Telescope rangefinder and distance measurement method based on telescope rangefinder

Abstract

The present application discloses a telescope rangefinder and a distance measurement method based on the telescope rangefinder, which are applied to the field of distance measurement technology. The method comprises: after receiving a distance measurement instruction, controlling a signal transmitting circuit to transmit N light pulses to a target position; determining whether the number of echo pulses received by a time-delayed detection (TDC) in the signal receiving circuit is greater than K; if the number is greater than K, setting a reference voltage value of a comparator in the signal receiving circuit to a first value and controlling the signal transmitting circuit to transmit A light pulses to the target position; otherwise, setting the reference voltage value of the comparator to a second value and controlling the signal transmitting circuit to transmit B light pulses to the target position; after the TDC converts each received echo pulse into a corresponding distance value, outputting the distance value with the highest frequency as the determined distance to the target position. The scheme of the present application can be used to perform distance measurement based on the telescope rangefinder, thereby improving the distance measurement accuracy, the distance measurement distance, and the convenience of distance measurement.

Description

Technical Field

[0001] The present invention relates to the technical field of distance measurement, and in particular to a telescopic rangefinder and a distance measurement method based on the telescopic rangefinder. Background Art

[0002] With the development of electronic technology, the combination of laser ranging technology and traditional optical telescopes has made it possible to obtain the distance to a target by simply looking at it. Currently, there are three methods for implementing infrared telescope rangefinders: 1. A comparator + CPLD (Complex Programmable Logic Device) / FPGA (Field Programmable Gate Array) solution; 2. An ADC (Analog to Digital Converter) + FPGA solution; and 3. A comparator + TDC (Time-to-Digital Converter) solution.

[0003] Although the first two methods have the ability to capture multiple pulses, the CPLD / FPGA operating clock is generally only around 300MHz at most, resulting in a corresponding ranging accuracy of around 0.5m. In addition, the ADC sampling speed is also limited (80-150MSPS), resulting in low ranging accuracy for the first two methods.

[0004] The third solution is to directly use the TDC to measure the time of the echo pulse, which has very high accuracy (centimeter level). The existing TDC also has the ability to capture 3 to 4 pulses, but when using the current TDC, the number of echo pulses must be set to be consistent with the set target number, and the captured pulses are valid. For example, if the set number of echo pulses is 4, but only 3 pulses are captured during the measurement process, the measurement results of the 3 captured pulses are considered invalid, which limits the ranging capability of the telescope rangefinder. Because the background light and the target being measured are uncertain in outdoor ranging, it is impossible to predict the echo pulse situation and number in each measurement process, so the multi-target capture capability of the TDC cannot be brought into play.

[0005] Therefore, while the current comparator + TDC approach offers high ranging accuracy, the number of echo pulses must match the set target number. Furthermore, the varying conditions and number of echo pulses during outdoor ranging operations mean that the number of echoes can only be set to one in current TDC applications. This necessitates a high signal-to-noise ratio (SNR) for the echo, which means the comparator threshold must be set very high. This means that only a truly strong target echo signal can pass the comparator threshold and be captured by the subsequent TDC. This significantly limits the range. The farther the target is to be measured, the lower the echo pulse energy becomes, making it difficult to effectively pass the comparator's high threshold. Furthermore, increasing the energy of a single pulse would cause the telescope's ranging transmission power to exceed safety regulations, effectively violating safety standards.

[0006] Current infrared telescope rangefinders, because the number of echoes is set to 1, usually obtain the target distance by taking the average of multiple distance measurements. However, when measuring long distances and small targets, and because telescope rangefinders are generally handheld, their stability cannot be guaranteed. Therefore, during the key measurement process, hand shaking or shaking may cause the pulse to deviate from the target. In this case, the algorithm of taking the average of multiple measurements is used, and the distance obtained may be an intermediate distance value between the front and rear targets, not the actual target distance.

[0007] In addition, when using the current TDC chip solution, a single measurement mode can only measure 0 to 200 meters. For distances greater than 200 meters, mode switching is required, which means that it is not possible to switch targets for measurement conveniently and quickly.

[0008] In summary, how to effectively measure distance based on a telescope rangefinder, improve the ranging accuracy, ranging distance, and convenience of ranging are technical problems that technicians in this field urgently need to solve. Summary of the Invention

[0009] The object of the present invention is to provide a telescopic rangefinder and a distance measuring method based on the telescopic rangefinder, so as to effectively perform distance measurement based on the telescopic rangefinder, improve the distance measurement accuracy, the distance measurement distance, and the convenience of distance measurement.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] A distance measurement method based on a telescope rangefinder, comprising:

[0012] After receiving the ranging command, the control signal transmitting circuit transmits N light pulses to the target position;

[0013] Determine whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K;

[0014] If it is greater than K, the reference voltage value of the comparator in the signal receiving circuit is set to a first value, and the signal transmitting circuit is controlled to transmit A light pulses to the target position;

[0015] If it is not greater than K, setting the reference voltage value of the comparator to a second value, and controlling the signal transmitting circuit to transmit B light pulses to the target position;

[0016] After the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position;

[0017] outputting the determined distance to the target position;

[0018] The first value is greater than the second value, N, A, and B are all preset positive integers not less than 2, and K is a preset positive integer and is less than N.

[0019] Preferably, when it is determined that the number of echo pulses received by the TDC in the signal receiving circuit is greater than K, after the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position, including:

[0020] For any one echo pulse output by the comparator, the rising edge of the echo pulse is detected by the first channel of the TDC and converted into a corresponding distance value, and the falling edge of the echo pulse is detected by the second channel of the TDC and converted into a corresponding distance value;

[0021] The smaller of the two distance values ​​with the highest frequency is used as the distance to be compensated, and the difference between the two distance values ​​with the highest frequency is used as the pulse width;

[0022] A corresponding error correction value is determined by the pulse width, and the distance to be compensated is corrected based on the error correction value, and the obtained correction result is used as the determined distance of the target position.

[0023] Preferably, controlling the signal transmitting circuit to transmit B light pulses to the target position includes:

[0024] The signal transmitting circuit is controlled to transmit B optical pulses to the target position, and when each of the B optical pulses is transmitted, each signal receiving channel of the TDC is controlled to be delayed for a first time period relative to a start signal of the optical pulse before being enabled.

[0025] Preferably, after receiving the ranging instruction, the method further includes:

[0026] The gate delay self-calibration of the TDC is performed through the external crystal oscillator of the TDC.

[0027] Preferably, it also includes:

[0028] After receiving the first channel selection instruction, the TDC is controlled to be in a multi-channel parallel working state; after receiving the second channel selection instruction, the TDC is controlled to be in a multi-channel serial working state.

[0029] Preferably, after the TDC converts each received echo pulse into a corresponding distance value, the method further includes:

[0030] All distance values ​​having an occurrence frequency higher than the first frequency threshold are output.

[0031] A telescopic rangefinder, comprising:

[0032] Prism, transmitting lens, receiving condenser lens, signal transmitting circuit, signal receiving circuit, output circuit;

[0033] Input circuit: used to send distance measurement instructions to the controller;

[0034] The controller is used to:

[0035] After receiving the ranging command, the control signal transmission circuit transmits N light pulses to the target position;

[0036] Determine whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K;

[0037] If it is greater than K, the reference voltage value of the comparator in the signal receiving circuit is set to a first value, and the signal transmitting circuit is controlled to transmit A light pulses to the target position;

[0038] If it is not greater than K, setting the reference voltage value of the comparator to a second value, and controlling the signal transmitting circuit to transmit B light pulses to the target position;

[0039] After the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position;

[0040] outputting the determined distance to the target position to the output circuit;

[0041] The first value is greater than the second value, N, A, and B are all preset positive integers not less than 2, and K is a preset positive integer and is less than N.

[0042] Preferably, the signal transmitting circuit includes:

[0043] a pulsed laser diode for emitting light pulses toward the prism during excitation;

[0044] a transmitting high-voltage circuit connected to the pulse laser diode and configured to provide electrical energy to the pulse laser diode;

[0045] The switch circuit connected to the pulse laser diode is used to control the excitation state of the pulse laser diode under the control of the controller.

[0046] Preferably, the switching circuit includes: a first switching tube, a first capacitor, and a driving circuit;

[0047] The control end of the first switch tube is connected to the controller through the drive circuit, the first end of the first switch tube is respectively connected to the first end of the first capacitor and the output end of the transmitting high-voltage circuit, and the second end of the first switch tube is grounded;

[0048] The second end of the first capacitor is connected to the cathode of the pulse laser diode, and the anode of the pulse laser diode is grounded.

[0049] Preferably, it further comprises: a second capacitor and a first resistor;

[0050] The first end of the second capacitor is connected to the cathode of the pulse laser diode, the second end of the second capacitor is connected to the first end of the first resistor, and the controller uses the second end of the first resistor as the start signal end of the light pulse to connect to the TDC, so that the TDC receives the start signal of the light pulse through the start signal end.

[0051] Preferably, the signal receiving circuit includes:

[0052] An avalanche photodiode with a grounded anode that generates current when receiving a light signal;

[0053] a reverse bias circuit connected to the cathode of the avalanche photodiode;

[0054] a third capacitor having a first end connected to the cathode of the avalanche photodiode and a first end connected to a transimpedance amplifier;

[0055] the transimpedance amplifier;

[0056] a voltage amplifier connected to the transimpedance amplifier;

[0057] The first input terminal is used to receive a reference voltage value, and the second input terminal is used for a comparator connected to the voltage amplifier;

[0058] The output of the comparator is connected to the TDC.

[0059] The technical solution provided by the embodiments of the present invention automatically distinguishes distances without switching modes. The controller then sets the reference voltage value for the comparator and controls the signal transmission circuit to emit a corresponding number of light pulses toward the target location. This solution facilitates distance measurement and allows for convenient and rapid target switching for measurement. Furthermore, the signal receiving circuit of the present application utilizes a comparator + TDC approach, resulting in high distance measurement accuracy.

[0060] After receiving the ranging instruction, the controller can control the signal transmission circuit to transmit N light pulses toward the target location. In this application, the distance to the target location can be determined by determining whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K. Specifically, if the number of echo pulses is greater than K, indicating a short-range ranging measurement, this application sets the reference voltage value of the comparator in the signal receiving circuit to a higher value, i.e., a first value, and controls the signal transmission circuit to transmit A light pulses toward the target location. Conversely, if the number of echo pulses is less than K, indicating a long-range ranging measurement, this application sets the reference voltage value of the comparator in the signal receiving circuit to a lower second value, and controls the signal transmission circuit to transmit B light pulses toward the target location. Since the comparator's reference voltage is higher during short-range ranging, it helps reduce the impact of interference, as noise is less likely to pass through the comparator with a high threshold. In contrast, during long-range ranging, the comparator's reference voltage is lower, which helps improve the ranging distance of this application. That is, even with lower echo pulse energy, it can still pass the lower comparator threshold during long-range ranging.

[0061] After the TDC converts each received echo pulse into a corresponding distance value, the present application uses the distance value with the highest frequency as the distance to the determined target position. That is, the distance value with the highest frequency is obtained by statistical means, rather than obtaining the distance to the target position by calculating the average value. This helps to avoid errors caused by factors such as hand shaking, shaking, and interference, and can obtain a more accurate distance to the target position.

[0062] In summary, the solution of the present application can effectively perform distance measurement based on a telescope rangefinder, thereby improving the ranging accuracy, ranging distance, and convenience of ranging. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0064] Figure 1 This is a flow chart of an implementation of a distance measurement method based on a telescope rangefinder in the present invention;

[0065] Figure 2a A distance statistics histogram during long-distance ranging in a specific embodiment of the present invention;

[0066] Figure 2b A distance statistics histogram during close-range distance measurement in a specific embodiment of the present invention;

[0067] Figure 3 This is a structural diagram of a telescope rangefinder in a specific embodiment of the present invention;

[0068] Figure 4a A schematic structural diagram of a high-voltage transmitting circuit in a specific embodiment of the present invention;

[0069] Figure 4b A schematic structural diagram of a switch circuit in a specific embodiment of the present invention;

[0070] Figure 4c A schematic structural diagram of a switch circuit in another specific embodiment of the present invention;

[0071] Figure 5a A schematic diagram of a portion of the structure of a signal receiving circuit in a specific embodiment of the present invention;

[0072] Figure 5b A schematic structural diagram of a comparator in a specific embodiment of the present invention;

[0073] Figure 5c A schematic structural diagram of a comparator in another specific embodiment of the present invention;

[0074] Figure 6 This is a schematic diagram of the chip structure of MS1003 in another specific embodiment of the present invention;

[0075] Figure 7 Schematic diagram of the principle of absolute error caused by echo intensity. DETAILED DESCRIPTION

[0076] The core of the present invention is to provide a distance measurement method based on a telescope rangefinder, which can effectively perform distance measurement based on the telescope rangefinder, thereby improving the distance measurement accuracy, distance measurement, and convenience of distance measurement.

[0077] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0078] Please refer to Figure 1 , Figure 1 This is a flow chart of an implementation of a distance measurement method based on a telescopic rangefinder in the present invention. The distance measurement method based on a telescopic rangefinder may include the following steps:

[0079] Step S101: After receiving the distance measurement instruction, the signal transmitting circuit is controlled to transmit N light pulses to the target position.

[0080] For details, see Figure 3 The user can operate the input circuit 50, thereby causing the input circuit 50 to send a distance measurement instruction to the controller 70. The specific structure of the input circuit 50 can be set and adjusted according to actual needs. For example, a key or button-type input circuit 50 can be used to facilitate user operation, or a touch screen-type input circuit 50 can be used, without affecting the implementation of the present invention.

[0081] The controller 70 receives a distance measurement instruction, indicating that the user needs to perform distance measurement. The controller 70 can control the signal transmitting circuit to transmit N light pulses to the target position to determine whether the target position to be measured is close or far. In addition, it can be understood that the distance of the target position described in this application is the distance between the target position and the telescope rangefinder.

[0082] N is a preset positive integer not less than 2, and the specific value can be set and adjusted as needed. For example, in one case, N is set to 10.

[0083] Furthermore, in practical applications, when the telescope rangefinder is powered on, a post-power-on initialization can be performed. For example, in one specific scenario, after the telescope rangefinder is powered on, the power supply starts up, supplying power to the controller 70. After powering on, the controller 70 can first configure its internal system clock and the properties of various input and output ports, and set the voltages of the high-voltage transmission circuit 11 in the signal transmission circuit and the reverse bias circuit 31 in the signal reception circuit. The controller 70 can then reset the TDC chip and configure its registers. For example, in one specific scenario, if the TDC chip is an MS1003, the controller 70 can send a negative pulse greater than 10 microseconds to the RSTN pin of the MS1003 via a port to perform a hardware reset. Then, a software reset can be performed by writing a 0x50 command via the SPI (Serial Peripheral Interface) port. After the reset is complete, the 32-bit configuration register of the MS1003 can be written via SPI. The configuration register operation command is 0x80, and the 32-bit data is written sequentially, with the high bit first and the low bit last. The above initialization operation only needs to be performed once after power-on, and no further operation is required.

[0084] The specific structure of the signal transmitting circuit can also be set as needed, as long as it can effectively transmit light pulses to the target position under the control of the controller 70.

[0085] Step S102: determine whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K; if greater than K, execute step S103; if not greater than K, execute step S104.

[0086] After the control signal transmission circuit transmits N light pulses to the target position, under ideal circumstances, N echo pulses can be received. However, due to factors such as interference and different distances to the target position, the number of echo pulses received by the TDC35 in the signal receiving circuit may not be equal to N.

[0087] The present application considers that as the distance to the target location increases, the energy of the echo pulse decreases, and the number of echo pulses received by the TDC 35 decreases. Therefore, the controller 70 can determine whether the number of echo pulses received by the TDC 35 in the signal receiving circuit is greater than K. K is a preset positive integer and is less than N. For example, in one embodiment, N is set to 10 and K is set to 8.

[0088] When the number of echo pulses received by TDC35 is greater than K, it means that the target position is close, so step S103 can be executed; otherwise, it means that the target position is far, so step S104 can be executed.

[0089] Furthermore, it should be noted that when executing steps S101 and S102 , the reference voltage value of the comparator 34 in the signal receiving circuit can be set to a higher first value so that weak echo signals and interference cannot exceed the threshold of the comparator 34 .

[0090] Step S103: setting the reference voltage value of the comparator in the signal receiving circuit to a first value, and controlling the signal transmitting circuit to transmit A light pulses to the target position.

[0091] Step S104: setting the reference voltage value of the comparator to a second value, and controlling the signal transmitting circuit to transmit B light pulses to the target position.

[0092] When the number of echo pulses received by TDC 35 exceeds K, it indicates that the target location is relatively close. Therefore, the reference voltage value of comparator 34 in the signal receiving circuit is set to the first value, so that only strong echo signals can cross the threshold of comparator 34, effectively reducing interference. Furthermore, when the target location is relatively close, the probability of TDC 35 receiving echo pulses caused by interference is low. Therefore, the value of A can be set to a small value. For example, if A is set to 100, the controller 70 will control the signal transmission circuit to transmit 100 optical pulses toward the target location.

[0093] When the number of echo pulses received by TDC 35 is no greater than K, it indicates that the target position is far away. Therefore, the reference voltage value of comparator 34 in the signal receiving circuit is set to a lower second value, so that even if the echo signal is weak, it can cross the threshold of comparator 34, effectively improving the measured distance. Of course, when the reference voltage value of comparator 34 is set to the lower second value, noise will also more easily cross the threshold of comparator 34, so the pulses output by comparator 34 are chaotic. This is because noise appears randomly, while the echo signal of the target position only appears near the target distance. The subsequent application is to calculate the frequency of occurrence of different distances. In a telescope rangefinder, noise and signal are random variables. According to statistical theory, the distribution of the sum of independent random variables converges to a normal distribution. Therefore, the distance value with the highest frequency of occurrence can be used as the determined distance of the target position.

[0094] Since the target location is far away, noise will more easily cross the threshold of the comparator 34. Therefore, the value of B can be set to a larger value, for example, A is set to 500. Of course, A and B are both preset positive integers not less than 2. The larger the values ​​of A and B, that is, the more measurements are made, the more statistically significant the results obtained. However, in actual applications, a balance needs to be struck between the number of measurements and the measurement time. Therefore, based on experimental data and theoretical analysis, in the above embodiment, A and B can be set to 100 and 500, respectively.

[0095] Step S105: After the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position.

[0096] For example, the controller 70 controls the signal transmission circuit to transmit 100 light pulses to the target position. After each light pulse is transmitted, the TDC 35 may receive 0 or several echo pulses. Of course, ideally, after each light pulse is transmitted, the TDC 35 should receive 1 echo pulse.

[0097] For any echo pulse, the echo pulse can be converted to the corresponding distance value according to D = △T * C0 / 2. △T represents the time between the emission of a light pulse and the reception of the echo pulse, which can be calculated by TDC35. C0 is the speed of light, and D is the distance value corresponding to the echo pulse. With distance as the horizontal axis and the frequency of distance occurrence as the vertical axis, the distance frequency within the entire distance range can be obtained. For example, Figure 2a In the histogram, the peak point is the point with the highest distance frequency. The horizontal axis here is the distance value with the highest frequency, which is used as the distance to the determined target position.

[0098] Step S106: outputting the determined distance to the target position;

[0099] After the distance to the target position is determined, an output can be performed. For example, in a specific scenario, the output circuit 60 includes an LCD driver connected to the controller 70, and a transmissive LCD display connected to the LCD driver. The user can view the distance to the target position displayed through the LCD display.

[0100] The specific structure of the telescope rangefinder of the present application can be set as needed, for example, it may include: a prism 21, a transmitting lens 22, a receiving condenser lens 40, a signal transmitting circuit, a signal receiving circuit, an output circuit 60, an input circuit 50 and a controller 70. The specific structure of each part can also be set as needed. For example, in a specific embodiment of the present invention, please refer to Figure 3 , the signal transmitting circuit may specifically include:

[0101] a pulsed laser diode PLD, for emitting light pulses toward the prism 21 during excitation;

[0102] A transmitting high-voltage circuit 11 connected to the pulse laser diode PLD and used to provide power to the pulse laser diode PLD;

[0103] The switch circuit 12 connected to the pulse laser diode PLD is used to control the excitation state of the pulse laser diode PLD under the control of the controller 70 .

[0104] Specifically, the transmitting high voltage circuit 11 provides electrical energy to the pulse laser diode PLD, that is, generates the high voltage required by the pulse laser diode PLD. For example, in actual applications, the transmitting high voltage circuit 11 generates a high voltage of 50 to 100V. In addition, the output voltage of the transmitting high voltage circuit 11 can be controlled by the controller 70. Figure 4a A schematic diagram of the structure of the transmitting high voltage circuit 11 in a specific embodiment is shown. Figure 4a The emission high voltage circuit 11 can boost the input low voltage of 3.3V / 5V to the high voltage of 50 to 100V required for the pulse laser diode PLD emission. Figure 4a TXHV in the figure indicates the high voltage output by the transmitting high voltage circuit 11. Considering that the voltage is relatively high, Figure 4a The two resistors form a voltage divider network, so that the controller 70 can use the ADC Figure 4a The sampling end in the middle collects the voltage, and the output voltage of the current transmitting high voltage circuit 11 can be calculated, and then the controller 70 can adjust Figure 4a The duty cycle of PWM1 in the controller 70 is controlled to feedback the high voltage output by the transmitting high voltage circuit 11, so that the high voltage output by the transmitting high voltage circuit 11 is stabilized to the preset value of the controller 70. Figure 4a A voltage stabilizing capacitor is provided at the input end of the transmitting high voltage circuit 11, and an RC filter circuit is provided at the output end. Figure 4a The diode in the circuit is designed with two diodes in series, which can increase the reverse breakdown voltage. Figure 4a You can choose to use a single diode or two diodes in series as needed.

[0105] In addition, it should be noted that for the reverse bias required by the avalanche photodiode APD in the following embodiments, the same or similar circuit structure can also be used, that is, the structure of the reverse bias circuit 31 can refer to Figure 4a The design will not be described in detail.

[0106] The specific type of the pulsed laser diode PLD of the present application can also be selected according to needs, for example, it can be specifically selected as an infrared PLD (Pulsed Laser Diode).

[0107] When the transmitting high-voltage circuit 11 is connected to the pulse laser diode PLD, it can be connected to the anode, and the conduction loop of the switch circuit 12 is connected to the cathode of the pulse laser diode PLD. This connection method is relatively simple. When the controller 70 controls the switch circuit 12 to be turned on, the high voltage output by the transmitting high-voltage circuit 11 flows from the anode of the pulse laser diode PLD into the pulse laser diode PLD, and then passes through the cathode of the pulse laser diode PLD and the switch circuit 12 in sequence and finally reaches the ground.

[0108] In a specific embodiment of the present invention, a method of connecting the transmitting high-voltage circuit 11 to the cathode of the pulse laser diode PLD is adopted, which is conducive to narrowing the pulse width, thereby obtaining a higher pulse amplitude within the energy allowable range, and thus improving the quality of the light pulse emitted by the signal transmitting circuit.

[0109] For details, please refer to Figure 4b , the switch circuit 12 may specifically include: a first switch tube Q1, a first capacitor C1, and a drive circuit 121;

[0110] The control end of the first switch tube Q1 is connected to the controller 70 through the drive circuit 121, the first end of the first switch tube Q1 is connected to the first end of the first capacitor C1 and the output end of the transmitting high-voltage circuit 11 respectively, and the second end of the first switch tube Q1 is grounded;

[0111] The second end of the first capacitor C1 is connected to the cathode of the pulse laser diode PLD, and the anode of the pulse laser diode PLD is grounded.

[0112] exist Figure 4b In the embodiment, the high voltage output by the transmitting high voltage circuit 11 is TXHV, the controller 70 can transmit a pulse trigger signal to the driving circuit 121, and the first switch tube Q1 can be a device such as a MOS tube. Taking the MOS tube as an example, after the controller 70 transmits a pulse trigger signal, the driving circuit 121 can provide the MOS tube with a large pulse source / sink current, so that the gate of the MOS tube can be quickly charged, so that the gate of the MOS tube has a high climbing rate, and the MOS tube can be quickly turned on subsequently.

[0113] On the other hand, when the MOS tube is turned off, TXHV charges the first capacitor C1 and stores the charge. When the MOS tube is turned on, the charge stored in the first capacitor C1 is quickly released. Figure 4b The voltage on the left plate of first capacitor C1 is momentarily reduced, triggering a sudden high current to flow through the pulsed laser diode (PLD) to the right of first capacitor C1, causing the pulsed laser diode (PLD) to emit laser light, for example, infrared laser light. The laser light emitted by the pulsed laser diode (PLD) passes through prism 21, couples with the emission optical path, and is focused and collimated by emission lens 22 before being directed toward the target location.

[0114] Figure 4c The schematic diagram of the structure of the switch circuit 12 in another specific embodiment is shown. The first switch tube Q1 can be implemented by a chip. The controller 70 transmits a pulse trigger signal to the drive circuit 121. Figure 4c The first capacitor C1 is realized by two parallel capacitors C11 and C12. Figure 4c In the circuit, a voltage-stabilizing capacitor and a current-limiting resistor are provided between TXHV and the first capacitor C1 to ensure the reliability of the circuit. A resistor and a diode are also provided in parallel with the pulse laser diode PLD to provide overcurrent protection for the pulse laser diode PLD.

[0115] Furthermore, in a specific embodiment of the present invention, it also includes: a second capacitor C2 and a first resistor R1; the first end of the second capacitor C2 is connected to the cathode of the pulsed laser diode PLD, and the second end of the second capacitor C2 is connected to the first end of the first resistor R1, and the controller 70 uses the second end of the first resistor R1 as the start signal end of the light pulse to connect to the TDC35, so that the TDC35 receives the start signal of the light pulse through the start signal end.

[0116] It is understandable that the solution of the present application requires TDC35 to calculate the distance value corresponding to each echo pulse according to D=△T*C0 / 2. Therefore, after the controller 70 controls the signal transmission circuit to transmit any one light pulse to the target position, it is necessary to inform TDC35 of the message so that TDC35 starts timing, that is, TDC35 needs to receive the start signal of the light pulse. For example, for Figure 4c In the embodiment, after the controller 70 transmits a pulse trigger signal Triger to the driving circuit 121, the controller 70 may simultaneously transmit the Triger to the TDC 35, so that the TDC 35 receives the start signal of the light pulse.

[0117] However, in this embodiment, there is a circuit delay between the time when the controller 70 transmits the pulse trigger signal and the time when the pulse laser diode PLD emits the laser light, thereby reducing the accuracy of the distance value calculated by the TDC 35. Therefore, in this embodiment, a second capacitor C2 and a first resistor R1 are connected to the cathode of the pulse laser diode PLD. The second end of the first resistor R1 serves as the start signal end of the light pulse to be connected to the TDC 35. Figure 4c The second end of the first resistor R1 is marked as FB Triger for connecting to the TDC 35 , so that the TDC 35 uses the signal here as the start signal of the light pulse, thus avoiding the influence of circuit delay and not reducing the accuracy of the distance value calculated by the TDC 35 .

[0118] In a specific embodiment of the present invention, please refer to Figure 3 , the signal receiving circuit may include:

[0119] An avalanche photodiode (APD) with a grounded anode for generating current when receiving a light signal;

[0120] A reverse bias circuit 31 connected to the cathode of the avalanche photodiode APD;

[0121] a third capacitor C3 having a first end connected to the cathode of the avalanche photodiode APD and a first end connected to the transimpedance amplifier 32;

[0122] Transimpedance amplifier 32;

[0123] a voltage amplifier 33 connected to the transimpedance amplifier 32;

[0124] The first input terminal is used to receive a reference voltage value, and the second input terminal is used for a comparator 34 connected to a voltage amplifier 33;

[0125] The TDC 35 is connected to the output terminal of the comparator 34 .

[0126] Specifically, a narrow pulse (10-20 nanoseconds) generated by the signal transmission circuit is projected toward the object being measured. After diffuse reflection from the target, a portion of the pulse is reflected back to the telescope rangefinder. The target can then be treated as a secondary emission source emitting energy into three-dimensional space. The amount of energy received by the telescope rangefinder depends on the area occupied by the receiving condenser lens 40, which is located on a spherical cap with the distance to the target as its radius. Therefore, the telescope rangefinder receives a very weak laser beam. The amount of energy received by the telescope rangefinder is inversely proportional to the square of the distance to the target and directly proportional to the area of ​​the receiving condenser lens 40. The receiving condenser lens 40 then focuses the energy across its entire surface onto a single point. The avalanche photodiode (APD) must be pre-focused to the focal plane of the receiving condenser lens 40. This can be achieved through optical focusing so that all of the energy collected by the receiving condenser lens 40 falls within the photosensitive surface of the APD, which typically measures 230-500 microns.

[0127] Under the condition that the reverse bias circuit 31 applies a relatively high directional bias, the avalanche photodiode APD can quickly convert the optical signal input on its photosensitive surface into a current signal output. The gain of the avalanche photodiode APD has a nonlinear positive relationship with the reverse bias at both ends. Generally, its gain can be set to about 100. Of course, it can be adjusted according to needs in different occasions.

[0128] exist Figure 5aIn the embodiment, RXHV represents the high voltage output by the reverse bias circuit 31. The current signal output by the avalanche photodiode APD needs to be transmitted to the input end of the transimpedance amplifier 32 through the third capacitor C3. The transimpedance amplifier 32 converts the current signal into a voltage signal and outputs it. The transimpedance amplifier 32 can be specifically selected as a model such as MS8257 or OPA857. In this embodiment, the third capacitor C3 is used for AC coupling to limit the input of background light to the greatest extent. Because the background light is mostly a DC component, the third capacitor C3 is used for AC coupling, so that only the pulse signal of the ranging can pass through, and the DC component generated by the background light is blocked, which can improve the signal-to-noise ratio.

[0129] The echo signal output by the transimpedance amplifier 32 is not large enough, so in this embodiment, a voltage amplifier 33 connected to the transimpedance amplifier 32 is provided. For example, the operational amplifier in the voltage amplifier 33 can be a high-speed and high-bandwidth operational amplifier, such as MS8052, SGM8052, etc. Figure 5a In the embodiment, a two-stage voltage amplifier 33 is provided, and sig represents the output of the voltage amplifier 33. The voltage signal amplified by the voltage amplifier 33 is large enough to be provided to the comparator 34 for processing.

[0130] The comparator 34 of the present application is equivalent to a 1-bit ADC, which can output a quantized value of 0 or 1. A high-speed comparator 34 can be used. The level signals to be compared are added to the positive and negative inputs of the comparator 34. In one specific embodiment, when the level at the positive input is greater than that at the negative input, the comparator 34 outputs 1, i.e., a high level; otherwise, it outputs 0, i.e., a low level. In practical applications, to obtain a positive pulse trigger, the amplified signal from the previous stage can be loaded onto the positive input, i.e., the output of the voltage amplifier 33 is loaded onto the positive input of the comparator 34. Furthermore, a DC level can be set for both the positive and negative inputs of the comparator 34. Of course, the DC level at the negative input needs to be greater than that at the positive input. In this way, when there is no signal and when the output signal of the voltage amplifier 33 is low, the output of the comparator 34 is consistent. In this embodiment, the output is always 0. The comparator 34 will only output 1 when the echo signal or noise pulse is coupled to the DC level of the positive terminal through the capacitor, making it greater than the DC level point at the negative input. In this example, the DC level of the inverting input terminal is the reference voltage value of the comparator 34 . As can be seen from the above description, the reference voltage value of the comparator 34 can be adjusted in the present application.

[0131] To obtain this variable threshold, we can use Figure 5b or Figure 5c comparator circuit. Figure 5bIn the specific circuit, the controller 70 controls Q51 to be in the off state, and the reference voltage value of the comparator 34 will be set to a higher value, that is, the first value. When Q51 is in the on state, R51 and R52 are connected in parallel, the equivalent resistance is reduced, and the reference voltage value of the comparator 34 will be set to a lower value, that is, the second value. Figure 5c In the figure, the controller 70 can output PWM2 with adjustable frequency and duty cycle, and output a DC level proportional to the duty cycle of PWM2 as the reference voltage value of the comparator 34 through a two-stage low-pass filter network composed of 2 resistors and 2 capacitors. It can be seen that the reference voltage value of the comparator 34 can be adjusted very flexibly through PWM2. Figure 5c In the embodiment, the controller 70 can also output a DC signal through the built-in DAC. The DAC is loaded onto the pull-down resistor R53 to obtain a corresponding DC voltage, which is the reference voltage value of the comparator 34. The reference voltage value of the comparator 34 can also be easily controlled, that is, the controller 70 can adjust the reference voltage value of the comparator 34 by adjusting the size of the output DAC.

[0132] The specific type of TDC35 of the present application can also be set and adjusted as needed, but it is understandable that the solution of the present application does not require that the number of echo pulses must be consistent with the set target number. Therefore, a TDC35 with multi-pulse capture capability can be selected, and the actual number of captured pulses can be allowed to be inconsistent with the set target number. For example, in one scenario, considering that the MS1003 single channel has a 10 pulse capture capability and the dual channel has a 20 pulse capture capability, and has the ability to have the actual number of captured pulses not be consistent with the set target number, and the echo measurement is still valid, the MS1003 can be selected as the TDC of the present application. MS1003 adopts advanced technology. Compared with the 60 to 80P picosecond accuracy of the traditional TDC35 solution, after applying the solution of the present application, the dual-channel single precision is 46 picoseconds and the single-channel double precision is 23 picoseconds, corresponding to a measurement accuracy of 3 to 4mm.

[0133] Of course, in other occasions, other TDC35s that meet the requirements can be selected according to actual needs.

[0134] See Figure 6 , is a schematic diagram of the chip structure of MS1003, which can communicate with the controller 70. The start signal of the optical pulse can be received through the START port, and the echo signal can be received through STOP1 and STOP2 to achieve time interval measurement.

[0135] In a specific embodiment of the present invention, when it is determined that the number of echo pulses received by the TDC 35 in the signal receiving circuit is greater than K, step S105 may specifically include:

[0136] For any echo pulse output by the comparator 34, the rising edge of the echo pulse is detected by the first channel of the TDC 35 and converted into a corresponding distance value, and the falling edge of the echo pulse is detected by the second channel of the TDC 35 and converted into a corresponding distance value;

[0137] The smaller of the two distance values ​​with the highest frequency is used as the distance to be compensated, and the difference between the two distance values ​​with the highest frequency is used as the pulse width;

[0138] The corresponding error correction value is determined by the pulse width, and the distance to be compensated is corrected based on the error correction value, and the obtained correction result is used as the determined distance of the target position.

[0139] This embodiment takes into account that when detecting the echo pulse, TDC35 usually performs rising edge detection, but please refer to Figure 7 At the same distance, different materials have different reflectivities, and the echo intensities will be different, which will lead to different detected time intervals, that is, the absolute error caused by the echo intensity.

[0140] In this regard, this implementation method will calculate the pulse width. Taking TDC35 as MS1003 as an example, STOP1 of MS1003 is its first channel and STOP2 is its second channel. In this implementation method, these two channels are used in parallel, that is, for any echo pulse output by the comparator 34, both STOP1 and STOP2 can receive it, and STOP1 detects the rising edge of the pulse and converts it into the corresponding distance value, while STOP2 detects the falling edge of the pulse and converts it into the corresponding distance value.

[0141] See Figure 2b The first peak of the histogram is the distance to be compensated, which represents the leading edge (rising edge) of the echo pulse. The second peak represents the trailing edge (falling edge) of the echo pulse. Pulse width = trailing edge - leading edge, that is, Figure 2b The difference between the two distance values ​​that appear most frequently is the pulse width.

[0142] Once the pulse width is determined, the corresponding error correction value can be determined from the pulse width. This correspondence can be determined in advance through experimental verification and theoretical analysis. For example, a corresponding list of pulse widths and error correction values ​​can be set, or a function can be fitted so that when the pulse width is input, the corresponding error correction value can be obtained. Finally, the distance to be compensated is corrected based on the error correction value. The corrected result is the determined distance to the target position. For example, a simple method is to directly superimpose the error correction value and the distance to be compensated.

[0143] In addition, it should be noted that at long distances, since the signals are relatively small, that is, the amplitude of the echo signal from the target position is comparable to the noise level, the ranging error caused by the amplitude can be ignored. Therefore, in long-distance testing, it is only necessary to capture the pulse leading edge, for example Figure 2a In an implementation manner, after capturing the leading edge of each echo pulse and converting it into a distance, the distance value with the highest output frequency can be directly used as the determined distance to the target position.

[0144] In a specific embodiment of the present invention, the control signal transmitting circuit in step S104 transmits B light pulses to the target position, which may specifically include:

[0145] The control signal transmitting circuit transmits B optical pulses to the target position, and when each of the B optical pulses is transmitted, each signal receiving channel of the control TDC 35 is enabled after delaying the first time relative to the start signal of the optical pulse.

[0146] This implementation takes into account that, in order to measure sufficiently far distances, a telescope rangefinder requires a single reflection energy safety rating of approximately 200 nJ. This energy release will cause certain fluctuations in the power supply and ground. Although isolation methods such as LC filters and magnetic beads are used, the impact of these fluctuations cannot be completely eliminated. Therefore, when the light pulse is transmitted, co-frequency interference will also appear at the receiving end. This interference only occurs for a certain period of time after transmission and has nothing to do with the object being measured or the ambient light. It is purely electronic interference. As described above, the received energy is inversely proportional to the square of the distance. Because the reference voltage value of comparator 34 is set to a high level, i.e., the first value, when performing close-range distance measurement, noise, including this electronic interference, is unlikely to cross the threshold of comparator 34.

[0147] However, when performing long-distance ranging, the reference voltage value of the comparator 34 is set at a low level. Noise, including the electronic interference, can exceed the threshold of the comparator 34. Therefore, in this embodiment, after each of the B light pulses is transmitted, a short distance is shielded. Taking MS1003 as an example, the controller 70 controls the STOP1 and STOP2 of MS1003 to be delayed for a first time period relative to the start signal of the light pulse before being enabled. Figure 6In this scenario, the controller 70 can implement delayed enabling of STOP1 and STOP2 through En_Stop1 and En_Stop2. That is, after transmitting any of the B optical pulses, since STOP1 and STOP2 have not yet been enabled, STOP1 and STOP2 will not receive any pulses. As described above, the interference only appears for a certain period of time after the transmission. After the delay, when STOP1 and STOP2 are enabled again, the electronic interference has disappeared.

[0148] In a specific embodiment of the present invention, after receiving the ranging instruction, the following steps may be further included:

[0149] The gate delay of TDC35 is self-calibrated by using the external crystal oscillator of TDC35.

[0150] This implementation takes into account that the TDC 35 needs to calculate the time interval and that fluctuations in ambient temperature and power supply voltage will cause changes in the gate delay time inside the TDC 35. Therefore, in this implementation, the gate delay of the TDC 35 is self-calibrated by using an external crystal oscillator of the TDC 35. Of course, when implementing this implementation, it is necessary to select a TDC 35 with an external crystal oscillator that can achieve gate delay self-calibration, such as Figure 6 The MS1003 chip is connected to a 4MHz high-precision crystal oscillator.

[0151] When performing the gate delay self-calibration of TDC35, the triggering timing can be selected as needed, for example, once after each power-on, or periodically, or before each ranging, the gate delay self-calibration of TDC35 is performed, which does not affect the implementation of the present invention.

[0152] In a specific embodiment of the present invention, after the TDC converts each received echo pulse into a corresponding distance value in step S105, the following steps may be further included:

[0153] All distance values ​​having an occurrence frequency higher than the first frequency threshold are output.

[0154] Because the solution of the present application obtains the distance to the target location through a statistical method, the solution of the present application can achieve the function of measuring the distance of multiple targets at a time. Specifically, after outputting each distance value with a frequency higher than the first frequency threshold, the user can easily determine which targets these distances correspond to. For example, when measuring the distance to a distant railing, if the telescopic rangefinder outputs distances of 600 meters and 601 meters, the user can know that 600 meters is the distance to the railing, and 601 meters is the distance to the wall behind the railing. The specific value of the first frequency threshold can be set and adjusted as needed.

[0155] It's also important to note that, taking the MS1003 as an example, a single channel has a capture capacity of 10 pulses, while a dual-channel one has a capture capacity of 20 pulses. In the aforementioned description, the MS1003's dual channels are used in parallel, meaning that Stop 1 and Stop 2 are connected in parallel. After transmitting any light pulse, Stop 1 can receive a maximum of 10 echo pulses, and similarly, Stop 2 can receive a maximum of 10 echo pulses. In actual applications, if strong background light is encountered outdoors, the probability of noise increases, potentially quickly filling up the 10 pulses in each channel, preventing the capture of subsequent echo pulses from more distant targets. Because the two channels operate in parallel, a noise pulse may be captured by both channels simultaneously, resulting in a reduction in the number of echo pulses actually captured from the target during the entire ranging process.

[0156] In this regard, in a specific embodiment of the present invention, the method may further include:

[0157] After receiving the first channel selection instruction, the TDC 35 is controlled to be in a multi-channel parallel working state. After receiving the second channel selection instruction, the TDC 35 is controlled to be in a multi-channel serial working state.

[0158] In this implementation, the TDC35 can be configured to operate in either a multi-channel serial or multi-channel parallel mode. When operating in parallel, each channel is connected in parallel and enabled simultaneously. In serial mode, each channel can be enabled sequentially and in a time-sharing manner. For example, with the dual-channel MS1003, STOP1 can be enabled first, followed by a waiting time, and then STOP2. This approach also increases the measurement range. The greater the number of channels, the greater the measurement range when operating in serial mode.

[0159] The technical solution provided by the embodiments of the present invention automatically distinguishes distances without switching modes. The controller 70 then sets the reference voltage value for the comparator 34 and controls the signal transmission circuit to transmit a corresponding number of light pulses toward the target location. Therefore, the solution of the present application facilitates distance measurement, allowing for convenient and rapid target switching for measurement. Furthermore, the signal receiving circuit of the present application utilizes a comparator 34 + TDC 35 approach, resulting in high distance measurement accuracy.

[0160] After receiving the ranging instruction, the controller 70 can control the signal transmission circuit to transmit N light pulses toward the target location. In this application, the distance to the target location can be determined by determining whether the number of echo pulses received by the TDC 35 in the signal receiving circuit is greater than K. Specifically, if the number of echo pulses is greater than K, indicating a short-range ranging measurement, the application sets the reference voltage value of the comparator 34 in the signal receiving circuit to a higher value, i.e., a first value, and controls the signal transmission circuit to transmit A light pulses toward the target location. Conversely, if the number of echo pulses is less than K, indicating a long-range ranging measurement, the application sets the reference voltage value of the comparator 34 in the signal receiving circuit to a lower second value, and controls the signal transmission circuit to transmit B light pulses toward the target location. Since the reference voltage value of the comparator 34 is higher during short-range ranging, it helps reduce the impact of interference, as noise is less likely to pass through the comparator 34, which has a high threshold. During long-distance ranging, the reference voltage value of the comparator 34 is relatively low, which is beneficial for improving the ranging distance of the present application. That is, during long-distance ranging, even if the energy of the echo pulse is relatively low, it can still cross the lower threshold of the comparator 34.

[0161] After TDC35 converts each received echo pulse into a corresponding distance value, the present application uses the distance value with the highest frequency as the distance to the determined target position. That is, the distance value with the highest frequency is obtained by statistical means, rather than obtaining the distance to the target position by calculating the average value. This helps to avoid errors caused by factors such as hand shaking, shaking, and interference, and can obtain a more accurate distance to the target position.

[0162] In summary, the solution of the present application can effectively perform distance measurement based on a telescope rangefinder, thereby improving the ranging accuracy, ranging distance, and convenience of ranging.

[0163] Corresponding to the above embodiment of the distance measurement method based on a telescope rangefinder, an embodiment of the present invention further provides a telescope rangefinder, which can be referenced in conjunction with the above. The telescope rangefinder may include:

[0164] Prism 21, transmitting lens 22, receiving condenser lens 40, signal transmitting circuit, signal receiving circuit, output circuit 60;

[0165] Input circuit 50: used to send distance measurement instructions to the controller 70;

[0166] The controller 70 is configured to:

[0167] After receiving the ranging command, the control signal transmitting circuit transmits N light pulses to the target position;

[0168] Determine whether the number of echo pulses received by TDC35 in the signal receiving circuit is greater than K;

[0169] If it is greater than K, the reference voltage value of the comparator 34 in the signal receiving circuit is set to the first value, and the signal transmitting circuit is controlled to transmit A light pulses to the target position;

[0170] If it is not greater than K, the reference voltage value of the comparator 34 is set to a second value, and the signal transmitting circuit is controlled to transmit B light pulses to the target position;

[0171] After the TDC 35 converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position;

[0172] Outputting the determined distance to the target position to the output circuit 60;

[0173] The first value is greater than the second value, N, A, and B are all preset positive integers not less than 2, and K is a preset positive integer and is less than N.

[0174] It should also be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0175] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0176] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the technical solutions and core concepts of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A distance measurement method based on a telescope rangefinder, characterized in that: include: After receiving the ranging command, the control signal transmission circuit transmits N light pulses to the target position; Determine whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K; If it is greater than K, the reference voltage value of the comparator in the signal receiving circuit is set to a first value, and the signal transmitting circuit is controlled to transmit A light pulses to the target position; If it is not greater than K, setting the reference voltage value of the comparator to a second value, and controlling the signal transmitting circuit to transmit B light pulses to the target position; After the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position; outputting the determined distance to the target position; The first value is greater than the second value, N, A, and B are all preset positive integers not less than 2, and K is a preset positive integer and is less than N.

2. The distance measurement method based on a telescope rangefinder according to claim 1, characterized in that: When it is determined that the number of echo pulses received by the TDC in the signal receiving circuit is greater than K, after the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position, including: For any one echo pulse output by the comparator, the rising edge of the echo pulse is detected by the first channel of the TDC and converted into a corresponding distance value, and the falling edge of the echo pulse is detected by the second channel of the TDC and converted into a corresponding distance value; The smaller of the two distance values ​​with the highest frequency is used as the distance to be compensated, and the difference between the two distance values ​​with the highest frequency is used as the pulse width; A corresponding error correction value is determined by the pulse width, and the distance to be compensated is corrected based on the error correction value, and the obtained correction result is used as the determined distance of the target position.

3. The distance measurement method based on a telescope rangefinder according to claim 1, characterized in that: The controlling the signal transmitting circuit to transmit B light pulses to the target position includes: The signal transmitting circuit is controlled to transmit B optical pulses to the target position, and when each of the B optical pulses is transmitted, each signal receiving channel of the TDC is controlled to be delayed for a first time period relative to a start signal of the optical pulse before being enabled.

4. The distance measurement method based on a telescope rangefinder according to claim 1, characterized in that: After receiving the ranging instruction, it also includes: The gate delay self-calibration of the TDC is performed through the external crystal oscillator of the TDC.

5. The distance measurement method based on a telescope rangefinder according to claim 1, characterized in that: Also includes: After receiving the first channel selection instruction, the TDC is controlled to be in a multi-channel parallel working state; after receiving the second channel selection instruction, the TDC is controlled to be in a multi-channel serial working state.

6. The distance measurement method based on a telescope rangefinder according to any one of claims 1 to 5, characterized in that: After the TDC converts each received echo pulse into a corresponding distance value, it also includes: All distance values ​​having an occurrence frequency higher than the first frequency threshold are output.

7. A telescopic rangefinder, characterized in that: include: Prism, transmitting lens, receiving condenser lens, signal transmitting circuit, signal receiving circuit, output circuit; Input circuit: used to send distance measurement instructions to the controller; The controller is used to: After receiving the ranging command, the control signal transmission circuit transmits N light pulses to the target position; Determine whether the number of echo pulses received by the TDC in the signal receiving circuit is greater than K; If it is greater than K, the reference voltage value of the comparator in the signal receiving circuit is set to a first value, and the signal transmitting circuit is controlled to transmit A light pulses to the target position; If it is not greater than K, setting the reference voltage value of the comparator to a second value, and controlling the signal transmitting circuit to transmit B light pulses to the target position; After the TDC converts each received echo pulse into a corresponding distance value, the distance value with the highest frequency is used as the determined distance to the target position; outputting the determined distance to the target position to the output circuit; The first value is greater than the second value, N, A, and B are all preset positive integers not less than 2, and K is a preset positive integer and is less than N.

8. The telescopic rangefinder according to claim 7, characterized in that: The signal transmitting circuit includes: a pulsed laser diode for emitting light pulses toward the prism during excitation; a transmitting high-voltage circuit connected to the pulse laser diode and configured to provide electrical energy to the pulse laser diode; The switch circuit connected to the pulse laser diode is used to control the excitation state of the pulse laser diode under the control of the controller.

9. The telescopic rangefinder according to claim 8, characterized in that: The switch circuit includes: a first switch tube, a first capacitor, and a drive circuit; The control end of the first switch tube is connected to the controller through the drive circuit, the first end of the first switch tube is respectively connected to the first end of the first capacitor and the output end of the transmitting high-voltage circuit, and the second end of the first switch tube is grounded; The second end of the first capacitor is connected to the cathode of the pulse laser diode, and the anode of the pulse laser diode is grounded.

10. The telescopic rangefinder according to claim 9, characterized in that: Also includes: a second capacitor and a first resistor; The first end of the second capacitor is connected to the cathode of the pulse laser diode, the second end of the second capacitor is connected to the first end of the first resistor, and the controller uses the second end of the first resistor as the start signal end of the light pulse to connect to the TDC, so that the TDC receives the start signal of the light pulse through the start signal end.

11. The telescopic rangefinder according to any one of claims 7 to 10, characterized in that: The signal receiving circuit includes: An avalanche photodiode with a grounded anode that generates current when receiving a light signal; a reverse bias circuit connected to the cathode of the avalanche photodiode; a third capacitor having a first end connected to the cathode of the avalanche photodiode and a first end connected to a transimpedance amplifier; the transimpedance amplifier; a voltage amplifier connected to the transimpedance amplifier; The first input terminal is used to receive a reference voltage value, and the second input terminal is used for a comparator connected to the voltage amplifier; The output of the comparator is connected to the TDC.

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