is implemented through a cascaded digital predistortion module, which includes: The output multiplexer non-ideal characteristic compensation module is used to compensate for the non-ideal amplitude-frequency and phase-frequency characteristics of the output multiplexer in the transmission link; A high-power amplifier non-ideal characteristic compensation module is used to compensate for the nonlinear distortion and memory effect of the high-power amplifier in the transmission link; The filter non-ideal characteristic compensation module is used to compensate for the non-ideal amplitude-frequency and phase-frequency characteristics of the filter in the transmission link.

9. The method according to claim 1, characterized in that, The process involves sensing interference and / or spoofing via a receiver and transmitting the sensing information to a ground station; the ground station making decisions based on the sensing information and generating adjustment commands for uploading to the satellite; and the satellite responding to the adjustment commands to adjust the power and / or signal mode of the navigation signal to achieve flexible broadcasting. Specifically, this includes: The receiver determines whether there is interference and / or deception, and transmits the information on whether there is interference, the frequency band of interference, and whether there is deception to the ground station. The ground station makes a comprehensive decision based on the feedback information from the receiver, generates an adjustment command that includes power adjustment parameters and / or signal system adjustment parameters, and uploads the adjustment command to the satellite; The satellite increases the overall broadcast power of the lunar navigation signal according to the power adjustment parameters in the adjustment instruction; and / or shuts down some signal components or reduces the power of some signal components, allocating power to key signal components; wherein, the shutdown of signal components and the adjustment of power allocation are achieved through the navigation signal multi-frequency multi-component multiplexing technology; The satellite determines whether it needs to change the frequency and / or modulation method of each navigation signal component according to the signal system adjustment parameters in the adjustment instruction. If so, it adjusts the frequency and / or modulation method of each navigation signal component through the navigation signal multi-frequency multi-component multiplexing technology to avoid interference frequency bands. The satellite determines whether it needs to change the spreading code and message of the navigation signal component to counter deception based on the signal system adjustment parameters in the adjustment instruction. If so, it replaces the spreading code and message of the navigation signal component according to the signal system adjustment parameters.

10. The method according to claim 2, characterized in that, The formula for the equivalent carrier-to-noise ratio is: ； in, This refers to the received power of the signal. The power spectral density of white noise. The normalized power spectral density of the signal. The received power of the interference signal. The normalized power spectral density of the interference signal, This refers to the bilateral receiving bandwidth of the receiver; When determining the minimum received power The received power of the lunar navigation signal of the current system. The normalized power spectral density of the lunar navigation signal of the current system. The maximum interference power received from other lunar navigation signals. Normalized power spectral density of received lunar navigation signal interference from other systems; When determining the maximum received power This is the minimum receiving power for lunar navigation signals from other systems. For the normalized power spectral density of lunar navigation signals from other systems, This represents the total interference power of the current system's lunar navigation signals received by other systems. This represents the normalized power spectral density of the lunar navigation signal in the current system.

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