GNSS antenna status monitoring and protection circuit

Abstract

This utility model provides a GNSS antenna status monitoring and protection circuit, including: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a user radio frequency interface, a switching unit, a first measurement port, a second measurement port, and a controller; wherein, the first end of the first resistor is coupled to a power supply, the second end of the first resistor is coupled to the first end of the second resistor, and the second end of the second resistor is grounded; the first end of the third resistor is coupled to the first end of the fourth resistor, the second end of the third resistor is coupled to the user radio frequency interface, and the second end of the fourth resistor is grounded; the first end of the fifth resistor is coupled to a power supply, and the second end of the fifth resistor is coupled to the switching unit; the first end of the switching unit is coupled to the second end of the fifth resistor, and the second end of the switching unit is coupled to the first port; the first measurement port is coupled to the second end of the first resistor; the second measurement port is coupled to the first end of the third resistor; and the controller is coupled to the switching unit.

Description

Technical Field

[0001] This utility model relates to the technical field of positioning device monitoring, and more specifically, to a GNSS antenna status monitoring and protection circuit. Background Technology

[0002] With the continuous and rapid development of the Global Navigation Satellite System (GNSS), a wide variety of GNSS receiving equipment is used in various industries, such as resource environment, disaster monitoring, surveying and mapping, power and telecommunications, urban management, engineering construction, autonomous driving, transportation, agriculture, forestry and animal husbandry, archaeology, daily life, the Internet of Things, and location services. GNSS receiving equipment generally requires a GNSS antenna. GNSS antennas are exposed to various harsh conditions such as sun and rain for extended periods, which can lead to open circuits, short circuits, and other abnormalities over time, causing significant economic losses to the equipment users.

[0003] Monitoring the status of GNSS antennas is crucial for minimizing or even avoiding economic losses. Currently, various solutions exist for monitoring the status of GNSS antennas. For example, some monitoring and protection circuits typically use current sensing IC chips to determine whether the antenna is functioning correctly by detecting changes in the antenna's current. However, this approach requires an additional power supply, and the high manufacturing cost of the current sensing IC chips contributes to the high cost of the entire monitoring and protection circuit, limiting its widespread adoption.

[0004] Therefore, the existing monitoring solutions for GNSS antenna condition monitoring suffer from high costs, which hinders their widespread application, especially in cost-sensitive scenarios such as large-scale IoT device deployments, small surveying equipment, and vehicle navigation system deployments. Thus, there is an urgent need for a lower-cost and more reliable GNSS antenna condition monitoring solution to meet market demands. Utility Model Content

[0005] This utility model provides a GNSS antenna status monitoring and protection circuit, which at least solves the problem of high cost of GNSS antenna status monitoring.

[0006] According to one embodiment of the present invention, a GNSS antenna status monitoring and protection circuit is provided, comprising: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a user radio frequency interface, a switching unit, a first measurement port, a second measurement port, and a controller; wherein, a first end of the first resistor is coupled to a power supply, a second end of the first resistor is coupled to a first end of the second resistor, and a second end of the second resistor is grounded; a first end of the third resistor is coupled to a first end of the fourth resistor, a second end of the third resistor is coupled to the user radio frequency interface, and a second end of the fourth resistor is grounded; a first end of the fifth resistor is coupled to the power supply, and a second end of the fifth resistor is coupled to the switching unit; the user radio frequency interface includes: a first port. The system comprises a first port, a second port, a third port, a fourth port, and a fifth port; wherein the first port is coupled to the second end of the third resistor, the second port and the fourth port are grounded, and the third port and the fifth port are coupled to a GNSS antenna; the first end of the switching unit is coupled to the second end of the fifth resistor, and the second end of the switching unit is coupled to the first port; the first measurement port is coupled to the second end of the first resistor and is used to acquire a first measurement voltage; the second measurement port is coupled to the first end of the third resistor and is used to acquire a second measurement voltage; the controller is coupled to the switching unit and is used to generate a control signal based on the difference between the first measurement voltage and the second measurement voltage and a preset threshold, so as to connect or disconnect the first port from the power supply based on the control signal.

[0007] Through the embodiments of this utility model, by adopting a scheme based on resistor voltage division and voltage difference detection, the use of high-cost current detection IC chips is avoided, the need for additional power supply is reduced, and intelligent monitoring is achieved through the efficient processing of the controller. These innovations significantly reduce the cost of the entire monitoring and protection circuit, thereby solving the problem of high monitoring costs in the prior art and achieving the effect of reducing the cost of GNSS antenna status monitoring. Attached Figure Description

[0008] The accompanying drawings, which are included to provide a further understanding of the present invention and constitute a part of this invention, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:

[0009] Figure 1 This is a circuit for GNSS antenna status monitoring and protection according to an embodiment of the present invention. Figure 1 ;

[0010] Figure 2 This is a circuit for GNSS antenna status monitoring and protection according to an embodiment of the present invention. Figure 2 . Detailed Implementation

[0011] The present invention will be described in detail below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0012] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. "Coupling" includes both direct electrical connections between multiple connected objects and indirect electrical connections between multiple connected objects.

[0013] This utility model embodiment provides a GNSS antenna status monitoring and protection circuit, which includes: a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a user radio frequency interface, a switching unit, a first measurement port, a second measurement port, and a controller; wherein,

[0014] The first end of the first resistor is coupled to a power supply, the second end of the first resistor is coupled to the first end of the second resistor, and the second end of the second resistor is grounded.

[0015] The first end of the third resistor is coupled to the first end of the fourth resistor, the second end of the third resistor is coupled to the user radio frequency interface, and the second end of the fourth resistor is grounded.

[0016] The first end of the fifth resistor is coupled to the power supply, and the second end of the fifth resistor is coupled to the switching unit;

[0017] The user radio frequency interface includes: a first port, a second port, a third port, a fourth port, and a fifth port; wherein, the first port is coupled to the second end of the third resistor, the second port and the fourth port are grounded, and the third port and the fifth port are coupled to a GNSS antenna;

[0018] The first end of the switching unit is coupled to the second end of the fifth resistor, and the second end of the switching unit is coupled to the first port;

[0019] The first measurement port is coupled to the second end of the first resistor and is used to acquire the first measurement voltage.

[0020] The second measurement port and the first end of the third resistor are used to acquire the second measurement voltage;

[0021] The controller is coupled to the switching unit and is used to generate a control signal based on the difference between the first measured voltage and the second measured voltage and a preset threshold, so as to connect or disconnect the first port from the power supply based on the control signal.

[0022] In one exemplary implementation, Figure 1 This is a circuit for GNSS antenna status monitoring and protection according to an embodiment of the present invention. Figure 1 ,like Figure 1 As shown, the power supply can be a +5.0V voltage source. When the controller detects a +5.0V power supply connected to the circuit, it controls the switching unit to close, thereby connecting the +5.0V power supply to the user RF interface J, and then connecting the +5.0V power supply to the GNSS antenna through the user RF interface J. The user RF interface J includes a first port 1, a second port 2, a third port 3, a fourth port 4, and a fifth port 5. Among them, the second port 2 and the fourth port 4 are grounded, and the third port 3 and the fifth port 5 are coupled to the GNSS antenna.

[0023] For example, in the fifth resistor The voltage on the left side is The voltage entering the user RF interface J is Based on the voltage divider principle, the first measurement voltage acquired by the first measurement port ADC_01 is: (Formula 1); The second measurement voltage acquired by the second measurement port ADC_02 is: (Formula 2). Then the first measurement voltage acquired by the first measurement port ADC_01... The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is: (Formula 3). The preset threshold can be set based on the actual situation, for example, it can be 0V or 30mV. In this embodiment of the present invention, 30mV is preferred. For example, the controller confirms... and If the difference between them is greater than 30mV, confirm that the GNSS antenna is in a normal coupling state. and If the difference between the two values ​​is less than 30mV, it is confirmed that the GNSS antenna is in an open-circuit state.

[0024] The following explanation uses examples, such as the fifth resistor. The resistance value is: The operating current of the GNSS antenna is: First resistor The resistance value is: Second resistor The resistance value is: Third resistor The resistance value is: Fourth resistor The resistance value is: .

[0025] Then the fifth resistor The voltage difference between the two ends is: .

[0026] The first measurement voltage acquired by the first measurement port ADC_01 The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is: .

[0027] It should be noted that the first measurement voltage acquired by the first measurement port ADC_01 mentioned above... The second measurement voltage acquired by the second measurement port ADC_02 The difference between The calculation process can be performed in the voltage comparison unit, which can be coupled to the controller or integrated within the controller. In summary, the controller can determine the first measurement voltage acquired by the first measurement port ADC_01 when the GNSS antenna is properly coupled and operating normally. The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is 0.2V.

[0028] By adopting the above technical solution, which uses a resistor-based voltage divider and voltage difference detection approach, the use of high-cost current detection IC chips is avoided, reducing the need for additional power supplies. Furthermore, intelligent monitoring is achieved through the efficient processing of the controller. These innovations significantly reduce the cost of the entire monitoring and protection circuit, thereby solving the problem of high monitoring costs in the background technology and effectively reducing the cost of GNSS antenna status monitoring.

[0029] In one embodiment, the switching unit includes: a first switch and a second switch; wherein, a first terminal of the first switch is coupled to the controller for acquiring the control signal; a second terminal of the first switch is grounded; a third terminal of the first switch is coupled to the first terminal of the second switch; a second terminal of the second switch is coupled to the second terminal of the fifth resistor; and a third terminal of the second switch is coupled to the first port.

[0030] In one exemplary implementation, Figure 2 This is a circuit for GNSS antenna status monitoring and protection according to an embodiment of the present invention. Figure 2,like Figure 2 As shown, the first switch Upon receiving the control signal from the controller, the first switch is triggered. Work. First switch. Work triggers the second switch On. Second switch. When the circuit is turned on, the +5.0V power supply will be connected to the user's RF interface J.

[0031] In one embodiment, the first switch is an N-MOSFET; wherein the gate of the first switch is coupled to the controller, the source of the first switch is grounded, and the drain of the first switch is coupled to the second switch.

[0032] The second switch is a P-MOSFET; wherein the gate of the second switch is coupled to the drain of the first switch, the source of the second switch is coupled to the second terminal of the fifth resistor, and the drain of the second switch is coupled to the first port.

[0033] In one exemplary implementation, such as Figure 2 As shown, the controller confirms the first measurement voltage acquired by the first measurement port ADC_01. The second measurement voltage acquired by the second measurement port ADC_02 When the voltage difference is 0.2V, a control signal is output. This control signal can be high. First switch. When the gate G receives this high level, it triggers the first switch. The source (S) and drain (D) are turned on to enable the first switch. The drain D is the second switch. Send control level.

[0034] First switch The drain D is the second switch. The control level can be low. Second switch. When the gate G receives this low level, it triggers the second switch. The source (S) and drain (D) are turned on to enable the second switch. This conducts the +5.0V power supply to the user's RF interface J.

[0035] In one embodiment, the switching unit further includes a sixth resistor; wherein a first end of the sixth resistor is coupled to the drain of the first switch, and a second end of the sixth resistor is coupled to the gate of the second switch.

[0036] In one exemplary implementation, such as Figure 2 As shown, based on the sixth resistor The voltage divider principle further enables the first switch The drain D is the second switch. The control level sent is pulled low, thus activating the second switch. The gate G sends a low-level control level.

[0037] In one embodiment, the circuit further includes an inductor; wherein a first end of the inductor is coupled to the drain of the second switch, and a second end of the inductor is coupled to the first port.

[0038] In one exemplary implementation, such as Figure 2 As shown, the inductor L can act as an isolation element to block the alternating current flowing through the user's RF interface J and the GNSS antenna from entering the second switch. Middle or third resistor In the circuit, this achieves the function of protecting the front-end circuit of inductor L.

[0039] In one embodiment, the circuit further includes a bidirectional transient voltage suppressor; wherein a first terminal of the bidirectional transient voltage suppressor is coupled to the first port, and a second terminal of the bidirectional transient voltage suppressor is grounded.

[0040] In one exemplary implementation, such as Figure 2 As shown, one end of the bidirectional transient voltage suppressor (TVS) is coupled to the first port 1 and the inductor L, while the other end is grounded. The TVS is then connected in parallel with the user's RF interface J. When the front-end circuit of inductor L is functioning normally, the TVS is in the off state, consuming only a certain amount of leakage current. The current flowing from inductor L mainly flows into the first port 1 of the user's RF interface J. When the front-end circuit of inductor L is abnormal, such as when an overvoltage occurs and reaches the breakdown voltage of the TVS (avalanche), the TVS rapidly changes from a high-resistance state to a low-resistance state to discharge the transient overcurrent caused by the abnormal overvoltage to ground and clamp the overvoltage to a lower level, thus protecting the user's RF interface J.

[0041] In one embodiment, the circuit further includes a diode; wherein the anode of the diode is coupled to the power supply, and the cathode of the diode is coupled to a first terminal of the fifth resistor.

[0042] In one exemplary implementation, such as Figure 2 As shown, the diode D is positioned to prevent reverse connection of the +5.0V power supply, protecting subsequent circuitry from damage. For example, when the +5.0V power supply is reverse connected, diode D is cut off, preventing current from flowing through it into the circuit, thus protecting components in the circuit from reverse voltage.

[0043] In one embodiment, the circuit further includes at least one first capacitor; wherein the first terminals of the at least one first capacitor are all coupled to the drain of the second switch, and the second terminals of the at least one first capacitor are all grounded.

[0044] In one exemplary implementation, such as Figure 2 As shown, the first capacitor can be capacitors connected in parallel. capacitors capacitors Capacitor capacitors capacitors The first end is connected to the second switch The drain of the capacitor is coupled to the capacitor. capacitors capacitors The second terminal of each capacitor is grounded. In this circuit, coupling a single first capacitor, or multiple first capacitors connected in parallel, can provide greater charge storage capacity, helping to smooth voltage fluctuations on the power line and provide a more stable voltage output. Secondly, due to the increased total capacitance, the circuit can store more energy. Alternatively, when using multiple first capacitors connected in parallel, if one capacitor fails, the others can still provide partial capacitance, thus preventing a complete circuit failure. This improves the stability of the circuit.

[0045] In one embodiment, the switching unit further includes a seventh resistor; wherein a first end of the seventh resistor is coupled to the gate of the first switch, and a second end of the seventh resistor is coupled to the source of the first switch.

[0046] In one exemplary implementation, such as Figure 2 As shown, the seventh resistor Parallel connection to the first switch The seventh resistor is located between the gate G and the source S. The rate of change of the gate voltage is limited, thereby controlling the first switch. The switching speed. This helps prevent voltage spikes and noise caused by rapid changes in gate voltage. Seventh resistor Helps to suppress due to the first switch The oscillations caused by parasitic diodes, parasitic inductance, and parasitic capacitance are used to improve the first switching... Stability. Seventh resistor. Limiting the gate current reduces energy loss during gate capacitance charging and discharging. (Seventh resistor) It can protect the first switch The gate S is protected from electrostatic discharge (ESD) damage. Without a seventh resistor... In such cases, ESD may directly break down the gate S, causing the first switch to fail. Damaged. Seventh resistor. Helps to achieve the first switch Soft switching, which involves gradually changing the gate voltage during the switching process, reduces voltage and current spikes during switching, thereby lowering electromagnetic interference (EMI). When the first switch... When closed, the seventh resistor It provides a discharge path for the gate capacitor, which helps the first switch. Quick shut-off. Seventh resistor. It can prevent the first switch Misleading turn-on occurs when there is an unexpectedly low impedance path between the gate (G) and the source (S).

[0047] In one embodiment, the switching unit further includes: a second capacitor and an eighth resistor; wherein,

[0048] The first terminal of the second capacitor is coupled to the source of the second switch, and the second terminal of the second capacitor is coupled to the gate of the second switch.

[0049] The first end of the eighth resistor is coupled to the source of the second switch, and the second end of the eighth resistor is coupled to the gate of the second switch.

[0050] In one exemplary implementation, such as Figure 2 As shown, specifically, when the second switch When it needs to be turned off, the second capacitor It can provide a fast discharge path, allowing the gate voltage to drop rapidly to 0V or lower, thereby accelerating the second switching. The closing speed of the second capacitor. It can help filter out high-frequency noise on the gate and reduce electromagnetic interference (EMI) during switching. Second capacitor The second switch can be improved. Its dynamic response makes it perform better in fast switching operations. Second capacitor It can provide a certain degree of voltage stability, preventing fluctuations in gate voltage caused by rapid changes in current.

[0051] Secondly, the eighth resistor With the second capacitor Together they form an RC time constant, controlling the second capacitor. The rate of discharge. The larger eighth resistor. The value will slow down the discharge rate, helping to prevent a second switch. An overshoot occurs when the circuit is turned off. (Eighth resistor) It helps suppress oscillations caused by gate capacitance and inductance, improving circuit stability. Eighth resistor. It can limit the flow of the second capacitor during charging and discharging. Current, protect the second switch The gate is not damaged by excessive current. Eighth resistor. This can improve the circuit's immunity to external noise and reduce the possibility of false triggering.

[0052] In summary, the eighth resistor Second capacitor Together, they form a simple RC filter that can filter out high-frequency noise while controlling the charging and discharging speed, thereby improving the performance of the second switch. The switching performance and stability are improved. The eighth resistor is controlled by adjusting the rate of change of the gate voltage. Second capacitor Helps to realize the second switch The soft switching reduces voltage and current spikes during switching, thus lowering EMI.

[0053] The circuit principle of the GNSS antenna status monitoring and protection circuit of this utility model embodiment is as follows:

[0054] Scenario 1: The GNSS antenna is confirmed to be in a normally coupled state. With the controller receiving a +5.0V power supply connected to the circuit, the controller sends a signal to the first switch. Send high level. First switch. When the gate G receives this high level, it triggers the first switch. The source (S) and drain (D) are turned on to enable the first switch. The drain D is the second switch. Send control level. Based on the sixth resistor. The voltage divider principle further enables the first switch The drain D is the second switch. The send control level is pulled low, thus enabling the second switch. The gate G sends a low-level control level. The second switch... When the gate G receives this low level, it triggers the second switch. The source (S) and drain (D) are turned on to enable the second switch. This conducts power, thereby connecting the +5.0V power supply to the user RF interface J, so that the GNSS antenna coupled to the user RF interface J can be powered.

[0055] Furthermore, in the fifth resistor The voltage on the left side is The voltage entering the user RF interface J is Based on the voltage divider principle, the first measurement voltage acquired by the first measurement port ADC_01 is: (Formula 1); The second measurement voltage acquired by the second measurement port ADC_02 is: (Formula 2). Then the first measurement voltage acquired by the first measurement port ADC_01... The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is: (Formula 3).

[0056] For example, the fifth resistor The resistance value is: The operating current of the GNSS antenna is: First resistor The resistance value is: Second resistor The resistance value is: Third resistor The resistance value is: Fourth resistor The resistance value is: .

[0057] Then the fifth resistor The voltage difference between the two ends is: .

[0058] The first measurement voltage acquired by the first measurement port ADC_01 The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is: .

[0059] The controller can determine the first measurement voltage acquired by the first measurement port ADC_01 when the GNSS antenna is properly coupled and operating normally. The second measurement voltage acquired by the second measurement port ADC_02 The difference is 0.2V. That is, this circuit can be used to determine that the GNSS antenna is in a normal coupling state.

[0060] Scenario 2: The GNSS antenna is confirmed to be in an open-circuit state. With the controller receiving a +5.0V power supply connected to the circuit, the controller sends a signal to the first switch. Send high level. First switch. When the gate G receives this high level, it triggers the first switch. The source (S) and drain (D) are turned on to enable the first switch. The drain D is the second switch. Send control level. Based on the sixth resistor. The voltage divider principle further enables the first switch The drain D is the second switch. The send control level is pulled low, thus enabling the second switch. The gate G sends a low-level control level. The second switch... When the gate G receives this low level, it triggers the second switch. The source (S) and drain (D) are turned on to enable the second switch. Conduction.

[0061] Due to the voltage divider effect of diode D, there is a voltage drop of approximately 0.2V when it is conducting. Therefore, the first resistor... With the fifth resistor The voltage at the coupling point is Since the circuit is open and there is no current, the voltage at the first port 1 of the user RF interface J is... And the first resistor With the fifth resistor The voltage at the coupling point and the input voltage of inductor L are both Simultaneously, the first measurement voltage acquired by the first measurement port ADC_01... The second measurement voltage acquired by the second measurement port ADC_02 The partial pressure ratios are all (included) , , , ).but ,Right now and The difference between them is: At this point, the controller determines that the GNSS antenna is in an open-circuit state. Alternatively, a preset threshold of 30mV can be set. and If the difference between the two values ​​is less than 30mV, it can be determined that the GNSS antenna is in an open-circuit state.

[0062] For example, at a certain moment, with the GNSS antenna normally coupled, due to the load current increasing to 35mV, the voltage at the first port 1 of the user RF interface J drops to: .

[0063] at this time, , , (Above 30mV). At this point, the controller determines that the GNSS antenna has returned to normal operation.

[0064] Scenario 3: Determining that the GNSS antenna is short-circuited. When the controller receives a +5.0V power supply connected to the circuit, and the first port 1 of the user RF interface J is short-circuited to ground... The controller detected a short circuit in the GNSS antenna. The controller quickly sent a signal to the first switch. Send low level. First switch. When the gate G receives this low level, it triggers the first switch. The source (S) and drain (D) are turned off. Supply to the second switch is stopped. Send a control level to activate the second switch. The system shuts off the +5.0V power supply, thereby disconnecting it from the user's RF interface J and stopping power supply to the GNSS antenna. Therefore, if the controller detects a short circuit in the GNSS antenna, it can disconnect the +5.0V power supply from the user's RF interface J, stopping power supply to the GNSS antenna and thus protecting it.

[0065] Furthermore, the controller begins to poll at regular intervals, and sends a notification to the first switch at regular intervals. Send a high level and read Is it still 0? If it is still 0, then the GNSS antenna is still in a short-circuit state, and the signal is sent to the first switch. Send a low level to enable the first switch. Second switch Shut down. If at a certain moment, it is detected that... A voltage above approximately 1V indicates that the first port 1 of the user's RF interface J is not short-circuited, thus confirming that the GNSS antenna is not short-circuited and is connected to the first switch. Send a high level to activate the first switch. Second switch The circuit is closed, thereby connecting the +5.0V power supply to the user RF interface J, so that the GNSS antenna coupled to the user RF interface J is powered.

[0066] It should be noted that the resistance ratio in the above scheme... , and the first measurement voltage acquired by the first measurement port ADC_01. The second measurement voltage acquired by the second measurement port ADC_02 The difference between them is 0.2V, which has been verified by theory and practice. It has shown good results in various scenarios with GNSS antenna current (5mA to 40mA).

[0067] The data from theoretical and practical verification are shown in Table 1:

[0068] Table 1

[0069]

[0070] According to another embodiment of the present invention, a GNSS antenna status monitoring and protection device is also provided, including the circuit described in any of the above claims.

[0071] In one exemplary embodiment, the circuit described in any of the above claims can be integrated into a physical device to obtain a GNSS antenna status monitoring and protection device, which can be integrated into a vehicle navigation system to monitor and protect the status of the antenna in the vehicle navigation system.

[0072] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A GNSS antenna state monitoring and protection circuit, characterized by, include: The system comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a user radio frequency interface, a switching unit, a first measurement port, a second measurement port, and a controller; wherein, The first end of the first resistor is coupled to a power supply, the second end of the first resistor is coupled to the first end of the second resistor, and the second end of the second resistor is grounded. The first end of the third resistor is coupled to the first end of the fourth resistor, the second end of the third resistor is coupled to the user radio frequency interface, and the second end of the fourth resistor is grounded. The first end of the fifth resistor is coupled to the power supply, and the second end of the fifth resistor is coupled to the switching unit; The user radio frequency interface includes: a first port, a second port, a third port, a fourth port, and a fifth port; wherein, the first port is coupled to the second end of the third resistor, the second port and the fourth port are grounded, and the third port and the fifth port are coupled to a GNSS antenna; The first end of the switching unit is coupled to the second end of the fifth resistor, and the second end of the switching unit is coupled to the first port; The first measurement port is coupled to the second end of the first resistor and is used to acquire the first measurement voltage. The second measurement port and the first end of the third resistor are used to acquire the second measurement voltage; The controller is coupled to the switching unit and is used to generate a control signal based on the difference between the first measured voltage and the second measured voltage and a preset threshold, so as to connect or disconnect the first port from the power supply based on the control signal.

2. The GNSS antenna state monitoring and protection circuit of claim 1, wherein, The switching unit includes: a first switch and a second switch; wherein, a first terminal of the first switch is coupled to the controller for acquiring the control signal; a second terminal of the first switch is grounded; a third terminal of the first switch is coupled to the first terminal of the second switch; a second terminal of the second switch is coupled to the second terminal of the fifth resistor; and a third terminal of the second switch is coupled to the first port.

3. The GNSS antenna state monitoring and protection circuit of claim 2, wherein, The first switch is an N-MOSFET; wherein, the gate of the first switch is coupled to the controller, the source of the first switch is grounded, and the drain of the first switch is coupled to the second switch; The second switch is a P-MOSFET; wherein the gate of the second switch is coupled to the drain of the first switch, the source of the second switch is coupled to the second terminal of the fifth resistor, and the drain of the second switch is coupled to the first port.

4. The GNSS antenna state monitoring and protection circuit of claim 3, wherein, Also includes: An inductor; wherein a first end of the inductor is coupled to the drain of the second switch, and a second end of the inductor is coupled to the first port.

5. The GNSS antenna status monitoring and protection circuit according to claim 4, characterized in that, Also includes: A bidirectional transient voltage suppressor; wherein, the first terminal of the bidirectional transient voltage suppressor is coupled to the first port, and the second terminal of the bidirectional transient voltage suppressor is grounded.

6. The GNSS antenna status monitoring and protection circuit according to claim 3, characterized in that, The switching unit further includes a sixth resistor; wherein a first end of the sixth resistor is coupled to the drain of the first switch, and a second end of the sixth resistor is coupled to the gate of the second switch.

7. The GNSS antenna status monitoring and protection circuit according to claim 1, characterized in that, Also includes: A diode; wherein the anode of the diode is coupled to the power supply, and the cathode of the diode is coupled to the first terminal of the fifth resistor.

8. The GNSS antenna status monitoring and protection circuit according to claim 3, characterized in that, Also includes: At least one first capacitor; wherein, the first terminal of the at least one first capacitor is coupled to the drain of the second switch, and the second terminal of the at least one first capacitor is grounded.

9. The GNSS antenna status monitoring and protection circuit according to claim 3, characterized in that, The switching unit further includes a seventh resistor; wherein a first end of the seventh resistor is coupled to the gate of the first switch, and a second end of the seventh resistor is coupled to the source of the first switch.

10. The GNSS antenna status monitoring and protection circuit according to claim 3, characterized in that, The switching unit further includes: a second capacitor and an eighth resistor; wherein... The first terminal of the second capacitor is coupled to the source of the second switch, and the second terminal of the second capacitor is coupled to the gate of the second switch. The first end of the eighth resistor is coupled to the source of the second switch, and the second end of the eighth resistor is coupled to the gate of the second switch.

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