Beidou pseudo satellite signal simulation generation method and system, and storage medium

Abstract

The invention relates to a Beidou pseudo satellite signal simulation generation method and system and a storage medium. Comprising the following steps: generating a baseband signal; generating a spreading code; performing digital orthogonal up-conversion; performing radio frequency processing; and transmitting the planar array antenna. By introducing the Beidou pseudo satellite technology, the geometric configuration of satellite distribution is optimized, and the positioning precision is improved. After the Beidou pseudolite is introduced, in order to facilitate joint calculation with a real satellite signal, a high-precision taming crystal oscillator is selected to be combined with a time synchronization correction algorithm, nanosecond-level synchronization of pseudolite and BDS time is guaranteed, and the time synchronization problem is solved. And finally, in order to enable the receiver to normally and stably receive the Beidou pseudo-satellite signal and the navigation satellite signal which are produced in a simulation manner and suppress the near-far effect, the signal is fed back through the receiver, and the power parameter of the Beidou pseudo-satellite transmitting signal is dynamically adjusted. Through collaborative optimization of self-defined frequency bands, clock synchronization and power regulation, the positioning availability is improved to 95% from 68% in a complex environment, and the elevation precision is optimized by 65%.

Description

Technical Field

[0001] This invention relates to the field of AGV (Automated Guided Vehicle) technology, and in particular to a method, system, and storage medium for simulating BeiDou pseudo-satellite signals. Background Technology

[0002] As my country's independently developed global satellite navigation system, the BeiDou Navigation Satellite System (BDS) faces challenges such as signal attenuation and signal blockage in complex environments. Specifically, these challenges manifest as follows: (i) Complex environmental limitations: In densely populated urban areas with high-rise buildings, deep mountain valleys, tunnels, indoor environments, etc., BeiDou satellite signals are easily blocked, resulting in insufficient number of visible satellites and interruption of positioning services; (ii) Vertical accuracy defects: Beidou satellites have a high elevation angle, and the vertical positioning error is usually 2 to 3 times that of the horizontal direction, which makes it difficult to meet the high-precision requirements of aircraft precision approach and dam monitoring; (III) Dynamic scenario challenges: Emerging fields such as autonomous driving and indoor robots require continuous navigation capabilities, which traditional BeiDou systems cannot support independently.

[0003] To address this, pseudosatellite technology was introduced to fill satellite blind spots and provide independent positioning services. However, in practical use, pseudosatellite technology still has the following problems: (i) When pseudo-satellites and BeiDou satellites use the same frequency band and modulation format, the signal spectrum may overlap, causing interference to the reception of BeiDou satellite signals. At the same time, pseudo-satellite signals are easily affected by terrain reflection, which exacerbates the multipath effect.

[0004] (ii) Existing BeiDou pseudo-satellite analog signals commonly use TCXO or OCXO crystal oscillators as the system reference clock. Among them, TCXO will accumulate errors in extreme temperature fluctuations or long-term operation scenarios, while OCXO will accumulate errors due to the aging of quartz crystals, affecting the positioning accuracy of the BeiDou system.

[0005] (iii) Existing Beidou pseudo-satellite analog signals often require manual adjustment of the transmitter power to suppress near-far effects. However, the dynamism and precision of manual adjustment cannot meet the needs of near and far areas, nor can it suppress multipath effects, resulting in high maintenance manpower and equipment costs. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention discloses a method, system, and storage medium for simulating BeiDou pseudo-satellite signals, in order to solve one or more problems in the prior art.

[0007] The technical solution adopted in this invention is as follows: A method for simulating and generating BeiDou pseudo-satellite signals includes the following steps: Baseband signal generation; Spread code generation; Digital quadrature upconversion; Radio frequency processing; Transmitted via planar array antenna.

[0008] Furthermore, the baseband signal generation step includes: Navigation message generation; The steps for generating the spreading code include: The digital signal is obtained by processing low-rate navigation messages and high-rate pseudo-random codes using the direct sequence spread spectrum method.

[0009] Furthermore, after the step of generating the navigation message, the method further includes the step of time synchronization; the time synchronization step includes: Beidou tames crystal oscillators; Dual closed-loop control algorithm.

[0010] Furthermore, the digital orthogonal up-conversion step includes: The aforementioned digital signal is modulated to an intermediate frequency using quadrature modulation. The radio frequency processing steps include: The digital signal is modulated to the center frequency by radio frequency modulation to obtain a radio frequency signal, and the radio frequency signal is amplified to a suitable power. The planar array antenna transmission includes: Radio frequency signals are transmitted through an array antenna.

[0011] Furthermore, prior to the baseband signal generation step, the method further includes a signal design step; the signal design step includes: Custom frequency bands; Signal parameter configuration.

[0012] Furthermore, after the planar array antenna transmission step, the method further includes the step of dynamic monitoring feedback adjustment; the dynamic monitoring feedback adjustment step includes: Real-time monitoring of receiver feedback signals; The transmission power is dynamically adjusted using a fuzzy PID algorithm.

[0013] The present invention also discloses a BeiDou pseudo-satellite signal simulation generation system that applies the aforementioned BeiDou pseudo-satellite signal simulation generation method, the BeiDou pseudo-satellite signal simulation generation system comprising:

[0014] Generation platform: used for baseband signal generation, spreading code generation, and digital quadrature upconversion; RF module: used for RF processing and amplifying RF signals to an appropriate power; Planar array transmitting antenna: used to transmit radio frequency signals.

[0015] Furthermore, the BeiDou pseudo-satellite signal simulation generation system also includes a receiver and a fuzzy PID controller. The fuzzy PID controller is used to monitor the receiver feedback signal and dynamically adjust the transmission power using a fuzzy PID algorithm.

[0016] Furthermore, the BeiDou pseudo-satellite signal simulation generation system also includes a time synchronization module, which is used to synchronize the pseudo-satellite signals with the time.

[0017] The present invention also discloses a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned method for simulating and generating BeiDou pseudo-satellite signals.

[0018] Compared with the prior art, the beneficial technical effects of the present invention are as follows: (I) The BeiDou pseudo-satellite signal simulation generation method of the present invention first addresses the problem of reduced positioning accuracy caused by the limited number and poor distribution of visible satellites tracked in complex environments, such as densely populated urban areas with high-rise buildings or deep mountain valleys. It introduces BeiDou pseudo-satellite technology to optimize the geometric configuration of satellite distribution and improve positioning accuracy. The BeiDou pseudo-satellite can simulate real BeiDou satellites, i.e., using acquired ephemeris data to simulate satellite signals in low-elevation angle ranges that cannot be directly received due to environmental factors, with orbital parameters similar to real satellites. Alternatively, it can simulate non-existent BeiDou satellites, i.e., the position of the BeiDou pseudo-satellite remains stable, and the signal it transmits is a stationary signal. The monitoring station's position is determined by using the known position of the BeiDou pseudo-satellite.

[0019] After introducing the BeiDou pseudo-satellite, in order to facilitate joint calculation with real satellite signals, a high-precision disciplined crystal oscillator joint time synchronization correction algorithm was selected to ensure nanosecond-level synchronization between the pseudo-satellite and BDS time, thus solving the time synchronization problem.

[0020] Finally, in order to enable the receiver to receive simulated BeiDou pseudo-satellite signals and navigation satellite signals normally and stably, and to suppress the near-far effect, the power parameters of the BeiDou pseudo-satellite transmission signal are dynamically adjusted through receiver feedback signals.

[0021] Through the coordinated optimization of custom frequency bands, clock synchronization, and power adjustment, the positioning availability is improved from 68% to 95% in complex environments, and the elevation accuracy is optimized by 65%, providing a complete enhanced positioning solution for the BeiDou system in scenarios such as autonomous driving, tunnel navigation, and deep mountain canyons.

[0022] (ii) Furthermore, by selecting 1589.742MHz±5.115MHz as the core operating frequency band, sensitive frequency bands such as the BeiDou B1 / B3 band (1561.098MHz, 1268.52MHz) and GPS L1 (1575.42MHz) are avoided. The signal is generated by digital orthogonal upconversion technology and combined with a planar array right-handed antenna to achieve spectrum isolation and multipath suppression, while being compatible with the characteristics of the receiver front-end filter, with an out-of-band rejection capability >50dB.

[0023] By replacing the TCXO or OCXO crystal oscillator with a BeiDou high-precision timing module and a disciplined crystal oscillator as the local clock, the stability is improved to 10. -11 Frequency accuracy improved to 10 -12 By continuously training and calibrating the crystal oscillator through the BeiDou high-precision timing module, the clock reference maintains a certain value with the atomic clock reference of the BeiDou satellite after long-term operation. This fixed error can be compensated during positioning, thereby achieving the reliability of pseudo-satellite high-precision positioning.

[0024] By dynamically adjusting the power parameters of the BeiDou pseudosatellite transmission signal through receiver feedback, the near-far effect is suppressed. The transmission power can be automatically and dynamically adjusted according to the installation environment, reducing operation and maintenance costs. Simultaneously, a planar array right-handed rotating transmitting antenna is used instead of the traditional right-handed circularly polarized transmitting antenna. The planar array, through the collaborative work of multiple elements, can achieve higher gain than a single antenna. Adaptive phase modulation technology suppresses multipath effects, and multi-element signal synthesis cancels out reflected wave interference, which is particularly effective in densely populated urban environments. Attached Figure Description

[0025] Figure 1 A flowchart of the BeiDou pseudo-satellite signal simulation generation method according to Embodiment 1 of the present invention is shown.

[0026] Figure 2 The flowchart of the dynamic monitoring feedback adjustment step in the BeiDou pseudo-satellite signal simulation generation method of Embodiment 2 of the present invention is shown.

[0027] Figure 3 The diagram shows the connection relationship of the Beidou pseudo-satellite signal simulation generation system according to Embodiment 3 of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this invention clearer, the device proposed by this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, only for the purpose of conveniently and clearly illustrating the embodiments of this invention. Please refer to the accompanying drawings to make the objectives, features, and advantages of this invention more apparent and understandable. It should be understood that the structures, proportions, sizes, etc., depicted in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationships, or adjustments to the size, without affecting the effects and objectives achieved by this invention, should still fall within the scope of the technical content disclosed in this invention.

[0029] In the description of this invention, the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0030] Example 1 like Figure 1 As shown, a method for simulating and generating BeiDou pseudo-satellite signals includes the following steps: Step S1: Baseband signal generation.

[0031] The steps for generating the baseband signal include: Step S11: Navigation message generation.

[0032] Specifically, considering satellite signal compatibility and high bandwidth utilization, this embodiment simulates BeiDou D1 / D2 navigation messages, including ephemeris, almanac, satellite information, and time information. The signal generated in this step is the same as the real BeiDou satellite signal, except that the center frequency is different and high-precision time synchronization is achieved using a low-precision temperature-compensated crystal oscillator, thus avoiding co-channel interference and efficiently utilizing high bandwidth.

[0033] Step S2: Spread code generation.

[0034] Specifically, the low-rate navigation message and high-rate pseudo-random code generated in step S11 are processed using the direct sequence spread spectrum method to obtain a digital signal. The generated digital signal has strong anti-interference ability, low power density, and is not easily affected by narrowband interference.

[0035] Step S3: Digital quadrature upconversion.

[0036] Specifically, the spreading code generated in step S2 is a zero-IF digital signal. To better transmit the signal and expand the radiation area, this digital signal is modulated onto a high-frequency carrier signal. That is, the zero-IF digital signal is modulated to a higher frequency, i.e., the intermediate frequency, through quadrature modulation, preparing for radio frequency modulation to the high-frequency carrier signal, i.e., the custom frequency band 1589.742MHz. Specifically, the BeiDou B1 frequency point is around 1.5GHz, and the commonly used frequency conversion intermediate frequency signal is generally several to tens of MHz, with different settings for each receiver. The frequency band designed in this invention has a deviation of tens of MHz from the actual BeiDou satellite frequency band, and the intermediate frequency signal is selected at a compromise of around 46MHz, which can accommodate multiple frequency points.

[0037] Step S4, radio frequency processing.

[0038] Specifically, the digital signal is modulated to the center frequency, i.e., the custom frequency band 1589.742MHz, through radio frequency modulation to obtain the radio frequency signal, and then the radio frequency signal is amplified to a suitable power.

[0039] Step S5: The planar array antenna transmits.

[0040] Specifically, radio frequency signals are transmitted through an array antenna.

[0041] Example 2 The existing BeiDou pseudosatellite analog signal modulation format is consistent with the BeiDou B1C / B2a frequency band, which may lead to signal spectrum overlap. Especially in areas with dense pseudosatellite coverage or improper power control, this may interfere with BeiDou satellite signal reception. When pseudosatellites and real satellites operate in the same frequency band, spectral aliasing occurs, and the measured interference intensity can reach -15dBm (100m from the transmitter).

[0042] Furthermore, prior to the baseband signal generation step, the method further includes: Step S0, Signal Design. The signal design steps include: Step S01: Define the frequency band.

[0043] This embodiment employs a dynamic spectrum sensing database to scan the 1556~1616MHz range in real time and select the sub-frequency bands with the least interference. The center frequency is selected as 1589.742MHz, offset from the BeiDou B1 band by 28MHz, meeting the 3dB bandwidth isolation requirement. Software-defined radio (SDR) technology is used to achieve adaptive band switching, avoiding interference from the BeiDou B1 band (1614.26MHz±4.08MHz) and the Galileo E1 band.

[0044] Step S02, Signal parameter configuration.

[0045] Specifically, the digital intermediate frequency signal parameters are configured as follows: center_freq = 1589.742e6 # Center frequency; chip_rate = 5.115e6 # Spread code rate; bw = 10.23e6 # Signal bandwidth; tx_power = -20 # Initial transmit power (dBm).

[0046] The planar array antenna adopts an 8-element microstrip patch design and achieves beamforming through phase control. The horizontal beamwidth is 60° and the gain is 12dBi, which is 4dB higher than that of traditional circularly polarized antennas.

[0047] Performance verification: In canyon terrain testing, the signal-to-noise ratio was improved by 3dB, the multipath suppression effect reached 42%, and the out-of-band radiation suppression was >45dBm / Hz, meeting the anti-interference requirements in complex electromagnetic environments.

[0048] This embodiment uses a custom frequency band design of 1589.742MHz to avoid the three major frequency bands in the north: 2491.75MHz for receiving, and 1614.26MHz and 1618.34MHz for transmitting; as well as the frequencies of BeiDou-2 and BeiDou-3. B1 band: B1I: ​​1561.098 MHz, B1C: 1575.42 MHz; B2 band: B2I: 1207.14 MHz, B2a: 1176.45 MHz, B2b: 1207.14 MHz; B3 band: B3I: 1268.52 MHz, B3Q / B3A: 1268.52 MHz; This embodiment designs a frequency band different from that of actual BeiDou satellites, selecting 1589.742MHz±5.115MHz as the core operating frequency band to avoid sensitive bands such as the BeiDou B1 / B3 band and GPS L1. Signals are generated using digital orthogonal upconversion technology, combined with a right-handed planar array antenna, achieving spectral isolation and multipath suppression while remaining compatible with receiver front-end filter characteristics, achieving out-of-band rejection capability >50dB.

[0049] The existing BeiDou pseudo-satellite analog signals commonly use TCXO or OCXO crystal oscillators as the system reference clock, which leads to the following problems and drawbacks: The TCXO improves stability through a temperature compensation circuit (stability approximately 10). -7 The cumulative error over 72 hours reached 1.2 μs (equivalent distance error of 360 m). However, in extreme temperature fluctuations or long-term operation scenarios, the nonlinear response of the compensation circuit can lead to residual frequency drift. This error accumulation may cause phase deviation of pseudo-satellite signals, affecting the positioning accuracy of the BeiDou system.

[0050] Although OCXO has high short-term stability (stability of approximately 10%) -9 However, its long-term stability is affected by the aging of quartz crystals, and the aging rate may reach 10%. -8 The annual cumulative error exceeds 100 ns (equivalent to 30 m). If pseudo-satellites are not calibrated regularly, their clock reference may deviate from the atomic clock reference of the BeiDou satellites after long-term operation, causing timing synchronization errors.

[0051] After the step of generating the navigation message, the method further includes: Step S12: Time synchronization.

[0052] The time synchronization steps include: Step S121: Beidou tames the crystal oscillator.

[0053] Specifically, the pseudo-satellite receives clock information from real BeiDou satellites and then provides a PPS (pps per second) signal to the internal taming crystal oscillator. The taming crystal oscillator references this PPS signal and, based on its internal temperature-controlled crystal oscillator, calculates and outputs a more accurate PPS signal and clock signal, thus achieving time synchronization between the pseudo-satellite and the BeiDou satellite system.

[0054] To quickly generate BeiDou satellite signals, the BeiDou taming crystal oscillator employs a three-stage adjustment mechanism: coarse adjustment stage (DDS frequency compensation, resolution 0.1Hz), fine adjustment stage (Δ-Σ modulator fine adjustment, resolution 0.001Hz), and hold stage (temperature drift dynamic compensation).

[0055] Step S122, dual closed-loop control algorithm.

[0056] Specifically, establish a clock bias model: Δt = a0 + a1(t-t0) + a2(t-t0)^2 + ε; Where a0 is the initial clock bias, a1 is the frequency deviation, a2 is the aging rate correction term, ε is random noise (<0.3ns), t0 represents the initial time, and t represents time t. The frequency stability is verified to be ≤1×10-11 (24 hours) and the timing error is <10ns / h by the dual-mixing time difference measurement method.

[0057] The performance indicators are shown in Table 1:

[0058] Table 1 Among them, the performance index is measured by the dual mixing time difference method (DMTD) to measure the small difference between the actual frequency and the reference frequency of the Beidou satellite signal.

[0059] Stability: The DMTD system continuously measures the time difference sequence τ[n] between the local clock and the BeiDou reference. Calculate the Allan bias (ADEV) and check the stability value of the 24-hour average time.

[0060] Timekeeping error: Calculate the change in time difference within adjacent one-hour time intervals from the time difference sequence τ[n]. This change directly reflects the cumulative time deviation of the local clock within one hour and should be less than 10 ns.

[0061] Second pulse jitter: The time difference between the second pulse and the reference second pulse is measured at a high sampling rate (e.g., 10 times per second), and the standard deviation (RMS) of the data sequence is directly calculated, which is the jitter value.

[0062] Frequency accuracy: The slope of the time difference data τ[n] over a long period of time (e.g., 24 hours) is the average frequency deviation, and the normalized value (divided by the carrier frequency) is the frequency accuracy.

[0063] Temperature stability: This was achieved using a frequency counter (with high-precision BeiDou satellite signal input) in a high and low temperature test chamber. A temperature profile was set, and isothermal measurements were performed. The maximum frequency deviation, i.e., the stability, was calculated across the entire temperature range.

[0064] This embodiment improves stability to 10 by using a BeiDou high-precision timing module and a disciplined crystal oscillator instead of a TCXO or OCXO crystal oscillator as the local clock. -11 Frequency accuracy improved to 10 -12 By continuously training and calibrating the crystal oscillator through the BeiDou high-precision timing module, the clock reference maintains a certain value with the atomic clock reference of the BeiDou satellite after long-term operation, compensating for this fixed error during positioning. This achieves reliable high-precision positioning for pseudo-satellites.

[0065] Existing BeiDou pseudo-satellite analog signals often require manual adjustment of the transmitter power to suppress near-far effects, which leads to the following problems and drawbacks: 1. Insufficient dynamics and precision in power regulation. Manually adjusting the transmit power relies on preset rules or empirical values, making it difficult to respond to dynamic changes in user activity in real time. For example, when a user moves from 10km to 10m away from a pseudosatellite, the signal strength difference can reach 60dBm. Manual adjustment cannot quickly balance the strong and weak signals and may still block the receiver channel.

[0066] While high power settings can expand coverage (such as in tunnels or underground environments), they may cause co-channel interference with BeiDou satellite signals in nearby areas (such as the B1C / B2a bands). Low power settings reduce interference but shrink the service area, leading to positioning failure in edge areas.

[0067] 2. Multipath effect and increased signal reflection When pseudosatellites are deployed on the ground, their signals are easily affected by reflections from buildings and terrain. Although TDMA time-division multiplexing reduces interference between base stations, single-base station signals can still experience multipath effects in complex environments (such as urban canyons), and manual power adjustment cannot suppress such reflection interference. For example, experiments show that indoor pseudosatellite multipath errors can reach 3-5m, requiring additional pulse modulation or shaped antenna technology for compensation.

[0068] Time slot leakage from strong signal base stations (such as insufficient protection time slots) may cause cross-correlation interference to weak signals in other time slots. Especially when the front-end filtering performance of the receiver is insufficient, the peak-to-average power ratio (PAPR) of the sliding window acquisition algorithm may not be able to completely eliminate residual noise.

[0069] 3. Rising maintenance costs Manual power adjustment requires regular on-site testing and parameter optimization (e.g., in tunnel scenarios, the transmission power needs to be adjusted according to traffic flow), and the TCXO / OCXO clock needs frequent calibration to offset aging errors, significantly increasing maintenance manpower and equipment costs.

[0070] Please refer to Figure 2 Furthermore, after the planar array antenna transmission step, the method further includes: Step S6, dynamic monitoring and feedback adjustment. The steps of dynamic monitoring and feedback adjustment include: Step S61: Monitor the receiver feedback signal in real time.

[0071] Specifically, a closed-loop control system for receiver feedback is constructed, in which the receiver monitors RSSI (Received Signal Strength) and BER (Bit Error Rate) in real time.

[0072] Step S62: Use a fuzzy PID algorithm to dynamically adjust the transmission power.

[0073] Specifically, the power control equation is: ΔP = Kpe(t) + Ki∫e(t)dt + Kd*de(t) / dt; Among them, the parameters are adaptively adjusted: urban environment (Kp=0.8, Ki=0.05, Kd=0.3) and canyon environment (Kp=1.2, Ki=0.03, Kd=0.5), and e(t) represents the difference between the received intensity and the transmitted intensity at time t.

[0074] The design of the three-dimensional fuzzy rule table based on which the PID parameters are adjusted is shown in Table 2:

[0075] Table 2 The dynamic adjustment strategy used to adjust the PID parameters is shown in Table 3.

[0076] Table 3 Performance verification: In actual tests at a hydropower station in a certain area, the power regulation response time was <200ms, the near-far effect suppression ratio was >25dB (10m-1km dynamic range), and the out-of-band stray radiation was <-45dBc / Hz (deviation from center frequency ±20MHz).

[0077] This embodiment uses receiver feedback signals to dynamically adjust the power parameters of the BeiDou pseudosatellite transmission signal to suppress near-far effects. The transmitter power can be automatically and dynamically adjusted according to the installation environment, reducing maintenance costs. Simultaneously, a planar array right-handed spiral transmitting antenna is used instead of the traditional right-handed circularly polarized transmitting antenna. The planar array, through multi-element collaborative operation, achieves higher gain than a single antenna. Adaptive phase modulation technology suppresses multipath effects, and multi-element signal synthesis cancels out reflected wave interference, resulting in significant effectiveness in densely populated urban environments.

[0078] Example 3 This invention also discloses a BeiDou pseudo-satellite signal simulation generation system. Please refer to [link / reference]. Figure 3 The BeiDou pseudo-satellite signal simulation generation system includes: Generation platform: used for baseband signal generation, spreading code generation, and digital quadrature upconversion.

[0079] Specifically, the production platform uses ZYNQ-7000 / FPGA.

[0080] RF module: Used for RF processing and amplifying RF signals to an appropriate power.

[0081] Specifically, the radio frequency module uses the AD9363.

[0082] Planar array transmitting antenna: used to transmit radio frequency signals.

[0083] Please refer to Figure 3 Furthermore, the BeiDou pseudo-satellite signal simulation generation system also includes a receiver and a fuzzy PID controller. The fuzzy PID controller is used to monitor the receiver feedback signal and dynamically adjust the transmission power using a fuzzy PID algorithm.

[0084] Please refer to Figure 3 Furthermore, the BeiDou pseudo-satellite signal simulation generation system also includes a time synchronization module, which is used to synchronize the pseudo-satellite signals with the time.

[0085] Specifically, the time synchronization module includes a BeiDou high-precision time synchronization module, a disciplined crystal oscillator, a PLL, and a VC-TCXO. The BeiDou high-precision time synchronization module receives clock information from real BeiDou satellites and then provides a PPS (pps per second) signal to the disciplined crystal oscillator inside the pseudo-satellite. The disciplined crystal oscillator is used by the high-precision time synchronization module to calibrate the local crystal oscillator, bringing its accuracy to that of an atomic clock. The PLL is a phase-locked loop that uses the disciplined crystal oscillator to generate a pseudo-BeiDou signal synchronized with the BeiDou satellite signal. The VC-TCXO, as a local low-precision crystal oscillator, generates the clock signal.

[0086] Example 4 The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the aforementioned method for simulating and generating BeiDou pseudo-satellite signals.

[0087] The readable storage medium of embodiments of the present invention can be any combination of one or more computer-readable media. The readable medium can be a computer-readable signal medium or a computer-readable storage medium. Computer-readable storage media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: electrical connections having one or more wires, portable computer hard disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, apparatus, or device.

[0088] Computer-readable signal media may include data signals propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media may also be any computer-readable medium other than computer-readable storage media, capable of sending, propagating, or transmitting programs for use by or in connection with an instruction execution system, apparatus, or device.

[0089] 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 method for simulating and generating BeiDou pseudo-satellite signals, characterized in that, Includes the following steps: Baseband signal generation; Spread code generation; Digital quadrature upconversion; Radio frequency processing; Transmitted via planar array antenna.

2. The method for simulating and generating BeiDou pseudo-satellite signals according to claim 1, characterized in that, The steps for generating the baseband signal include: Navigation message generation; The steps for generating the spreading code include: The digital signal is obtained by processing low-rate navigation messages and high-rate pseudo-random codes using the direct sequence spread spectrum method.

3. The method for simulating and generating BeiDou pseudo-satellite signals according to claim 1, characterized in that, Following the step of generating the navigation message, the method further includes the step of time synchronization; The time synchronization steps include: Beidou tames crystal oscillators; Dual closed-loop control algorithm.

4. The method for simulating and generating BeiDou pseudo-satellite signals according to claim 1, characterized in that, The steps of the digital quadrature upconversion include: The aforementioned digital signal is modulated to an intermediate frequency using quadrature modulation. The radio frequency processing steps include: The digital signal is modulated to the center frequency by radio frequency modulation to obtain a radio frequency signal, and the radio frequency signal is amplified to a suitable power. The planar array antenna transmission includes: Radio frequency signals are transmitted through an array antenna.

5. The method for simulating and generating BeiDou pseudo-satellite signals according to claim 1, characterized in that, Before the baseband signal generation step, the method further includes the step of signal design; The signal design steps include: Custom frequency bands; Signal parameter configuration.

6. The method for simulating and generating BeiDou pseudo-satellite signals according to claim 1, characterized in that, Following the planar array antenna transmission step, the method further includes the step of dynamic monitoring feedback adjustment; the dynamic monitoring feedback adjustment step includes: Real-time monitoring of receiver feedback signals; The transmission power is dynamically adjusted using a fuzzy PID algorithm.

7. A BeiDou pseudo-satellite signal simulation generation system using the BeiDou pseudo-satellite signal simulation generation method according to any one of claims 1 to 6, characterized in that: The BeiDou pseudo-satellite signal simulation generation system includes: Generation platform: used for baseband signal generation, spreading code generation, and digital quadrature upconversion; RF module: used for RF processing and amplifying RF signals to an appropriate power; Planar array transmitting antenna: used to transmit radio frequency signals.

8. The BeiDou pseudo-satellite signal simulation generation system according to claim 7, characterized in that: The BeiDou pseudo-satellite signal simulation generation system also includes a receiver and a fuzzy PID controller. The fuzzy PID controller is used to monitor the receiver feedback signal and dynamically adjust the transmission power using a fuzzy PID algorithm.

9. The BeiDou pseudo-satellite signal simulation generation system according to claim 8, characterized in that: The BeiDou pseudo-satellite signal simulation generation system also includes a time synchronization module, which is used to synchronize the pseudo-satellite signals with the time.

10. A computer-readable storage medium storing a computer program therein, characterized in that: When the computer program is executed by the processor, it implements the BeiDou pseudo-satellite signal simulation generation method according to any one of claims 1 to 6.

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