Laser radar APD protection method, device, storage medium and laser radar system

Abstract

The present application relates to the technical field of laser radar, and in particular to a laser radar APD protection method, device, storage medium and laser radar system, wherein a laser radar APD protection method is applied to the main control unit of a laser radar system including a main control unit, a laser and an APD, and the method comprises the following steps: emitting a pulse signal at a certain repetition rate to trigger the laser to emit a light pulse; generating a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state in a blind area, and the blind area is a distance range predefined according to measurement requirements. The present application controls the working state of the APD by setting a control signal, so that the APD does not work in the blind area, thereby reducing the occurrence of the APD being burned due to the small distance between the measurement point and the target object and the strong return light signal received by the APD. The probability of the APD being burned is reduced without increasing the cost and ensuring the detection performance of the APD.

Description

Technical Field

[0001] The present application relates to the technical field of laser radar, and in particular to a laser radar APD protection method, device, storage medium and laser radar system. Background Art

[0002] LiDAR is an active remote sensing device that emits laser beams to detect the position, speed and other characteristic quantities of the target. LiDAR usually includes a transmitting system, a receiving system, and an information processing system. Among them, the receiving system of LiDAR usually includes various forms of photodetectors, such as APD (Avalanche Photo Diode) photodetectors. Specifically, the working principle of LiDAR using APD as a photodetector is as follows: two laser signals are generated through the transmitting system (usually a laser), one of which is a reference light and the other is a detection light. The reference light is recorded as the laser emission moment, and the detection light is used to detect the target. When the detection light hits the target, a return light signal is generated. The APD receives the return light signal and converts it into an electrical signal for processing, and the distance information is obtained under the joint action of the information processing system.

[0003] Among them, APD usually has a damage threshold. When the return light intensity is greater than the APD damage threshold, the APD will be burned. APD usually requires low voltage +5v, -5V (provided by the low voltage circuit) and high voltage (provided by the high voltage circuit) for photoelectric conversion. Generally, in order to ensure that the APD detector has higher sensitivity and smaller dark noise, the high voltage of the APD needs to be set to an appropriate value. At the same time, in order to prevent the APD from being burned, the high voltage cannot be set too high.

[0004] In order to achieve the above purposes at the same time, the existing solutions are to use APDs with higher damage thresholds or to reduce the high voltage supply voltage. However, the use of APDs with higher damage thresholds has the defect of high cost, while reducing the high voltage supply voltage has the defect of affecting the sensitivity of the APD and thus affecting the measurement range.

[0005] Based on the above situation, the relevant technology needs to be further improved. Summary of the invention

[0006] In order to reduce the probability of APD photoelectric detectors being burned out without increasing costs and ensuring the detection performance of APD photoelectric detectors, and to provide a certain degree of protection for APDs, the present application provides a laser radar APD protection method, device, storage medium and laser radar system.

[0007] In the first aspect, a laser radar APD protection method provided in the present application adopts the following technical solution:

[0008] A laser radar APD protection method is applied to a main control unit in a laser radar system including a main control unit, a laser and an APD, and the method comprises the following steps:

[0009] Emitting a pulse signal at a certain repetition rate to trigger the laser to emit light pulses;

[0010] A control signal is generated to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area, and the blind area is a distance range predefined according to measurement requirements.

[0011] By adopting the above technical solution, the working state of the APD is controlled by the set control signal, so that the APD does not work in the blind area, thereby reducing the possibility that the APD is burned due to the small distance between the measurement point and the target object and the strong return light signal received by the APD. Compared with the technical solutions in the related art that control the high-voltage power supply circuit of the APD or select a higher damage threshold, the technical solution of the present application reduces the probability of the APD being burned without increasing the cost and ensuring the detection performance of the APD, and plays a good protective role for the APD.

[0012] Optionally, the low-voltage power supply circuit of the APD includes a MOS tube, and the on-off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is turned on or off, and the generating a control signal to cut off the low-voltage power supply circuit of the APD so that the APD is in an off state in the blind area includes:

[0013] A control signal is generated to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state in the blind area.

[0014] By adopting the above technical solution, by setting the MOS tube, and controlling the MOS tube through the control signal, the purpose of controlling the on and off of the low-voltage power supply circuit of the APD is achieved. The overall setting is simple and the working reliability is strong.

[0015] Optionally, the control signal is generated a certain time before the rising edge of the pulse signal.

[0016] By adopting the above technical solution, taking into account the turn-on delay of the MOS tube, the control signal generated by the main control unit is generated a certain time before the rising edge of the pulse signal to ensure that when the laser emits a light pulse, the control signal generated by the main control unit has already cut off the low-voltage power supply circuit of the APD, thereby making the APD in a non-working state in the blind area, so as to achieve the technical effect of preventing the APD from being burned in the blind area.

[0017] In the second aspect, a laser radar APD protection device provided in the present application adopts the following technical solution:

[0018] A laser radar APD protection device is applied to a main control unit in a laser radar system including a main control unit, a laser and an APD, comprising:

[0019] A transmitting module, used for transmitting a pulse signal at a certain repetition rate to trigger the laser to emit light pulses;

[0020] And, a control module is used to generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area, and the blind area is a distance range predefined according to measurement requirements.

[0021] By adopting the above technical solution, a control signal is generated by the control module to control the working state of the APD, so that the APD does not work in the blind area, thereby reducing the possibility that the APD is burned due to the small distance between the measurement point and the target object and the strong return light signal received by the APD. Compared with the technical solutions in the related art that control the high-voltage power supply circuit of the APD or select a higher damage threshold, the technical solution of the present application reduces the probability of the APD being burned without increasing the cost and ensuring the detection performance of the APD, and plays a good protective role for the APD.

[0022] Optionally, the low-voltage power supply circuit of the APD includes a MOS tube, and the on / off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The control module includes a cut-off unit, and the cut-off unit is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within the blind area.

[0023] Optionally, an adjustment module is further included, and the adjustment module is used to enable the control signal to be generated a certain time before the rising edge of the pulse signal.

[0024] In a third aspect, a laser radar system provided in this application adopts the following technical solution:

[0025] A laser radar system includes a main control unit, a laser and an APD. The main control unit is connected to the laser and is used to emit a pulse signal with a certain repetition rate to trigger the laser to emit light pulses. The main control unit is connected to the APD and is used to generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area. The blind area is a distance range predefined according to measurement requirements.

[0026] By adopting the above technical solution, a control signal is generated by the main control unit to control the working state of the APD, so that the APD does not work in the blind area, thereby reducing the possibility that the APD is burned due to the small distance between the measurement point and the target object and the strong return light signal received by the APD. Compared with the technical solutions in the related art that control the high-voltage power supply circuit of the APD or select a higher damage threshold, the technical solution of the present application reduces the probability of the APD being burned without increasing the cost and ensuring the detection performance of the APD, and plays a good protective role for the APD.

[0027] Optionally, the low-voltage power supply circuit of the APD includes a MOS tube, and the main control unit is connected to the MOS tube. The main control unit is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within the blind area.

[0028] Optionally, the main control unit includes an FPGA chip.

[0029] In a fourth aspect, a storage medium provided by the present application adopts the following technical solution:

[0030] A storage medium stores a computer program, which, when executed on a computer, implements the laser radar APD burnout prevention method as described above.

[0031] As can be seen from the above, the beneficial technical effects of the present application include: controlling the working state of the APD by setting a control signal so that the APD does not work in the blind area, thereby reducing the possibility of the APD being burned due to the small distance between the measurement point and the target object and the strong return light signal received by the APD. Compared with the technical solutions in the related art that control the high-voltage power supply circuit of the APD or select a higher damage threshold, the technical solution of the present application reduces the probability of the APD being burned without increasing the cost and ensuring the detection performance of the APD, and plays a good protective role for the APD.

[0032] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the embodiments of the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic flow chart of a laser radar APD protection method in an embodiment of the present application.

[0034] Figure 2 It is a schematic structural diagram of a laser radar APD protection device in an embodiment of the present application.

[0035] Figure 3 It is a power supply timing diagram of the APD in the embodiment of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0037] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0038] First, refer to Figure 1 The embodiment of the present application discloses a laser radar APD protection method, which is applied to a main control unit in a laser radar system including a main control unit, a laser and an APD, and the method includes the following steps:

[0039] S1. Send a pulse signal with a certain repetition rate to trigger the laser to emit light pulses.

[0040] S2. Generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state within the blind area. The blind area is a distance range predefined according to measurement requirements.

[0041] In some embodiments, the low-voltage power supply circuit of the APD includes a MOS tube, and the on / off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The above step S2 specifically includes:

[0042] A control signal is generated to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state in the blind area.

[0043] In some embodiments, the control signal is generated a certain time before the rising edge of the pulse signal.

[0044] In some embodiments, the main control unit uses an FPGA chip.

[0045] Specifically, the main control unit sends out a pulse signal with a certain repetition frequency (it should be noted that the range of the repetition frequency here can be selected according to the specific measurement requirements), and the pulse signal triggers the laser to generate an optical pulse signal with the repetition frequency. The optical pulse signal generated by the laser usually includes two paths, one of which is a reference optical signal and the other is a detection optical signal. The reference optical signal is usually converted into an electrical signal through a PIN diode, and a high-speed comparator is used to extract the rising edge signal of the reference optical signal in a constant threshold manner as the start signal of each cycle. The detection optical signal is emitted, and when it encounters a target object, it is diffusely reflected and received by the APD in the form of a return light signal. After amplification, shaping and high-speed comparison, the termination signal stop is obtained. Finally, the time interval measurement method is used to convert the time difference between stop and start into distance information to obtain the measurement result.

[0046] Specifically, APD usually has a damage threshold. When the target object is too close to the measurement point, it is easy to cause the intensity of the return light signal to be greater than the damage threshold of the APD, which in turn causes the APD to be burned. In order to reduce the occurrence of this situation, in the technical solution of the present application, a blind area is pre-defined, and a control signal is generated by the main control unit to make the APD in the off state within the blind area. Among them, the blind area can be pre-set according to the measurement requirements, and the blind area is usually a closer distance between the target object and the measurement point. For example, for a laser radar system with a range of 1500m, the blind area can be set to 0m-15m, and for a laser radar system with a range of 1000m, the blind area can be set to 0m-10m.

[0047] Specifically, when the APD is working normally, an external power supply needs to provide +5V, -5V and a certain value of high voltage at the same time, where +5V and -5V are provided by a low-voltage power supply circuit, and a certain value of high voltage is provided by a high-voltage power supply circuit. In order to make the APD in the off state in the blind area, in the technical solution of the present application, a control signal that can control the on and off of the APD low-voltage power supply circuit is generated by the main control unit, so that the APD does not work in the blind area but works in the non-blind area.

[0048] Specifically, the low-voltage power supply circuit of the APD includes a MOS tube (wherein, MOS tube is the abbreviation of MOSFET. MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor, that is, metal-oxide semiconductor field effect transistor, abbreviated as gold-oxide-semiconductor field-effect transistor.) In the technical solution of the present application, the control signal generated by the main control unit is used to control whether the MOS tube is turned on or off, thereby controlling the on and off of the low-voltage power supply circuit of the APD through the MOS tube, thereby achieving the technical effect of making the APD not work in the blind area but work in the non-blind area.

[0049] Specifically, taking into account the situation that there is a turn-on delay in the MOS tube, in the technical solution of the present application, the control signal generated by the main control unit is generated a certain time before the rising edge of the pulse signal to ensure that when the laser emits a light pulse, the control signal generated by the main control unit has already cut off the low-voltage power supply circuit of the APD, thereby making the APD in an inoperative state in the blind area, so as to achieve the technical effect of preventing the APD from being burned in the blind area.

[0050] Specifically, the main control unit may be an MCU, a single-chip microcomputer or an FPGA chip, etc. In the technical solution of the present application, an FPGA chip with excellent parallel processing capability is preferred.

[0051] For example, the FPGA chip triggers the laser to emit light pulses with a pulse signal with a repetition rate of 100kHz, so the repetition rate of the light pulse is also 100kHz, that is, the laser light emission interval is 10 microseconds. According to the formula L=0.5*C*T (where L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, and T here is the light emission period), the maximum distance that can be measured in each light emission period is L=0.5*3*10^8*10μs=1500m. The predefined blind area is 15m, so the formula L=0.5*C*T (L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, where T is the time interval). It can be calculated that the time interval corresponding to the blind area of ​​15m is 100ns. In order to prevent the APD from working within the blind area, a control signal is generated through the FPGA to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a non-working state within the above 100ns. After 100ns, the MOS tube is controlled to connect the low-voltage power supply circuit of the APD to make the APD work normally. Among them, considering that the MOS tube has a delay in turning on or off, the control signal can be generated a certain time before the pulse signal. For example, the control signal is generated 10ns before the rising edge of the start signal start. The MOS tube is controlled by the control signal to cut off the low-voltage power supply circuit of the APD. After (100-10)ns, that is, 90ns, the MOS tube is controlled by the control signal to connect the low-voltage power supply circuit of the APD to make the APD work normally. For details, please refer to Figure 3 The APD power supply timing diagram shown in the figure, fpluse represents the start signal start, ctrl represents the control signal, and U represents the +5V voltage in the APD low-voltage power supply circuit. It should be noted that the -5V control method can be designed with reference to +5V.

[0052] Second, refer to Figure 2The embodiment of the present application discloses a laser radar APD protection device, which is applied to a main control unit in a laser radar system including a main control unit, a laser and an APD. The device includes:

[0053] The transmitting module 100 is used to transmit a pulse signal at a certain repetition rate to trigger the laser to emit light pulses;

[0054] And, the control module 200 is used to generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state within the blind area, and the blind area is a distance range predefined according to measurement requirements.

[0055] In some embodiments, the low-voltage power supply circuit of the APD includes a MOS tube, and the on / off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The control module 200 includes a cut-off unit, which is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within the blind area.

[0056] In some embodiments, the laser radar APD protection device also includes an adjustment module, which is used to enable the control signal to be generated a certain time before the rising edge of the pulse signal.

[0057] Specifically, the main control unit sends a pulse signal with a certain repetition frequency (it should be noted that the range of the repetition frequency here can be selected according to the specific measurement requirements) through the transmitting module 100, and triggers the laser to generate an optical pulse signal with the repetition frequency through the pulse signal. The optical pulse signal generated by the laser usually includes two paths, one of which is a reference optical signal and the other is a detection optical signal. The reference optical signal is usually converted into an electrical signal through a PIN diode, and a high-speed comparator is used to extract the rising edge signal of the reference optical signal in a constant threshold manner as the start signal start of each cycle. The detection optical signal is emitted, and when it encounters a target object, it is diffusely reflected and received by the APD in the form of an echo signal. After amplification, shaping and high-speed comparison, the termination signal stop is obtained. Finally, the time interval measurement method is used to convert the time difference between stop and start into distance information to obtain the measurement result.

[0058] Specifically, APD usually has a damage threshold. When the target object is too close to the measurement point, it is easy to cause the intensity of the return light signal to be greater than the damage threshold of the APD, which in turn causes the APD to be burned. In order to reduce the occurrence of this situation, in the technical solution of the present application, a blind area is pre-defined, and the main control unit generates a control signal through the control module 200 to make the APD in the off state within the blind area. Among them, the blind area can be pre-set according to the measurement requirements, and the blind area is usually a closer distance between the target object and the measurement point. For example, for a laser radar system with a range of 1500m, the blind area can be set to 0m-15m, and for a laser radar system with a range of 1000m, the blind area can be set to 0m-10m.

[0059] Specifically, when the APD is working normally, an external power supply needs to provide +5V, -5V and a certain value of high voltage at the same time, where +5V and -5V are provided by a low-voltage power supply circuit, and a certain value of high voltage is provided by a high-voltage power supply circuit. In order to make the APD in the off state in the blind area, in the technical solution of the present application, a control signal that can control the on and off of the APD low-voltage power supply circuit is generated by the main control unit, so that the APD does not work in the blind area but works in the non-blind area.

[0060] Specifically, the low-voltage power supply circuit of the APD includes a MOS tube (wherein, MOS tube is the abbreviation of MOSFET. MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor, that is, metal-oxide semiconductor field effect transistor, abbreviated as gold-oxide-semiconductor field-effect transistor.) In the technical solution of the present application, the control signal generated by the main control unit is used to control whether the MOS tube is turned on or off, thereby controlling the on and off of the low-voltage power supply circuit of the APD through the MOS tube, thereby achieving the technical effect of making the APD not work in the blind area but work in the non-blind area.

[0061] Specifically, taking into account the situation that there is a turn-on delay in the MOS tube, an adjustment module is also provided in the technical solution of the present application. The main control unit uses the adjustment module to generate a control signal a certain time before the rising edge of the pulse signal to ensure that when the laser emits a light pulse, the control signal generated by the main control unit has already cut off the low-voltage power supply circuit of the APD, thereby making the APD in a non-working state in the blind area, so as to achieve the technical effect of preventing the APD from being burned in the blind area.

[0062] Specifically, the main control unit may be an MCU, a single-chip microcomputer or an FPGA chip, etc. In the technical solution of the present application, an FPGA chip with excellent parallel processing capability is preferred.

[0063] For example, the FPGA chip triggers the laser to emit light pulses with a pulse signal with a repetition rate of 100kHz, so the repetition rate of the light pulse is also 100kHz, that is, the laser light emission interval is 10 microseconds. According to the formula L=0.5*C*T (L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, and T is the light emission period here), the maximum distance that can be measured in each light emission period is L=0.5*3*10^8*10μs=1500m. The predefined blind area is 15m, so the formula L= 0.5*C*T (L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, where T is the time interval) can be calculated to obtain that the time interval corresponding to the blind area of ​​15m is 100ns. In order to prevent the APD from working within the blind area, a control signal is generated through the FPGA to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a non-working state within the above 100ns. After 100ns, the MOS tube is controlled to connect the low-voltage power supply circuit of the APD to make the APD work normally. Among them, considering that the MOS tube has a delay in turning on or off, the control signal can be generated a certain time before the pulse signal. For example, the control signal is generated 10ns before the rising edge of the start signal start. The MOS tube is controlled by the control signal to cut off the low-voltage power supply circuit of the APD. After (100-10)ns, that is, 90ns, the MOS tube is controlled by the control signal to connect the low-voltage power supply circuit of the APD to make the APD work normally. For details, please refer to Figure 3 The APD power supply timing diagram shown in the figure, fpluse represents the start signal start, ctrl represents the control signal, and U represents the +5V voltage in the APD low-voltage power supply circuit. It should be noted that the -5V control method can be designed with reference to +5V.

[0064] On the third aspect, the present application provides a laser radar system, including a main control unit, a laser and an APD. The main control unit is connected to the laser and is used to emit a pulse signal with a certain repetition rate to trigger the laser to emit light pulses. The main control unit is connected to the APD and is used to generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area. The blind area is a distance range predefined according to measurement requirements.

[0065] In some embodiments, the low-voltage power supply circuit of the APD includes a MOS tube, and the on / off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The main control unit is connected to the MOS tube, and the main control unit is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within the blind area.

[0066] In some embodiments, the main control unit includes an FPGA chip.

[0067] Specifically, the main control unit sends out a pulse signal with a certain repetition frequency (it should be noted that the range of the repetition frequency here can be selected according to the specific measurement requirements), and the pulse signal triggers the laser to generate an optical pulse signal with the repetition frequency. The optical pulse signal generated by the laser usually includes two paths, one of which is a reference optical signal and the other is a detection optical signal. The reference optical signal is usually converted into an electrical signal through a PIN diode, and a high-speed comparator is used to extract the rising edge signal of the reference optical signal in a constant threshold manner as the start signal of each cycle. The detection optical signal is emitted, and when it encounters a target object, it is diffusely reflected and received by the APD in the form of a return light signal. After amplification, shaping and high-speed comparison, the termination signal stop is obtained. Finally, the time interval measurement method is used to convert the time difference between stop and start into distance information to obtain the measurement result.

[0068] Specifically, APD usually has a damage threshold. When the target object is too close to the measurement point, it is easy to cause the intensity of the return light signal to be greater than the damage threshold of the APD, which in turn causes the APD to be burned. In order to reduce the occurrence of this situation, in the technical solution of the present application, a blind area is pre-defined, and a control signal is generated by the main control unit to make the APD in the off state within the blind area. Among them, the blind area can be pre-set according to the measurement requirements, and the blind area is usually a closer distance between the target object and the measurement point. For example, for a laser radar system with a range of 1500m, the blind area can be set to 0m-15m, and for a laser radar system with a range of 1000m, the blind area can be set to 0m-10m.

[0069] Specifically, when the APD is working normally, an external power supply needs to provide +5V, -5V and a certain value of high voltage at the same time, where +5V and -5V are provided by a low-voltage power supply circuit, and a certain value of high voltage is provided by a high-voltage power supply circuit. In order to make the APD in the off state in the blind area, in the technical solution of the present application, a control signal that can control the on and off of the APD low-voltage power supply circuit is generated by the main control unit, so that the APD does not work in the blind area but works in the non-blind area.

[0070] Specifically, the low-voltage power supply circuit of the APD includes a MOS tube (wherein, MOS tube is the abbreviation of MOSFET. MOSFET, Metal-Oxide-Semiconductor Field-Effect Transistor, that is, metal-oxide semiconductor field effect transistor, abbreviated as gold-oxide-semiconductor field-effect transistor.) In the technical solution of the present application, the control signal generated by the main control unit is used to control whether the MOS tube is turned on or off, thereby controlling the on and off of the low-voltage power supply circuit of the APD through the MOS tube, thereby achieving the technical effect of making the APD not work in the blind area but work in the non-blind area.

[0071] Specifically, taking into account the situation that there is a turn-on delay in the MOS tube, in the technical solution of the present application, the control signal generated by the main control unit is generated a certain time before the rising edge of the pulse signal to ensure that when the laser emits a light pulse, the control signal generated by the main control unit has already cut off the low-voltage power supply circuit of the APD, thereby making the APD in an inoperative state in the blind area, so as to achieve the technical effect of preventing the APD from being burned in the blind area.

[0072] Specifically, the main control unit may be an MCU, a single-chip microcomputer or an FPGA chip, etc. In the technical solution of the present application, an FPGA chip with excellent parallel processing capability is preferred.

[0073] For example, the FPGA chip triggers the laser to emit light pulses with a pulse signal with a repetition rate of 100kHz, so the repetition rate of the light pulse is also 100kHz, that is, the laser light emission interval is 10 microseconds. According to the formula L=0.5*C*T (L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, and T is the light emission period here), the maximum distance that can be measured in each light emission period is L=0.5*3*10^8*10μs=1500m. The predefined blind area is 15m, so the formula L= 0.5*C*T (L is the distance, C is the speed of light in a vacuum, C=3*10^8m / s, T is the time, where T is the time interval) can be calculated to obtain that the time interval corresponding to the blind area of ​​15m is 100ns. In order to prevent the APD from working within the blind area, a control signal is generated through the FPGA to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a non-working state within the above 100ns. After 100ns, the MOS tube is controlled to connect the low-voltage power supply circuit of the APD to make the APD work normally. Among them, considering that the MOS tube has a delay in turning on or off, the control signal can be generated a certain time before the pulse signal. For example, the control signal is generated 10ns before the rising edge of the start signal start. The MOS tube is controlled by the control signal to cut off the low-voltage power supply circuit of the APD. After (100-10)ns, that is, 90ns, the MOS tube is controlled by the control signal to connect the low-voltage power supply circuit of the APD to make the APD work normally. For details, please refer to Figure 3 The APD power supply timing diagram shown in the figure, fpluse represents the start signal start, ctrl represents the control signal, and U represents the +5V voltage in the APD low-voltage power supply circuit. It should be noted that the -5V control method can be designed with reference to +5V.

[0074] In a fourth aspect, an embodiment of the present application further provides a storage medium having a computer program stored thereon. When the computer program is executed, a method in any optional implementation of the above-mentioned embodiment is executed.

[0075] Among them, the storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable red-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk.

[0076] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0077] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0078] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0079] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0080] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser radar APD protection method, applied to a main control unit in a laser radar system including a main control unit, a laser and an APD, It is characterized in that The method comprises the following steps: Emitting a pulse signal at a certain repetition rate to trigger the laser to emit light pulses; Generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area, where the blind area is a distance range predefined according to measurement requirements; The low-voltage power supply circuit of the APD includes a MOS tube, and the on-off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The generating a control signal to cut off the low-voltage power supply circuit of the APD so that the APD is in an off state in the blind area includes: Generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state within the blind area; The control signal is generated a certain time before the rising edge of the pulse signal.

2. A laser radar APD protection device, applied to the main control unit of a laser radar system including a main control unit, a laser and an APD, It is characterized in that include: A transmitting module, used for transmitting a pulse signal at a certain repetition rate to trigger the laser to emit light pulses; and a control module, for generating a control signal to cut off the low voltage power supply circuit of the APD so that the APD is in an off state within a blind area, wherein the blind area is a distance range predefined according to measurement requirements; The low-voltage power supply circuit of the APD includes a MOS tube, and the on-off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The generating a control signal to cut off the low-voltage power supply circuit of the APD so that the APD is in an off state in the blind area includes: Generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in a shutdown state within the blind area; The control signal is generated a certain time before the rising edge of the pulse signal.

3. A laser radar APD protection device according to claim 2, It is characterized in that The low-voltage power supply circuit of the APD includes a MOS tube, and the on / off of the low-voltage power supply circuit of the APD is controlled by whether the MOS tube is on or off. The control module includes a cut-off unit, and the cut-off unit is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within the blind area.

4. The laser radar APD protection device according to claim 2, It is characterized in that It also includes an adjustment module, which is used to make the control signal be generated a certain time before the rising edge of the pulse signal.

5. A laser radar system, It is characterized in that The method described in claim 1 includes a main control unit, a laser and an APD, wherein the main control unit is connected to the laser and is used to emit a pulse signal with a certain repetition rate to trigger the laser to emit light pulses, and the main control unit is connected to the APD and is used to generate a control signal to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state within a blind area, and the blind area is a distance range predefined according to measurement requirements.

6. A laser radar system according to claim 5, It is characterized in that The low-voltage power supply circuit of the APD includes a MOS tube, and the main control unit is connected to the MOS tube. The main control unit is used to generate a control signal to control the MOS tube to cut off the low-voltage power supply circuit of the APD, so that the APD is in an off state in the blind area.

7. A laser radar system according to claim 5, It is characterized in that The main control unit includes an FPGA chip.

8. A storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed on a computer, the method according to claim 1 is implemented.

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