Satellite navigation receiver principle teaching experiment system

Abstract

The invention relates to the technical field of navigation learning, in particular to a satellite navigation receiver principle teaching experiment system which comprises a teaching terminal, a signal terminal, an algorithm terminal and an interaction terminal which are in signal connection with one another. And the teaching terminal generates an intelligent answer to understand the knowledge reserve condition of mechanical and automation professional students for the satellite navigation receiver principle, and comprises a teaching support module and a scenarized experiment module. According to the invention, by combining the professional knowledge backgrounds of students professional in mechanical engineering and automation, the students are helped to better understand and master the principle of the satellite navigation receiver through a gradually deep guiding mode. Meanwhile, the system enhances the relevance with the navigation receiver by driving the students to simulate the unmanned aerial vehicle and automatic driving, and improves the learning effect and practical ability.

Description

Technical Field

[0001] The invention relates to the technical field of navigation learning, and in particular to a satellite navigation receiver principle teaching experiment system. Background Art

[0002] The principle of satellite navigation receiver is the core content and an important part of the teaching of satellite navigation major. It involves multiple links such as the reception and processing of satellite signals and the extraction of navigation information. With the rapid development of technologies such as drones and autonomous driving, the application of satellite navigation technology in these fields is becoming more and more extensive. Therefore, it is particularly important for students majoring in mechanical engineering and automation to understand and master the principle of satellite navigation receiver. Students in these majors need to understand how satellite navigation technology can provide precise positioning for drones, how to support path planning and safe navigation of autonomous driving systems, and how to ensure the accuracy and reliability of navigation information in complex environments.

[0003] In the teaching process, the teaching of satellite navigation receiver principles usually needs to be combined with experimental operations so that students can intuitively understand and master the relevant principles and technologies. However, the traditional satellite navigation receiver principle teaching experiment system is mainly designed for students majoring in navigation. For students majoring in mechanical engineering and automation, they need to understand the connection between navigation technology and their own majors such as drones and autonomous driving. However, the traditional teaching experiment system is mainly designed around the core knowledge and skills of the navigation major. For students majoring in marginal majors, there are many professional terms and technical details, and it is difficult to strongly relate them to their majors. Therefore, it is difficult for these students to quickly understand and master the principles of satellite navigation receivers. Summary of the invention

[0004] To solve the above problems, the present invention provides a satellite navigation receiver principle teaching experiment system, which helps students better understand and master the satellite navigation receiver principle by combining the professional knowledge background of mechanical engineering and automation majors and guiding them step by step. At the same time, the system also enhances the correlation between students and navigation receivers by driving them to simulate drones and automatic driving, thereby improving learning effects and practical abilities.

[0005] In order to achieve the above-mentioned object, the technical scheme of the present invention is as follows: a satellite navigation receiver principle teaching experiment system, comprising a teaching terminal, a signal terminal, an algorithm terminal and an interactive terminal which are mutually signal-connected;

[0006] The signal terminal is used to generate simulated satellite signals based on teaching experiments. Students can select several satellite navigation systems, frequency bands and signal strengths to simulate the multipath effect, ionospheric delay and noise interference process of the receiver. The signal terminal can capture and track the signal, and the navigation message and pseudo-range measurement value in the signal can be processed and extracted and passed to the algorithm terminal for solution.

[0007] The algorithm terminal is used to receive the navigation message and pseudo-range measurement value transmitted by the signal terminal. Students learn to solve the pseudo-range and calculate the positioning error through the teaching terminal, and control the algorithm terminal to calculate the pseudo-range and positioning error through the operation of the interactive terminal, obtain the positioning results of the user's position, speed and time, and transmit the positioning results to the teaching terminal;

[0008] The teaching terminal is used to combine the cross-knowledge points of the mechanical and automation major with the field of satellite navigation receivers, generate intelligent answers to evaluate students' mastery of the principles of satellite navigation receivers, and adjust the focus of the background knowledge introduction and the teaching direction according to the answer results; the teaching terminal is also used to receive the positioning results of the algorithm terminal, combine the actual application scenarios of drone flight and vehicle navigation to simulate and provide them to students for simulation operations;

[0009] The teaching terminal includes a teaching support module and a scenario-based experiment module. The scenario-based experiment module is used to generate a UAV model to simulate the flight of the UAV and generate a vehicle model to simulate the application of vehicle navigation in actual scenarios and perform simulations, and transmit the scenario simulation results to the interactive terminal. At the same time, the scenario-based experiment module is also used to display the satellite signal coverage of the UAV or vehicle range and positioning error in the simulation scenario;

[0010] The interactive terminal is used to select different interactive contents through buttons, sliders and drop-down menu controls to dynamically display the signal capture process of the signal terminal, the data analysis process of the algorithm terminal, the answering and background knowledge introduction of the teaching terminal and the simulation scene animation of the teaching terminal.

[0011] Further, the signal terminal includes a satellite signal generating module and a signal receiving and processing module;

[0012] Satellite signal generation module, used to generate simulated satellite signals. Students select several satellite navigation systems and L1, L2 and L5 frequency bands through the switching terminal, and generate satellite signals by adjusting signal strength and simulating multipath effects, ionospheric delay and noise interference, and transmit them to the signal receiving and processing module;

[0013] The signal receiving and processing module is used to use FFT or parallel frequency search algorithm to capture the satellite signal generated by the satellite signal production module, and generate a spectrum diagram for the satellite signal. The signal receiving and processing module has built-in pseudocode. In the process of learning the content of this module, students observe the spectrum diagram and pseudocode phase alignment effect, and complete signal tracking through the interactive terminal operation delay lock loop and carrier lock loop, extract the navigation message and pseudorange measurement values, and pass the navigation message and pseudorange measurement values ​​to the algorithm terminal.

[0014] Furthermore, the signal receiving and processing module includes a signal capturing unit, a signal tracking unit and a navigation message demodulation unit;

[0015] The signal capture unit is used to detect satellite signals through FFT or parallel frequency search algorithm. Students verify the accuracy of signal capture by observing the spectrum diagram and pseudo code phase alignment effect displayed by the signal capture unit;

[0016] The signal tracking unit is used to realize carrier stripping and pseudo code synchronization through a delay lock loop and a carrier lock loop. Students understand the principle of signal tracking by observing the tracking waveform displayed by the signal tracking unit in real time.

[0017] The navigation message demodulation unit is used to extract satellite ephemeris, time information and ionospheric correction parameters from the signal. Students verify the accuracy of the signal processing data through the demodulated navigation message and pass the demodulated navigation message to the algorithm terminal.

[0018] Further, the algorithm terminal includes a pseudo-range measurement unit, a positioning settlement unit and an error analysis unit;

[0019] The pseudo-range measurement unit is used to calculate the user's position, speed and time based on the pseudo-range measurement values ​​and navigation messages transmitted by the signal terminal. Students calculate the positioning results based on the pseudo-range measurement values ​​and navigation messages obtained by the pseudo-range measurement unit and understand the principle of pseudo-range measurement.

[0020] The positioning solution unit is used to receive the user position, speed and time from the pseudo-range measurement unit and calculate the positioning result through the extended Kalman filter. Students can verify the accuracy of the positioning algorithm by observing the simulated UAV or autonomous driving vehicle position and satellite distribution displayed on the three-dimensional map during the positioning solution course learning on the teaching terminal.

[0021] The error analysis unit is used to calculate positioning errors and analyze the sources of errors. Students understand the factors that affect positioning accuracy through learning error analysis.

[0022] Furthermore, the algorithm terminal also includes a multi-sensor fusion module, which is used to fuse satellite positioning results with inertial sensor and visual sensor data. Students can understand the advantages of multi-sensor fusion by comparing the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation.

[0023] The multi-sensor fusion module includes an inertial sensor data fusion unit, a visual sensor data fusion unit and an integrated navigation unit;

[0024] The inertial sensor data fusion unit is used to receive the accelerometer and gyroscope data of the inertial sensor. Students use the interactive terminal to set up the Kalman filter to fuse the satellite positioning results and observe the fused trajectory;

[0025] The visual sensor data fusion unit is used to receive image data from the visual sensor. Students can understand the principle of visual navigation through visual SLAM algorithm-assisted positioning.

[0026] The combined navigation unit is used to compare the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation. Students observe the fused trajectory and then obtain the error analysis results.

[0027] Furthermore, the scenario-based experiment module includes a UAV navigation unit, an autonomous driving unit, and a dynamic scenario simulation unit;

[0028] The UAV navigation experiment unit is used to simulate the navigation process of a UAV in a complex environment. Students operate the UAV through an interactive terminal and observe the flight trajectory and satellite signal obstruction during the operation.

[0029] The autonomous driving experiment unit is used to simulate the navigation and obstacle avoidance of vehicles in urban environments. Students learn the application of satellite navigation receivers in the field of autonomous driving technology through vehicle obstacle avoidance.

[0030] The dynamic scene simulation unit is used to support the linkage between virtual and physical devices. Students learn about the changes in satellite signals in actual application scenarios through the satellite signal coverage and positioning errors in the simulated scenes.

[0031] Furthermore, the teaching support module includes an assessment unit and an explanation unit;

[0032] The assessment unit is used to generate intelligent questions based on the cross-disciplinary issues between the major of machinery and automation and satellite navigation receivers to evaluate students' knowledge of the principles of satellite navigation receivers, and analyze the answer results and upload them to the teaching support module;

[0033] The explanation unit module is used to adjust the emphasis and difficulty of background knowledge introduction according to the answer results, and to understand the principles of satellite navigation receivers from the perspective of mechanics and automation.

[0034] Furthermore, the assessment unit is also used to check the students' mastery of theoretical and practical knowledge again according to the students' operation status of the interactive terminal and the learning progress of the teaching terminal;

[0035] Students calculate the satellite positions by downloading ephemeris files, filling in the positions and pseudoranges of four or more satellites, calculating the positioning results of the user receiver, generating a trajectory map of the results through the algorithm terminal and uploading it to the assessment unit. The assessment unit generates an analysis report, and students check for deficiencies and strengthen their learning based on the feedback from the report.

[0036] Furthermore, the interactive terminal includes a signal processing visualization interface, a positioning result visualization interface, and a data comparison and analysis tool;

[0037] The signal processing visualization interface is used to dynamically display the signal capture, tracking and demodulation process according to the parameters of each module of the receiver filled in by students during the operation, and supports parameter adjustment and real-time feedback;

[0038] The positioning result visualization interface is used to display the animation association between the current position of students and the satellite distribution when operating a virtual drone or virtual automated driving on a 3D map, and to display the positioning error information in real time. The positioning result visualization interface is also used to save the operation data for trajectory playback;

[0039] Data comparison and analysis tools are used to record students' experimental data during the operation and generate statistical charts, and export the data to the assessment unit to generate reports on students' learning progress.

[0040] Furthermore, it also includes a database module for storing historical data of the satellite navigation system, simulated signal data, navigation messages, pseudo-range measurements, positioning results, answer results, background knowledge content and simulation scenario data generated by students during the operation.

[0041] The above scheme has the following beneficial effects:

[0042] 1. This scheme and system successfully combine the major of mechanical engineering and automation with the principle of satellite navigation receivers. Through a step-by-step and in-depth guidance method, it helps students to gradually understand and master the core principles of satellite navigation receivers based on their own professional knowledge. This interdisciplinary teaching method not only broadens students' knowledge, but also enhances their comprehensive ability in practical applications. Through a step-by-step and in-depth guidance method, it helps students better understand the working principles of satellite navigation receivers.

[0043] 2. In this scheme, the system combines the signal reception process of the satellite navigation receiver with the actual application scenarios by simulating drone flight and autonomous driving scenarios, so as to enhance students' practical understanding of theoretical knowledge. Students can intuitively observe the satellite signal coverage, positioning error and navigation effect by operating virtual drones and autonomous driving vehicles, and improve their practical operation capabilities.

[0044] 3. In this solution, the assessment unit and explanation unit in the teaching support module can intelligently adjust the teaching content and difficulty according to the students' answer results and learning progress to achieve personalized teaching. At the same time, the assessment unit can also generate detailed learning reports by recording and analyzing the data of students during the operation process, providing students with targeted feedback and guidance; the database module can store and manage various data generated by students during the operation process, including historical data of the satellite navigation system, analog signal data, navigation telegrams, pseudo-range measurement values, positioning results, answer results, background knowledge content and simulation scene data. This not only facilitates teachers' teaching management, but also provides students with rich learning resources and review materials.

[0045] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The system framework diagram of the satellite navigation receiver principle teaching experiment system embodiment of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0049] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The following is further described in detail through specific implementation methods:

[0051] Embodiment 1:

[0052] As attached Figure 1 As shown: A satellite navigation receiver principle teaching experiment system, including a teaching terminal, a signal terminal, an algorithm terminal and an interactive terminal connected to each other;

[0053] The signal terminal is used to generate simulated satellite signals based on teaching experiments. Students can select several satellite navigation systems, frequency bands and signal strengths to simulate the multipath effect, ionospheric delay and noise interference process of the receiver. The signal terminal can capture and track the signal, and the navigation message and pseudo-range measurement value in the signal can be processed and extracted and passed to the algorithm terminal for solution.

[0054] The algorithm terminal is used to receive the navigation message and pseudo-range measurement value transmitted by the signal terminal. Students learn how to solve the pseudo-range and calculate the positioning error through the teaching terminal, and control the algorithm terminal to calculate the pseudo-range and positioning error by operating the interactive terminal, and obtain the positioning results of the user's position, speed and time, and transmit the positioning results to the teaching terminal;

[0055] The teaching terminal is used to combine the cross-knowledge points of the mechanical and automation major with the field of satellite navigation receivers, generate intelligent answers to evaluate students' mastery of the principles of satellite navigation receivers, and adjust the focus of the background knowledge introduction and the teaching direction according to the answer results; the teaching terminal is also used to receive the positioning results of the algorithm terminal, combine the actual application scenarios of drone flight and vehicle navigation to simulate and provide them to students for simulation operations;

[0056] The teaching terminal includes a teaching support module and a scenario-based experiment module. The scenario-based experiment module is used to generate a UAV model to simulate the flight of the UAV and generate a vehicle model to simulate the application of vehicle navigation in actual scenarios and perform simulations, and transmit the scenario simulation results to the interactive terminal. At the same time, the scenario-based experiment module is also used to display the satellite signal coverage of the UAV or vehicle range and positioning error in the simulation scenario;

[0057] The scenario-based experiment module includes the UAV navigation unit, the autonomous driving unit and the dynamic scenario simulation unit;

[0058] The UAV navigation experiment unit is used to simulate the navigation process of a UAV in a complex environment. Students operate the UAV through an interactive terminal and observe the flight trajectory and satellite signal obstruction during the operation.

[0059] The autonomous driving experiment unit is used to simulate the navigation and obstacle avoidance of vehicles in urban environments. Students learn the application of satellite navigation receivers in the field of autonomous driving technology through vehicle obstacle avoidance.

[0060] The dynamic scene simulation unit is used to support the linkage between virtual and physical devices. Students learn about the changes in satellite signals in actual application scenarios through the satellite signal coverage and positioning errors in the simulated scenes.

[0061] The teaching support module includes assessment units and explanation units;

[0062] The assessment unit is used to generate intelligent questions based on the cross-disciplinary issues between the major of machinery and automation and satellite navigation receivers to evaluate students' knowledge of the principles of satellite navigation receivers, and analyze the answer results and upload them to the teaching support module;

[0063] The assessment unit is also used to re-examine students’ mastery of theoretical and practical knowledge based on the students’ operation of the interactive terminal and the learning progress of the teaching terminal;

[0064] Students calculate the satellite positions by downloading ephemeris files, filling in the positions and pseudoranges of four or more satellites, calculating the positioning results of the user receiver, generating a trajectory map of the results through the algorithm terminal and uploading it to the assessment unit. The assessment unit generates an analysis report, and students check for deficiencies and strengthen their learning based on the feedback from the report.

[0065] The explanation unit module is used to adjust the emphasis and difficulty of background knowledge introduction according to the answer results, and to understand the principles of satellite navigation receivers from the perspective of mechanics and automation.

[0066] The interactive terminal is used to select different interactive contents through buttons, sliders and drop-down menu controls to dynamically display the signal capture process of the signal terminal, the data analysis process of the algorithm terminal, the answering and background knowledge introduction of the teaching terminal and the simulation scene animation of the teaching terminal.

[0067] The interactive terminal includes a signal processing visualization interface, a positioning result visualization interface, and data comparison and analysis tools;

[0068] The signal processing visualization interface is used to dynamically display the signal capture, tracking, and demodulation process according to the parameters of each module of the receiver filled in by students during the operation, and supports parameter adjustment and real-time feedback;

[0069] The positioning result visualization interface is used to display the animation association between the current position of students and the satellite distribution when operating a virtual drone or virtual automated driving on a 3D map, and to display the positioning error information in real time. The positioning result visualization interface is also used to save the operation data for trajectory playback;

[0070] Data comparison and analysis tools are used to record students' experimental data during the operation and generate statistical charts, and export the data to the assessment unit to generate reports on students' learning progress.

[0071] The specific implementation process is as follows: Specifically, this system aims at helping students majoring in mechanical and automation to understand the principles of satellite navigation receivers from the shallower to the deeper level. Students log in to the teaching terminal of this system and enter the main interface of the system. The assessment unit generates questions, and the content revolves around the cross-knowledge points of mechanical and automation majors and satellite navigation receivers (such as multi-sensor fusion and control algorithm optimization). After the students finish answering the questions, the assessment unit automatically analyzes the answer results, generates a knowledge reserve report, and transmits it to the explanation unit. The explanation unit plays a background knowledge introduction video on the principles of satellite navigation receivers based on the students' current understanding of satellite navigation receivers. The content covers: the development and current status of satellite navigation systems (such as GPS, Beidou, GLONASS, Galileo), the working principles and composition architecture of navigation receivers (such as RF front-end, baseband processing, positioning solution), and the application scenarios of satellite navigation in the fields of drones and autonomous driving. After the explanation unit ends, the assessment unit generates relevant questions about the current explanation content. After completing the study of each course of satellite navigation receivers, students enter the signal terminal or algorithm terminal interface through the interactive terminal for actual operation.

[0072] Since the fields related to satellite navigation receivers for students majoring in mechanical and automation are mostly navigation driving, the scenario-based experiment module of the teaching terminal will provide scenario-based experiments. Students can dynamically adjust the virtual receiver parameters in the signal terminal through the signal processing visualization interface of the interactive terminal according to the steps of the explanation unit during the learning process, observe the real-time changes of signal capture, tracking, and demodulation, and generate satellite signals through the algorithm terminal. During the drone navigation experiment, students enter the drone navigation experiment unit of the scenario-based experiment module, design the drone flight trajectory, simulate the navigation process of the drone in a complex environment through the drone experiment unit, and display the animation and parameters of the flight trajectory and satellite signal occlusion. Students observe the impact of positioning error on flight stability and adjust control parameters (such as PID gain) to optimize flight performance. Similarly, students enter the autonomous driving experiment unit, set the vehicle starting point and destination, and the autonomous driving experiment unit will simulate the navigation and obstacle avoidance of the vehicle in an urban environment, display the path planning and real-time positioning effects, and test the obstacle avoidance ability of the autonomous driving system by adding virtual obstacles. When the UAV flight trajectory or autonomous driving path design is completed, the trajectory or path will be imported into the dynamic scene simulation unit, and the simulation scene (such as city, mountainous area) will be selected. The dynamic simulation unit will display the satellite signal coverage and positioning error in the simulation scene. When students operate virtual UAVs or autonomous driving vehicles on the three-dimensional map, they can dynamically adjust the receiver parameters to observe the real-time changes in signal capture, tracking, and demodulation. The signal processing visualization interface will display the animated association between the current position and satellite distribution in real time. At the same time, the positioning result visualization interface will display the positioning error information in real time and save the operation data for trajectory playback.

[0073] After students complete a round of study, the assessment unit will give a comprehensive evaluation report based on the students' answers in the assessment unit, their learning situation in the explanation unit, the experimental operation data of the signal terminal and the algorithm terminal, and the trajectory diagram generated by the answers in the assessment unit. Students will enter the explanation unit to check for deficiencies and fill in the gaps based on the feedback in the evaluation report. The assessment unit will adjust the focus and difficulty of understanding of the background knowledge introduction based on the students' weak links, and gradually guide them to learn in depth.

[0074] Embodiment 2:

[0075] As attached Figure 1 As shown, the difference from embodiment 1 is that the signal terminal includes a satellite signal generating module and a signal receiving and processing module;

[0076] Satellite signal generation module, used to generate simulated satellite signals. Students select several satellite navigation systems and L1, L2 and L5 frequency bands through the switching terminal, and generate satellite signals by adjusting signal strength and simulating multipath effects, ionospheric delay and noise interference, and transmit them to the signal receiving and processing module;

[0077] The signal receiving and processing module is used to use FFT or parallel frequency search algorithm to capture the satellite signal generated by the satellite signal production module, and generate a spectrum diagram for the satellite signal. The signal receiving and processing module has built-in pseudocode. In the process of learning the content of this module, students observe the spectrum diagram and pseudocode phase alignment effect, and complete signal tracking through the interactive terminal operation delay lock loop and carrier lock loop, extract the navigation message and pseudorange measurement values, and pass the navigation message and pseudorange measurement values ​​to the algorithm terminal.

[0078] The signal receiving and processing module includes a signal capturing unit, a signal tracking unit and a navigation message demodulation unit;

[0079] The signal capture unit is used to detect satellite signals through FFT or parallel frequency search algorithm. Students verify the accuracy of signal capture by observing the spectrum diagram and pseudo code phase alignment effect displayed by the signal capture unit;

[0080] The signal tracking unit is used to realize carrier stripping and pseudo code synchronization through a delay lock loop and a carrier lock loop. Students understand the principle of signal tracking by observing the tracking waveform displayed by the signal tracking unit in real time.

[0081] The navigation message demodulation unit is used to extract satellite ephemeris, time information and ionospheric correction parameters from the signal. Students verify the accuracy of the signal processing data through the demodulated navigation message and pass the demodulated navigation message to the algorithm terminal.

[0082] The specific implementation process is as follows: In the signal terminal learning stage, students select the satellite navigation system to be simulated by the satellite signal production module through the interactive terminal, select the L1, L2 or L5 frequency band, observe the impact of different frequency bands on signal transmission, use the slider of the interactive terminal to adjust the signal strength, observe the impact of changes in signal strength on signal reception, simulate multipath effects, ionospheric delay and noise interference through the slider, and observe the impact of these factors on signal quality.

[0083] In the signal capture unit, choose to use FFT or parallel frequency search algorithm to detect satellite signals, observe the spectrum diagram, understand the frequency distribution of the signal, check the pseudo code phase alignment effect, and understand the basic principles of signal capture. In the signal tracking unit, start the delay locked loop (DLL) and carrier locked loop (PLL) to achieve carrier stripping and pseudo code synchronization, observe the tracking waveform in real time, and understand the process and effect of signal tracking. In the navigation message demodulation unit, extract satellite ephemeris, time information and ionospheric correction parameters from the signal, observe the demodulated navigation message, and understand the content and function of the navigation message. In the above learning process, the data comparison and analysis tool will record the spectrum diagram, tracking waveform, navigation message and other data obtained during the experiment, analyze the impact of different signal strengths, frequency bands and environmental effects on signal reception and processing, and understand the differences between students' operation process and the standard process.

[0084] Embodiment 3:

[0085] As attached Figure 1 As shown, the difference from Example 2 is that the algorithm terminal includes a pseudorange measurement unit, a positioning settlement unit and an error analysis unit;

[0086] The pseudo-range measurement unit is used to calculate the user's position, speed and time based on the pseudo-range measurement value and navigation message transmitted by the signal terminal. Students calculate the positioning result based on the pseudo-range measurement value obtained by the pseudo-range measurement unit and the navigation message, and understand the principle of pseudo-range measurement.

[0087] The positioning solution unit is used to receive the user position, speed and time from the pseudo-range measurement unit and calculate the positioning result through the extended Kalman filter. Students can verify the accuracy of the positioning algorithm by observing the simulated UAV or autonomous driving vehicle position and satellite distribution displayed on the three-dimensional map during the positioning solution course learning on the teaching terminal.

[0088] The error analysis unit is used to calculate positioning errors and analyze the sources of errors. Students understand the factors that affect positioning accuracy through learning error analysis.

[0089] The algorithm terminal also includes a multi-sensor fusion module, which is used to fuse satellite positioning results with inertial sensor and visual sensor data. Students can understand the advantages of multi-sensor fusion by comparing the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation.

[0090] The multi-sensor fusion module includes an inertial sensor data fusion unit, a visual sensor data fusion unit and an integrated navigation unit;

[0091] The inertial sensor data fusion unit is used to receive the accelerometer and gyroscope data of the inertial sensor. Students use the interactive terminal to set up the Kalman filter to fuse the satellite positioning results and observe the fused trajectory;

[0092] The visual sensor data fusion unit is used to receive image data from the visual sensor. Students understand the principle of visual navigation through visual SLAM algorithm-assisted positioning.

[0093] The combined navigation unit is used to compare the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation. Students observe the fused trajectory and then draw error analysis results.

[0094] The specific implementation process is as follows: When students are learning and operating the algorithm terminal, the algorithm terminal calculates the current user position, speed and time by receiving the pseudo-range measurement value and navigation message of the signal terminal:

[0095] Based on the pseudo-range measurement value and navigation message, the user's three-dimensional position (longitude, latitude, altitude) is calculated using the least squares method or the weighted least squares method; the user's speed is calculated through the Doppler frequency shift; the user's receiver time is calculated based on the satellite time information. The calculated user position, speed and time are then passed to the positioning solution unit.

[0096] The positioning solution unit uses the extended Kalman filter to optimize the user's position and speed to improve positioning accuracy. It considers system noise and measurement noise, dynamically adjusts the filter parameters, and displays the simulated position of the drone or autonomous vehicle on the three-dimensional map of the scenario experiment module. It also displays the distribution of currently visible satellites to help students understand the impact of satellite geometric distribution on positioning accuracy, and passes the optimized positioning results to the error analysis unit and the multi-sensor fusion module. The inertial sensor data fusion unit receives the raw data of the inertial sensor (accelerometer and gyroscope), uses the Kalman filter to fuse the inertial sensor data with the satellite positioning results, improves the positioning accuracy and stability in a short period of time, and outputs the fused position and speed information. The visual sensor data fusion unit receives the image data of the visual sensor, uses the visual SLAM (simultaneous localization and mapping) algorithm, extracts feature points and builds an environmental map to assist in positioning, and fuses the visual positioning results with the satellite positioning results to improve the positioning accuracy in complex environments. The combined navigation unit helps students understand the advantages of multi-sensor fusion technology in improving positioning accuracy and robustness by comparing the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation (satellite + inertial + vision).

[0097] At the same time, during the simulation of the scenario-based experiment module, the fused trajectory displayed on the three-dimensional map will be compared with the actual position (known or simulated) through the error analysis unit operation to calculate the positioning error, which includes horizontal errors (such as longitude and latitude) and vertical errors (such as altitude). After analyzing the main sources of errors such as satellite geometric distribution, multipath effects, ionospheric delay, tropospheric delay and receiver noise, the error analysis unit generates an error analysis result and transmits it to the teaching terminal for scenario simulation and teaching support.

[0098] Embodiment 4:

[0099] As attached Figure 1 As shown, the difference from Example 3 is that it also includes a database module for storing historical data of the satellite navigation system, simulated signal data, navigation telegrams, pseudo-range measurement values, positioning results, answer results, background knowledge content and simulation scenario data generated by students during the operation.

[0100] The specific implementation process is as follows: students perform experimental operations through interactive terminals, and the database module collects and stores pseudorange measurement values, positioning results, answer results and other data in real time. At the same time, the database module also stores analog signal data, navigation messages and background knowledge content for students to consult and use during the experiment. During or after the experiment, students can back up the database to prevent data loss or damage.

[0101] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A satellite navigation receiver principle teaching experiment system, characterized in that: It includes teaching terminals, signal terminals, algorithm terminals and interactive terminals that are connected to each other by signals; The signal terminal is used to generate simulated satellite signals based on teaching experiments. Students can select several satellite navigation systems, frequency bands and signal strengths to simulate the multipath effect, ionospheric delay and noise interference process of the receiver. The signal terminal can capture and track the signal, and the navigation message and pseudo-range measurement value in the signal can be processed and extracted and passed to the algorithm terminal for solution. The algorithm terminal is used to receive the navigation message and pseudo-range measurement value transmitted by the signal terminal. Students learn to solve the pseudo-range and calculate the positioning error through the teaching terminal, and control the algorithm terminal to calculate the pseudo-range and positioning error through the operation of the interactive terminal, obtain the positioning results of the user's position, speed and time, and transmit the positioning results to the teaching terminal; The teaching terminal is used to combine the cross-knowledge points of the mechanical and automation major with the field of satellite navigation receivers, generate intelligent answers to evaluate students' mastery of the principles of satellite navigation receivers, and adjust the focus of the background knowledge introduction and the teaching direction according to the answer results; the teaching terminal is also used to receive the positioning results of the algorithm terminal, combine the actual application scenarios of drone flight and vehicle navigation to simulate and provide them to students for simulation operations; The teaching terminal includes a teaching support module and a scenario-based experiment module. The scenario-based experiment module is used to generate a UAV model to simulate the flight of the UAV and generate a vehicle model to simulate the application of vehicle navigation in actual scenarios and perform simulations, and transmit the scenario simulation results to the interactive terminal. At the same time, the scenario-based experiment module is also used to display the satellite signal coverage of the UAV or vehicle range and positioning error in the simulation scenario; The interactive terminal is used to select different interactive contents through buttons, sliders and drop-down menu controls to dynamically display the signal capture process of the signal terminal, the data analysis process of the algorithm terminal, the answering and background knowledge introduction of the teaching terminal and the simulation scene animation of the teaching terminal.

2. The satellite navigation receiver principle teaching experiment system according to claim 1 is characterized in that: The signal terminal includes a satellite signal generating module and a signal receiving and processing module; Satellite signal generation module, used to generate simulated satellite signals. Students select several satellite navigation systems and L1, L2 and L5 frequency bands through the switching terminal, and generate satellite signals by adjusting signal strength and simulating multipath effects, ionospheric delay and noise interference, and transmit them to the signal receiving and processing module; The signal receiving and processing module is used to use FFT or parallel frequency search algorithm to capture the satellite signal generated by the satellite signal production module, and generate a spectrum diagram for the satellite signal. The signal receiving and processing module has built-in pseudocode. In the process of learning the content of this module, students observe the spectrum diagram and pseudocode phase alignment effect, and complete signal tracking through the interactive terminal operation delay lock loop and carrier lock loop, extract the navigation message and pseudorange measurement values, and pass the navigation message and pseudorange measurement values ​​to the algorithm terminal.

3. The satellite navigation receiver principle teaching experiment system according to claim 2 is characterized in that: The signal receiving and processing module includes a signal capturing unit, a signal tracking unit and a navigation message demodulation unit; The signal capture unit is used to detect satellite signals through FFT or parallel frequency search algorithm. Students verify the accuracy of signal capture by observing the spectrum diagram and pseudo code phase alignment effect displayed by the signal capture unit; The signal tracking unit is used to realize carrier stripping and pseudo code synchronization through a delay lock loop and a carrier lock loop. Students understand the principle of signal tracking by observing the tracking waveform displayed by the signal tracking unit in real time. The navigation message demodulation unit is used to extract satellite ephemeris, time information and ionospheric correction parameters from the signal. Students verify the accuracy of the signal processing data through the demodulated navigation message and pass the demodulated navigation message to the algorithm terminal.

4. The satellite navigation receiver principle teaching experiment system according to claim 3 is characterized in that: The algorithm terminal includes a pseudo-range measurement unit, a positioning settlement unit and an error analysis unit; The pseudo-range measurement unit is used to calculate the user's position, speed and time based on the pseudo-range measurement values ​​and navigation messages transmitted by the signal terminal. Students calculate the positioning results based on the pseudo-range measurement values ​​and navigation messages obtained by the pseudo-range measurement unit and understand the principle of pseudo-range measurement. The positioning solution unit is used to receive the user position, speed and time from the pseudo-range measurement unit and calculate the positioning result through the extended Kalman filter. Students can verify the accuracy of the positioning algorithm by observing the simulated UAV or autonomous driving vehicle position and satellite distribution displayed on the three-dimensional map during the positioning solution course learning on the teaching terminal. The error analysis unit is used to calculate positioning errors and analyze the sources of errors. Students understand the factors that affect positioning accuracy through learning error analysis.

5. The satellite navigation receiver principle teaching experiment system according to claim 4 is characterized in that: The algorithm terminal also includes a multi-sensor fusion module, which is used to fuse satellite positioning results with inertial sensor and visual sensor data. Students can understand the advantages of multi-sensor fusion by comparing the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation. The multi-sensor fusion module includes an inertial sensor data fusion unit, a visual sensor data fusion unit and an integrated navigation unit; The inertial sensor data fusion unit is used to receive the accelerometer and gyroscope data of the inertial sensor. Students use the interactive terminal to set up the Kalman filter to fuse the satellite positioning results and observe the fused trajectory; The visual sensor data fusion unit is used to receive image data from the visual sensor. Students can understand the principle of visual navigation through visual SLAM algorithm-assisted positioning. The combined navigation unit is used to compare the positioning accuracy and trajectory smoothness of single satellite navigation and combined navigation. Students observe the fused trajectory and then obtain the error analysis results.

6. The satellite navigation receiver principle teaching experiment system according to claim 5 is characterized in that: The scenario-based experiment module includes the UAV navigation unit, the autonomous driving unit and the dynamic scenario simulation unit; The UAV navigation experiment unit is used to simulate the navigation process of a UAV in a complex environment. Students operate the UAV through an interactive terminal and observe the flight trajectory and satellite signal obstruction during the operation. The autonomous driving experiment unit is used to simulate the navigation and obstacle avoidance of vehicles in urban environments. Students learn the application of satellite navigation receivers in the field of autonomous driving technology through vehicle obstacle avoidance. The dynamic scene simulation unit is used to support the linkage between virtual and physical devices. Students learn about the changes in satellite signals in actual application scenarios through the satellite signal coverage and positioning errors in the simulated scenes.

7. The satellite navigation receiver principle teaching experiment system according to claim 6 is characterized in that: The teaching support module includes assessment units and explanation units; The assessment unit is used to generate intelligent questions based on the cross-disciplinary issues between the major of machinery and automation and satellite navigation receivers to evaluate students' knowledge of the principles of satellite navigation receivers, and analyze the answer results and upload them to the teaching support module; The explanation unit module is used to adjust the emphasis and difficulty of background knowledge introduction according to the answer results, and to understand the principles of satellite navigation receivers from the perspective of mechanics and automation.

8. The satellite navigation receiver principle teaching experiment system according to claim 7 is characterized in that: The assessment unit is also used to re-examine students’ mastery of theoretical and practical knowledge based on the students’ operation of the interactive terminal and the learning progress of the teaching terminal; Students calculate the satellite positions by downloading ephemeris files, filling in the positions and pseudoranges of four or more satellites, calculating the positioning results of the user receiver, generating a trajectory map of the results through the algorithm terminal and uploading it to the assessment unit. The assessment unit generates an analysis report, and students check for deficiencies and strengthen their learning based on the feedback from the report.

9. The satellite navigation receiver principle teaching experiment system according to claim 8, characterized in that: The interactive terminal includes a signal processing visualization interface, a positioning result visualization interface, and data comparison and analysis tools; The signal processing visualization interface is used to dynamically display the signal capture, tracking and demodulation process according to the parameters of each module of the receiver filled in by students during the operation, and supports parameter adjustment and real-time feedback; The positioning result visualization interface is used to display the animation association between the current position of students and the satellite distribution when operating a virtual drone or virtual automated driving on a 3D map, and to display the positioning error information in real time. The positioning result visualization interface is also used to save the operation data for trajectory playback; Data comparison and analysis tools are used to record students' experimental data during the operation and generate statistical charts, and export the data to the assessment unit to generate reports on students' learning progress.

10. The satellite navigation receiver principle teaching experiment system according to claim 9, characterized in that: It also includes a database module for storing historical data of the satellite navigation system, simulated signal data, navigation messages, pseudo-range measurements, positioning results, answer results, background knowledge content and simulation scenario data generated by students during the operation.

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