A train dispatching main and standby station platform antenna automatic switching device and implementation method

Abstract

This invention relates to an automatic antenna switching device and method for main and backup station platforms in train dispatching. The device includes a radio frequency (RF) interface, an RF switch, a directional coupler, a detector, a microcontroller, and LED indicators. RF interface I is connected to the antenna, and RF interfaces II and III are connected to the main and backup stations, respectively. The RF switch, under the control of the microcontroller, enables automatic switching between the antenna and the main and backup stations. The directional coupler and detector are used to collect the forward and reverse power of the transmitted signal. The microcontroller calculates the standing wave ratio (VSWR) based on the detected voltage and performs threshold judgment. The method flow is as follows: after power-on, the antenna is connected to the main station by default. When the detected signal from the backup station meets the threshold, it automatically switches to the backup station. If the backup station signal is insufficient, the main station remains operational, and LEDs provide indication and alarms. This device achieves rapid automatic switching between main and backup stations, reduces communication interruption time, and effectively improves the reliability and automation level of the communication system.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and in particular to an automatic switching device and method for switching between main and backup station antennas. Background Technology

[0002] Currently, railway wireless train dispatching communication systems play a crucial role in train operation scheduling. To ensure the continuity and reliability of communication, stations are typically equipped with two sets of train dispatching base station systems, one primary and one backup, sharing a single antenna system. Existing primary and backup train dispatching stations usually rely on manual antenna switching: when the primary station equipment malfunctions or is shut down for maintenance, maintenance personnel must manually unplug and plug the RF cable to switch the antenna interface from the primary station to the backup station interface.

[0003] However, this manual switching method has significant limitations. For example, manually completing an antenna switch typically takes 3 to 5 minutes, and its response time is affected by personnel availability and operational procedures, which is detrimental to improving train dispatch communication efficiency. This method relies on maintenance personnel for on-site operation, requiring the allocation of personnel to perform the corresponding switching tasks; at the same time, the frequent plugging and unplugging of RF connectors during the switching process causes repeated friction on the mechanical contact parts of the connectors, easily leading to wear and deterioration of contact performance, thereby shortening the lifespan of the interface and placing significant pressure on the system in terms of labor input and operating costs.

[0004] Currently, some solutions attempt to use external relay switching to achieve shared use of primary and backup station antennas. However, such solutions generally suffer from large size, slow switching speed, and low isolation. Furthermore, they lack real-time detection capabilities for radio frequency signal status, making it impossible to determine the station's transmission status and antenna standing wave condition. This makes it difficult to meet the high reliability and low latency requirements of railway train dispatching systems.

[0005] Therefore, there is an urgent need for an automatic antenna switching device and method that can achieve automatic detection, rapid response, and seamless switching without changing the existing main and backup telemetry system architecture, so as to improve the reliability and intelligence level of the communication system. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the present invention provides an automatic switching device and method for antennas between primary and backup train dispatching stations. Without changing the existing structure of the train dispatching stations, the device automatically detects the transmission signals of the primary and backup stations to achieve automatic switching of antennas between the primary and backup stations, thereby improving efficiency, reducing operation and maintenance costs, shortening switching response time, reducing communication interruptions, and reducing the risk of interface damage.

[0007] To achieve the above objective, the technical solution of the present invention is: an automatic switching device for main and backup station antennas, comprising: RF interface I, RF interface II, RF interface III, RF switch, directional coupler I, directional coupler II, detector I, detector II, detector III, detector IV, LED I, LED II, and a microcontroller; RF interface I is used to connect to the antenna and is bidirectionally connected to pin C of the RF switch; pin A of the RF switch is bidirectionally connected to pin 2 of directional coupler I, pin B is bidirectionally connected to pin 2 of directional coupler II, and pin S is unidirectionally connected to GPIO I of the microcontroller; pin 1 of directional coupler I is bidirectionally connected to RF interface II, pin 3 is unidirectionally connected to the positive terminal of detector II, and pin 4 is connected to the detector… The positive terminal of detector I is unidirectionally connected, and the negative terminals of detector I and detector II are unidirectionally connected to the microcontroller's ADC I and ADC II, respectively. Pin 1 of directional coupler II is bidirectionally connected to RF interface III, pin 3 is unidirectionally connected to the positive terminal of detector IV, and pin 4 is unidirectionally connected to the positive terminal of detector III. The negative terminals of detector III and detector IV are unidirectionally connected to the microcontroller's ADC III and ADC IV, respectively. The microcontroller's GPIO II is unidirectionally connected to the positive terminal of LED I, and GPIO III is unidirectionally connected to the positive terminal of LED II. The negative terminals of both LED I and LED II are grounded. The microcontroller controls the RF switch, detection signal, and LED indication to achieve automatic detection and automatic switching of the main and backup station platform antennas of the train dispatching system.

[0008] The implementation method of the automatic switching device for main and backup station antennas of the present invention includes the following steps:

[0009] A. System initialization phase: After the automatic switching device for the main and backup station antennas of the train dispatching system is powered on, the microcontroller initializes and configures the GPIO port and ADC module. GPIO I outputs a high level, which controls the RF switch to connect to RF interface II by default through RF interface I and directional coupler I, so that the antenna is connected to the main station of the train dispatching system. At the same time, GPIO II outputs a high level to light up LED I, and GPIO III outputs a low level to turn off LED II, indicating that the antenna is connected to the main station by default.

[0010] B. Detecting the transmission signal of the backup station: The microcontroller acquires the positive power detection voltage VFⅡ of the backup station through ADCⅢ and compares it with the threshold voltage. When VFⅡ is greater than the threshold, it controls GPIOⅠ to output a low level, so that the RF switch connects RF interfaceⅠ and directional couplerⅡ, realizing the connection between the antenna and the RF interfaceⅢ of the backup station. Otherwise, it executes step D.

[0011] C. Standby Station VSWR Detection and Indication: After the antenna is connected to the standby station, the microcontroller collects the forward power detection voltage VFⅡ and the reverse power detection voltage VRⅡ of the standby station through ADCⅢ and ADCⅣ respectively, and calculates the voltage standing wave ratio VSWRⅡ. When VSWRⅡ exceeds the set threshold, GPIOⅢ outputs a square wave with a period of 500ms to drive LEDⅡ to flash to issue a standby station transmission VSWR over-limit alarm; when VSWRⅡ is less than or equal to the VSWR threshold, GPIOⅢ outputs a high level to light up LEDⅡ, indicating that the standby station transmission is normal; then it returns and continues to execute step B.

[0012] D. Detecting the main station's transmitted signal: When VFⅡ is less than the threshold in step B, the microcontroller collects the positive power detection voltage VFⅠ of the main station through ADCⅠ and determines whether it exceeds the threshold. When VFⅠ is greater than the threshold, it controls GPIOⅠ to output a high level, so that the RF switch switches back to the main station channel.

[0013] E. Main Station Standing Wave Detection and Indication: When the antenna is connected to the main station, the microcontroller collects the forward power detection voltage VFⅠ and the reverse power detection voltage VRⅠ of the main station through ADCⅠ and ADCⅡ respectively, and calculates the voltage standing wave ratio VSWRⅠ. When VSWRⅠ exceeds the standing wave threshold, GPIOⅡ outputs a square wave with a period of 500ms to drive LEDⅠ to flash, indicating that the main station is transmitting abnormally; when VSWRⅠ does not exceed the standing wave threshold, GPIOⅡ outputs a high level to light up LEDⅠ, indicating that the main station is transmitting normally; then it returns and continues to execute step B;

[0014] F. Cyclic Detection and Dynamic Switching: The microcontroller continuously executes steps B to E above in a cyclic manner, alternately detecting the transmission status and standing wave condition of the main and backup stations. When the main station signal is detected to have returned to normal, the system automatically switches back to the main station channel, realizing automatic switching control with the main station taking priority and the backup station providing backup.

[0015] The beneficial effects of this invention are as follows: First, without changing the existing train shunting stations, this invention achieves automatic switching between the antenna and the main / backup stations by automatically detecting the transmission signals of the main and backup stations, which greatly reduces the switching response time: from 3-5 minutes for manual switching to less than 100ms, effectively reducing the duration of communication interruption and basically achieving seamless switching.

[0016] Secondly, this invention utilizes automatic detection and control, avoiding reliance on manual operation for antenna switching, significantly improving operation and maintenance efficiency, thereby reducing manpower input and operation and maintenance costs.

[0017] Furthermore, this invention avoids the risk of mechanical damage that may be caused by repeated manual plugging and unplugging of the RF interface through an automated RF switch switching method, significantly improving the durability of the interface and the reliability of the overall system.

[0018] Finally, this invention has good scalability and applicability. It can be applied not only to railway train dispatching communication systems, but also to scenarios that require primary and backup redundancy switching, such as power dispatching, airport communication and emergency communication. It has broad application prospects and significant practical value. Attached Figure Description

[0019] Figure 1 This is a circuit block diagram of the automatic switching device for main and backup station antennas of the present invention.

[0020] Figure 2 This is a schematic diagram showing the connection between the device of the present invention and the main and backup stations and antennas;

[0021] Figure 3 This is a flowchart of the automatic switching method for main and backup station antennas in this invention. Detailed Implementation

[0022] The technical solution of the present invention will be further described below with reference to the embodiments and accompanying drawings:

[0023] like Figure 1 As shown, an automatic switching device for main and backup station antennas for train dispatching includes: radio frequency interface I, radio frequency interface II, radio frequency interface III, radio frequency switch, directional coupler I, directional coupler II, detector I, detector II, detector III, detector IV, microcontroller, and LED I and LED II.

[0024] Among them, RF interface I is used to connect to the antenna and is bidirectionally connected to pin C of the RF switch; pin A of the RF switch is bidirectionally connected to pin 2 of directional coupler I, and pin B of the RF switch is bidirectionally connected to pin 2 of directional coupler II; pin S of the RF switch is unidirectionally connected to GPIO I of the microcontroller to realize the switching control of the RF channel.

[0025] Pin 1 of directional coupler I is bidirectionally connected to RF interface II for coupling detection of RF signals from the main station platform; pin 3 is unidirectionally connected to the positive terminal of detector II to obtain a reverse power signal, and pin 4 is unidirectionally connected to the positive terminal of detector I to obtain a forward power signal. The negative terminal of detector I is unidirectionally connected to the microcontroller's ADC I to transmit the forward power detection voltage; the negative terminal of detector II is unidirectionally connected to the microcontroller's ADC II to transmit the reverse power detection voltage.

[0026] The microcontroller's GPIO II is unidirectionally connected to the positive terminal of LED I, and the negative terminal of LED I is grounded, used to indicate the working status of the main station platform; the microcontroller's GPIO III is unidirectionally connected to the positive terminal of LED II, and the negative terminal of LED II is grounded, used to indicate the status of the standby station platform.

[0027] Pin 1 of directional coupler II is bidirectionally connected to RF interface III for coupling detection of RF signals from the standby station. Pin 3 is unidirectionally connected to the positive terminal of detector IV to obtain the reverse power signal, and pin 4 is unidirectionally connected to the positive terminal of detector III to obtain the forward power signal. The negative terminal of detector III is unidirectionally connected to the microcontroller's ADCⅢ for transmitting the forward power detection voltage of the standby station; the negative terminal of detector IV is unidirectionally connected to the microcontroller's ADCⅣ for transmitting the reverse power detection voltage of the standby station.

[0028] Through the above connection, the system can collect the forward and reflected power signals of the main and backup stations in real time. After being converted into voltage by the detector, the signals are input to the microcontroller. The microcontroller calculates the voltage standing wave ratio (VSWR) and judges the status of the radio frequency link accordingly. At the same time, it combines radio frequency switch control to realize automatic switching between the main and backup stations and uses LED I and LED II to indicate the status.

[0029] In this embodiment, RF interfaces I, II, and III all use NK-type RF sockets to ensure low insertion loss and high mechanical reliability. Directional couplers I and II are implemented using PCB microstrip lines, featuring small size, high coupling accuracy, and ease of mass production. The RF switch uses a PIN diode MA4P1250-1072T, which offers advantages such as fast switching speed, low insertion loss, and high isolation, making it suitable for use in railway train dispatching communication systems. Detectors I to IV all use BAT6302VH6327 Schottky detector diodes, enabling fast response and low power loss at high frequencies. The microcontroller is an STM32F405RGT6, equipped with abundant GPIO and high-precision ADC interfaces to meet the requirements for real-time acquisition and logic control of RF power signals. LEDs I and II are high-brightness red LEDs (model LDDH5-1φ6-3) used to display the connection status between the main and backup station platforms and the antenna, as well as alarm status.

[0030] like Figure 2 As shown, the RF interface I of the automatic switching device for main and backup station antennas is bidirectionally connected to an external antenna for input and output of antenna signals. RF interface II is bidirectionally connected to the main station antenna interface of the main station for transmitting and receiving main station signals; RF interface III is bidirectionally connected to the backup station antenna interface of the backup station for transmitting and receiving backup station signals. Through these connections, rapid switching and stable communication between the antenna and the main and backup stations can be achieved.

[0031] like Figure 3 As shown, the implementation method of the automatic switching device for main and backup station antennas of the present invention is as follows:

[0032] A. System initialization phase:

[0033] After the automatic switching device for the main and backup station antennas of the train dispatching system is powered on, the microcontroller first initializes and configures the GPIO ports and the ADC module. At this time, GPIO I outputs a high level, controlling the RF switch to connect RF interface II by default through RF interface I and directional coupler I, so that the antenna is connected to the main station of the train dispatching system. GPIO II outputs a high level to light up LED I, and GPIO III outputs a low level to turn off LED II, indicating that the antenna is connected to the main station by default.

[0034] B. Detect the signal transmitted by the backup station:

[0035] The microcontroller acquires the forward power detection voltage VFⅡ of the standby station via ADCⅢ and compares it with a threshold voltage. If VFⅡ is greater than the threshold, it indicates that the standby station is in transmit mode. The system immediately controls GPIOⅠ to output a low level, controlling the RF switch to connect RF interface Ⅰ and directional coupler Ⅱ, thus connecting the antenna to the standby station. Otherwise, step D is executed.

[0036] C. Standby station standing wave detection and indication:

[0037] After the antenna is connected to the backup station, the system uses ADCⅢ and ADCⅣ to collect the forward power detection voltage VFII and the reverse power voltage VRⅡ of the backup station, respectively. The voltage standing wave ratio (VSWR) is calculated using the formula VSWRII = (VFII + VRⅡ) / (VFII - VRⅡ). The system then checks if VSWRII exceeds the VSWR threshold. If VSWRII exceeds the set threshold, GPIOⅢ outputs a 500ms period square wave to drive LEDⅡ to flash, indicating an abnormal VSWR exceeding the limit at the backup station. If VSWRII does not exceed the threshold, GPIOⅢ outputs a high level, and LEDⅡ remains lit, indicating normal transmission from the backup station. The system then returns to and continues with step B.

[0038] D. Detect the signal transmitted by the main station:

[0039] If VFⅠ is less than the threshold in step B, the microcontroller will acquire the forward power detection voltage VFⅠ of the main station through ADCⅠ and determine whether it exceeds the threshold. If VFⅠ is greater than the threshold, it indicates that the main station is in the transmit state. At this time, the system controls GPIOⅠ to output a high level and controls the RF switch to switch back to the main station.

[0040] E. Main station standing wave detection and indication:

[0041] When the antenna is connected to the main station, the microcontroller acquires the forward power detection voltage VFⅠ and the reverse power voltage VRⅠ of the main station through ADCⅠ and ADCⅡ respectively, and calculates the voltage standing wave ratio VSWR of the main station using the formula VSWRI=(VFI+VRI) / (VFI-VRI). If VSWRⅠ exceeds the threshold, GPIOⅡ outputs a 500ms period square wave to drive LEDⅠ to flash, indicating that the main station is transmitting abnormally. If VSWRⅠ does not exceed the threshold, GPIOⅡ outputs a high level, and LEDⅠ remains lit, indicating that the main station is transmitting normally; then it returns and continues to execute step B.

[0042] F. Loop detection and dynamic switching:

[0043] The microcontroller continuously and alternately monitors the transmission status and standing wave ratio of the primary and backup stations, repeating steps B through E in a loop. When the primary station signal is detected to have returned to normal, the system automatically switches back to the primary station, thus ensuring primary station priority and backup station support.

[0044] In the above embodiment, the threshold voltage is 0.1V and the standing wave threshold is 2.5.

Claims

1. An automatic switching device for main and backup station antennas in train dispatching, characterized in that, include: The system includes an RF interface I, an RF interface II, an RF interface III, an RF switch, a directional coupler I, a directional coupler II, a detector I, a detector II, a detector III, a detector IV, an LED I, an LED II, and a microcontroller. The RF interface I is used to connect to the antenna and is bidirectionally connected to pin C of the RF switch. Pin A of the RF switch is bidirectionally connected to pin 2 of the directional coupler I, pin B of the RF switch is bidirectionally connected to pin 2 of the directional coupler II, and pin S of the RF switch is unidirectionally connected to GPIO I of the microcontroller. Pin 1 of the directional coupler I is bidirectionally connected to the RF interface II, pin 3 of the directional coupler I is unidirectionally connected to the positive terminal of the detector II, and pin 4 of the directional coupler I is unidirectionally connected to the positive terminal of the detector I. The negative terminals of detectors I and II are unidirectionally connected to the microcontroller's ADC I and ADC II, respectively; pin 1 of directional coupler II is bidirectionally connected to RF interface III, pin 3 of directional coupler II is unidirectionally connected to the positive terminal of detector IV, pin 4 of directional coupler II is unidirectionally connected to the positive terminal of detector III, and the negative terminals of detectors III and IV are unidirectionally connected to the microcontroller's ADC III and ADC IV, respectively; the microcontroller's GPIO II is unidirectionally connected to the positive terminal of LED I, and GPIO III is unidirectionally connected to the positive terminal of LED II; the negative terminals of both LED I and LED II are grounded; the microcontroller controls the RF switch, the detection signal, and the LED indication to realize the automatic detection and automatic switching function of the main and backup station platform antennas of the train dispatching system.

2. The automatic switching device for main and backup station platform antennas according to claim 1, characterized in that, The RF interfaces I, II, and III are all NK-type RF sockets, used to achieve low insertion loss and high mechanical reliability. The directional couplers I and II are implemented using a PCB microstrip line structure to reduce size and improve coupling accuracy. The RF switch uses a PIN diode MA4P1250-1072T to achieve high-speed switching, low insertion loss, and high isolation. Detectors I, II, III, and IV all use Schottky detector diodes BAT6302VH6327 to achieve fast response and low power loss under high-frequency conditions. The microcontroller uses an STM32F405RGT6 chip with multiple GPIOs and a high-precision ADC interface for RF power signal acquisition and logic control. LEDs I and II are high-brightness red light-emitting diodes, model LDDH5-1φ6-3, used to indicate the connectivity status of the main and backup stations and antennas, as well as the transmission alarm status.

3. The automatic switching device for main and backup station platform antennas according to claim 1, characterized in that, The radio frequency interface I is bidirectionally connected to an external antenna for input and output of antenna signals. The radio frequency interface II is bidirectionally connected to the main station antenna interface of the main station platform for transmitting and receiving radio frequency signals. The radio frequency interface III is bidirectionally connected to the backup station antenna interface of the backup station platform for transmitting and receiving radio frequency signals. Through the connection between the radio frequency interfaces I, II, and III, fast switching and stable communication between the antenna and the main and backup stations are achieved.

4. A method for implementing the automatic switching device for main and backup station antennas as described in any one of claims 1 to 3, characterized in that, Includes the following steps: A. System initialization phase: After the automatic switching device for the main and backup station antennas of the train dispatching system is powered on, the microcontroller initializes and configures the GPIO port and ADC module. GPIO I outputs a high level, which controls the RF switch to connect to RF interface II by default through RF interface I and directional coupler I, so that the antenna is connected to the main station of the train dispatching system. At the same time, GPIO II outputs a high level to light up LED I, and GPIO III outputs a low level to turn off LED II, indicating that the antenna is connected to the main station by default. B. Detecting the transmission signal of the backup station: The microcontroller acquires the forward power detection voltage VFⅡ of the backup station through ADCⅢ and compares it with the threshold voltage. When VFⅡ is greater than the threshold, it controls GPIOⅠ to output a low level, so that the RF switch connects RF interfaceⅠ and directional couplerⅡ, realizing the connection between the antenna and the RF interfaceⅢ of the backup station; otherwise, it executes step D. C. Standby Station VSWR Detection and Indication: After the antenna is connected to the standby station, the microcontroller collects the forward power detection voltage VFⅡ and the reverse power detection voltage VRⅡ of the standby station through ADCⅢ and ADCⅣ respectively, and calculates the voltage standing wave ratio VSWRⅡ. When VSWRⅡ exceeds the set threshold, GPIOⅢ outputs a square wave with a period of 500ms to drive LEDⅡ to flash to issue a standby station transmission VSWR over-limit alarm; when VSWRⅡ is less than or equal to the VSWR threshold, GPIOⅢ outputs a high level to light up LEDⅡ, indicating that the standby station transmission is normal; then it returns and continues to execute step B. D. Detecting the main station's transmitted signal: When VFⅡ is less than the threshold in step B, the microcontroller collects the positive power detection voltage VFⅠ of the main station through ADCⅠ and determines whether it exceeds the threshold. When VFⅠ is greater than the threshold, it controls GPIOⅠ to output a high level, so that the RF switch switches back to the main station channel. E. Main station standing wave detection and indication: When the antenna is connected to the main station, the microcontroller collects the forward power detection voltage VFⅠ and the reverse power detection voltage VRⅠ of the main station through ADCⅠ and ADCⅡ respectively, and calculates the voltage standing wave ratio VSWRⅠ. When VSWRⅠ exceeds the standing wave threshold, GPIOⅡ outputs a square wave with a period of 500ms to drive LEDⅠ to flash to indicate the main station transmission abnormality. When VSWRⅠ does not exceed the standing wave threshold, GPIOⅡ outputs a high level to light up LEDⅠ, indicating that the main station is transmitting normally; then it returns and continues to execute step B; F. Cyclic Detection and Dynamic Switching: The microcontroller continuously executes steps B to E above in a cyclic manner, alternately detecting the transmission status and standing wave condition of the main and backup stations. When the main station signal is detected to have returned to normal, the system automatically switches back to the main station channel, realizing automatic switching control with the main station taking priority and the backup station providing backup.

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