GNSS antenna fault detection circuit and control method thereof

Abstract

The invention relates to the technical field of antenna fault detection, and provides a GNSS antenna fault detection circuit and a control method thereof. The GNSS antenna fault detection circuit comprises a sampling circuit, a comparison circuit, a processor, a level conversion circuit and a protection circuit. The voltage output end of the sampling circuit is connected with the input end of the comparison circuit, the first end of the sampling circuit is connected with the input end of the level conversion circuit and the first end of the protection circuit, the second end of the protection circuit is connected with the GNSS antenna, and the output end of the level conversion circuit and the output end of the comparison circuit are both connected with the input end of the processor. And the processor is used for acquiring the satellite receiving number of the GNSS antenna and judging the state of the GNSS antenna according to the satellite receiving number of the GNSS antenna, the output signal of the comparison circuit and the output signal of the level conversion circuit. According to the invention, misjudgment of antenna fault detection caused by faults of the fault detection circuit can be avoided, and the accuracy of fault detection is improved.

Description

Technical Field

[0001] The present application relates to the technical field of antenna fault detection, and in particular to a GNSS antenna fault detection circuit and a control method thereof. Background Art

[0002] Satellite receivers and integrated navigation and positioning modules and other devices with fault detection and reporting functions need to monitor the status of each externally connected Global Navigation Satellite System (GNSS) antenna in real time, including normal access, short circuit, and open circuit. Especially in the automotive industry, autonomous driving currently relies on satellite navigation to provide positioning results. The antenna status determines the availability of positioning information for intelligent driving and affects the user experience. Moreover, as the functions of vehicle-mounted terminal devices increase and the number of analog-to-digital converter (ADC) interfaces of the microcontroller unit (MCU) is limited, the antenna detection function may be limited by the number of ADC interfaces. Conventional detection methods focus on hardware circuits, and the circuit structure is usually complex, making it difficult to identify abnormalities in the detection circuit itself, resulting in misjudgment of antenna fault detection. Summary of the Invention

[0003] The present application provides a GNSS antenna fault detection circuit and a control method thereof, which can solve the problem of misjudgment in antenna fault detection.

[0004] In a first aspect, the present application provides a GNSS antenna fault detection circuit, which includes a sampling circuit, a comparison circuit, a processor, a level conversion circuit, and a protection circuit;

[0005] Among them, the voltage output end of the sampling circuit is connected to the input end of the comparison circuit, the first end of the sampling circuit is respectively connected to the input end of the level conversion circuit and the first end of the protection circuit, the second end of the protection circuit is connected to the GNSS antenna, the output end of the level conversion circuit and the output end of the comparison circuit are both connected to the input end of the processor, and the processor is used to obtain the number of satellites received by the GNSS antenna, and judge the status of the GNSS antenna according to the number of satellites received by the GNSS antenna, the output signal of the comparison circuit and the output signal of the level conversion circuit; the number of satellites received is the number of satellite signals currently received by the GNSS antenna.

[0006] Optionally, the sampling circuit includes a sampling resistor and an operational amplifier;

[0007] The second end of the sampling resistor is the first end of the sampling circuit, and the output end of the operational amplifier is the voltage output end of the sampling circuit;

[0008] The positive input terminal of the operational amplifier is connected to the first terminal of the sampling resistor, and the negative input terminal of the operational amplifier is connected to the second terminal of the sampling resistor.

[0009] Optionally, the comparison circuit includes a first resistor, a second resistor and a comparator;

[0010] The first input terminal of the comparator is the input terminal of the comparison circuit, and the output terminal of the comparator is the output terminal of the comparison circuit;

[0011] The first end of the first resistor is connected to the reference power supply, the second end of the first resistor is respectively connected to the first end of the second resistor and the second input end of the comparator, and the second end of the second resistor is grounded.

[0012] Optionally, the level conversion circuit includes a level converter;

[0013] The first end of the level converter is the input end of the level converter circuit, and the second end of the level converter is the output end of the level converter circuit.

[0014] Optionally, the protection circuit includes a diode;

[0015] The anode of the diode is the first end of the protection circuit, and the cathode of the diode is the second end of the protection circuit.

[0016] Optionally, the GNSS antenna fault detection circuit further includes a power supply circuit;

[0017] The power supply end of the power supply circuit is connected to the first end of the sampling resistor, and the control end of the power supply circuit is connected to the output end of the processor.

[0018] Optionally, the power supply circuit includes a power supply, a fuse and a MOS tube;

[0019] The gate of the MOS tube is the control end of the power supply circuit, and the drain of the MOS tube is the power supply end of the power supply circuit;

[0020] A first end of the fuse is connected to the power supply, and a second end of the fuse is connected to the source of the MOS tube.

[0021] In a second aspect, the present application provides a control method for a GNSS antenna fault detection circuit, the control method comprising:

[0022] Obtain the number of satellites received by the GNSS antenna connected to the GNSS antenna fault detection circuit; the number of satellites received is the number of satellite signals currently received by the GNSS antenna;

[0023] When the number of satellites received by the GNSS antenna is equal to 0, the state detection result of the GNSS antenna is determined according to the output signal of the comparison circuit and the output signal of the level conversion circuit;

[0024] When the number of satellites received by the GNSS antenna is greater than 0, it is determined that the status detection result of the GNSS antenna is in a normal working state.

[0025] Optionally, the control method further includes:

[0026] The voltage threshold of the comparator in the comparison circuit is determined by the following formula:

[0027]

[0028] Where V represents the voltage threshold, R represents the resistance of the first resistor in the comparison circuit of the GNSS antenna fault detection circuit, and R ' Represents the resistance of the second resistor in the comparison circuit of the GNSS antenna fault detection circuit, V ' Indicates the voltage value of the reference power supply connected to the comparison circuit.

[0029] Optionally, determining a state detection result of the GNSS antenna according to an output signal of the comparison circuit and an output signal of the level conversion circuit includes:

[0030] If the output signal of the comparison circuit and the output signal of the level conversion circuit are both high, the state detection result of the GNSS antenna is obtained as a normal working state;

[0031] If the output signal of the comparison circuit is a low level and the output signal of the level conversion circuit is a high level, the GNSS antenna open circuit state detection result is an open circuit state;

[0032] If the output signal of the level conversion circuit is a low level, the GNSS antenna short-circuit state detection result is a short-circuit state.

[0033] The above solution of the present application has the following beneficial effects:

[0034] In an embodiment of the present application, a GNSS antenna fault detection circuit is constructed, comprising a sampling circuit, a comparison circuit, a processor, a level shifter circuit, and a protection circuit. The sampling circuit has a voltage output connected to an input of the comparison circuit, a first terminal of the sampling circuit is connected to an input of the level shifter circuit and a first terminal of the protection circuit, respectively, a second terminal of the protection circuit is connected to the GNSS antenna, and an output of the level shifter circuit and an output of the comparison circuit are both connected to an input of the processor. The processor is configured to obtain the number of satellites received by the GNSS antenna and determine the status of the GNSS antenna based on the number of satellites received by the GNSS antenna, an output signal of the comparison circuit, and an output signal of the level shifter circuit. The GNSS antenna fault detection circuit has a small number of circuit components and does not require an AD sampling channel. Only three input and output interfaces on the processor are required for signal transmission, resulting in a simple structure and improved circuit reliability. For detection of multiple antennas, the circuit can be replicated. Furthermore, incorporating the number of satellites received by the GNSS antenna into fault detection can avoid misjudgments of antenna faults due to faults in the fault detection circuit, thereby improving the accuracy of fault detection.

[0035] Other beneficial effects of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0037] Figure 1 A structural diagram of a GNSS antenna fault detection circuit provided in one embodiment of the present application;

[0038] Figure 2 A schematic diagram of the specific structure of a GNSS antenna fault detection circuit provided in one embodiment of the present application;

[0039] Figure 3 A flow chart of a control method provided in one embodiment of the present application;

[0040] Figure 4 A schematic diagram of state transition provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0042] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0043] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0044] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0045] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0046] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0047] To address the low accuracy of existing antenna fault detection, the present application provides a GNSS antenna fault detection circuit and control method thereof. The GNSS antenna fault detection circuit comprises a sampling circuit, a comparison circuit, a processor, a level conversion circuit, and a protection circuit. The sampling circuit has a voltage output connected to an input of the comparison circuit, a first terminal of the sampling circuit is connected to an input of the level conversion circuit and a first terminal of the protection circuit, respectively, and a second terminal of the protection circuit is connected to the GNSS antenna. The output of the level conversion circuit and the output of the comparison circuit are both connected to an input of the processor. The processor is configured to obtain the number of satellites received by the GNSS antenna and determine the status of the GNSS antenna based on the number of satellites received by the GNSS antenna, an output signal of the comparison circuit, and an output signal of the level conversion circuit. The GNSS antenna fault detection circuit has a small number of circuit components and does not require an AD sampling channel. Only three input and output interfaces on the processor are required for signal transmission, resulting in a simple structure and improved circuit reliability. For detection of multiple antennas, the circuit can be replicated. Furthermore, incorporating the number of satellites received by the GNSS antenna into fault detection can avoid misjudgments of antenna fault detection due to faults in the fault detection circuit, thereby improving fault detection accuracy.

[0048] Next, the structure of the GNSS antenna fault detection circuit provided in this application is exemplified.

[0049] like Figure 1 As shown, the GNSS antenna fault detection circuit includes a sampling circuit, a comparison circuit, a processor, a level conversion circuit and a protection circuit;

[0050] Among them, the voltage output end of the sampling circuit is connected to the input end of the comparison circuit, the first end of the sampling circuit is respectively connected to the input end of the level conversion circuit and the first end of the protection circuit, the second end of the protection circuit is connected to the GNSS antenna, the output end of the level conversion circuit and the output end of the comparison circuit are both connected to the input end of the processor, and the processor is used to obtain the number of satellites received by the GNSS antenna, and judge the status of the GNSS antenna according to the number of satellites received by the GNSS antenna, the output signal of the comparison circuit and the output signal of the level conversion circuit; the number of satellites received is the number of satellite signals currently received by the GNSS antenna.

[0051] It should be noted that the sampling circuit is used to sample the voltage at the first terminal of the protection circuit, the comparison circuit is used to compare the voltage sampled by the sampling circuit with a voltage threshold, and outputs a high-level signal when the voltage is greater than or equal to the voltage threshold, and outputs a low-level signal when the voltage is less than the voltage threshold. The level conversion circuit is used to convert the transmission level of the voltage signal at the first terminal of the protection circuit to adapt it to the operating voltage of the processor, ensuring that the processor can normally receive the signal. The protection circuit is used to protect the sampling circuit, comparison circuit, level conversion circuit, and processor in the GNSS antenna fault detection circuit to prevent power backflow. The processor is used to determine the status of the GNSS antenna based on the number of satellites received by the GNSS antenna, the output signal of the comparison circuit, and the output signal of the level conversion circuit. It is worth noting that the processor can determine the status of the GNSS antenna based on the output signal of the comparison circuit and the output signal of the level conversion circuit, and further determine the status of the GNSS antenna by introducing the number of satellites received, which is irrelevant to the circuit, to avoid the GNSS antenna fault detection circuit from misjudging the status based on the output signal of the comparison circuit and the output signal of the level conversion circuit.

[0052] like Figure 2 As shown, the sampling circuit includes a sampling resistor ( Figure 2 The sampling resistor R1) and the operational amplifier ( Figure 2 Op amp U2 in the PCB);

[0053] The second end of the sampling resistor is the first end of the sampling circuit, and the output end of the operational amplifier is the voltage output end of the sampling circuit;

[0054] The positive input terminal of the operational amplifier is connected to the first terminal of the sampling resistor, and the negative input terminal of the operational amplifier is connected to the second terminal of the sampling resistor.

[0055] It should be noted that the sampling resistor is used to connect to the GNSS antenna through the protection circuit, so that the operational amplifier can achieve sampling by calculating the difference between the voltages at both ends of the sampling resistor and amplifying the difference according to a certain amplification factor to output a sampling voltage.

[0056] The comparison circuit includes a first resistor ( Figure 2 R3 in), the second resistor ( Figure 2 R2 in) and the comparator ( Figure 2 The first input terminal of the comparator is the input terminal of the comparison circuit, and the output terminal of the comparator is the output terminal of the comparison circuit; the first terminal of the first resistor is connected to the reference power supply ( Figure 2 The second end of the first resistor is connected to the first end of the second resistor and the second input end of the comparator respectively, and the second end of the second resistor is grounded.

[0057] It should be noted that the first resistor and the second resistor are used to provide a voltage threshold for comparison for the comparator (i.e., the voltage value of the second input terminal of the comparator). The comparator is used to compare the voltage transmitted by the operational amplifier (i.e., the above-mentioned sampling voltage) with the voltage threshold. If the voltage is greater than or equal to the voltage threshold, a high-level signal is output; if the voltage is less than the voltage threshold, a low-level signal is output.

[0058] The level conversion circuit includes a level converter ( Figure 2 Level conversion U4 in the);

[0059] The first end of the level converter is the input end of the level converter circuit, and the second end of the level converter is the output end of the level converter circuit.

[0060] It should be noted that the level converter is used to convert the transmission level of the voltage signal at the first end of the protection circuit to adapt it to the operating voltage of the processor, thereby ensuring that the processor can normally receive the signal.

[0061] The protection circuit includes a diode ( Figure 2 D1 in the figure), the anode of the diode is the first end of the protection circuit, and the cathode of the diode is the second end of the protection circuit.

[0062] It should be noted that the diode is used to protect the sampling circuit, comparison circuit, level conversion circuit and processor to prevent power backflow.

[0063] The GNSS antenna fault detection circuit further includes a power supply circuit; a power supply end of the power supply circuit is connected to the first end of the sampling resistor, and a control end of the power supply circuit is connected to the output end of the processor.

[0064] It should be noted that when the connected GNSS antenna is a passive antenna, the processor controls the power supply circuit to be connected and power is supplied to the GNSS antenna. When the connected GNSS antenna is an active antenna, the processor controls the power supply circuit to be disconnected and no power is supplied to the GNSS antenna.

[0065] The power supply circuit includes a feed power supply ( Figure 2 Feed power supply V1), fuse ( Figure 2 Fuse F1) and MOS tube ( Figure 2 The MOS tube Q1 in the circuit); the gate of the MOS tube is the control end of the power supply circuit, and the drain of the MOS tube is the power supply end of the power supply circuit; the first end of the fuse is connected to the power supply, and the second end of the fuse is connected to the source of the MOS tube.

[0066] The power supply is used to provide power, while the fuse protects the power supply from failure if the GNSS antenna is short-circuited. The MOS transistor controls the connection and disconnection of the power supply circuit. If the connected GNSS antenna is a passive antenna, the processor sends a control signal to turn on the MOS transistor, supplying power to the GNSS antenna. If the connected GNSS antenna is an active antenna, the processor sends a control signal to turn off the MOS transistor, stopping power supply to the GNSS antenna.

[0067] Figure 2 ANT_IN+ represents the positive input of the operational amplifier, ANT_IN- represents the negative input of the operational amplifier, ANT_DETECT represents the output signal of the comparator, ANT_SHORT_N represents the voltage signal at the anode of the diode. After the signal is converted by the level converter, the level converter outputs the converted signal. ANT_OFF represents the control signal sent by the processor to the MOS tube, which is used to control the switching of the MOS tube. U1 represents the processor, which can be an ARM or MCU. V2 represents the GNSS power output (that is, the voltage at one end connected to the GNSS antenna).

[0068] It should be noted that the fuse is used to protect the power supply in the event of a short circuit in the downstream circuitry, including the antenna. The power supply can be 5V or 3.3V. The diode is used to prevent crosstalk and power backflow between multiple circuits. The level converter can be a level conversion circuit constructed using diodes and resistors and capacitors (such as a diode level conversion circuit). It converts the voltage of the received signal to the operating voltage of the processor to ensure signal transmission. The comparator compares two voltages and outputs the comparison result. The operational amplifier amplifies the input voltage difference by a certain multiple. The processor uses the ANT_OFF function to control the switching of the MOSFET, thereby controlling the power output of the circuit. This allows compatibility with both active antennas (GNSS antennas with their own power supply) and passive antennas (GNSS antennas without their own power supply but requiring power supply). It also cuts off the power supply in the event of a short circuit to ensure smooth operation of the backend. For example, if the GNSS antenna connected to the GNSS antenna fault detection circuit is an active antenna, the ANT_OFF function disconnects the MOSFET, eliminating the need for a power supply. If the GNSS antenna is a passive antenna, the ANT_OFF function turns the MOSFET on, connecting the power supply and providing power to the GNSS antenna.

[0069] For example, the GNSS antenna may be connected to the negative terminal of the diode using a Fakra or SubMiniature version A connector (SMA) connection interface of a radio frequency device.

[0070] The following is an exemplary description of the control method of the GNSS antenna fault detection circuit provided in this application.

[0071] like Figure 3 As shown, the control method of the GNSS antenna fault detection circuit provided in this application includes the following steps:

[0072] Step 31: Obtain the number of satellites received by the GNSS antenna connected to the GNSS antenna fault detection circuit.

[0073] The number of satellites received is the number of satellite signals currently received by the GNSS antenna.

[0074] For example, the processor can be located within an antenna receiver, receiving signals from multiple satellites. Using the satellite position and time information in the navigation message, it calculates its own three-dimensional coordinates and time offset, and outputs a positioning result. Furthermore, it must process various errors and interference to improve positioning accuracy and reliability. The number of satellites received by the receiver is called the satellite count.

[0075] Step 32 : When the number of satellites received by the GNSS antenna is equal to 0, a state detection result of the GNSS antenna is determined according to the output signal of the comparison circuit and the output signal of the level conversion circuit.

[0076] Specifically, if the output signal of the comparison circuit and the output signal of the level conversion circuit are both high levels, the state detection result of the GNSS antenna is obtained as a normal working state;

[0077] If the output signal of the comparison circuit is a low level and the output signal of the level conversion circuit is a high level, the GNSS antenna open circuit state detection result is an open circuit state;

[0078] If the output signal of the level conversion circuit is a low level, the GNSS antenna short-circuit state detection result is a short-circuit state.

[0079] When the output signal of the comparison circuit and the output signal of the level conversion circuit are both high, it means that the voltage difference across the sampling resistor is greater than or equal to the voltage threshold, the current passing through the sampling circuit and the protection circuit is normal, and the connected GNSS antenna is in normal working condition.

[0080] When the output signal of the comparison circuit is low and the output signal of the level conversion circuit is high, it means that the voltage difference across the sampling resistor is less than the voltage threshold, the current passing through the sampling circuit is weak, and the connected GNSS antenna is in an open circuit state.

[0081] When the output signal of the level conversion circuit is low, it means that the voltage of the cathode of the diode is 0. After the diode is turned on, the voltage of the anode is also almost 0, and the connected GNSS antenna is in a short-circuit state.

[0082] It should be noted that the output signal of the level conversion circuit reflects the voltage condition of the anode of the diode (when the voltage here is 0, the output signal is low level, and when the voltage here is greater than 0, the output signal is high level).

[0083] When the GNSS antenna is open, the voltage difference across the sampling resistor in the GNSS antenna fault detection circuit is 0, and the operational amplifier outputs 0V. The comparator compares 0V and finds that it is less than the voltage threshold. The comparator outputs a low level signal. At the same time, the voltage at the anode of the diode is not 0, and the output signal of the level conversion circuit is a high level signal.

[0084] The voltage threshold of the comparator in the comparison circuit (i.e., the voltage at the second input terminal of the comparator) is:

[0085]

[0086] Where V represents the voltage threshold value, R represents the resistance of the first resistor in the comparison circuit in the GNSS antenna fault detection circuit, and R ' Represents the resistance of the second resistor in the comparison circuit of the GNSS antenna fault detection circuit, V ' Indicates the voltage value of the reference power supply connected to the comparison circuit.

[0087] For example, the resistance of the sampling resistor is 1 ohm, the resistance of the first resistor is 4.7k, the resistance of the second resistor is 10k, the reference voltage is 3.3V, and the voltage threshold is calculated by the above formula to be 1.055V. The amplification factor GA of the operational amplifier is 50 times, the model is INA180A2IDBVR, the model of the comparator is LMV331IDCKR, and when the GNSS antenna is open, the output value of the operational amplifier is 0V, which is less than 1.055V, and the output signal of the comparator is low.

[0088] When the GNSS antenna is operating normally, the voltage difference across the sampling resistor is greater than 0. After being amplified by the operational amplifier, the voltage value input to the comparator is greater than or equal to the voltage threshold. The comparator's output signal is high. At the same time, the voltage at the anode of the diode is not 0, and the output signal of the level conversion circuit is high.

[0089] For example, the operating current is 25 milliamperes (mA), and the voltage difference across the sampling resistor is 25 millivolts (mV). After the operational amplifier amplifies this voltage 50 times, the output is 1.25V, which is greater than the voltage threshold of 1.055V, and the comparator output signal is high. In this example, reverse calculation based on the voltage threshold shows that when the GNSS antenna is operating normally, the operating current of the circuit should be greater than 21.1mA. The detection threshold and accuracy can be adjusted by adjusting the resistance values ​​of the sampling resistor, the first resistor, and the second resistor, as well as the amplification factor of the operational amplifier.

[0090] When the GNSS antenna is short-circuited, the voltage at the cathode of the diode is pulled down to 0V, causing the diode to be conductive to the ground. At the same time, the fuse is disconnected, the voltage at the anode of the diode is 0, and the output signal of the level conversion circuit is low.

[0091] It should be noted that, in this case, there is no need to analyze the output signal of the comparison circuit.

[0092] Exemplarily, this step is implemented using a processor in a GNSS antenna fault detection circuit. The judgment of the fault detection process is shown in Table 1.

[0093] Antenna status Output signal of the level conversion circuit Output signal of the comparison circuit Access is working normally 1 1 Access short circuit 0 X open circuit 1 0

[0094] Table 1

[0095] Among them, X means it doesn’t matter whether it is high or low, 1 means high level, and 0 means low level.

[0096] Step 33: When the number of satellites received by the GNSS antenna is greater than 0, it is determined that the status detection result of the GNSS antenna is in a normal working state.

[0097] Specifically, when the number of received satellites is greater than 0, it indicates that the GNSS antenna is operating normally. In this case, there is no need to perform fault detection based on the output signal of the comparison circuit and the output signal of the level conversion circuit. If the output signal of the comparison circuit and the output signal of the level conversion circuit indicate that the GNSS antenna is short-circuited or open-circuited, it indicates that the GNSS antenna fault detection circuit may be faulty or abnormal.

[0098] It should be noted that the execution subject of the above control method is the GNSS antenna fault detection circuit mentioned above.

[0099] The present application is illustrated below with reference to a specific example.

[0100] This application determines the state transition of the antenna state as follows Figure 4As shown, the GNSS antenna includes three states: normal access, open circuit, and short circuit. In the normal access state, if the number of received satellites = 0, the signal ANT_DETECT = 0 (this signal is the output signal of the comparison circuit mentioned above) and (& in the figure) the signal ANT_SHORT_N = 1 (this signal is converted by the level conversion module to obtain the output signal of the level conversion circuit. The level conversion only changes the voltage of the signal transmission but does not change the true value of the signal), then the GNSS antenna should be in the open circuit state. If the number of received satellites = 0 and the signal ANT_SHORT_N = 0, then the GNS The S antenna should be in a short-circuit state. In the short-circuit state, if the number of received satellites = 0, the signal ANT_DETECT = 0, and the signal ANT_SHORT_N = 1, the GNSS antenna should be switched to an open-circuit state. In the open-circuit state, if the number of received satellites = 0 and the signal ANT_SHORT_N = 0, the GNSS antenna should be in a short-circuit state. In the open-circuit or short-circuit state, if the number of received satellites is greater than 0, regardless of the states of the two signals (such as ANT_DETECT = 1 and ANT_SHORT_N = 1), the GNSS antenna is determined to be normally connected.

[0101] It is worth mentioning that introducing the number of satellites received by the GNSS antenna in fault detection can avoid misjudgment caused by faults in the fault detection circuit and further improve the accuracy of fault detection.

[0102] Furthermore, the GNSS antenna fault detection circuit of this application incorporates fuses and diodes to prevent power backflow and short circuits that could cause power or backend malfunctions, ensuring circuit safety. The circuit structure of this application is also low in complexity, improving fault detection accuracy while reducing circuit complexity. For fault detection of multiple antennas, the circuit can be replicated without occupying analog-to-digital conversion sampling, requiring only three input / output interfaces on the processor. The circuit's chips and resistors can be flexibly matched, making it suitable for different antennas.

[0103] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant description of other embodiments.

[0104] The above is a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles described in the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A GNSS antenna fault detection circuit, characterized in that: The GNSS antenna fault detection circuit includes a sampling circuit, a comparison circuit, a processor, a level conversion circuit and a protection circuit; The voltage output end of the sampling circuit is connected to the input end of the comparison circuit, the first end of the sampling circuit is respectively connected to the input end of the level conversion circuit and the first end of the protection circuit, the second end of the protection circuit is connected to the GNSS antenna, the output end of the level conversion circuit and the output end of the comparison circuit are both connected to the input end of the processor, and the processor is used to obtain the number of satellites received by the GNSS antenna and determine the status of the GNSS antenna based on the number of satellites received by the GNSS antenna, the output signal of the comparison circuit, and the output signal of the level conversion circuit; the number of satellites received is the number of satellite signals currently received by the GNSS antenna.

2. The GNSS antenna fault detection circuit according to claim 1, characterized in that: The sampling circuit includes a sampling resistor and an operational amplifier; The second end of the sampling resistor is the first end of the sampling circuit, and the output end of the operational amplifier is the voltage output end of the sampling circuit; The positive input terminal of the operational amplifier is connected to the first terminal of the sampling resistor, and the negative input terminal of the operational amplifier is connected to the second terminal of the sampling resistor.

3. The GNSS antenna fault detection circuit according to claim 1, characterized in that: The comparison circuit includes a first resistor, a second resistor and a comparator; The first input terminal of the comparator is the input terminal of the comparison circuit, and the output terminal of the comparator is the output terminal of the comparison circuit; The first end of the first resistor is connected to a reference power supply, the second end of the first resistor is connected to the first end of the second resistor and the second input end of the comparator respectively, and the second end of the second resistor is grounded.

4. The GNSS antenna fault detection circuit according to claim 1, characterized in that: The level conversion circuit includes a level converter; The first end of the level converter is the input end of the level conversion circuit, and the second end of the level converter is the output end of the level conversion circuit.

5. The GNSS antenna fault detection circuit according to claim 1, characterized in that: The protection circuit includes a diode; The anode of the diode is the first end of the protection circuit, and the cathode of the diode is the second end of the protection circuit.

6. The GNSS antenna fault detection circuit according to claim 2, characterized in that: The GNSS antenna fault detection circuit further includes a power supply circuit; The power supply end of the power supply circuit is connected to the first end of the sampling resistor, and the control end of the power supply circuit is connected to the output end of the processor.

7. The GNSS antenna fault detection circuit according to claim 6, characterized in that: The power supply circuit includes a feed power supply, a fuse and a MOS tube; The gate of the MOS transistor is the control terminal of the power supply circuit, and the drain of the MOS transistor is the power supply terminal of the power supply circuit; The first end of the fuse is connected to the power supply, and the second end of the fuse is connected to the source of the MOS tube.

8. A control method for a GNSS antenna fault detection circuit, applied to the GNSS antenna fault detection circuit according to any one of claims 1 to 7, the control method comprising: Obtaining the number of satellites received by the GNSS antenna connected to the GNSS antenna fault detection circuit; The number of satellites received is the number of satellite signals currently received by the GNSS antenna; When the number of satellites received by the GNSS antenna is equal to 0, determining a state detection result of the GNSS antenna according to an output signal of the comparison circuit and an output signal of the level conversion circuit; When the number of satellites received by the GNSS antenna is greater than 0, it is determined that the state detection result of the GNSS antenna is in a normal working state.

9. The control method according to claim 8, characterized in that: The control method further includes: The voltage threshold of the comparator in the comparison circuit is determined by the following formula: Wherein, V represents the voltage threshold, R represents the resistance value of the first resistor of the comparison circuit in the GNSS antenna fault detection circuit, and R ' represents the resistance value of the second resistor in the comparison circuit of the GNSS antenna fault detection circuit, V ' Indicates the voltage value of the reference power supply connected to the comparison circuit.

10. The control method according to claim 8, characterized in that: The determining the state detection result of the GNSS antenna according to the output signal of the comparison circuit and the output signal of the level conversion circuit includes: If the output signal of the comparison circuit and the output signal of the level conversion circuit are both high, the state detection result of the GNSS antenna is obtained as a normal working state; If the output signal of the comparison circuit is at a low level and the output signal of the level conversion circuit is at a high level, the GNSS antenna open circuit state detection result is an open circuit state; If the output signal of the level conversion circuit is at a low level, the detection result of the short-circuit state of the GNSS antenna is a short-circuit state.

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