A Beidou and mobile communication fusion positioning method based on modulation detection

Abstract

The application relates to a Beidou and mobile communication fusion positioning method based on modulation detection, and belongs to the technical field of satellite navigation and communication engineering. The method comprises the following steps: acquiring a Beidou positioning signal and a high-frequency carrier frequency signal, extracting a frequency parameter of the Beidou positioning signal and presetting a carrier frequency screening condition, constructing an amplitude modulation binding scheme, forming an initial composite signal, constructing a multi-path integration multiplexing mechanism, according to the number of signal paths and time delay requirements, adopting a combined superposition or time slot allocation mode to complete signal integration, establishing a same network transmission mode, transmitting the signal to a target area by means of existing transmission resources, setting a signal separation and restoration process, restoring the Beidou positioning signal through carrier frequency extraction, signal separation and interference filtering, and according to signal purity feedback, iteratively optimizing modulation amplitude and detection filtering parameters. Efficient compatibility of the Beidou positioning signal and the mobile communication network is realized, existing communication facilities are reused without additional wiring, and the problem of Beidou signal transmission in a complex shielding scene is solved.

Description

Technical Field

[0001] This invention belongs to the field of satellite navigation and communication engineering technology, specifically relating to a BeiDou and mobile communication fusion positioning method based on modulation detection. Background Technology

[0002] With the rapid development of urban underground space development, intelligent transportation, and Internet of Things technologies, BeiDou positioning technology has become the core support for positioning and navigation of various terminal devices due to its advantages of high precision and wide coverage. However, BeiDou satellite signals are easily affected by building blockage and terrain shielding. In indoor and semi-enclosed scenarios such as underground parking lots, urban utility tunnels, and short tunnels, the signal attenuation is severe, making it difficult to achieve effective positioning.

[0003] Meanwhile, mobile communication networks (such as 5G and 4G) have built a transmission system with full coverage, and their indoor and outdoor communication distribution systems can penetrate complex environments to achieve stable signal transmission. However, this network only undertakes communication functions and has not formed an effective synergy with BeiDou positioning signals. In order to solve the positioning problem in scenarios where BeiDou signals are blocked, the industry has gradually explored the integrated positioning mode of BeiDou and mobile communication, but existing technologies still have many bottlenecks that need to be solved. First, the transmission characteristics of BeiDou positioning signals and mobile communication networks are fundamentally incompatible. BeiDou positioning signals are mainly concentrated in the L-band, which has a low frequency and weak signal amplitude, resulting in poor anti-interference capabilities. In contrast, mobile communication networks (5G, 4G) mostly use high-frequency transmission, with dense spectrum resources and specific transmission protocols. If BeiDou positioning signals are directly connected to mobile communication networks, they are very likely to overlap with the network's existing signals and cause intermodulation interference, making it impossible for both types of signals to be transmitted normally. At the same time, the transmission format and power parameters of BeiDou signals do not meet the access standards of mobile communication networks. Existing technologies require the additional laying of dedicated positioning signal transmission lines, which not only incurs significant costs for pipe materials, construction, and subsequent maintenance, but also faces challenges such as the difficulty of modifying existing building structures and long construction periods, severely restricting large-scale promotion and application.

[0004] Secondly, existing integrated solutions lack efficient and adaptable signal modulation and detection mechanisms. Some solutions, in order to achieve signal compatibility, adopt complex protocol conversion modules or modify the hardware of mobile communication equipment, which not only increases system complexity and cost, but also has poor compatibility issues. They cannot be adapted to communication indoor distribution systems of different operators and different frequency bands, and it is difficult to reuse the transmission resources of existing networks. Other solutions simplify the modulation and detection process to reduce costs, using only basic amplitude modulation or envelope detection methods without optimizing parameters for the coupling characteristics of Beidou signals and carrier frequencies. This results in feature loss during modulation, severe distortion during transmission, and a large amount of interference components remaining after detection, directly causing increased positioning errors and failing to meet the requirements of high-precision positioning.

[0005] Third, the integration and multiplexing logic of multiple positioning signals is rigid and lacks adaptability. Existing fusion solutions mostly adopt a single signal integration method. Either they forcibly merge multiple BeiDou modulated signals through a fixed combiner, ignoring the differences in the spectral characteristics of different signals, resulting in mutual interference between signals and low transmission efficiency; or they adopt a simple time-division multiplexing mode, which allocates transmission time slots in a fixed manner and cannot be dynamically adjusted according to the actual number of signals and transmission timeliness requirements. This rigid integration logic is prone to transmission congestion in scenarios with dense terminal devices and high demand for positioning signals, and causes resource waste in scenarios with low signal quantity and low timeliness requirements. In addition, some solutions require additional deployment of hardware devices such as splitters and amplifiers, which further increases energy consumption and operation and maintenance costs, and is difficult to adapt to the differentiated positioning needs of multiple scenarios and multiple terminals.

[0006] In summary, existing BeiDou and mobile communication fusion positioning technologies suffer from prominent problems such as poor compatibility, high deployment costs, insufficient positioning accuracy and stability, and weak scene adaptability, making it impossible to effectively solve the positioning problem in complex occlusion scenarios. Summary of the Invention

[0007] To address the aforementioned problems in the existing technology, this invention provides a BeiDou and mobile communication fusion positioning method based on modulation detection. The objective of this invention can be achieved through the following technical solution: include: S1: Acquire BeiDou positioning signal and high-frequency carrier signal, extract frequency parameters of BeiDou positioning signal, and preset carrier frequency screening conditions based on the frequency parameters; construct modulation binding scheme of BeiDou positioning signal and carrier frequency; use amplitude modulation to attach BeiDou positioning signal as modulation signal to high-frequency carrier frequency that meets carrier frequency screening conditions to form initial composite signal; S2: Based on the initial composite signal, a multi-path integration and multiplexing mechanism is constructed; for multiple composite signals that have been modulated and bound, two integration paths are set; the first path is to combine all composite signals into a unified signal according to the principle of spectrum compatibility through signal merging logic; the second path is to preset the transmission time slots corresponding to each composite signal according to the preset signal system, and set the time interval and allocation rules of the transmission time slots. S3: Based on the integrated composite signal, establish a network-based transmission mode for the composite signal and the original signal of the communication network; with the help of the network's existing transmission resources and coverage paths, and according to the network coverage of the target application area, transmit the integrated composite signal to the preset target area. S4: Set the separation and restoration process of BeiDou positioning signals. When the composite signal arrives at the target area, the corresponding high-frequency carrier frequency is extracted from the transmitted mixed signal through targeted frequency identification and filtering logic. The BeiDou positioning signal is separated from the extracted high-frequency carrier frequency, and the separated positioning signal is processed through interference filtering logic. Related data in the signal transmission process are correlated, and the amplitude parameters in the modulation process and the filtering parameters in the detection process are optimized based on the purity feedback of the separated and restored positioning signal.

[0008] Specifically, the process of setting the carrier frequency screening conditions is as follows: based on the extracted BeiDou positioning signal frequency parameters, the carrier frequency is set to be higher than the positioning signal frequency; the specific standard for dividing the spectrum interval between the BeiDou positioning signal and the high-frequency carrier frequency signal is defined; the basic signal carrying attributes that the carrier frequency must possess are sorted out, including signal stability and transmission compatibility, and the screening criteria are organized according to the attribute requirements and frequency standards to form a core standard for carrier frequency screening that can be directly executed.

[0009] Specifically, the process of constructing the modulation binding scheme of BeiDou positioning signal and carrier frequency is as follows: using BeiDou positioning signal as modulation signal and high-frequency carrier frequency as carrier signal, setting the coupling mode of modulation signal and carrier signal, and setting the corresponding ratio of positioning signal strength change and carrier frequency amplitude fluctuation; planning the operation steps of signal superposition, and formulating the operation specifications when positioning signal and carrier frequency are combined.

[0010] Specifically, the process of forming the initial composite signal is as follows: using amplitude modulation, the strength changes and frequency fluctuations of the BeiDou positioning signal are mapped onto the amplitude of the high-frequency carrier signal; the changes in the BeiDou positioning signal are captured in real time, and the carrier frequency amplitude is adjusted to synchronize the changes in the carrier frequency amplitude with the positioning signal in real time; the BeiDou positioning signal and the high-frequency carrier signal are organically combined and processed to form the initial composite signal after signal fusion.

[0011] Specifically, the process of constructing the multi-path integration and multiplexing mechanism is as follows: Each modulated and bound composite signal is acquired one by one, and its spectrum range, peak frequency, transmission bandwidth and required transmission rate are analyzed. The core parameters of each signal are recorded. Two independent integration logics are designed. The first is the signal merging logic, which uses a combiner and a multiplexer to sort the signals according to their spectrum range from small to large. Adjacent spectrum signals are then connected to the multiplexer in sequence and then combined into one channel by the combiner. The second type is time-division multiplexing logic, which sorts signals according to transmission priority, allocates transmission time slots for each signal, calculates the interval between adjacent time slots, and sets the time slot switching trigger conditions.

[0012] Specifically, the process of combining all composite signals into a single unified signal according to the principle of spectral compatibility is as follows: Each composite signal is detected using a spectrum detection device, and the spectrum range and peak frequency data of each signal are recorded. The signals are superimposed using a complementary spectral method. During the superposition process, filtering techniques are used to suppress noise generation, and the spectral status of the superimposed signal is monitored in real time.

[0013] Specifically, the process of presetting the transmission time slots corresponding to each composite signal and setting the time interval and allocation rules for the transmission time slots is as follows: Based on the preset signal system, the transmission priority of each composite signal is calculated, and a transmission time period is allocated to each signal according to its priority. Calculate the interval between adjacent time slots based on signal transmission duration and data volume requirements; The preset transmission sorting rules prioritize the transmission of high-priority signals, while signals of the same priority are transmitted in the order they were submitted.

[0014] Specifically, the process of establishing the same-network transmission mode for the composite signal and the original signal of the communication network is as follows: Analyze the transmission protocols, spectrum resource distribution, and transmission path layout of the existing signals in the communication network; Based on the analysis results, match the transmission adaptation parameters of the corresponding composite signal, including signal format and transmission rate; Plan the same network transmission channels for composite signals and original signals, preset the timing coordination rules when composite signals and original signals share transmission resources, and record the time nodes for signal transmission and reception.

[0015] Specifically, the process of transmitting the integrated composite signal to the preset target area is as follows: Obtain network coverage data for a preset target area using signal monitoring equipment; Adjust the transmission power of the composite signal based on network coverage data, adjust the signal coverage direction of the antenna, and optimize the signal transmission path; The composite signal is transmitted to the target area through transmission facilities.

[0016] Specifically, the process for separating and restoring the BeiDou positioning signal is as follows: The execution order is planned according to the logic of frequency extraction, signal separation, and interference filtering. The frequency extraction stage matches the preset carrier frequency with a bandpass filter, and sets the filter passband width to match the carrier frequency; the signal separation stage sets the device operating voltage to match the signal amplitude, and sets the detection timing to synchronize with the signal transmission rate; the interference filtering stage presets the effective signal frequency threshold. The connection logic of each link is preset. After the signal output of the previous link is detected, the amplitude is detected. If the value meets the standard, the next link is triggered.

[0017] Specifically, the process of processing the separated positioning signal through interference filtering logic is as follows: A filtering component is selected to process the separated positioning signal in a targeted manner. The separated positioning signal is scanned, and the frequency range in which the signal amplitude is concentrated is taken as the effective frequency range. Adjust the cutoff frequency of the filter component to match the upper limit of the effective frequency range; The system continuously scans the signal spectrum to intercept and eliminate harmonics and noise that exceed the effective frequency range, while simultaneously monitoring the phase and amplitude relationship of the positioning signal.

[0018] Specifically, the process of optimizing the amplitude parameters in the modulation process and the filtering parameters in the detection process is as follows: The purity data of the separated and restored positioning signal is obtained at a preset time interval, the preset signal purity standard value is retrieved, and the difference between the actual purity and the standard value is calculated. Adjust the amplitude coupling ratio between the positioning signal and the carrier frequency in the modulation stage according to the difference ratio; Simultaneously adjust the frequency response range of the filter components in the detection stage, and re-acquire signal purity data after each adjustment. Repeat this iterative adjustment process.

[0019] The beneficial effects of this invention are as follows: (1) By setting up a carrier frequency screening standard based on the frequency parameters of Beidou positioning signal, a signal binding scheme for amplitude modulation, and a transmission mode of composite signal and original signal of communication network in the same network, the carrier frequency is first screened according to the spectrum spacing requirements, and then the positioning signal is stably attached to the carrier frequency to form a composite signal through amplitude modulation. Subsequently, the signal is transmitted by relying on the transmission resources and paths of the existing communication indoor distribution system. There is no need to lay additional dedicated transmission lines. This not only solves the spectrum compatibility problem between Beidou signal and mobile communication network, but also greatly reduces the deployment and maintenance cost of integrated positioning, and realizes the efficient reuse of existing communication resources. (2) By setting up a multi-path integration and multiplexing mechanism with two independent logics, a step-by-step positioning signal separation and restoration process, and a parameter optimization method based on signal purity feedback, the signal merging or time-division multiplexing path can be flexibly selected according to the number of signals and the transmission timeliness requirements. Then, the carrier frequency is extracted by bandpass filtering, the signal is separated by passive detection, and interference components are filtered in a targeted manner. Finally, the modulation and filtering parameters are iteratively adjusted according to the purity difference. This not only adapts to the differentiated positioning requirements of multiple scenarios and multiple terminals, but also effectively eliminates harmonics and noise in the transmission process, improves the purity and stability of the positioning signal, and ensures the positioning accuracy in complex obstruction scenarios.

[0020] (3) The modulation detection-based fusion positioning method proposed in this invention for the problem of BeiDou signal transmission in complex obstruction scenarios has an essential technical difference from the existing frequency-shifting BeiDou fusion passive DAS technology: the frequency-shifting BeiDou technology shifts the BeiDou signal to the passive DAS supported frequency band through the near-end unit and then restores it through the far-end unit, which solves the signal pollution problem caused by multiple antennas transmitting the same signal in passive DAS fusion; while this invention adopts the amplitude modulation detection method, attaches the BeiDou positioning signal as the modulation signal to the high-frequency carrier frequency to form a composite signal, and realizes the transmission of BeiDou and mobile communication on the same network through the modulation-transmission-restoration full link, without frequency shifting and restoration steps throughout the process, which solves the problem of compatible transmission of BeiDou signal and mobile communication network and signal attenuation in complex obstruction scenarios. The two technologies have completely different technical routes, core problems solved, and implementation methods, and belong to different technical solutions in the field of satellite navigation and communication fusion. Attached Figure Description

[0021] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0022] Figure 1 This is a flowchart illustrating a BeiDou and mobile communication fusion positioning method based on modulation detection according to the present invention. Figure 2 This is a data flow diagram of a BeiDou and mobile communication fusion positioning method based on modulation detection according to the present invention. Detailed Implementation

[0023] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0024] Please see Figure 1-2 A BeiDou and mobile communication fusion positioning method based on modulation detection; include: S1: Acquire BeiDou positioning signal and high-frequency carrier signal, extract frequency parameters of BeiDou positioning signal, and preset carrier frequency screening conditions based on the frequency parameters; construct modulation binding scheme of BeiDou positioning signal and carrier frequency; use amplitude modulation to attach BeiDou positioning signal as modulation signal to high-frequency carrier frequency that meets carrier frequency screening conditions to form initial composite signal; S2: Based on the initial composite signal, a multi-path integration and multiplexing mechanism is constructed; for multiple composite signals that have been modulated and bound, two integration paths are set; the first path is to combine all composite signals into a unified signal according to the principle of spectrum compatibility through signal merging logic; the second path is to preset the transmission time slots corresponding to each composite signal according to the preset signal system, and set the time interval and allocation rules of the transmission time slots. S3: Based on the integrated composite signal, establish a network-based transmission mode for the composite signal and the original signal of the communication network; with the help of the network's existing transmission resources and coverage paths, and according to the network coverage of the target application area, transmit the integrated composite signal to the preset target area. S4: Set the separation and restoration process of BeiDou positioning signals. When the composite signal arrives at the target area, the corresponding high-frequency carrier frequency is extracted from the transmitted mixed signal through targeted frequency identification and filtering logic. The BeiDou positioning signal is separated from the extracted high-frequency carrier frequency, and the separated positioning signal is processed through interference filtering logic. Related data in the signal transmission process are correlated, and the amplitude parameters in the modulation process and the filtering parameters in the detection process are optimized based on the purity feedback of the separated and restored positioning signal.

[0025] In this embodiment, the BeiDou positioning signal refers to the L-band positioning core signal broadcast by the BeiDou satellite, which includes essential positioning content such as satellite ephemeris data, pseudorange measurement information, and carrier phase data. It is the basic signal that carries the positioning and navigation function, and its frequency parameters are the core reference for subsequent carrier frequency selection. The high-frequency carrier signal refers to the high-frequency carrier signal that is adapted to the transmission characteristics of existing mobile communication networks (such as 4G and 5G). It must meet the selection requirements of having a frequency higher than that of the BeiDou positioning signal and have basic attributes such as signal stability and transmission compatibility. It is used to carry the BeiDou positioning signal to access the mobile communication network and realize the same network transmission.

[0026] In this embodiment, the amplitude parameters in the modulation process include the amplitude coupling ratio between the BeiDou positioning signal and the high-frequency carrier frequency, the upper limit of the modulation signal input amplitude, the carrier frequency reference amplitude value, and the correspondence coefficient between the strength of the positioning signal and the amplitude fluctuation of the carrier frequency. These parameters directly determine the attachment stability of the positioning signal on the carrier frequency and avoid signal distortion during the modulation process. The filtering parameters in the detection process cover the cutoff frequency, passband width, frequency response range, effective signal frequency threshold, and the interception amplitude standard of harmonics and clutter of the filtering component, which are used to accurately screen the effective positioning signal and eliminate interference components generated during transmission.

[0027] In this embodiment, the attribute requirements specifically include signal stability (signal amplitude fluctuation range, frequency drift amplitude), transmission compatibility (adaptation to mobile communication network transmission protocols, spectrum adaptability), ensuring that the carrier frequency can stably carry the positioning signal and integrate into the existing communication network; the frequency standards include that the carrier frequency must be higher than the BeiDou positioning signal frequency, the specific value of the spectrum interval between the BeiDou positioning signal and the carrier frequency (to avoid spectrum overlap), and the carrier frequency must fall within the effective transmission frequency band of the mobile communication network to ensure that the signal transmission is conflict-free and interference-free.

[0028] Specifically, the process of setting the carrier frequency screening conditions is as follows: based on the extracted BeiDou positioning signal frequency parameters, the carrier frequency is set to be higher than the positioning signal frequency; the specific standard for dividing the spectrum interval between the BeiDou positioning signal and the high-frequency carrier frequency signal is defined; the basic signal carrying attributes that the carrier frequency must possess are sorted out, including signal stability and transmission compatibility, and the screening criteria are organized according to the attribute requirements and frequency standards to form a core standard for carrier frequency screening that can be directly executed.

[0029] Specifically, the process of constructing the modulation binding scheme of BeiDou positioning signal and carrier frequency is as follows: using BeiDou positioning signal as modulation signal and high-frequency carrier frequency as carrier signal, setting the coupling mode of modulation signal and carrier signal, and setting the corresponding ratio of positioning signal strength change and carrier frequency amplitude fluctuation; planning the operation steps of signal superposition, and formulating the operation specifications when positioning signal and carrier frequency are combined.

[0030] Specifically, the process of forming the initial composite signal is as follows: using amplitude modulation, the strength changes and frequency fluctuations of the BeiDou positioning signal are mapped onto the amplitude of the high-frequency carrier signal; the changes in the BeiDou positioning signal are captured in real time, and the carrier frequency amplitude is adjusted to synchronize the changes in the carrier frequency amplitude with the positioning signal in real time; the BeiDou positioning signal and the high-frequency carrier signal are organically combined and processed to form the initial composite signal after signal fusion.

[0031] Specifically, the process of constructing the multi-path integration and multiplexing mechanism is as follows: Each modulated and bound composite signal is acquired one by one, and its spectrum range, peak frequency, transmission bandwidth and required transmission rate are analyzed. The core parameters of each signal are recorded. Two independent integration logics are designed. The first is the signal merging logic, which uses a combiner and a multiplexer to sort the signals according to their spectrum range from small to large. Adjacent spectrum signals are then connected to the multiplexer in sequence and then combined into one channel by the combiner. The second type is time-division multiplexing logic, which sorts signals according to transmission priority, allocates transmission time slots for each signal, calculates the interval between adjacent time slots, and sets the time slot switching trigger conditions.

[0032] Specifically, the process of combining all composite signals into a single unified signal according to the principle of spectral compatibility is as follows: Each composite signal is detected using a spectrum detection device, and the spectrum range and peak frequency data of each signal are recorded. The signals are superimposed using a complementary spectral method. During the superposition process, filtering techniques are used to suppress noise generation, and the spectral status of the superimposed signal is monitored in real time.

[0033] Specifically, the process of presetting the transmission time slots corresponding to each composite signal and setting the time interval and allocation rules for the transmission time slots is as follows: Based on the preset signal system, the transmission priority of each composite signal is calculated, and a transmission time period is allocated to each signal according to its priority. Calculate the interval between adjacent time slots based on signal transmission duration and data volume requirements; The preset transmission sorting rules prioritize the transmission of high-priority signals, while signals of the same priority are transmitted in the order they were submitted.

[0034] Specifically, the process of establishing the same-network transmission mode for the composite signal and the original signal of the communication network is as follows: Analyze the transmission protocols, spectrum resource distribution, and transmission path layout of the existing signals in the communication network; Based on the analysis results, match the transmission adaptation parameters of the corresponding composite signal, including signal format and transmission rate; Plan the same network transmission channels for composite signals and original signals, preset the timing coordination rules when composite signals and original signals share transmission resources, and record the time nodes for signal transmission and reception.

[0035] Specifically, the process of transmitting the integrated composite signal to the preset target area is as follows: Obtain network coverage data for a preset target area using signal monitoring equipment; Adjust the transmission power of the composite signal based on network coverage data, adjust the signal coverage direction of the antenna, and optimize the signal transmission path; The composite signal is transmitted to the target area through transmission facilities.

[0036] Specifically, the process for separating and restoring the BeiDou positioning signal is as follows: The execution order is planned according to the logic of frequency extraction, signal separation, and interference filtering. The frequency extraction stage matches the preset carrier frequency with a bandpass filter, and sets the filter passband width to match the carrier frequency; the signal separation stage sets the device operating voltage to match the signal amplitude, and sets the detection timing to synchronize with the signal transmission rate; the interference filtering stage presets the effective signal frequency threshold. The connection logic of each link is preset. After the signal output of the previous link is detected, the amplitude is detected. If the value meets the standard, the next link is triggered.

[0037] Specifically, the process of processing the separated positioning signal through interference filtering logic is as follows: A filtering component is selected to process the separated positioning signal in a targeted manner. The separated positioning signal is scanned, and the frequency range in which the signal amplitude is concentrated is taken as the effective frequency range. Adjust the cutoff frequency of the filter component to match the upper limit of the effective frequency range; The system continuously scans the signal spectrum to intercept and eliminate harmonics and noise that exceed the effective frequency range, while simultaneously monitoring the phase and amplitude relationship of the positioning signal.

[0038] Specifically, the process of optimizing the amplitude parameters in the modulation process and the filtering parameters in the detection process is as follows: The purity data of the separated and restored positioning signal is obtained at a preset time interval, the preset signal purity standard value is retrieved, and the difference between the actual purity and the standard value is calculated. Adjust the amplitude coupling ratio between the positioning signal and the carrier frequency in the modulation stage according to the difference ratio; Simultaneously adjust the frequency response range of the filter components in the detection stage, and re-acquire signal purity data after each adjustment. Repeat this iterative adjustment process.

[0039] In this embodiment, during the interference filtering process, to address the signal pollution problem caused by multiple antennas transmitting the same BeiDou positioning signal in indoor and semi-enclosed scenarios, an identification and suppression step for the superposition pollution of multiple antenna signals at the same frequency is added: the phase characteristics of the separated positioning signal are captured by the spectrum feature acquisition module, the multi-phase superposition components of the same BeiDou satellite signal are identified, and a reverse phase compensation signal is generated based on the phase cancellation algorithm to cancel the redundant multi-phase superposition components; at the same time, a signal phase similarity threshold is set, and the co-frequency redundant signal components exceeding the threshold are eliminated, retaining only the BeiDou positioning signal with a single effective phase, thus completing the targeted suppression of signal pollution and avoiding the impact of the superposition of multiple antenna signals at the same frequency on positioning accuracy.

[0040] In this embodiment, the specific implementation of the preset carrier frequency screening conditions is as follows: A signal acquisition and analysis module is used to access the BeiDou receiving front end to acquire and extract two basic frequency parameters of the BeiDou positioning signal: center frequency and bandwidth. The parameters are then uploaded to the signal processing unit. Based on the analyzed positioning signal parameters, the processing unit sets the reference frequency of the high-frequency carrier frequency to be higher than the center frequency of the BeiDou positioning signal, defines the spectral interval between the two types of signals, and limits the carrier frequency amplitude fluctuation range to construct a frequency-level screening scale. Simultaneously, the unit sorts out the carrier attributes that the carrier frequency must meet, converts the attribute requirements into detectable hardware adaptation indicators, integrates the frequency scale and attribute indicators, and generates an execution standard that can be directly used for carrier frequency selection and signal screening, thus completing the complete setting of the carrier frequency screening conditions.

[0041] In this embodiment, the specific implementation method for constructing the modulation binding scheme of BeiDou positioning signal and carrier frequency to form an initial composite signal is as follows: the BeiDou positioning signal is configured as the input modulation signal of amplitude modulation, the selected high-frequency carrier frequency is configured as the carrier, and a signal role configuration command is sent to the modulation module; the module internally sets the mapping ratio between the amplitude change of the positioning signal and the amplitude change of the carrier frequency, first inputs the high-frequency carrier frequency signal to the modulation module to complete the preheating and amplitude calibration of the carrier link inside the module, and then continuously inputs the BeiDou positioning signal; the amplitude and frequency changes of the positioning signal are sampled in real time, and the output amplitude of the carrier frequency is adjusted synchronously so that the carrier frequency amplitude changes synchronously with the positioning signal. The two signals are fused and superimposed through the internal coupling circuit to output the initial composite signal after amplitude modulation.

[0042] In this embodiment, the specific implementation of the multi-channel integration and multiplexing mechanism is as follows: The modulated composite signals are collected one by one using a spectrum analyzer, and the spectrum range, peak frequency, and transmission bandwidth parameters of each signal are recorded. These parameters are then aggregated to the multiplexing control unit. The unit is designed with two parallel integration logics. The first is a frequency domain merging logic, which selects a multiplexer and a combiner to form a hardware link. The composite signals are sorted according to their spectrum range from low to high and sequentially connected to the corresponding input ports of the multiplexer. After spectrum isolation by the multiplexer, the signals are sent to the combiner and aggregated into a single output signal. The second is a time domain time slot logic, which divides the transmission priority according to the signal source, allocates an independent transmission time slot to each signal, sets a protection interval between adjacent time slots, configures a time slot switching trigger command, and automatically triggers the opening of the next time slot after the previous signal transmission ends, thus completing the orderly time-division transmission configuration of multiple signals.

[0043] In this embodiment, the specific implementation of the BeiDou positioning signal separation and restoration process is as follows: a three-level processing link is built according to the order of frequency extraction, signal separation, and interference filtering; the first-level frequency extraction uses a bandpass filter, matching the filter passband width to the bandwidth of the target high-frequency carrier frequency, and performs bandpass filtering on the transmitted mixed signal, retaining only the signal component in the frequency band of the target carrier frequency; the second-level signal separation connects to a passive detector, sets the device operating voltage to match the operating voltage with the amplitude range of the input signal, synchronously calibrates the detection timing to align the detection sampling time with the signal transmission rate, and demodulates the original BeiDou positioning signal from the carrier frequency signal; the third-level interference filtering presets an effective signal frequency threshold, builds amplitude triggering logic between links, and automatically starts the next-level processing unit after the amplitude of the output signal of the previous level reaches the standard, completing the timing and logic connection of the entire process.

[0044] In this embodiment, the specific implementation of optimizing the modulation amplitude parameters and detection filter parameters is as follows: A purity detection module is deployed at the signal restoration output end to continuously collect waveform and amplitude distribution data of the positioning signal at fixed time intervals, and the collected data is transmitted to the parameter control unit; the unit retrieves the internally preset purity standard value, calculates the deviation between the collected data and the standard value, and issues an adjustment command to the modulation module based on the deviation to change the amplitude coupling ratio between the positioning signal and the carrier frequency; simultaneously, an adjustment command is issued to the filtering unit to change the frequency response range and cutoff frequency point of the filtering component; after a single adjustment is completed, the signal acquisition and deviation calculation process is restarted, and the operations of parameter adjustment, data acquisition, and deviation calculation are repeated to complete the closed-loop iterative adjustment of the modulation and filtering parameters.

[0045] In this embodiment, a public parking lot on the second basement level of a large urban commercial complex is used as an example. The upper part of this area is a reinforced concrete structure, ground-level shops, and a green layer. Direct BeiDou satellite signals are completely blocked. An operator's 5G communication indoor distribution system is deployed in the area, including existing transmission facilities such as feeders, indoor antennas, couplers, and power dividers, for communication between mobile phones and IoT terminals. The specific implementation process is as follows: A BeiDou signal receiving unit and a signal modulation processing unit are deployed in the ground equipment room. The BeiDou signal receiving unit receives the BeiDou positioning signal directly from the sky, extracts two types of frequency parameters, namely the center frequency and the signal bandwidth, and transmits the parameters to the modulation processing unit. The processing unit sets carrier frequency screening rules based on the above parameters, selects high-frequency carrier frequency signals with frequencies higher than the BeiDou positioning signal and with a fixed interval from the positioning signal spectrum, and verifies the amplitude stability and communication network transmission compatibility of the carrier frequency to screen out high-frequency carrier frequencies that can be accessed by the 5G indoor distribution system. The BeiDou positioning signal is configured as the modulation signal, and the screened high-frequency carrier frequency is configured as the bearer signal. An amplitude modulation method is used to establish the coupling relationship between the two, and a mapping relationship between the amplitude change of the positioning signal and the amplitude change of the carrier frequency is set. First, the high-frequency carrier frequency is input to the modulation module to complete the link calibration, and then the BeiDou positioning signal is continuously input. The module samples the amplitude fluctuation of the positioning signal in real time and adjusts the carrier frequency amplitude synchronously to keep the carrier frequency amplitude synchronized with the changes in the positioning signal. The two signals are superimposed and fused through the internal coupling circuit to output multiple independent initial composite signals. The initial composite signals are acquired one by one using a spectrum analyzer, and the spectrum range, peak frequency, and transmission bandwidth of each signal are recorded. The parameters are then uploaded to the multiplexing control unit. The multiplexing control unit uses two parallel integration logics: the first is frequency domain merging logic, which uses a multiplexer and an RF combiner to build a hardware link. The composite signals are sorted from low to high spectrum range and sequentially connected to the corresponding input ports of the multiplexer. After spectrum isolation by the multiplexer, the signals are sent to the combiner to combine the multiple signals into a single unified output signal. The second is time domain time slot allocation logic, which divides the transmission level according to the signal source and terminal access priority, allocates an independent transmission time slot to each composite signal, sets the protection interval between adjacent time slots, and configures the time slot switching trigger condition. The next time slot is automatically triggered after the transmission of the previous signal ends. The control unit selects an integration path to activate based on the number of currently connected signals and the transmission delay requirements to complete the integration processing of multiple composite signals. The signal processing unit reads the transmission protocol, spectrum resource allocation, feeder and antenna layout data of the 5G indoor distribution system in the underground parking lot, matches and integrates the transmission format and transmission rate of the composite signal to ensure that the composite signal parameters are consistent with the indoor distribution system access specifications; it connects the integrated composite signal to the indoor distribution system combining port, establishes a shared network transmission channel for the composite signal and 5G communication signal using feeders, power dividers, and indoor antennas, sets timing coordination rules for the two types of signals to share transmission resources, and marks the timing nodes for signal transmission and reception; based on the coverage zoning of the underground parking lot, it adjusts the signal output power and antenna coverage direction, optimizes the feeder routing, and distributes the composite signal evenly to all parking spaces, passages, and inspection areas of the second-level underground parking lot through existing indoor distribution transmission facilities; After the vehicle-mounted positioning terminal and inspection terminal enter the underground parking area, they receive the mixed signal transmitted by the indoor antenna. The demodulation unit inside the terminal performs the restoration process in the order of frequency extraction, signal separation, and interference filtering. First, a bandpass filter is used to filter the mixed signal by frequency band. The passband width of the filter is matched with the bandwidth of the high-frequency carrier frequency at the front end, retaining only the signal component of the target carrier frequency band. Then, a passive detector is connected, and the device's operating voltage is set to match the amplitude range of the input signal. The detection sampling timing and signal transmission rate are synchronized to demodulate the original Beidou positioning signal from the carrier frequency component. Then, the amplitude distribution range of the demodulated signal is scanned by the filtering component, and this range is set as the active range. The effective frequency range is adjusted so that the filter cutoff frequency is aligned with the upper limit of the effective range to eliminate harmonic and noise components generated during transmission, while monitoring the relationship between signal phase and amplitude. The terminal transmits the purity data of the processed positioning signal back to the parameter control unit in the ground control room. The unit collects purity data at fixed time intervals, calculates the difference with the preset standard value, and adjusts the amplitude coupling ratio of the front-end modulation module according to the difference ratio, while simultaneously adjusting the frequency response range of the detection and filtering components. After each adjustment, the signal purity data is collected again, and the operation of parameter adjustment, data acquisition, and difference comparison is repeated to complete the closed-loop iterative optimization of the modulation amplitude parameter and the detection and filtering parameter.

[0046] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A BeiDou and mobile communication fusion positioning method based on modulation detection, characterized in that, include: S1: Acquire BeiDou positioning signal and high-frequency carrier signal, extract frequency parameters of BeiDou positioning signal, and preset carrier frequency screening conditions based on the frequency parameters; construct modulation binding scheme of BeiDou positioning signal and carrier frequency; use BeiDou positioning signal as modulation signal, attach it to high-frequency carrier frequency that meets carrier frequency screening conditions, and form initial composite signal through signal modulation; S2: Based on the initial composite signal, a multi-path integration and multiplexing mechanism is constructed; for multiple composite signals that have been modulated and bound, two integration paths are set; the first path is to use signal merging logic to combine all composite signals into a unified signal according to the principle of spectrum compatibility; the second path is to preset the transmission time slots corresponding to each composite signal according to the preset signal system, and set the time interval and allocation rules of the transmission time slots. S3: Based on the integrated composite signal, establish a network-based transmission mode for the composite signal and the original signal of the communication network; with the help of the network's existing transmission resources and coverage paths, and according to the network coverage of the target application area, transmit the integrated composite signal to the preset target area. S4: Set the separation and restoration process of BeiDou positioning signals. When the composite signal arrives at the target area, the corresponding high-frequency carrier frequency is extracted from the transmitted mixed signal through targeted frequency identification and filtering logic. The BeiDou positioning signal is separated from the extracted high-frequency carrier frequency, and the separated positioning signal is processed through interference filtering logic. Related data in the signal transmission process are correlated, and the amplitude parameters in the modulation process and the filtering parameters in the detection process are optimized based on the purity feedback of the separated and restored positioning signal.

2. The method according to claim 1, characterized in that, The specific process of the preset carrier frequency screening conditions is as follows: based on the extracted BeiDou positioning signal frequency parameters, the carrier frequency is set to be higher than the positioning signal frequency; the specific standard for dividing the spectrum interval between the BeiDou positioning signal and the high-frequency carrier frequency signal is defined; the basic signal carrying attributes that the carrier frequency must possess are sorted out, including signal stability and transmission compatibility, and the screening criteria are organized according to the attribute requirements and frequency standards to form a core standard for carrier frequency screening that can be directly executed.

3. The method according to claim 1, characterized in that, The specific process of constructing the modulation binding scheme of BeiDou positioning signal and carrier frequency is as follows: using BeiDou positioning signal as modulation signal and high-frequency carrier frequency as carrier signal, setting the coupling mode of modulation signal and carrier signal, and setting the corresponding ratio of positioning signal strength change and carrier frequency amplitude fluctuation; planning the operation steps of signal superposition, and formulating the operation specifications when positioning signal and carrier frequency are combined.

4. The method according to claim 1, characterized in that, The specific process for forming the initial composite signal is as follows: using amplitude modulation, the strength changes and frequency fluctuations of the BeiDou positioning signal are mapped onto the amplitude of the high-frequency carrier signal; the changes in the BeiDou positioning signal are captured in real time, and the carrier frequency amplitude is adjusted to synchronize the changes in the carrier frequency amplitude with the positioning signal in real time; the BeiDou positioning signal and the high-frequency carrier signal are organically combined and processed to form the initial composite signal after signal fusion.

5. The method according to claim 1, characterized in that, The specific process for constructing the multi-path integration and reuse mechanism is as follows: Each modulated and bound composite signal is acquired one by one, and its spectrum range, peak frequency, transmission bandwidth and required transmission rate are analyzed. The core parameters of each signal are recorded. Two independent integration logics are designed. The first is the signal merging logic, which uses a combiner and a multiplexer to sort the signals according to their spectrum range from small to large. Adjacent spectrum signals are then connected to the multiplexer in sequence and then combined into one channel by the combiner. The second type is time-division multiplexing logic, which sorts signals according to transmission priority, allocates transmission time slots to each signal, calculates the interval between adjacent time slots, and sets the time slot switching trigger conditions.

6. The method according to claim 1, characterized in that, The specific process of combining all composite signals into a single unified signal according to the principle of spectral compatibility is as follows: Each composite signal is detected using a spectrum detection device, and the spectrum range and peak frequency data of each signal are recorded. The signals are superimposed using a complementary spectral method. During the superposition process, filtering techniques are used to suppress noise generation, and the spectral status of the superimposed signal is monitored in real time.

7. The method according to claim 1, characterized in that, The specific process of presetting the transmission time slots corresponding to each composite signal and setting the time interval and allocation rules of the transmission time slots is as follows: Based on the preset signal system, the transmission priority of each composite signal is calculated, and a transmission time period is allocated to each signal according to its priority. Calculate the interval between adjacent time slots based on signal transmission duration and data volume requirements; The preset transmission sorting rules prioritize the transmission of high-priority signals, while signals of the same priority are transmitted in the order they were submitted.

8. The method according to claim 1, characterized in that, The specific process for establishing a co-network transmission mode for composite signals and existing signals in the communication network is as follows: Analyze the transmission protocols, spectrum resource distribution, and transmission path layout of the existing signals in the communication network; Based on the analysis results, match the transmission adaptation parameters of the corresponding composite signal, including signal format and transmission rate; Plan the same network transmission channels for composite signals and original signals, preset the timing coordination rules when composite signals and original signals share transmission resources, and record the time nodes for signal transmission and reception.

9. The method according to claim 1, characterized in that, The specific process of transmitting the integrated composite signal to the preset target area is as follows: Obtain network coverage data for a preset target area using signal monitoring equipment; Adjust the transmission power of the composite signal based on network coverage data, adjust the signal coverage direction of the antenna, and optimize the signal transmission path; The composite signal is transmitted to the target area through transmission facilities.

10. The method according to claim 1, characterized in that, The specific process of separating and restoring the BeiDou positioning signal is as follows: The execution order is planned according to the logic of frequency extraction, signal separation, and interference filtering. The frequency extraction stage matches the preset carrier frequency with a bandpass filter, and sets the filter passband width to match the carrier frequency; the signal separation stage sets the device operating voltage to match the signal amplitude, and sets the detection timing to synchronize with the signal transmission rate; the interference filtering stage presets the effective signal frequency threshold. The connection logic of each link is preset. After the signal output of the previous link is detected, the amplitude is detected. If the value meets the standard, the next link is triggered.

11. The method according to claim 1, characterized in that, The specific process of processing the separated positioning signal through interference filtering logic is as follows: A filtering component is selected to process the separated positioning signal in a targeted manner. The separated positioning signal is scanned, and the frequency range in which the signal amplitude is concentrated is taken as the effective frequency range. Adjust the cutoff frequency of the filter component to match the upper limit of the effective frequency range; The system continuously scans the signal spectrum to intercept and eliminate harmonics and noise that exceed the effective frequency range, while simultaneously monitoring the phase and amplitude relationship of the positioning signal.

12. The method according to claim 1, characterized in that, The specific process of optimizing the amplitude parameters in the modulation process and the filtering parameters in the detection process is as follows: The purity data of the separated and restored positioning signal is obtained at a preset time interval, the preset signal purity standard value is retrieved, and the difference between the actual purity and the standard value is calculated. Adjust the amplitude coupling ratio between the positioning signal and the carrier frequency in the modulation stage according to the difference ratio; Simultaneously adjust the frequency response range of the filter components in the detection stage, and re-acquire signal purity data after each adjustment. Repeat this iterative adjustment process.

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