Rail train speed detection circuit and rail train

Abstract

The invention provides a rail train speed detection circuit and a rail train, and can be applied to the technical field of train operation control. The circuit comprises a first detection module used for detecting the speed of a train through satellite navigation positioning so as to obtain a first detection signal; the second detection module is used for detecting the speed of the train through laser reflection ranging so as to obtain a second detection signal; the gating module is used for gating the first detection signal or the second detection signal to the processing module based on the signal intensity of the first detection signal; and the processing module is used for obtaining the running speed of the train based on the first detection signal or the second detection signal.

Description

Technical Field

[0001] This disclosure relates to the field of train operation control technology, specifically to a rail train speed detection circuit and a rail train. Background Technology

[0002] In the operation of modern rail transit systems, accurate train speed detection is not only a core element in ensuring operational safety, but also a key support for improving line operation efficiency and optimizing scheduling plans. Today, as rail transit networks continue to extend into complex environments such as underground areas and densely populated high-rise buildings, the industry is placing higher demands on the stability and reliability of speed measurement systems.

[0003] However, during the research process, it was found that the speed measurement systems in the relevant technologies have low accuracy when facing the above-mentioned complex environments, making it difficult to meet the needs of obtaining accurate speed data in actual operation scenarios. Summary of the Invention

[0004] In view of this, the present disclosure provides a rail train speed detection circuit and a rail train.

[0005] One aspect of this disclosure provides a rail train speed detection circuit, comprising: a first detection module for detecting the train speed via satellite navigation positioning to obtain a first detection signal; a second detection module for detecting the train speed via laser reflection ranging to obtain a second detection signal; a gating module for gating either the first detection signal or the second detection signal to a processing module based on the signal strength of the first detection signal; and a processing module for obtaining the train's travel speed based on the first detection signal or the second detection signal.

[0006] According to an embodiment of this disclosure, the selection module includes: a first comparator, the inverting input of the first comparator being electrically connected to a first detection module, the non-inverting input of the first comparator being used to receive a first preset level signal, the first comparator being used to compare the first detection signal with the first preset level signal to obtain a first comparison signal; and a switching unit being electrically connected to the output of the first comparator, the switching unit being used to control the first detection module or the second detection module to be turned on under the control of the first comparison signal, so as to select the first detection signal or the second detection signal to the processing module.

[0007] According to an embodiment of the present disclosure, the first comparator is configured to output a first comparison signal at a low potential when the first detection signal is greater than or equal to a first preset level signal, and to output a first comparison signal at a high potential when the first detection signal is less than the first preset level signal.

[0008] According to embodiments of this disclosure, the switching unit is used to control the first detection module to turn on under the control of a first comparison signal at a low potential, and to control the second detection module to turn on under the control of a first comparison signal at a high potential.

[0009] According to an embodiment of this disclosure, the switching unit includes a first switch and a second switch; wherein, the control terminal of the first switch is electrically connected to the output terminal of the first comparator, the first terminal of the first switch is electrically connected to a power supply, and the second terminal of the first switch is electrically connected to a first detection module, and the power supply is used to supply power to the first detection module and the second detection module respectively; and the control terminal of the second switch is electrically connected to the output terminal of the first comparator, the first terminal of the second switch is electrically connected to the second detection module, and the second terminal of the second switch is electrically connected to a processing module.

[0010] According to embodiments of this disclosure, a first switch is configured to be turned on under the control of a first comparison signal at a low potential to connect the power supply path to the first detection module, thereby turning on the first detection module, and is configured to be turned off under the control of a first comparison signal at a high potential to disconnect the first detection module; and a second switch is configured to be turned on under the control of a first comparison signal at a high potential to connect the second detection module and the processing module, so as to provide the second detection signal generated by the second detection module to the processing module, and is configured to be turned off under the control of a first comparison signal at a low potential to disconnect the second detection module.

[0011] According to an embodiment of this disclosure, the circuit further includes: a failure detection module electrically connected to the first detection module and the second detection module respectively; a third switch, the control terminal of the third switch being electrically connected to the failure detection module, the first terminal of the third switch being electrically connected to the output terminal of the first comparator, and the second terminal of the third switch being electrically connected to the switching unit; and a third detection module electrically connected to the output terminal of the first comparator and the processing module respectively.

[0012] According to an embodiment of this disclosure, the failure detection module is used to provide a failure signal to the third switch when it is determined that both the first detection module and the second detection module are malfunctioning; the third switch is used to disconnect the electrical connection between the first comparator and the switching unit under the control of the failure signal, so that the first comparator outputs a high-impedance signal; the third detection module is used to visually detect the speed of the train to obtain a third detection signal, and provides the third detection signal to the processing module under the control of the high-impedance signal; the processing module is also used to obtain the train's speed based on the third detection signal.

[0013] According to embodiments of this disclosure, the failure detection module includes a second comparator, a third comparator, and an AND gate unit; wherein, the inverting input of the second comparator is electrically connected to the first detection module, the non-inverting input of the second comparator is used to receive a second preset level signal, and the output of the second comparator is electrically connected to the first input of the AND gate unit; the inverting input of the third comparator is electrically connected to the second detection module, the non-inverting input of the third comparator is used to receive a third preset level signal, and the output of the third comparator is electrically connected to the second input of the AND gate unit; and the output of the AND gate unit is electrically connected to the control terminal of the third switch.

[0014] According to an embodiment of this disclosure, a second comparator is used to output a second comparison signal at a high potential when the first detection signal is less than a second preset level signal; a third comparator is used to output a third comparison signal at a high potential when the second detection signal is less than a third preset level signal; and an AND gate unit is used to output a failure signal based on the second comparison signal at a high potential and the third comparison signal at a high potential.

[0015] According to an embodiment of this disclosure, the third detection module includes: an imaging unit for acquiring images of the train's wheel rotation and converting the wheel rotation images into an initial detection signal; an edge detection unit for converting the initial detection signal into a square wave pulse; a pulse conversion unit for outputting a third detection signal based on the square wave pulse; and a tri-state gate unit, the enable terminal of which is electrically connected to the output terminal of the first comparator, the tri-state gate unit being used to provide the third detection signal to the processing module under the control of a high-impedance state signal.

[0016] According to an embodiment of this disclosure, the first detection module includes a satellite positioning unit, which is used to collect satellite positioning signals and obtain a first detection signal based on multiple continuously collected satellite positioning signals.

[0017] According to an embodiment of this disclosure, the second detection module includes a lidar unit and an echo detection unit; wherein the lidar signal is used to excite a laser signal toward the detection target; and the echo detection unit is used to collect the echo signal and obtain a second detection signal based on the optical frequency of the echo signal and the optical frequency of the laser signal, wherein the echo signal is formed by the laser signal reflected by the detection target.

[0018] Another aspect of this disclosure provides a rail train including the rail train speed detection circuit described above.

[0019] According to embodiments of this disclosure, multiple detection modules are set in the rail train speed detection circuit. The first detection module measures speed using satellite navigation positioning, and the second detection module measures speed using laser reflection ranging. A selection module automatically selects either the first or second detection signal to the processing module based on the strength of the first detection signal, and the processing module calculates the train speed. Because a dynamic switching mechanism based on signal strength allows for timely switching to the second detection module when the signal from the first detection module is blocked, it at least partially overcomes the technical problem of low speed measurement accuracy in complex scenarios. This reduces the risk of detection errors caused by environmental factors. Furthermore, the hardware-based rapid switching mechanism achieves low-latency response, meeting the technical requirements of urban rail transit train operation. Attached Figure Description

[0020] The above and other objects, features, and advantages of this disclosure will become clearer from the following description of embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of a rail train speed detection circuit according to an embodiment of the present disclosure is shown.

[0022] Figure 2 A schematic diagram of a rail train speed detection circuit according to another embodiment of the present disclosure is shown.

[0023] Figure 3 A schematic diagram of a rail train speed detection circuit according to yet another embodiment of the present disclosure is shown.

[0024] Figure 4 A schematic diagram of a rail train speed detection circuit according to another embodiment of the present disclosure is shown.

[0025] Figure 5 A schematic diagram of the third detection module according to this disclosure is shown;

[0026] Figure 6 A schematic diagram illustrating the switching logic between multiple detection modules according to this disclosure is shown. Detailed Implementation

[0027] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0028] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0029] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0030] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0031] In the embodiments disclosed herein, the collection, updating, analysis, processing, use, transmission, provision, disclosure, and storage of data (e.g., including but not limited to user personal information) comply with relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. In particular, necessary measures have been taken to prevent unauthorized access to user personal information data and to safeguard user personal information security, network security, and national security.

[0032] In the embodiments disclosed herein, user authorization or consent is obtained before acquiring or collecting user personal information.

[0033] The research revealed that accurate detection of train speed and position is crucial for ensuring operational safety and improving efficiency in modern urban rail transit systems. However, traditional speed measurement and positioning technologies face numerous challenges in complex and ever-changing urban environments. For example, wheel speed sensors are prone to errors when wheels slip or spin, while satellite positioning technology is susceptible to interference or even signal loss in obstructed environments such as tunnels, underground tracks, or densely populated areas with tall buildings, resulting in unstable speed measurement and positioning data.

[0034] Furthermore, adverse weather conditions such as rain and fog can negatively impact the performance of optical equipment. These problems are particularly pronounced in scenarios such as long tunnels, underground tracks, and densely built-up areas, making it difficult for traditional detection systems to continuously provide reliable speed and position data, thereby affecting the normal operation of train automatic control and dispatching systems.

[0035] In view of the above, embodiments of this disclosure provide a rail train speed detection circuit, characterized in that it includes: a first detection module for detecting the speed of the train by satellite navigation positioning to obtain a first detection signal; a second detection module for detecting the speed of the train by laser reflection ranging to obtain a second detection signal; a gating module for gating the first detection signal or the second detection signal to a processing module based on the signal strength of the first detection signal; and a processing module for obtaining the train's travel speed based on the first detection signal or the second detection signal.

[0036] Figure 1 A schematic diagram of a rail train speed detection circuit according to an embodiment of the present disclosure is shown.

[0037] like Figure 1 As shown, the rail train speed detection circuit includes: a first detection module 110, a second detection module 120, a gating module 130, and a processing module 140.

[0038] The first detection module 110 is used to detect the speed of the train by satellite navigation positioning in order to obtain the first detection signal.

[0039] The second detection module 120 is used to detect the speed of the train by laser reflection ranging in order to obtain a second detection signal.

[0040] The gating module 130 is used to select either the first detection signal or the second detection signal to the processing module 140 based on the signal strength of the first detection signal.

[0041] The processing module 140 is used to obtain the train's speed based on the first detection signal or the second detection signal.

[0042] The first detection module 110 can be the main detection module, and the second detection module 120 can be the auxiliary detection module. That is, when the first detection signal is determined to be reliable, the path from the first detection module 110 to the processing module 140 can be selected; and when the first detection signal is determined to be unreliable, the path from the second detection module 120 to the processing module 140 can be selected.

[0043] The specific implementation of the first detection module 110 is not limited. It can be a speed measurement and positioning module with high sensitivity that supports multiple satellite systems. The first detection module 110 can achieve higher speed measurement and positioning accuracy in open environments, receive satellite signals in real time, calculate train speed data, and has low power consumption, making it suitable for long-term stable operation on trains.

[0044] The implementation method of the second detection module 120 is not limited; it can be implemented using lidar. For example, train speed can be calculated by laser reflection ranging. Alternatively, the second detection module 120 can be a millimeter-wave radar or an ultrasonic sensor.

[0045] The gating module 130 can determine the credibility of the first detection signal by detecting its signal strength. When the strength of the first detection signal meets a preset threshold, it can be determined to be credible; when the strength of the first detection signal is lower than the preset threshold, it can be determined to be untrustworthy.

[0046] In some embodiments, the first detection module 110 and the second detection module 120 may each integrate an intensity detection module 150. The intensity detection module 150 can perform digital-to-analog conversion on the initial detection signal output by the first detection module 110 or the second detection module 120 to obtain a converted voltage signal, i.e., a target detection signal. This facilitates the corresponding processing of the voltage signal. The target detection signal can be either the first detection signal or the second detection signal.

[0047] In some embodiments, the strength detection module 150 can be disposed in the rail train speed detection circuit, and its input terminal can be electrically connected to the first detection module 110 or the second detection module 120, so that the initial detection signal output by the first detection module 110 or the second detection module 120 can be converted from digital to analog by the strength detection module 150 and then output to the gating module 130 or the processing module 140. The output terminal of the strength detection module 150 can be electrically connected to the input terminal of the gating module 130 and / or the input terminal of the processing module 140.

[0048] When the strength detection module 150 is electrically connected to the communication module, the signal strength of the main detection module or the auxiliary detection module can be better detected through the strength detection module 150 and the communication module.

[0049] In some embodiments, the intensity detection module 150 can also be used to buffer and amplify the input detection signal, and to perform digital-to-analog conversion on the buffered and amplified detection signal. For example, the intensity detection module 150 may include an analog-to-digital (A / D) converter chip, and a buffer amplification circuit may be provided at the input terminal to perform digital-to-analog conversion on the initial detection signal after buffer amplification, and then input it to the subsequent gating module 130. The intensity detection module 150 may also use a dedicated radio frequency signal intensity detection chip, for example, by using a wideband logarithmic amplifier in the chip to filter and isolate the initial detection signal before performing digital-to-analog conversion, and then sending the output voltage to the gating module 130.

[0050] In some embodiments, the first detection module 110 may be electrically connected to the strength detection module 150 and the processing module 140 for detecting the speed and position of the train.

[0051] The processing module 140 can be electrically connected to the alarm module to transmit the detected value of the train speed and issue an alarm signal when the train speed exceeds a preset speed threshold.

[0052] The specific implementation of the processing module 140 is not limited. It can be a processor with strong computing power, support for complex data fusion algorithms, and multiple interface support, so as to improve detection accuracy and facilitate integration with other train control systems.

[0053] In some embodiments, based on the multi-interface system integrated in the processing module 140, speed data from the first detection module 110 and the second detection module 120 are received. A precise and stable train speed is calculated using a fusion algorithm, based on the reliability and signal quality of the module outputs. Simultaneously, the processing module 140 checks in real time whether the speed exceeds a set threshold. When an abnormal speed is detected, the alarm module is activated to issue an audible and visual alarm to alert the operator.

[0054] The rail train speed detection circuit disclosed herein can also detect the position of the train.

[0055] According to embodiments of this disclosure, multiple detection modules are set in the rail train speed detection circuit, with the first detection module 110 measuring speed via satellite navigation positioning and the second detection module 120 measuring speed via laser reflection ranging. A selection module 130 automatically selects either the first or second detection signal to the processing module 140 based on the strength of the first detection signal, and the processing module 140 calculates the train speed. Because a dynamic switching mechanism based on signal strength allows for timely switching to the second detection module 120 when the signal from the first detection module 110 is blocked, this at least partially overcomes the technical problem of low speed measurement accuracy in complex scenarios, thereby reducing the risk of detection errors caused by environmental factors. Simultaneously, the hardware-based rapid switching mechanism achieves low-latency response, meeting the technical requirements of urban rail transit train operation.

[0056] According to an embodiment of the present disclosure, the gating module 130 includes a first comparator 131 and a switching unit 132.

[0057] The first comparator 131 has its inverting input terminal electrically connected to the first detection module 110, and its non-inverting input terminal used to receive a first preset level signal. The first comparator 131 is used to compare the first detection signal with the first preset level signal to obtain a first comparison signal.

[0058] The switching unit 132 is electrically connected to the output terminal of the first comparator 131. The switching unit 132 is used to control the first detection module 110 or the second detection module 120 to be turned on under the control of the first comparison signal, so as to select the first detection signal or the second detection signal to the processing module 140.

[0059] The specific implementation of the first comparator 131 is not limited; it can be a hysteresis comparator, a level detection comparator, etc.

[0060] The output of the first comparator 131 is electrically connected to the processing module 140 and the switching unit 132, respectively. The output of the first comparator 131 is connected to the power supply and ground via pull-up resistors and pull-down resistors, respectively.

[0061] When the first comparator 131 is a hysteresis comparator, compared with the conventional comparator, it can reduce jitter when the input signal is close to the threshold, reduce frequent switching, and improve the system switching stability.

[0062] The inverting input of the first comparator 131 can be electrically connected to the output of the first detection module 110 to receive the first detection signal output by the first detection module 110. The non-inverting input can be connected to a first preset level signal through a corresponding circuit structure. This preset level signal can be provided by a precision voltage source or obtained from a stable power supply through a resistor divider network to ensure the accuracy and stability of its voltage value.

[0063] When the first detection signal is input to the inverting input terminal, the first comparator 131 compares the signal with the first preset level signal at the non-inverting input terminal in real time. Based on the comparison result, it outputs a first comparison signal at a different potential.

[0064] The implementation of the switching unit 132 is not limited; it can be a transistor or a relay, etc.

[0065] By electrically connecting the control terminal of the switching unit 132 to the output terminal of the first comparator 131, the first comparison signal can be received and used as the control basis for switching. The two signal input terminals of the switching unit 132 can be connected to the signal output terminals of the first detection module 110 and the second detection module 120 respectively, while its signal output terminal is connected to the signal input terminal of the processing module 140.

[0066] Based on the control effect of the first comparison signal, the channel connected to the first detection module 110 or the second detection module 120 is turned on. For example, when the first comparison signal is at a low potential, the first detection signal is selected to the processing module 140. This realizes the automatic selection of the output signals of the two detection modules according to the first comparison signal.

[0067] According to the embodiments of this disclosure, the first comparator 131 and the switching unit 132 can realize the rapid switching between the first detection module 110 and the second detection module 120 at the hardware level. This switching method is faster and has a shorter response time than switching methods such as chip algorithms, making it more suitable for the high-speed working environment of trains. The modular design also facilitates replacement and maintenance in the future.

[0068] According to an embodiment of the present disclosure, the first comparator 131 is configured to output a first comparison signal at a low potential when the first detection signal is greater than or equal to a first preset level signal, and to output a first comparison signal at a high potential when the first detection signal is less than the first preset level signal.

[0069] Normally, when the train is running in a normal environment, the first detection module 110 can detect the train speed normally, and the signal strength of the first detection signal is usually strong. That is, under this environment, the voltage value of the first detection signal is usually greater than the first preset level signal.

[0070] In more complex environments, such as when a train enters a long tunnel or a densely built-up area, the signal strength of the first detection module 110 may weaken, which may lead to errors in the detection results of the first detection signal. Therefore, by comparing the first detection signal with the first preset level signal, it can be determined whether the first detection signal is still reliable.

[0071] For example, when the train is running normally, the first detection module 110 detects the train speed normally, and the detected voltage corresponding to its signal strength, i.e., the first detection signal, is greater than or equal to the comparison voltage, i.e., the first preset level signal. The first comparator 131 outputs a low-level first comparison signal. When the train enters a long tunnel or a densely built-up area, the signal strength of the first detection module 110 weakens, and the first detection signal may be less than the first preset level signal. In this case, the first comparator 131 outputs a high-level first comparison signal.

[0072] According to embodiments of this disclosure, by comparing the first detection signal with a first preset level signal, a more accurate calculation of whether the first detection signal is reliable can be achieved, thereby enabling control of the detection module conduction path connected to the processing module 140.

[0073] According to an embodiment of the present disclosure, the switching unit 132 is used to control the first detection module 110 to turn on under the control of the first comparison signal at a low potential, and to control the second detection module 120 to turn on under the control of the first comparison signal at a high potential.

[0074] According to embodiments of this disclosure, by controlling the switching unit 132 with first comparison signals at different potentials, the detection module that needs to be turned on can be quickly determined, thereby enabling continuous turning on of the first detection module 110 or rapid switching from the first detection module 110 to the second detection module 120.

[0075] According to an embodiment of the present disclosure, the switching unit 132 includes a first switch 1321 and a second switch 1322.

[0076] The control terminal of the first switch 1321 is electrically connected to the output terminal of the first comparator 131. The first terminal of the first switch 1321 is electrically connected to the power supply. The second terminal of the first switch 1321 is electrically connected to the first detection module 110. The power supply is used to supply power to the first detection module 110 and the second detection module 120 respectively.

[0077] The control terminal of the second switch 1322 is electrically connected to the output terminal of the first comparator 131, the first terminal of the second switch 1322 is electrically connected to the second detection module 120, and the second terminal of the second switch 1322 is electrically connected to the processing module 140.

[0078] The first switch 1321 is used to be turned on under the control of the first comparison signal at a low potential to turn on the power supply path to the first detection module 110, so as to turn on the first detection module 110, and is used to be turned off under the control of the first comparison signal at a high potential to turn off the first detection module 110.

[0079] The second switch 1322 is used to be turned on under the control of the first comparison signal at a high potential to connect the second detection module 120 and the processing module 140 so as to provide the second detection signal generated by the second detection module 120 to the processing module 140, and is used to be turned off under the control of the first comparison signal at a low potential to disconnect the second detection module 120.

[0080] Figure 2 A schematic diagram of a rail train speed detection circuit according to another embodiment of the present disclosure is shown.

[0081] like Figure 2 As shown, the switching unit 132 may include a first switch 1321 and a second switch 1322. The first switch 1321 and the second switch 1322 are electrically connected to the first detection module 110 and the second detection module 120, respectively, and are used to control the working state of the first detection module 110 and the second detection module 120, respectively, and the switching states of the first switch 1321 and the second switch 1322 are opposite.

[0082] The rail train speed detection circuit also includes a power module 210. The power module 210 can be a modular battery pack used to power the entire system. In this embodiment, only the connection relationship between the power module 210 and the first detection module 110 and the second detection module 120 is described. The rest can be powered normally according to common electrical knowledge, and will not be elaborated here.

[0083] The first switch 1321 can be electrically connected between the power module 210 and the first detection module 110, and the second switch 1322 can be electrically connected between the second detection module 120 and the processing module 140.

[0084] The implementation of the first switch 1321 and the second switch 1322 is not limited; they can be transistors or relays, depending on the engineering requirements.

[0085] The control terminal of the first switch 1321 is electrically connected to the output terminal of the first comparator 131, the input terminal can be electrically connected to the power supply module 210, and the output terminal can be electrically connected to the first detection module 110.

[0086] The control terminal of the second switch 1322 is electrically connected to the output terminal of the first comparator 131, the input terminal is electrically connected to the second detection module 120, and the output terminal is electrically connected to the processing module 140.

[0087] The first switch 1321 can be turned on when the first comparison signal is at a low potential, and the second switch 1322 can be turned on when the first comparison signal is at a high potential.

[0088] In addition, the intensity detection module 150 can be connected in series after the first detection module 110 to realize voltage signal conversion.

[0089] In some embodiments, the first switch 1321 may be a positive-negative-positive (PNP) transistor. The second switch 1322 may be a negative-positive-negative (NPN) transistor.

[0090] The NPN transistor is active high and can be connected between the second detection module 120 and the processing module 140, i.e., power module 210 - secondary detection module - NPN transistor - integrated processing module 140. The PNP transistor is active low and can be connected between the power module 210 and the first detection module 110, i.e., power module 210 - PNP transistor - first detection module 110 - processing module 140. Both sets of transistors function as switches.

[0091] According to the embodiments of this disclosure, although the first switch 1321 and the second switch 1322 are located in different positions in the circuit, it does not mean that their functions are different. It is just that the common wiring methods of the two different transistors are different. The NPN transistor is suitable for low-side switching, and the PNP transistor is suitable for high-side switching. Both are used as switches in the circuit.

[0092] In some embodiments, when the train is running normally, the first detection module 110 detects the train speed normally, the first comparator 131 outputs a low-level first comparison signal, the NPN transistor is not turned on, and the second detection module 120 is not started; conversely, when the train enters a long tunnel, the signal strength of the second detection module 120 is poor, the first comparator 131 outputs a high level, the NPN transistor is turned on, the PNP transistor is not turned on, the second detection module 120 is started, and the first detection module 110 is turned off, thereby realizing the switching between detection modules, avoiding the reduction of detection accuracy of the second detection module 120 in environments with poor signals such as long tunnels, and achieving the effect of improving the system's environmental adaptability and measurement accuracy.

[0093] According to embodiments of this disclosure, the coordinated action of the first comparison signal, the first switch 1321, and the second switch 1322 enables rapid switching from the first detection module 110 to the second detection module 120 when the reliability of the first detection signal decreases, thereby improving the system's environmental adaptability and detection accuracy.

[0094] According to embodiments of this disclosure, the above-described rail train speed detection circuit further includes:

[0095] The failure detection module 320 is electrically connected to the first detection module 110 and the second detection module 120, respectively.

[0096] The third switch has its control terminal electrically connected to the failure detection module 320, its first terminal electrically connected to the output terminal of the first comparator 131, and its second terminal electrically connected to the switch unit 132.

[0097] The third detection module 310 is electrically connected to the output of the first comparator 131 and the processing module 140, respectively.

[0098] Figure 3 A schematic diagram of a rail train speed detection circuit according to yet another embodiment of the present disclosure is shown.

[0099] like Figure 3 As shown, the rail train speed detection circuit may also include a failure detection module 320 and a third detection module 310.

[0100] The failure detection module 320 is electrically connected to the first detection module 110 and the second detection module 120, and is used to monitor the working status of the first detection module 110 and the second detection module 120.

[0101] The third detection module 310 can be another speed detection module besides the first detection module 110 and the second detection module 120, used to perform supplementary detection when the detection results of the first detection module 110 and the second detection module 120 are both inaccurate.

[0102] Figure 4 A schematic diagram of a rail train speed detection circuit according to another embodiment of the present disclosure is shown.

[0103] like Figure 4 As shown, the rail train speed detection circuit may also include a third switch.

[0104] The third switch can be connected between the first comparator 131 and the switch unit 132, so that the path between the first comparator 131 and the switch unit 132 can be connected or disconnected under the control of the control signal output by the failure detection module 320.

[0105] According to an embodiment of this disclosure, the failure detection module 320 is used to provide a failure signal to the third switch when it is determined that both the first detection module 110 and the second detection module 120 are malfunctioning.

[0106] The third switch is used to disconnect the electrical connection between the first comparator 131 and the switching unit 132 under the control of the failure signal, so that the first comparator 131 outputs a high-impedance signal.

[0107] The third detection module 310 is used to visually detect the speed of the train to obtain a third detection signal, and provides the third detection signal to the processing module 140 under the control of the high impedance signal.

[0108] The processing module 140 is also used to obtain the train's speed based on the third detection signal.

[0109] The failure detection module 320 can detect the first detection signal and the second detection signal respectively. By comparing the first detection signal and the second detection signal with their respective preset level signals, it can determine whether the first detection module 110 and the second detection module 120 have any malfunctions.

[0110] If both the first detection module 110 and the second detection module 120 are found to be malfunctioning, a failure signal is provided to the third switch. Conversely, if neither the first detection module 110 nor the second detection module 120 is found to be malfunctioning, no failure signal is output.

[0111] There are no restrictions on the implementation method of the third switch; it can be an analog switch chip, a semiconductor switch device, etc.

[0112] When the third switch receives a failure signal, the third detection module 310 will disconnect the electrical connection between the first comparator 131 and the switching unit 132 under the action of the failure signal, causing the first comparator 131 to be in a high-impedance state and output a high-impedance signal. Based on this high-impedance signal, the third detection module 310 will start and perform speed detection.

[0113] The processor can obtain the train's speed based on the third detection signal output by the third detection module 310.

[0114] According to the embodiments of this disclosure, the failure detection module 320 performs real-time detection on the first detection module 110 and the second detection module 120. When the first detection module 110 and the second detection module 120 are found to be malfunctioning, the second detection module 120 is switched to the third detection module 310 for speed detection through smooth circuit control, thereby reducing the overall detection time and improving the detection accuracy.

[0115] According to embodiments of this disclosure, the failure detection module 320 may include a second comparator, a third comparator, and an AND gate unit.

[0116] The inverting input of the second comparator is electrically connected to the first detection module 110, the non-inverting input of the second comparator is used to receive the second preset level signal, and the output of the second comparator is electrically connected to the first input of the AND gate unit.

[0117] The inverting input of the third comparator is electrically connected to the second detection module 120, the non-inverting input of the third comparator is used to receive the third preset level signal, and the output of the third comparator is electrically connected to the second input of the AND gate unit.

[0118] The output terminal of the AND gate unit is electrically connected to the control terminal of the third switch.

[0119] The implementation of the second and third comparators is not limited; they can be hysteresis comparators, level detection comparators, etc.

[0120] By electrically connecting the inverting input of the second comparator to the first detection module 110 and using its non-inverting input to receive the second preset level signal, the comparison between the first detection signal and the second preset level signal can be realized, and the corresponding second comparison signal can be output based on the comparison process.

[0121] By electrically connecting the inverting input of the third comparator to the second detection module 120 and using its non-inverting input to receive the third preset level signal, the comparison between the second detection signal and the third preset level signal can be realized, and the corresponding third comparison signal can be output based on the comparison process.

[0122] The AND gate unit can determine the working status of the first detection module 110 and the second detection module 120 by receiving the second comparison signal and the third comparison signal.

[0123] According to an embodiment of the present disclosure, the second comparator is used to output a second comparison signal at a high potential when the first detection signal is less than a second preset level signal.

[0124] The third comparator is used to output a third comparison signal at a high potential when the second detection signal is less than the third preset level signal.

[0125] The AND gate unit is used to output a failure signal based on a second comparison signal that is at a high level and a third comparison signal that is at a high level.

[0126] The input of the second comparator is electrically connected to the output of the first detection module 110. It outputs a high-level second comparison signal when the signal strength is consistently low. Specifically, it compares the first detection signal with a second preset level signal. If the voltage value of the first detection signal is less than the voltage value of the second preset level signal, it outputs a high-level second comparison signal. Conversely, if the voltage value of the first detection signal is greater than or equal to the voltage value of the second preset level signal, it outputs a low-level second comparison signal.

[0127] The second detection signal can be either a voltage signal or a current signal. If the second detection signal is a voltage signal, it can be implemented by integrating or electrically connecting the strength detection module 150. Alternatively, it can be implemented by integrating a current sampling circuit in the second detection module 120 or by connecting a current sampling circuit in series between the second detection module 120 and the second comparator.

[0128] When the second detection signal is a current signal, it can also be achieved through a current sampling circuit.

[0129] The current sampling current can convert the initial detection signal output by the second detection module 120 into a current signal or voltage signal that is easier to measure, process, or analyze.

[0130] By comparing the current or voltage value of the second detection signal with the corresponding third preset level signal, the third comparison signal can be determined. When the current or voltage value of the second detection signal is determined to be less than the third preset level signal, the third comparator outputs a high-level third comparison signal. Conversely, when the current or voltage value of the second detection signal is determined to be greater than or equal to the third preset level signal, the third comparator outputs a low-level third comparison signal.

[0131] For example, the current sampling circuit is connected in series in the power supply circuit of the second detection module 120. After sampling, it is electrically connected to the input terminal of the third comparator. It is used to output a third comparison signal at a high potential when the current in the power supply circuit of the second detection module 120 is lower than the threshold current.

[0132] When both the second and third comparison signals output by the second and third comparators are at a high level, the signal output by the AND gate unit can be a failure signal. Conversely, if neither the second nor the third comparison signal is at a high level, the output signal is not a failure signal, meaning it does not have the function of controlling the third switch to disconnect the electrical connection between the first comparator 131 and the switching unit 132.

[0133] According to embodiments of this disclosure, the second detection module 120 may also be affected by more complex weather conditions, such as rain and fog. Therefore, when working in rainy, foggy, and densely built-up environments, both the first and second detection modules 110 may temporarily fail. To mitigate this risk, a visual detection module is introduced. When the second and third comparators determine that the signal strengths of both the first and second detection modules 110 and 120 are low, the first comparator 131 is placed in a high-impedance state via an AND gate. At this time, the third detection module 310 can transmit the detection data to the processing module 140 in real time and perform more accurate speed detection based on the visual detection module.

[0134] Figure 5 A schematic diagram of the third detection module according to this disclosure is shown.

[0135] like Figure 5 As shown, the third detection module 310 in the embodiments of this disclosure includes:

[0136] The imaging unit is used to acquire images of the train's wheel rotation and convert these images into initial detection signals.

[0137] The edge detection unit is used to convert the initial detection signal into a square wave pulse.

[0138] The pulse conversion unit is used to output a third detection signal based on a square wave pulse.

[0139] The tri-state gate unit is electrically connected to the output of the first comparator 131. The tri-state gate unit is used to provide the third detection signal to the processing module 140 under the control of the high impedance signal.

[0140] The third detection module 310 is electrically connected to the processing module 140 and is used to generate a speed pulse signal by detecting the edge of the wheel when both the first detection module 110 and the second detection module 120 fail.

[0141] The implementation method of the imaging unit is not limited and can be a linear charge-coupled device (CCD) sensor, a complementary metal-oxide-semiconductor image sensor (CMOS image sensor, CIS), etc.

[0142] The imaging unit can be mounted vertically above the track and aligned with the edge of the wheel to generate an initial detection signal as the wheel rotates.

[0143] The edge detection unit may include a fourth comparator and a Schmitt trigger for converting the initial detection signal generated by the imaging unit into a square wave pulse.

[0144] The pulse conversion unit may include a counter and a quartz oscillator for outputting a third detection signal that is linearly related to the frequency of the square wave pulse. This third detection signal may be a voltage signal.

[0145] There are no restrictions on the implementation method of the tri-state gate unit; it can be implemented using a tri-state gate chip.

[0146] The output of the pulse conversion unit can be electrically connected to the input of the tri-state gate unit, the enable terminal of the tri-state gate unit is electrically connected to the output of the first comparator 131, and the output of the tri-state gate unit is electrically connected to the processing module 140. Thus, when the tri-state gate chip detects a high-impedance signal input to the first comparator 131, it turns on and provides the third detection result to the processing module 140.

[0147] The imaging unit can work by relying on the changes in brightness at the boundary between the wheel and the track. When the wheel rotates, the boundary produces a continuous movement of shadow jumps on the imaging unit, thus forming a sinusoidal waveform. Compared with traditional image recognition technologies such as camera image acquisition and image recognition, this detection method does not rely on image recognition algorithms, has a shorter response time, and is more suitable for fast-moving scenarios such as trains.

[0148] The tri-state gate unit can transmit data to the processing module 140 when the vision inspection module is working.

[0149] According to an embodiment of this disclosure, when the tri-state gate unit receives a high-impedance signal, the tri-state gate unit is turned on, so that the data of the third detection module 310 can be transmitted to the processing module 140 in real time, and the train speed is calculated based on the third detection signal output by the third detection module 310.

[0150] Since the third detection signal can be a voltage analog to speed that is linearly related to the square wave pulse frequency, and the wheel rotation period is linearly positively correlated with the square wave pulse frequency, the processing module 140 can quickly calculate the train speed based on the pre-measured correlation coefficient and wheel diameter. Furthermore, in the specific calculation, the frequency, wheel circumference, correlation coefficient, etc., can be multiplied together to obtain the calculation result quickly and easily.

[0151] Furthermore, the third detection module 310 employs an imaging unit mounted above the track, vertically aligned with the wheel edge, to generate an analog signal by monitoring changes in brightness at the wheel edge. This signal is converted into a square wave pulse by the edge detection unit, and then into an analog speed voltage linearly related to the pulse frequency by the pulse conversion unit. It is electrically connected to the processing module 140 via a tri-state gate unit controlled by a high-impedance signal. This tri-state gate unit conducts when the first comparison module enters a high-impedance state, enabling data transmission even when the first detection module 110 and the second detection module 120 fail, thus reducing signal interference.

[0152] According to an embodiment of this disclosure, the first detection module 110 includes a satellite positioning unit, which is used to collect satellite positioning signals and obtain a first detection signal based on multiple continuously collected satellite positioning signals.

[0153] The satellite positioning unit included in the first detection module 110 can use an integrated satellite positioning chip as the core component. This chip supports the signal reception of mainstream satellite navigation systems to improve the stability of signal acquisition in complex environments.

[0154] The satellite positioning unit receives radio signals transmitted by multiple satellites in the sky through its built-in radio frequency front-end circuit. The baseband processing circuit amplifies, filters, demodulates, and processes the signals to extract key information such as satellite ephemeris and timestamps.

[0155] After continuously acquiring multiple satellite positioning signals, the processor inside the unit performs differential calculations on the satellite positioning data at adjacent times based on the Doppler effect principle. Combined with satellite orbital parameters, it calculates the train's speed within that time period. Simultaneously, by analyzing the coordinate changes of consecutive positioning points, the accuracy of the speed calculation results is further verified. The processed speed information is then converted into a corresponding voltage signal, which is output as the first detection signal.

[0156] According to embodiments of this disclosure, obtaining a first detection signal based on continuously acquired satellite positioning signals can improve the accuracy of subsequent calculations. Furthermore, in the above embodiments, the first detection signal can be obtained based on radio signals transmitted by multiple satellites and differential calculations and coordinate change analysis of multiple sets of positioning data. This not only leverages the compatibility of multiple satellite systems to improve signal reception capabilities in complex environments and reduce the risk of detection interruption caused by signal blockage from a single system, but also improves the accuracy of speed detection results through continuous data comparison and verification.

[0157] According to an embodiment of this disclosure, the second detection module 120 includes a lidar unit and an echo detection unit; the lidar signal is used to excite a laser signal towards the detection target. The echo detection unit is used to collect the echo signal and obtain a second detection signal based on the optical frequency of the echo signal and the optical frequency of the laser signal, wherein the echo signal is formed by the laser signal reflected by the detection target.

[0158] The target of the inspection is not limited and can include the wheel flange, axle, or brake disc of a train.

[0159] A lidar unit can be implemented using a laser transmitter, which can use a semiconductor laser as the core device and work with a driving circuit to generate a laser signal with a specific wavelength and power.

[0160] The echo detection unit includes a photodetector, signal processing circuit, and data calculation submodule. When a laser signal illuminates the surface of the target and is reflected to form an echo signal, the photodetector receives the echo signal and converts it into a corresponding electrical signal. After processing by a preamplifier circuit and a filter circuit, noise interference is removed to extract the effective signal components.

[0161] The signal processing circuit accurately measures the optical frequency of the echo signal and simultaneously acquires the optical frequency of the laser signal emitted by the laser transmitter, transmitting both to the data calculation module. The data calculation module calculates the difference between the echo signal frequency and the laser signal frequency, and, combined with physical parameters such as the speed of light, calculates the target's speed relative to the lidar. This speed information is then converted into an electrical signal conforming to the circuit's transmission standards, serving as the second detection signal output.

[0162] According to embodiments of this disclosure, the lidar emits a collimated laser signal towards the target through a transmitter. After the echo detection unit captures the reflected echo signal, it calculates a second detection signal based on the optical frequency difference between the reflected signal and the emitted laser signal. Thus, relying on the high directionality and frequency characteristics of laser light, it can stably measure speed in complex environments where satellite positioning signals are blocked. It also reduces the impact of slippage and wheel spin on traditional wheel speed detection, achieving complementarity with the first detection module 110 and improving the overall environmental adaptability and detection accuracy of the speed measurement system.

[0163] According to embodiments of this disclosure, when the signal of the first detection module 110 is weak or fails, the second detection module 120 is responsible for calculating the train speed through laser reflection ranging. Through the coordinated action of the main and auxiliary detection modules, the overall environmental adaptability of the system can be improved, thereby providing accurate speed information even when satellite signals are blocked.

[0164] According to embodiments of this disclosure, the rail train speed detection circuit achieves accurate train speed detection in complex environments through multi-module collaboration, thereby improving train operation safety. The first detection module 110 detects the train speed via satellite navigation positioning, receives satellite signals in real time, outputs train speed data, and simultaneously provides signal strength information through its own signal quality indicator or Received Signal Strength Indicator (RSSI) interface. The output of the first detection module 110 can be electrically connected to the strength detection module 150 and the processing module 140. The strength detection module 150 converts the received satellite signal strength into a voltage signal through buffer amplification and digital-to-analog conversion, or by using a dedicated radio frequency signal strength detection chip, and transmits it to the first comparator 131 for judgment.

[0165] The first comparator 131 compares the voltage signal of the intensity detection module 150, i.e., the first detection signal, with a preset threshold, i.e., the first preset level signal, to determine the strength of the first detection signal. When the signal strength of the first detection module 110 is strong, the first comparator 131 outputs a low-level or low-potential first comparison signal, indicating that the first detection module 110 is working normally. When the signal strength drops below the threshold, the first preset level signal outputs a high-level or high-potential first comparison signal, meaning that the signal of the first detection module 110 is weak and backup detection needs to be activated. In extreme cases, if both the first detection module 110 and the second detection module 120 fail, the failure detection unit continuously monitors the signal strength and the current of the second detection module 120, and uses the second comparator and the current sampling unit in conjunction with the third comparator to determine the working status of the two modules. When the detection status of both modules is abnormal, the AND gate unit outputs a signal at a high potential, controlling the analog switch to disconnect the output of the comparator module, causing it to enter a high-impedance state, thereby further triggering the third detection module 310 to work.

[0166] The second detection module 120 is activated primarily when the signal quality of the first detection module 110 is poor or malfunctions. This module calculates the train speed by measuring the laser reflection distance, and its output is electrically connected to the processing module 140. The power supply path of the second detection module 120 is controlled by the switching unit 132, and is the opposite phase to the power supply path of the first detection module 110. The switching unit 132 contains two sets of switches, which achieve rapid switching between the first detection module 110 and the second detection module 120 through inverted switching signals, resulting in a short response time that meets the requirements for high-speed train detection.

[0167] The third detection module 310 is the third detection method of the circuit, mainly used in extreme environments where both the first and second detection modules 120 fail.

[0168] The processing module 140, based on a powerful microcontroller, integrates a multi-interface system to receive speed data from the main detection module, the lidar auxiliary detection module, and the visual detection module. Through a fusion algorithm, it calculates a precise and stable train speed based on the reliability and signal quality of the module outputs. Simultaneously, the integrated processing module 140 continuously monitors whether the speed exceeds a set threshold. When an abnormal speed is detected, it activates the alarm module to issue an audible and visual alarm, alerting the operator.

[0169] The overall power supply is provided by a modular battery pack, ensuring stable power supply to the system. The switching module is rationally designed, controlling the power paths of the first and second detection modules 120 using the first switch 1321 and the second switch 1322 respectively. This allows the circuit to automatically switch sensors under different environments, improving the environmental adaptability and accuracy of the detection. The failure detection module 320 monitors signal strength and power supply status to ensure timely switching or activation of the third detection module 310 when a sensor malfunctions, better guaranteeing the continuity and reliability of speed data.

[0170] In summary, the disclosed rail train speed detection circuit, through a combination of satellite navigation positioning detection, laser reflection ranging detection, and visual detection methods, along with signal strength monitoring, comparison and judgment, and hardware switch control, achieves rapid switching between train speed detection modules, ensuring continuous and accurate detection of train speed under various complex environmental conditions. The electrical connections between modules are orderly, and a rationally distributed comparison circuit, buffer, and amplification circuit ensure stable signal transmission. Furthermore, the well-designed power supply control switch and failure detection mechanism give the system high reliability and anti-interference capabilities, guaranteeing the safety and monitoring accuracy of high-speed train operation from a hardware perspective.

[0171] Figure 6 A schematic diagram illustrating the switching logic between multiple detection modules according to this disclosure is shown.

[0172] like Figure 6As shown, during the operation of the rail train, it is possible to detect in real time whether the first detection signal is less than the first preset level signal. If it is determined that the first detection signal is greater than or equal to the first preset level signal, the first detection module performs train speed detection.

[0173] And if the first detection signal is less than the first preset level signal, determine whether it is due to complex weather, such as rainy or foggy weather.

[0174] If the weather is confirmed to be rainy or foggy, the third detection module will perform the train speed detection. If the weather is not rainy or foggy, the second detection module will perform the train speed detection.

[0175] It also monitors in real time whether the train has arrived at the station. If the train has arrived, the speed detection process ends. If the train has not arrived, it continues to monitor whether the first detection signal is less than the first preset level signal and then performs subsequent operations.

[0176] Another aspect of this disclosure provides a rail train including the rail train speed detection circuit described above.

[0177] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present disclosure can be combined and / or combined in various ways, even if such combinations are not explicitly described in the present disclosure. In particular, the features described in the various embodiments of this disclosure can be combined and / or combined in various ways without departing from the spirit and teachings of this disclosure. All such combinations and / or combinations fall within the scope of this disclosure.

[0178] The embodiments of this disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of this disclosure. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of this disclosure, and all such substitutions and modifications should fall within the scope of this disclosure.

Claims

1. A rail train speed detection circuit, characterized in that, include: The first detection module is used to detect the speed of the train through satellite navigation positioning in order to obtain the first detection signal; The second detection module is used to detect the speed of the train by laser reflection ranging in order to obtain a second detection signal; The gating module is used to select either the first detection signal or the second detection signal to the processing module based on the signal strength of the first detection signal; as well as The processing module is used to obtain the train's speed based on the first detection signal or the second detection signal.

2. The rail train speed detection circuit according to claim 1, characterized in that, The gating module includes: A first comparator, wherein the inverting input of the first comparator is electrically connected to the first detection module, and the non-inverting input of the first comparator is used to receive a first preset level signal; the first comparator is used to compare the first detection signal with the first preset level signal to obtain a first comparison signal; and A switching unit is electrically connected to the output terminal of the first comparator. The switching unit is used to control the first detection module or the second detection module to be turned on under the control of the first comparison signal, so as to select the first detection signal or the second detection signal to the processing module.

3. The rail train speed detection circuit according to claim 2, characterized in that, The first comparator is configured to output a first comparison signal at a low potential when the first detection signal is greater than or equal to the first preset level signal, and to output a first comparison signal at a high potential when the first detection signal is less than the first preset level signal. The switching unit is used to control the first detection module to turn on under the control of the first comparison signal at a low potential, and to control the second detection module to turn on under the control of the first comparison signal at a high potential.

4. The rail train speed detection circuit according to claim 3, characterized in that, The switching unit includes a first switch and a second switch; Wherein, the control terminal of the first switch is electrically connected to the output terminal of the first comparator, the first terminal of the first switch is electrically connected to the power supply, the second terminal of the first switch is electrically connected to the first detection module, and the power supply is used to supply power to the first detection module and the second detection module respectively. The control terminal of the second switch is electrically connected to the output terminal of the first comparator, the first terminal of the second switch is electrically connected to the second detection module, and the second terminal of the second switch is electrically connected to the processing module. The first switch is configured to be turned on under the control of the first comparison signal at a low potential, to connect the power supply path to the first detection module, thereby turning on the first detection module; and to be turned off under the control of the first comparison signal at a high potential, thereby turning off the first detection module; and The second switch is configured to be turned on under the control of the first comparison signal at a high potential to connect the second detection module and the processing module, so as to provide the second detection signal generated by the second detection module to the processing module, and to be turned off under the control of the first comparison signal at a low potential to disconnect the second detection module.

5. The rail train speed detection circuit according to claim 2, characterized in that, Also includes: The failure detection module is electrically connected to both the first detection module and the second detection module. The third switch has its control terminal electrically connected to the failure detection module, its first terminal electrically connected to the output terminal of the first comparator, and its second terminal electrically connected to the switch unit. as well as The third detection module is electrically connected to the output of the first comparator and the processing module, respectively.

6. The rail train speed detection circuit according to claim 5, characterized in that, The failure detection module is used to provide a failure signal to the third switch when it is determined that both the first detection module and the second detection module are malfunctioning. The third switch is used to disconnect the electrical connection between the first comparator and the switching unit under the control of the failure signal, so that the first comparator outputs a high-impedance signal. The third detection module is used to visually detect the speed of the train to obtain a third detection signal, and provides the third detection signal to the processing module under the control of the high impedance signal. The processing module is also used to obtain the train's speed based on the third detection signal.

7. The rail train speed detection circuit according to claim 5, characterized in that, The failure detection module includes a second comparator, a third comparator, and an AND gate unit; Wherein, the inverting input terminal of the second comparator is electrically connected to the first detection module, the non-inverting input terminal of the second comparator is used to receive a second preset level signal, and the output terminal of the second comparator is electrically connected to the first input terminal of the AND gate unit; The inverting input of the third comparator is electrically connected to the second detection module, the non-inverting input of the third comparator is used to receive a third preset level signal, and the output of the third comparator is electrically connected to the second input of the AND gate unit; and The output terminal of the AND gate unit is electrically connected to the control terminal of the third switch.

8. The rail train speed detection circuit according to claim 7, characterized in that, The second comparator is used to output a second comparison signal at a high potential when the first detection signal is less than the second preset level signal; The third comparator is used to output a third comparison signal at a high potential when the second detection signal is less than the third preset level signal; The AND gate unit is used to output the failure signal based on the second comparison signal that is at a high potential and the third comparison signal that is at a high potential.

9. The rail train speed detection circuit according to claim 5, characterized in that, The third detection module includes: An imaging unit is used to acquire images of the train's wheel rotation and convert the wheel rotation images into initial detection signals; An edge detection unit is used to convert the initial detection signal into a square wave pulse; A pulse conversion unit is configured to output the third detection signal based on the square wave pulse; and The tri-state gate unit has its enable terminal electrically connected to the output terminal of the first comparator. The tri-state gate unit is used to provide the third detection signal to the processing module under the control of the high-impedance state signal.

10. The rail train speed detection circuit according to claim 1, characterized in that, The first detection module includes a satellite positioning unit, which is used to collect satellite positioning signals and obtain the first detection signal based on the continuously collected multiple satellite positioning signals; The second detection module includes a lidar unit and an echo detection unit; the lidar signal is used to generate a laser signal towards the detection target; The echo detection unit is used to acquire echo signals and obtain the second detection signal based on the optical frequency of the echo signal and the optical frequency of the laser signal, wherein the echo signal is formed by the laser signal reflected by the detection target.

11. A rail train, characterized in that, Includes a rail train speed detection circuit as described in any one of claims 1 to 10.

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