Train millimeter wave radar speed measurement method and system based on mixed frequency band redundancy architecture

Abstract

The application discloses a train millimeter wave radar speed measurement method and system based on a mixed frequency band redundancy architecture, adopts a double digital signal processing redundancy structure design, fully utilizes different frequency band radar performance characteristics, adopts a double frequency band parallel working redundancy mechanism, and adopts a continuous wave modulation (CW) + frequency modulation continuous wave (FMCW) double mode working system, effectively avoids interference of signals of the same frequency, and further improves stability and precision of the radar. In actual measurement, train low-speed operation conditions and some external environments can interfere with the radar, influence measurement of the train speed, and through combination with an accelerometer for data fusion, the radar speed measurement is corrected, so that anti-interference capability of system speed measurement is improved, and measurement precision is improved.

Description

Technical Field

[0001] This invention relates to the field of radar testing technology, and in particular to a method and system for measuring train speed using millimeter-wave radar based on a hybrid frequency band redundancy architecture. Background Technology

[0002] Traditional train speed measurement methods are mostly contact-based, often facing errors due to special operating conditions such as bearing wear and slippage. In high-speed train speed measurement systems, the drawbacks of traditional contact-based methods become even more pronounced due to the extremely high train speeds. Radar speed measurement technology, based on the Doppler effect, obtains speed values ​​through a non-contact method of transmitting and receiving microwave signals. This effectively avoids a series of problems caused by contact between the speed measurement system and the locomotive, thus radar speed measurement has been widely used in train control systems of various rail transit systems.

[0003] Radar speed measurement is a direct method of measuring speed, providing the actual operating speed of a train without the need for indirect measurement based on wheel rotation information. A speed-measuring radar is installed on the underside of the train. As the train runs, it continuously emits electromagnetic waves towards the rails. Due to the relative motion between the train and the rails, a frequency difference is generated between the emitted and reflected waves based on the Doppler frequency shift effect. By measuring this frequency difference, the train's speed can be calculated.

[0004] As the front-end component of the entire system, the radar microwave module is responsible for transmitting and receiving radar microwaves, and performing preliminary processing such as mixing and phase shifting on the transmitted and received waves to obtain the output difference frequency signal for subsequent circuit processing. Its working principle is to first transmit radar waves and receive the reflected waves, process the reflected and transmitted waves to obtain the frequency difference signal between them, and then supply this signal to the subsequent circuits for speed calculation. It can be seen that the radar microwave section is the source of signal flow in the entire system, so its stable operation directly determines the system's signal transmission rate and the final speed calculation result; therefore, its design and selection are crucial.

[0005] Existing speed measurement radar systems use single-band microwave (CW), which is limited by the external environment and suffers from drawbacks such as inaccurate speed measurement that is difficult to resolve, low availability, and complex hardware structure. Furthermore, the speed measurement radars currently widely used in the industry are manufactured by foreign companies. These radar models are products from the 1990s and are technologically outdated; the core technology is exclusively controlled by foreign manufacturers, leading to untimely software updates and subsequent maintenance, as well as high costs. In practical applications, under special operating conditions, existing speed measurement radars have revealed inaccurate speed measurement defects that are difficult to resolve. For example: the radar still outputs speed readings after the train has come to a complete stop; the radar outputs false speed readings when the train stops in the switching track area, especially in rainy conditions; the radar exhibits speed jumps in the wheel guard rail area; and the radar shows a lower speed reading in specific areas when the maglev train is running. Summary of the Invention

[0006] The purpose of this invention is to provide a train millimeter-wave radar speed measurement method and system based on a hybrid frequency band redundancy architecture, which can enhance anti-interference capability and improve the safety, reliability and availability of radar speed measurement schemes.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture includes: two radar speed measurement devices and a host computer;

[0009] The host computer is responsible for controlling the two radar speed measuring devices and receiving the train speed output by the two radar speed measuring devices.

[0010] The two radar speed measuring devices operate in different frequency bands and employ different operating modes. The workflow of each radar speed measuring device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency by performing spectrum analysis on the digital signals and solving for the original train speed; determining whether to correct the original train speed based on the current train status, and outputting the original train speed or the corrected train speed to the host computer.

[0011] A train speed measurement method based on a hybrid frequency band redundancy architecture using millimeter-wave radar includes:

[0012] The host computer controls the two radar speed measuring devices and receives the train speed output from the two radar speed measuring devices.

[0013] The two radar speed measuring devices operate in different frequency bands and employ different operating modes. The workflow of each radar speed measuring device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency by performing spectrum analysis on the digital signals and solving for the original train speed; determining whether to correct the original train speed based on the current train status, and outputting the original train speed or the corrected train speed to the host computer.

[0014] As can be seen from the technical solution provided by the present invention, by making full use of the performance characteristics of radars of different frequency bands and different systems, and by fusing speed measurement information with acceleration information to correct radar speed measurement, the anti-interference capability of the radar speed measurement scheme can be improved and the measurement accuracy can be increased. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 A schematic diagram of a train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture provided in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the signal in the CW and FMCW hybrid mode provided in an embodiment of the present invention;

[0018] Figure 3 The flowchart of the main program of the system software provided in the embodiments of the present invention;

[0019] Figure 4 A flowchart of the train speed correction algorithm provided in an embodiment of the present invention;

[0020] Figure 5 The flowchart is provided for the multiplication-two redundancy algorithm in the embodiments of the present invention. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0022] First, the following explanations are provided for the terms that may be used in this article:

[0023] The terms "comprising," "including," "containing," "having," or other similar semantic descriptions should be interpreted as non-exclusive inclusion. For example, including a technical feature element (such as raw material, component, ingredient, carrier, dosage form, material, size, part, component, mechanism, device, step, process, method, reaction conditions, processing conditions, parameter, algorithm, signal, data, product or article of manufacture, etc.) should be interpreted as including not only the expressly listed technical feature element, but also other technical feature elements that are not expressly listed and are well-known in the art.

[0024] The term "composed of" excludes any technical features not expressly listed. When used in a claim, it closes the claim to exclude all technical features other than those expressly listed, except for associated conventional impurities. If the term appears only in a clause of a claim, it limits the claim to the elements expressly listed in that clause; elements recited in other clauses are not excluded from the overall claim.

[0025] Unless otherwise explicitly specified or limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this document according to the specific circumstances.

[0026] The following is a detailed description of a train millimeter-wave radar speed measurement method and system based on a hybrid frequency band redundancy architecture provided by this invention. Contents not described in detail in the embodiments of this invention are prior art known to those skilled in the art. Where specific conditions are not specified in the embodiments of this invention, they are performed according to conventional conditions in the art or conditions recommended by the manufacturer. Where the manufacturers of the instruments used in the embodiments of this invention are not specified, they are all conventional products that can be purchased commercially.

[0027] Example 1

[0028] This invention provides a train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture, comprising: two radar speed measurement devices and a host computer; wherein, the host computer is responsible for controlling the two radar speed measurement devices and receiving the train speed output by the two radar speed measurement devices; the two radar speed measurement devices operate in different frequency bands and adopt different operating modes, and the workflow of each radar speed measurement device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency by performing spectrum analysis on the digital signals and solving for the original train speed; determining whether to correct the original train speed according to the current train status, and outputting the original train speed or the corrected train speed to the host computer.

[0029] Figure 1 The overall architecture of the system provided by the present invention is shown. In the embodiments of the present invention, each of the two radar speed measuring devices includes: a power supply, a microwave signal module, an analog signal conditioning module, an acceleration information module, a digital signal processing module, a logic operation and information fusion module, and an interface module.

[0030] (1) The power supply is used to supply power to the microwave signal module, the analog signal conditioning module, the acceleration information module, the digital signal processing module, and the logic operation and information fusion module.

[0031] (2) The microwave signal module is used to transmit microwave signals and receive Doppler signals. Specifically, it is a front-end component of the entire system and is a device that converts microwave signals into electrical signals for output, realizing the transmission, reception and Doppler frequency output of radar microwaves. In this embodiment of the invention, the microwave signal modules in the two radar speed measuring devices transmit microwave signals of different frequency bands.

[0032] (3) The analog signal conditioning module is used to amplify, filter, and convert the corresponding Doppler signal into a digital signal. The analog signal conditioning module functions to enhance the amplitude of the Doppler signal and reduce noise and interference through hardware circuitry, and to obtain a high-quality digital signal through analog-to-digital conversion circuitry.

[0033] (4) The digital signal processing module is used to perform spectrum analysis on the digital signal to obtain the Doppler frequency and solve for the original train speed. The digital signal processing module is the core layer of the scheme. The two radar speed measuring devices adopt a software heterogeneous and algorithm heterogeneous approach. The digital signal processor performs spectrum analysis to obtain the Doppler frequency and complete the corresponding train speed (radar speed) solution.

[0034] (5) The acceleration information module is used to collect train acceleration.

[0035] (6) The logic operation and information fusion module is used to determine whether to correct the original train speed based on the current state of the train. If not, the original train speed is transmitted to the interface module. If so, the original train speed is corrected by combining the obtained train acceleration, and then the corrected train speed is transmitted to the interface module.

[0036] In this embodiment of the invention, the logic operation and information fusion module is responsible for the logical timing control of the entire system and coordinates the collaborative operation between various modules. Specifically, the logic operation and information fusion module mainly performs the following: 1) The logic operation and information fusion module conducts data exchange and logical operations. The exchanged data mainly includes the working status of the master and slave devices and speed information. In the redundant working mode, one of the radar speed measuring devices is configured as the master. The logic operation and information fusion module in the master is responsible for the logical timing control of the entire system, controlling the operation between various modules, and calculating the train speed. The logic operation and information fusion module in the slave device is mainly responsible for calculating the train speed; 2) The logic operation and information fusion module is pre-configured with radar speed correction logic operation and multiplication mode logic operation; 3) The logic operation and information fusion module has an acceleration information interface. The logic operation and information fusion module communicates with the acceleration information module through the acceleration information interface, thereby obtaining the train's acceleration information from the acceleration information module. 4) Radar speed correction logic algorithm: The input of the logic operation and information fusion module includes speed information and acceleration information. The speed information of the two trains obtained by the solution is fused with the acceleration information to calculate the corrected speed of the train. The two logic operation and information fusion modules exchange data and perform logic operations. The interface module of the host outputs the corrected speed of the train.

[0037] (7) The interface module is used to output the original train speed or the corrected train speed to the host computer. Specifically, the interface module is responsible for outputting the results (i.e., measurement results) of the operation of the radar speed measuring device, sending measurement result messages, sending master-slave communication messages, and sending log messages.

[0038] In this embodiment of the invention, the master-slave communication message mainly includes master-slave working status information (e.g., whether self-test passed) and slave measurement results. The log mainly includes: system working status, whether it is in FMCW-CW hybrid speed measurement mode, whether it is in redundant working mode, whether speed correction is enabled, and other related information.

[0039] In this embodiment of the invention, the hardware and software parts of the two radar speed measuring devices are completely independent. Radar speed measuring device 1 and radar speed measuring device 2 are mainly used to identify the two radar speed measuring devices. They adopt a dual-band redundancy mechanism. When one radar speed measuring device fails, the other radar speed measuring device can work normally independently. The microwave signal modules have different microwave operating frequencies and are powered by different power supply modules.

[0040] In this embodiment of the invention, the host computer is equipped with control software, including an on-board control system and a human-machine interface. The on-board control system is used to receive control commands from the on-board train control equipment, thereby controlling the two radar speed measuring devices, and receiving the train speed output by the two radar speed measuring devices and displaying it through the human-machine interface.

[0041] Specifically, the host computer control software mainly performs the following tasks: 1) displaying the speed measurement process and results; 2) receiving control commands from the on-board train control equipment; 3) controlling the train speed measurement radar device; 4) communicating with the logic operation and information fusion module of the radar speed measurement device; and 5) recording the speed measurement log and outputting the speed measurement results.

[0042] Overall, the above system adopts a "1+1" structure design with complete hardware / software redundancy based on DSP digital signal processing technology. The purpose of this is to make full use of the performance characteristics of radars in different frequency bands and improve the reliability and availability of radars through information fusion algorithms.

[0043] To more clearly demonstrate the technical solution and its effects provided by the present invention, the system provided by the embodiments of the present invention will be described in detail below with reference to specific examples.

[0044] I. System speed measurement principle.

[0045] 1. Introduction to the overall principle.

[0046] The microwave signal module realizes the transmission, reception, and Doppler frequency output of mixed-band radar microwaves. The preamplifier circuit in the analog signal conditioning module enhances the output signal amplitude through intermediate frequency amplification, reducing noise and interference, thereby more effectively acquiring useful signals and reducing the complexity of back-end processing. A high-precision, high-speed, and low-power AD converter performs analog-to-digital conversion to obtain a high-quality digital signal for better subsequent data processing. The digital signal undergoes spectrum analysis by the DSP (Digital Signal Processing module) to derive the Doppler frequency and perform corresponding speed calculations. The train speed is corrected through a logic operation and information fusion module, and finally, the speed information is transmitted to the train control system in various forms through the interface module. The logic operation and information fusion module is responsible for the logical timing control of the entire system, coordinating the collaborative operation between various modules.

[0047] In this embodiment of the invention, the two radar speed measuring devices employ a dual-mode approach: single-band microwave (CW) and frequency-modulated continuous wave (FMCW). The train speed calculation speed in single-band microwave mode is faster than in FMCW mode, while the train speed calculation accuracy in FMCW mode is higher. Furthermore, FMCW mode can also detect train direction. Specifically, CW radar is a continuous wave radar that emits only a single-frequency signal, utilizing the Doppler effect to acquire speed information. Subsequent digital signal processing is simple and it is typically used for speed measurement. This invention uses CW mode radar to quickly measure train speed under high-speed conditions. FMCW transmits a linearly swept frequency signal to measure the speed, distance, and angle of targets. The measurement is precise and used to accurately detect changes in train speed and direction under low-speed conditions. FMCW is more effective in determining the location of the measured object and filtering out background clutter.

[0048] Specifically, in this embodiment of the invention, the microwave signal module in one radar speed measuring device transmits a 24GHz signal and operates in CW mode; the microwave signal module in another radar speed measuring device transmits a 77GHz signal and operates in FMCW mode.

[0049] like Figure 2 The diagram shows a signal schematic of the FMCW-CW hybrid speed measurement mode. Solid lines represent the transmitted signal, dashed lines represent the echo signal, flat lines represent CW mode, and triangular waves represent FMCW mode. The CW and FMCW radars transmit waveforms alternately. The horizontal axis t represents time, and the vertical axis f represents frequency; B is the frequency modulation bandwidth in FMCW mode; T1 is the unit time for transmitting a single frequency signal in CW mode; T2 is the unit time for transmitting a swept frequency signal in FMCW mode; f... b It is the difference frequency obtained after mixing the frequency-sweep transmit signal and the frequency-sweep receive signal; τ is the time delay between the transmit signal and the receive signal.

[0050] In this embodiment of the invention, the digital signal processing module contains a system software main program, which is burned into the flash memory of the digital signal processing module, such as... Figure 3 As shown, the main tasks of the system software program are as follows: 1) Initialize the settings of each functional sub-module of the system; 2) Acquire radar Doppler frequency information and acceleration information; 3) Calculate and process the Doppler frequency to calculate the train speed and direction, and then calculate the mileage by integrating the calculated train speed with time; 4) Perform logical correction calculation on the radar speed based on the acceleration information; 5) Master-slave logic control; 6) Send measurement result messages and output test logs.

[0051] 2. Speed ​​correction principle.

[0052] In this embodiment of the invention, the system determines whether to correct the original train speed based on the current state of the train, and outputs the original train speed or the corrected train speed to the host computer. For example... Figure 4 As shown, it mainly includes:

[0053] (1) Determine whether the train is in a non-stationary state; if not, correct the original train speed to 0 and output it to the host computer; if it is in a non-stationary state and in non-correction mode, and the acceleration is within the legal range, then no correction is required, and the original train speed is output to the host computer.

[0054] (2) If not in non-correction mode, the original train speed is corrected using acceleration information, and it is determined whether the correction mode has timed out. If it has timed out, the corrected train speed is output to the host computer. If it has not timed out, it is determined whether the original train speed, the corrected train speed, and the acceleration are within their respective threshold ranges. If they are all within their respective threshold ranges, the correction mode is exited, and the original train speed is output to the host computer. If one of them is not within the corresponding threshold range, an error signal is output.

[0055] In this section, it is determined whether the original train speed, the corrected train speed, and the acceleration are within their respective threshold ranges. This mainly involves making a reasonable judgment on the above three items. The judgment process is part of the self-check process. When the judgment result is an error, it means that the radar speed measuring device has failed the self-check.

[0056] (3) If in non-correction mode and the acceleration is not within the legal range, record the current calculated original train speed as the starting value of the correction speed, enter correction mode, and output the original train speed.

[0057] 3. Redundancy mechanism of radar speed measurement device.

[0058] In this embodiment of the invention, the logic operation and information fusion modules in the two radar speed measurement devices are pre-configured with a multi-two redundancy algorithm and have a self-testing function. For example... Figure 5As shown, the main components include: After power-on, the digital signal processing modules of the two radar speed measuring devices first initialize, control the power-on and self-test of their respective radar speed measuring devices, read the self-test results, and control the operation of each radar speed measuring device in the corresponding mode based on the self-test results. If both radar speed measuring devices pass the self-test, they are in a redundant operating mode; if one radar speed measuring device fails the self-test, it is in a non-redundant operating mode. In the non-redundant operating mode, the interface module in the radar speed measuring device that passed the self-test outputs the measurement results to the host computer. When the system is in a redundant operating mode, the two radar speed measuring devices work simultaneously, with one radar speed measuring device configured as the master and the other as the slave. The slave sends its own measurement results to the master. When the master is in normal working condition, it outputs its own measurement results to the host computer; when the master is in abnormal working condition, it outputs the slave's measurement results to the host computer.

[0059] Figure 5 This description focuses on a single radar speed measuring device. 1) For a single radar speed measuring device, its interface module includes port 1 and port 2, which refer to the physical interface. 2) In non-redundant operating mode, port 1 outputs the measurement results of the radar speed measuring device. That is, two radar speed measuring devices output their own measurement results independently, without affecting each other. However, in this operating mode, some radar speed measuring devices may fail their self-test. In redundant operating mode, the host outputs the measurement results through "host port 1," and the slave device sends its measurement results to the host through "slave port 2." In other words, port 1 is the host's port. A "host abnormal state" indicates that the host's measurement results are out of range and unreasonable, so the host sends the slave's measurement results out through host port 1.

[0060] It should be noted that the numbers 1 and 2 following the devices and modules in the attached diagram mainly serve as identifiers to distinguish between two identical devices, modules, or ports.

[0061] II. Radar speed measurement device.

[0062] 1. Microwave signal module.

[0063] In this embodiment of the invention, the microwave signal module can employ a transceiver microstrip flat panel antenna. The microwave signal is mainly divided into two parts: the microwave antenna and the radio frequency (RF) circuit. The microwave antenna is a flat panel antenna, and the RF circuit consists of a mixer and a signal source. One radar speed measurement device uses a 24GHz microwave antenna, operating in CW mode, within the 24GHz frequency band; the other radar speed measurement device uses a 77GHz microwave antenna, operating in FMCW mode, within the 77GHz frequency band. The 77GHz millimeter wave frequency is higher and the wavelength is shorter, thus requiring a smaller antenna size.

[0064] 2. Analog signal conditioning module.

[0065] The analog signal conditioning module's front-end is the output of the RF circuit, and its rear-end is the input of the digital signal processing board.

[0066] Because the Doppler frequency signal received by the microwave signal module is mixed with reflected signals from other directions, the Doppler frequency signal output after mixing and detection by the radar microwave module will also contain cluttered signals, and its output signal is very weak. Therefore, some processing of the Doppler frequency signal is required. A preamplifier circuit is designed to enhance the output signal amplitude through intermediate frequency amplification, reducing noise and interference, thereby more effectively acquiring the useful signal and reducing the complexity of back-end processing. The Doppler signal output by the microwave sensor module is very weak and needs to be amplified thousands of times before further processing. In addition, during amplification, the signal must also pass through a low-frequency bandpass filter to remove high-frequency and very low-frequency interference.

[0067] To ensure the accuracy and real-time performance of speed information, a high-precision, high-speed, and low-power AD converter is used for analog-to-digital conversion, thereby obtaining a high-quality digital signal for better subsequent data processing.

[0068] 3. Digital Signal Processing Module

[0069] The digital signal processing module employs an industrial-grade, high-performance 32-bit floating-point DSP processor. It performs spectrum analysis using a fusion algorithm combining classical spectrum analysis and power spectrum estimation to calculate the dual-band Doppler frequencies in parallel and determine the corresponding speed. The digital signal processing modules in the two radar speed measurement devices are configured with different software algorithms. These algorithms are used to perform spectrum analysis to obtain the Doppler frequencies and calculate the original train speed. The use of different software algorithms further enhances the reliability of the speed measurement results.

[0070] 4. Logical operation and information fusion module.

[0071] The logic operation and information fusion module is responsible for the logical timing control of the entire system and coordinates the collaborative operation between various modules, including: system initialization, interrupt management, A / D sampling control, data analysis, status display, log storage and transmission, alarm information processing, and calculating the corrected speed of the train by fusing acceleration information.

[0072] 5. Interface module.

[0073] The interface module is responsible for the output of the system operation results, including sending measurement result messages, master / slave communication messages, and log messages. The interface module mainly consists of two RS422 external output communication interfaces.

[0074] In this embodiment of the invention, the measurement result mainly refers to the original train speed or the corrected train speed. Specifically, if the original train speed has been corrected, the corrected train speed is the measurement result; otherwise, the original train speed is the measurement result. Alternatively, it may also include information such as train direction and / or mileage.

[0075] The above are the main technical solutions provided by the embodiments of the present invention. In general, the above solutions can utilize the Doppler effect to detect train speed and direction. The system adopts a dual-set digital signal processing redundancy structure design, fully utilizing the performance characteristics of radars in different frequency bands. Through the FMCW / CW hybrid speed measurement mode, the on-board speed measurement system combining speed measuring radar and acceleration sensors, through information fusion algorithms, further improves safety and enhances the reliability and availability of the radar. Meanwhile, currently, train speed measuring radars use the 24GHz operating frequency band. Compared to the 200MHz bandwidth of the 24GHz band, the SRR band in the 77GHz band can provide a scanning bandwidth of up to 4GHz, significantly improving range resolution, speed resolution, and radar accuracy. This system adopts a dual-band parallel working redundancy mechanism of 24GHz and 77GHz, and uses a dual-mode working system of continuous wave modulation (CW) + frequency modulated continuous wave (FMCW), effectively avoiding interference from signals of the same frequency, further improving the stability and accuracy of the radar. In actual measurements, low-speed train operation and some external environmental factors can interfere with radar and affect train speed measurement. By combining radar speed measurement with accelerometer data fusion, the radar speed measurement can be corrected, thereby improving the system's anti-interference capability and measurement accuracy.

[0076] Therefore, the above-mentioned solution provided by the embodiments of the present invention mainly achieves the following beneficial effects:

[0077] (1) Hybrid frequency band microwave radar speed measurement, based on FMCW-CW hybrid speed measurement mode, improves the reliability and accuracy of train speed measurement, improves the anti-interference capability of the speed measurement system, and improves safety and operation and maintenance efficiency.

[0078] (2) Use embedded MEMS accelerometers to correct radar velocity measurement and improve system safety and reliability.

[0079] (3) It can adapt to special working conditions and reduce the interference of the external environment on train radar speed measurement, realize the speed measurement of rail transit with wide speed range, strong real-time and high precision, and has the advantages of high reliability and high redundancy, further improving the system safety and availability, and meeting the application needs of different types of rail transit such as high-speed railway, maglev train, urban rail transit, and intercity railway.

[0080] (4) Lightweight design: Compared with 24GHz radar, 77GHz millimeter wave radar has the advantages of smaller size, lower power consumption and better performance.

[0081] (5) To reduce mutual interference between vehicle radars, different microwave frequency bands and signal modulation methods can effectively reduce mutual interference between microwave signals.

[0082] (6) Higher velocity resolution. The Doppler frequency is proportional to the carrier frequency. Under the same speed conditions, theoretically, the velocity resolution of a 77GHz radar can reach about three times that of a 24GHz radar.

[0083] (7) The software and algorithm heterogeneity improve the reliability and accuracy of train radar speed measurement.

[0084] Example 2

[0085] This invention also provides a train millimeter-wave radar speed measurement method based on a hybrid frequency band redundancy architecture. This method is mainly based on the system provided in Embodiment 1 above, and mainly includes:

[0086] The host computer controls the two radar speed measuring devices and receives the train speed output from the two radar speed measuring devices.

[0087] The two radar speed measuring devices operate in different frequency bands and employ different operating modes. The workflow of each radar speed measuring device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency by performing spectrum analysis on the digital signals and solving for the original train speed; determining whether to correct the original train speed based on the current train status, and outputting the original train speed or the corrected train speed to the host computer.

[0088] The specific technical details involved in the above method have been described in detail in the aforementioned Embodiment 1, and therefore will not be repeated here.

[0089] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture, characterized in that, include: Two radar speed measuring devices and a host computer; The host computer is responsible for controlling the two radar speed measuring devices and receiving the train speed output by the two radar speed measuring devices. The two radar speed measuring devices operate in different frequency bands and employ different operating modes. The workflow of each radar speed measuring device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency through spectrum analysis of the digital signals and solving for the original train speed; determining whether to correct the original train speed based on the current train status, and outputting the original train speed or the corrected train speed to the host computer, including: Determine if the train is not in a stable state; if not, correct the original train speed to 0 and output it to the host computer; if it is in a stable state, in non-correction mode, and the acceleration is within the legal range, no correction is needed, and the original train speed is output to the host computer. If not in non-correction mode, the original train speed is corrected using acceleration information, and it is determined whether the correction mode has timed out. If it has timed out, the corrected train speed is output to the host computer. If it has not timed out, it is determined whether the original train speed, the corrected train speed, and the acceleration are within their respective threshold ranges. If they are all within their respective threshold ranges, the correction mode is exited, and the original train speed is output to the host computer. If any one of them is not within the corresponding threshold range, an error signal is output. If in non-correction mode and the acceleration is not within the legal range, the original train speed currently calculated is recorded as the starting value of the corrected speed, and the correction mode is entered to output the original train speed.

2. The train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 1, characterized in that, Both radar velocity measurement devices include: a power supply, a microwave signal module, an analog signal conditioning module, an acceleration information module, a digital signal processing module, a logic operation and information fusion module, and an interface module; among which: The power supply is used to power the microwave signal module, the analog signal conditioning module, the acceleration information module, the digital signal processing module, and the logic operation and information fusion module. The microwave signal module is used to transmit microwave signals and receive Doppler signals; the microwave signal modules in the two radar velocity measuring devices transmit microwave signals in different frequency bands. The analog signal conditioning module is used to amplify, filter and convert the corresponding Doppler signal into an analog-to-digital signal, and output the corresponding digital signal. The digital signal processing module is used to perform spectral analysis on the digital signal to obtain the Doppler frequency and to solve for the original train speed. The acceleration information module is used to collect train acceleration; The logic operation and information fusion module is used to determine whether to correct the original train speed based on the current state of the train. If not, the original train speed is transmitted to the interface module; if so, the original train speed is corrected by combining the obtained train acceleration, and then the corrected train speed is transmitted to the interface module. The interface module is used to output the original train speed or the corrected train speed to the host computer.

3. The train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 2, characterized in that, The microwave signal module includes a microwave antenna and a radio frequency circuit. The microwave antenna in one radar speed measuring device is a 24GHz antenna, using the 24GHz operating frequency band, and the microwave antenna in the other radar speed measuring device is a 77GHz antenna, using the 77GHz operating frequency band.

4. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 2 or 3, characterized in that, The two radar speed measuring devices adopt a dual-mode approach of single-band microwave and frequency-modulated continuous wave. One radar speed measuring device operates in single-band microwave mode, while the other operates in frequency-modulated continuous wave mode. The train speed calculation speed in single-band microwave mode is faster than that in frequency-modulated continuous wave mode. The train speed calculation accuracy in frequency-modulated continuous wave mode is higher than that in single-band microwave mode, and the train direction can also be detected in frequency-modulated continuous wave mode.

5. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 1 or 2, characterized in that, The digital signal processing modules in the two radar speed measuring devices are equipped with different software algorithms. The Doppler frequency is obtained through spectrum analysis using different software algorithms, and the original train speed is calculated.

6. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 2, characterized in that, The logic operation and information fusion modules in the two radar speed measurement devices are pre-configured with a multi-two redundancy algorithm and have self-testing capabilities. After the digital signal processing module in the two radar speed measuring devices is powered on, it first initializes, controls the power-on of its respective radar speed measuring device and performs a self-test, reads the self-test results, and controls the radar speed measuring device to work in the corresponding mode according to the self-test results. If both radar speed measuring devices pass the self-test, they are in a redundant working mode. If one radar speed measuring device fails the self-test, it is in a non-redundant working mode. When in redundant working mode, two radar speed measuring devices work simultaneously. One radar speed measuring device is configured as the master and the other radar speed measuring device is configured as the slave. The slave sends its own measurement results to the master. When the host is in normal working condition, it outputs its own measurement results to the host computer. When the host is in abnormal working condition, it outputs the slave measurement results to the host computer. The measurement result refers to the original train speed or the corrected train speed.

7. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 6, characterized in that, Also includes: In redundant operating mode, one radar speed measuring device is configured as the master and the other radar speed measuring device is configured as the slave. The logic operation and information fusion module in the master is responsible for the logical timing control of the system, controlling the operation between modules, and calculating the train speed. The logic operation and information fusion module in the slave is responsible for calculating the train speed.

8. A train millimeter-wave radar speed measurement system based on a hybrid frequency band redundancy architecture according to claim 1, characterized in that, The host computer is equipped with control software, including an on-board control system and a human-machine interface. The on-board control system is used to receive control commands from the on-board train control equipment, thereby controlling the two radar speed measuring devices, and receiving the train speed output by the two radar speed measuring devices, which is then displayed through the human-machine interface.

9. A train speed measurement method based on a hybrid frequency band redundancy architecture using millimeter-wave radar, characterized in that, Based on the system implementation according to any one of claims 1 to 8, the method includes: The host computer controls the two radar speed measuring devices and receives the train speed output from the two radar speed measuring devices. The two radar speed measuring devices operate in different frequency bands and employ different operating modes. The workflow of each radar speed measuring device includes: transmitting microwave signals of the corresponding frequency band in the corresponding operating mode; acquiring the corresponding Doppler signals and then conditioning the signals to output the corresponding digital signals; obtaining the Doppler frequency by performing spectrum analysis on the digital signals and solving for the original train speed; determining whether to correct the original train speed based on the current train status, and outputting the original train speed or the corrected train speed to the host computer.

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