Laser radar ranging system and method based on digital logic

Abstract

The invention discloses a laser radar ranging system and method based on digital logic, and belongs to the technical field of signal processing, and the system comprises a laser transmitting unit which is used for generating a modulation optical signal and transmitting the modulation optical signal to a target object, and transmitting reflected light to a signal processing unit; the signal processing unit is used for converting the received reflected light into a standardized electric signal, extracting phase or time difference information and outputting two paths of signals to the distance resolving unit; and a distance calculation unit that calculates the target distance on the basis of the phase difference or time difference information. According to the system and the method, through collaborative design of a diode logic network and a linear conversion link, direct linear mapping from a phase difference to a distance value is realized, two laser ranging modes of continuous waves and pulses can be adapted, and the system and the method are suitable for scenes requiring high-precision real-time ranging, such as automatic driving and industrial detection. The system and the method can realize high-precision and low-delay distance measurement, and have the advantages of simple structure, low cost, fast response and the like.

Description

Technical Field

[0001] The present invention belongs to the field of signal processing technology, and in particular relates to a laser radar ranging system and method based on digital logic. Background Art

[0002] In the field of signal processing technology, laser ranging systems are widely used due to their fast response speed and strong anti-interference capabilities. This is particularly true in scenarios such as autonomous driving and industrial inspection that require high-precision real-time ranging. However, current phase detection technology faces three major technical bottlenecks:

[0003] 1. Complex architecture: Traditional analog phase difference measurement solutions require multiple components such as mixers, local oscillators, and filters, which dramatically increases circuit size and cost.

[0004] 2. Poor dynamic performance: The digital oversampling solution has a processing delay of more than 1μs, which is difficult to meet the requirements of high-speed ranging;

[0005] 3. Nonlinear error: The sensitivity of sinusoidal phase difference measurement approaches zero in the 0° / 180° area, forming a measurement blind area. Summary of the Invention

[0006] To address the aforementioned shortcomings of the existing technology, the present invention provides a digital logic-based laser radar ranging system and method. This system and method utilizes a diode logic network in conjunction with a linear conversion link (RC low-pass filter + voltage-controlled current source) to achieve a direct linear mapping of phase difference to distance. This system and method is adaptable to both continuous wave and pulsed laser ranging modes, making it suitable for scenarios requiring high-precision, real-time ranging, such as autonomous driving and industrial inspection. This system and method enables high-precision, low-latency distance measurement and offers advantages such as a simple structure, low cost, and fast response.

[0007] The present invention is achieved through the following technical solutions:

[0008] A laser radar ranging system based on digital logic, comprising:

[0009] A laser emitting unit is used to generate a modulated light signal and emit it to the target object, and the reflected light is sent to the signal processing unit;

[0010] A signal processing unit is used to convert the received reflected light into a standardized electrical signal, extract phase or time difference information, and output two signals to the distance calculation unit;

[0011] The distance calculation unit calculates the target distance based on the phase difference or time difference information, satisfying the following formula:

[0012]

[0013] Where C is the speed of light, V HFor logic high, V th is the fast recovery diode conduction threshold, τ0 is the reference pulse width, T is the signal period, and V0 is the DC component of the RC filter output.

[0014] Furthermore, the laser emitting unit includes a local oscillator 5, a laser intensity modulator 6, an optical fiber amplifier 7 and an optical circulator 8 in continuous wave mode; the local oscillator 5 generates a high-frequency sinusoidal electrical signal, the laser intensity modulator 6 drives the laser diode to convert the electrical signal into a continuous laser signal, and after the optical power is increased by the optical fiber amplifier 7, it is directionally emitted to the target through the optical circulator 8, and the reflected light signal 12 is received.

[0015] Furthermore, in pulse mode, the laser emitting unit includes a pulse signal generator 10, an LD driver 11, an optical fiber amplifier 7 and an optical circulator 8; the pulse signal generator 10 generates a narrow pulse electrical signal, the LD driver 11 drives the laser diode to emit a light pulse, which is amplified by the optical fiber amplifier 7 and then emitted to the target through the optical circulator 8, and the reflected light pulse 17 is received.

[0016] Furthermore, the signal processing unit comprises a photoelectric converter 13, a conditioning circuit 14, a high-speed comparator, a logic operation unit and a linear conversion module in the continuous wave mode; the reflected light signal 12 is converted into an electrical signal with a phase difference by the photoelectric converter 13 and then sent to the conditioning circuit 14; the conditioning circuit 14 performs transimpedance amplification, automatic gain control and bandpass filtering to obtain an input signal v with the same frequency but different phase. i1 and v i2 The high-speed comparator receives an input signal and outputs a square wave signal with a phase difference to a logic operation unit. The logic operation unit adopts a diode logic network, including a first fast recovery diode 29 and a second fast recovery diode 30, and generates a step waveform containing two jumps in each cycle through different conduction states; the linear conversion module is used to extract the DC component of the above-mentioned step waveform and convert it into a current signal linearly related to the phase difference, thereby realizing the quantized output of phase information.

[0017] Furthermore, the high-speed comparator includes a first comparator 27 and a second comparator 28, wherein the positive input terminal of the first comparator 27 is connected to the first input signal v i1 , the negative input terminal is connected to the reference voltage V REF The positive input terminal of the second comparator 28 is connected to the first input signal v i2 , the negative input terminal is connected to the reference voltage V REF The two comparator outputs generate square wave signals v corresponding to the zero crossing points of the input signal. 01 and v 02 The positive electrode of the first fast recovery diode 29 is connected to v 01The cathode of the signal line is connected to the output node v0; the cathode of the second fast recovery diode 30 is connected to v 02 Signal line, the positive pole is connected to the output node v0; node v0 is connected to the power supply voltage Vcc through a pull-up resistor, and outputs a step waveform.

[0018] Furthermore, in the pulse mode, the signal processing unit includes an APD detector 18, a pulse shaping circuit 19, a logic operation unit and a linear conversion module; the reflected light pulse 17 is converted into an electrical signal by the APD detector 18 and sent to the pulse shaping circuit 19, and the pulse shaping circuit 19 performs shaping processing on the electrical signal. The logic operation unit adopts a diode logic network, including a first fast recovery diode 29 and a second fast recovery diode 30, and generates a square wave characteristic waveform with a pulse width proportional to the time difference Δt between the transmitted pulse and the received pulse through different conduction states; the linear conversion module is used to extract the DC component of the above-mentioned square wave characteristic waveform and convert it into a current signal linearly related to the time difference, thereby realizing the quantitative output of the flight time information.

[0019] Furthermore, the linear conversion module includes an RC low-pass filter and a voltage-controlled current source 4. The RC low-pass filter is used to extract the DC component V0 of the characteristic waveform v0, and to establish a linear mathematical model between the output node V0 and the flight time variable τ to analyze the phase difference Wherein, K is a proportional coefficient; the voltage-controlled current source is used to convert the DC component V0 into a current signal that is linearly mapped with the delay time τ, thereby realizing the quantized output of the time-of-flight information.

[0020] Furthermore, the distance calculation unit includes a signal acquisition module 20, a digital processing module 21, a mode selection module 22 and a microprocessor 23;

[0021] Among them, the signal acquisition module is used to receive the transmission trigger signal and the receiving pulse signal output by the signal processing unit;

[0022] The digital processing module is used to extract the flight time difference;

[0023] The mode selection module is used to select an appropriate mode, which includes a continuous wave mode and a pulse mode;

[0024] The microprocessor is used to calculate the distance using a temperature compensation algorithm and output the calculated distance to the display terminal 26 .

[0025] On the other hand, the present invention provides a ranging method for a laser radar ranging system based on digital logic, which specifically includes the following steps:

[0026] Step 1: Initialize the configuration and select continuous wave mode or pulse mode;

[0027] Step 2: Continuous wave mode: emit continuous laser light, capture the reflected light and generate a standardized electrical signal with phase difference;

[0028] Pulse mode: emits light pulses, captures reflected pulses and generates time difference electrical signals;

[0029] Step 3: Continuous Wave Mode: A staircase waveform is synthesized through a diode logic network, and its level characteristics are linearly related to the phase difference;

[0030] Pulse mode: The transmit trigger signal and the receive pulse signal are logically operated through the diode logic network to generate a square wave characteristic waveform with a pulse width proportional to the time difference Δt;

[0031] Step 4: Calculate the target distance based on the phase difference or time difference using the following formula:

[0032]

[0033] Compared with the prior art, the advantages of the present invention are as follows:

[0034] 1. Minimal circuit and low cost;

[0035] A dual-diode logic network is used to replace the traditional mixer / phase-locked loop architecture, reducing components by more than 60% and hardware costs by 50%, while achieving fully digital phase detection.

[0036] 2. Full-link linear high precision;

[0037] Through the coordinated design of step wave duty cycle and RC filtering, dual linear conversion of phase difference-voltage-current is achieved (error <±1.5%), breaking through the nonlinear bottleneck of the traditional sinusoidal phase detection method in the critical region. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly describes the drawings required for the specific embodiments or the description of the prior art. Similar elements or parts are generally identified by similar reference numerals throughout the drawings. Elements or parts in the drawings are not necessarily drawn to scale.

[0039] Figure 1 Schematic diagram of the overall structure of a laser radar ranging system based on digital logic of the present invention;

[0040] Figure 2 This is a schematic diagram of the structure of the laser emission unit in continuous wave mode;

[0041] Figure 3 This is a schematic diagram of the structure of the laser emission unit in pulse mode;

[0042] Figure 4 It is a structural diagram of the signal processing unit in continuous wave mode;

[0043] Figure 5 It is a structural diagram of the signal processing unit in pulse mode;

[0044] Figure 6 It is a structural diagram of the distance solving unit;

[0045] Figure 7 This is a schematic diagram of a high-speed comparator circuit;

[0046] Figure 8 It is a schematic diagram of the logic operation unit and the linear conversion module;

[0047] Figure 9 is the square wave signal v 01 v 02 And v0 waveform diagram;

[0048] Figure 10 is a waveform diagram of the characteristic waveform v0;

[0049] Figure 11 The waveform diagram of the circuit input signal;

[0050] Figure 12 Build a voltage-controlled current source schematic for an existing op amp (LM358 / OPA2188);

[0051] Figure 13 Schematic diagram of building a voltage-controlled current source using the instrumentation amplifier AD620 (16) or AD621;

[0052] In the figure, there are a laser emitting unit 1, a signal processing unit 2, a logic operation unit 3, a voltage-controlled current source 4, a local oscillator 5, a laser intensity modulator 6, a fiber amplifier 7, an optical circulator 8, a target object 9, a pulse signal generator 10, an LD driver 11, a reflected light signal 12, a photoelectric converter 13, a conditioning circuit 14, a high-speed comparator 15, a reflected light pulse 17, an APD detector 18, a pulse shaping circuit 19, a signal acquisition module 20, a digital processing module 21, a mode selection module 22, a microprocessor 23, a temperature compensation algorithm 24, a calculation formula 25, a display terminal 26, a first high-speed comparator 27, a second high-speed comparator 28, a first fast recovery diode 29, and a second fast recovery diode 30. DETAILED DESCRIPTION

[0053] In order to clearly and completely describe the technical solution and specific working process of the present invention, the specific implementation methods of the present invention are as follows in conjunction with the accompanying drawings:

[0054] Example 1

[0055] like Figure 1 As shown, this embodiment provides a laser radar ranging system based on digital logic, which is used to measure the laser radar distance in continuous wave mode. The system includes: a laser emitting unit, a signal processing unit and a distance solving unit;

[0056] A laser emitting unit is used to generate a modulated light signal and emit it to the target object, and the reflected light is sent to the signal processing unit;

[0057] A signal processing unit is used to convert the received reflected light into a standardized electrical signal, extract phase or time difference information, and output two signals to the distance calculation unit;

[0058] The distance calculation unit calculates the target distance based on the phase difference or time difference information, satisfying the following formula:

[0059]

[0060] Where C is the speed of light, V H For logic high, V th is the fast recovery diode conduction threshold, τ0 is the reference pulse width, T is the signal period, and V0 is the DC component of the RC filter output.

[0061] The following combination Figure 2 The following describes in detail a laser emitting unit in continuous wave mode, which includes a local oscillator 5, a laser intensity modulator 6, a fiber amplifier 7, and an optical circulator 8. The local oscillator 5 generates a high-frequency sinusoidal electrical signal, and the laser intensity modulator 6 drives the laser diode to convert the electrical signal into a continuous laser signal. After the optical power is increased by the fiber amplifier 7, the signal is directed to the target through the optical circulator 8, and the reflected light signal 12 is received.

[0062] The following combination Figure 4 The signal processing unit in the continuous wave mode is introduced in detail. The signal processing unit includes a photoelectric converter 13, a conditioning circuit 14, a high-speed comparator, a logic operation unit and a linear conversion module. The reflected light signal 12 is converted into an electrical signal with a phase difference by the photoelectric converter 13 and sent to the conditioning circuit 14. The conditioning circuit 14 performs transimpedance amplification, automatic gain control and bandpass filtering to obtain an input signal v with the same frequency but different phase. i1 and v i2 , the high-speed comparator receives the input signal and outputs a square wave signal with a phase difference to the logic operation unit, such as Figure 8 As shown, the logic operation unit uses dual fast recovery diodes to construct a nonlinear logic network, including a first fast recovery diode 29 and a second fast recovery diode 30. The positive electrode of the first fast recovery diode 29 is connected to v 01 The cathode of the signal line is connected to the output node v0; the cathode of the second fast recovery diode 30 is connected to v02 Signal line, the positive pole is connected to the output node v0; the node v0 is connected to the power supply voltage Vcc through a pull-up resistor, defining the high level reference value V H =Vcc-V f (V H It is a fixed value (high level) related to the comparator and Vcc, that is, only the device is fixed, Vcc is fixed, V H That is a fixed high level value, such as TTL high level; V f The linear conversion module is used to extract the DC component of the staircase waveform and convert it into a current signal that is linearly related to the phase difference, thereby achieving quantized output of phase information.

[0063] Table 1 Four-state synthesis logic output characteristics table:

[0064]

[0065] As shown in Table 1, in each signal cycle, the v0 waveform forms two step jumps. That is to say, the function of four-state input and three-state output is realized, and the total duration of high level is the same as There is a strict linear relationship, the signal waveform and parameters of v0 are as follows Figure 10 shown.

[0066] like Figure 7 As shown, in this embodiment, the high-speed comparator includes a first comparator 27 and a second comparator 28, wherein the positive input terminal of the first comparator 27 is connected to the first input signal v i1 , the negative input terminal is connected to the reference voltage V REF The positive input terminal of the second comparator 28 is connected to the first input signal v i2 , the negative input terminal is connected to the reference voltage V REF The two comparator outputs generate square wave signals v corresponding to the zero crossing points of the input signal. 01 and v 02 The positive electrode of the first fast recovery diode 29 is connected to v 01 The cathode of the signal line is connected to the output node v0; the cathode of the second fast recovery diode 30 is connected to v 02 Signal line, the positive pole is connected to the output node v0; node v0 is connected to the power supply voltage Vcc through a pull-up resistor, and outputs a step waveform.

[0067] like Figure 8As shown, the linear conversion module includes an RC low-pass filter and a voltage-controlled current source 4. The RC low-pass filter is used to extract the DC component V0 of the characteristic waveform v0, and establish a linear mathematical model of the output node V0 and the phase variable τ to analyze the phase difference Wherein, K is a proportional coefficient; the voltage-controlled current source is used to convert the DC component V0 into a current signal that is linearly mapped with the delay time τ, thereby realizing quantized output of phase information.

[0068] There are two solutions for voltage-controlled current source circuits:

[0069] 1. If Figure 12 As shown, a voltage-controlled current source is built using an ordinary operational amplifier, which consists of an operational amplifier, a core amplification unit, a voltage-current linear conversion achieved through negative feedback, resistors R1 and R2, a sampling resistor Rs and an ammeter.

[0070] Among them, the sampling resistor Rs is a current detection element that converts the output current into a voltage feedback signal;

[0071] Rs<<R1,Rs<<R2, then

[0072] According to the above formula, the current meter display value and The relationship is:

[0073] 2. If Figure 13 As shown, the voltage-controlled voltage source is realized by using the instrumentation amplifier AD620 (16) or AD621, which is composed of the AD620 (16) or AD621 resistor Rf and the sampling resistor Rs, as shown in FIG. Figure 13 As shown. The ammeter displays the current value Ammeter display value I s The relationship with the phase difference is:

[0074] like Figure 6 As shown, the distance calculation unit includes a signal acquisition module 20, a digital processing module 21, a mode selection module 22 and a microprocessor 23;

[0075] The signal acquisition module is used to receive the local oscillator signal v output by the signal processing unit. i1 and the reflected signal v i2 ;

[0076] The digital processing module is used to extract the phase difference or time difference;

[0077] The mode selection module is used to select an appropriate mode, which includes a continuous wave mode and a pulse mode;

[0078] The microprocessor is used to calculate the distance using a temperature compensation algorithm and output the calculated distance to the display terminal 26 .

[0079] Example 2

[0080] This embodiment provides a ranging method for the laser radar ranging system based on the digital logic described in Example 1, which specifically includes the following steps:

[0081] Step 1: Initialize configuration and calibrate zero point;

[0082] Step 2: Signal transmission and reception: Transmit continuous laser light, receive reflected light and generate a standardized electrical signal v with phase difference i2 ;

[0083] Step 3: Phase difference extraction: Generate square wave v through high-speed comparator 01 and v 02 , the step wave is synthesized by the diode logic network, and the DC component V0 is extracted by RC filtering;

[0084] Step 4: Distance calculation: According to the formula Calculate the target distance.

[0085] The input signal of the circuit is Figure 6 As shown, V im is the signal amplitude, which can be measured or manually set, and T is a fixed period.

[0086] Phase difference time variable τ: two input signals v i1 With v i2 The zero-crossing time difference satisfies Reference pulse width τ0: Comparator reference voltage V REF The single cycle high level time is determined by

[0087] Then τ0 is expressed as:

[0088] The linear relationship between the DC component V0 output after RC filtering and τ is:

[0089] Where: V H =Vcc-V f is a logic high level (V f is the forward voltage drop of the diode, typically 0.5-0.7V); V th is the fast recovery diode conduction threshold (typical value 0.6V). Obviously, V0 and the time difference variable τ are linearly related. Under normal circumstances, V H >>V th , Therefore, V0 decreases linearly as τ increases;

[0090] Input zero phase difference signal (τ=0), record Input τ=τ0 signal, record

[0091] By measuring the DC voltage V0, we can calculate τ. Combining the above formulas, we can get the phase difference calculation formula: Determine the conversion factor

[0092] Example 3

[0093] like Figure 1 As shown, this embodiment provides a laser radar ranging system based on digital logic, which is used to measure the laser radar distance in pulse mode. The system includes:

[0094] A laser emitting unit is used to generate a modulated light signal and emit it to the target object, and the reflected light is sent to the signal processing unit;

[0095] A signal processing unit is used to convert the received reflected light into a standardized electrical signal, extract the time-of-flight information, and output two signals to the distance calculation unit;

[0096] The distance calculation unit calculates the target distance based on the phase difference or time difference information, satisfying the following formula:

[0097]

[0098] Where C is the speed of light, V H For logic high, V th is the fast recovery diode conduction threshold, τ0 is the reference pulse width, T is the signal period, and V0 is the DC component of the RC filter output.

[0099] like Figure 3 As shown, a laser emitting unit in pulse mode is introduced in detail. The laser emitting unit includes a pulse signal generator 10, an LD driver 11, an optical fiber amplifier 7 and an optical circulator 8; the pulse signal generator 10 generates a narrow pulse electrical signal, and the LD driver 11 drives the laser diode to emit an optical pulse, which is amplified by the optical fiber amplifier 7 and then emitted to the target through the optical circulator 8, and the reflected light pulse 17 is received.

[0100] like Figure 5As shown, a signal processing unit in pulse mode is introduced in detail, including an APD detector 18, a pulse shaping circuit 19, a logic operation unit and a linear conversion module; the reflected light pulse 17 is converted into an electrical signal by the APD detector 18 and sent to the pulse shaping circuit 19, and the pulse shaping circuit 19 performs shaping processing on the electrical signal. The logic operation unit adopts a diode logic network, including a first fast recovery diode 29 and a second fast recovery diode 30, and generates a square wave characteristic waveform with a pulse width proportional to the time difference Δt between the transmitted pulse and the received pulse through different conduction states; the linear conversion module is used to extract the DC component of the above square wave characteristic waveform and convert it into a current signal linearly related to the time difference, thereby realizing the quantitative output of the flight time information.

[0101] The linear conversion module includes an RC low-pass filter and a voltage-controlled current source 4. The RC low-pass filter is used to extract the DC component V0 of the characteristic waveform v0, establish a linear mathematical model of the output node V0 and the flight time variable τ to analyze the phase difference Wherein, K is a proportional coefficient; the voltage-controlled current source is used to convert the DC component V0 into a current signal that is linearly mapped with the delay time τ, thereby realizing the quantized output of the time-of-flight information.

[0102] like Figure 6 As shown, the distance calculation unit includes a signal acquisition module 20, a digital processing module 21, a mode selection module 22 and a microprocessor 23;

[0103] Among them, the signal acquisition module is used to receive the transmission trigger signal and the receiving pulse signal output by the signal processing unit;

[0104] The digital processing module is used to extract the flight time difference;

[0105] The mode selection module is used to select an appropriate mode, which includes a continuous wave mode and a pulse mode;

[0106] The microprocessor is used to calculate the distance using a temperature compensation algorithm and output the calculated distance to the display terminal 26 .

[0107] This embodiment provides a ranging method based on the system of embodiment 3, including:

[0108] 1. Initialization: calibrate the time reference pulse width τ0;

[0109] 2. Signal transmission and reception: transmit light pulses, receive reflected pulses and generate time difference electrical signals;

[0110] 3. Time difference extraction: Generate a pulse width square wave through a diode logic network, and extract the DC component through RC filtering;

[0111] 4. Distance calculation: according to the formula Calculate the target distance.

[0112] While the preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, the present invention is not limited to the specific details of the aforementioned embodiments. Within the scope of the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made. These simple variations all fall within the scope of protection of the present invention.

[0113] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0114] In addition, various embodiments of the present invention may be arbitrarily combined, as long as they do not violate the concept of the present invention, and they are also regarded as the contents disclosed by the present invention.

Claims

1. A laser radar ranging system based on digital logic, characterized in that: include: A laser emitting unit is used to generate a modulated light signal and emit it to the target object, and the reflected light is sent to the signal processing unit; A signal processing unit is used to convert the received reflected light into a standardized electrical signal, extract phase or time difference information, and output two signals to the distance calculation unit; The distance calculation unit calculates the target distance based on the phase difference or time difference information, satisfying the following formula: Where C is the speed of light, V H For logic high, V th is the fast recovery diode conduction threshold, τ0 is the reference pulse width, T is the signal period, and V0 is the DC component of the RC filter output.

2. A laser radar ranging system based on digital logic as claimed in claim 1, characterized in that: The laser emission unit comprises a local oscillator (5), a laser intensity modulator (6), an optical fiber amplifier (7) and an optical circulator (8) in a continuous wave mode; the local oscillator (5) generates a high-frequency sinusoidal electrical signal, the laser intensity modulator (6) drives a laser diode to convert the electrical signal into a continuous laser signal, and after the optical power is increased by the optical fiber amplifier (7), the signal is directionally emitted to a target through the optical circulator (8), and a reflected light signal (12) is received.

3. The laser radar ranging system based on digital logic according to claim 1, characterized in that: The laser emission unit comprises a pulse signal generator (10), an LD driver (11), an optical fiber amplifier (7) and an optical circulator (8) in a pulse mode; the pulse signal generator (10) generates a narrow pulse electrical signal, the LD driver (11) drives the laser diode to emit a light pulse, which is amplified by the optical fiber amplifier (7) and then emitted to a target through the optical circulator (8), and a reflected light pulse (17) is received.

4. The laser radar ranging system based on digital logic according to claim 1, characterized in that: The signal processing unit comprises a photoelectric converter (13), a conditioning circuit (14), a high-speed comparator, a logic operation unit and a linear conversion module in a continuous wave mode; the reflected light signal (12) is converted by the photoelectric converter (13) into an electrical signal containing a phase difference and then sent to the conditioning circuit (14); the conditioning circuit (14) performs transimpedance amplification, automatic gain control and bandpass filtering to obtain an input signal v with the same frequency but different phase. i1 and v i2 The high-speed comparator receives an input signal and outputs a square wave signal with a phase difference to a logic operation unit. The logic operation unit adopts a diode logic network, including a first fast recovery diode (29) and a second fast recovery diode (30), and generates a step waveform containing two jumps in each cycle through different conduction states; the linear conversion module is used to extract the DC component of the step waveform and convert it into a current signal linearly related to the phase difference, thereby realizing the quantized output of phase information.

5. The laser radar ranging system based on digital logic according to claim 4, characterized in that: The high-speed comparator comprises a first comparator (27) and a second comparator (28), wherein the positive input terminal of the first comparator (27) is connected to the first input signal v i1 , the negative input terminal is connected to the reference voltage V REF The positive input terminal of the second comparator (28) is connected to the first input signal v i2 , the negative input terminal is connected to the reference voltage V REF The two comparator outputs generate square wave signals v corresponding to the zero crossing points of the input signal. 01 and v 02 The positive electrode of the first fast recovery diode (29) is connected to v 01 The negative electrode of the signal line is connected to the output node v0; the negative electrode of the second fast recovery diode (30) is connected to v 02 Signal line, the positive pole is connected to the output node v0; node v0 is connected to the power supply voltage Vcc through a pull-up resistor, and outputs a step waveform.

6. The laser radar ranging system based on digital logic according to claim 1, characterized in that: In pulse mode, the signal processing unit includes an APD detector (18), a pulse shaping circuit (19), a logic operation unit, and a linear conversion module; the reflected light pulse (17) is converted into an electrical signal by the APD detector (18) and then sent to the pulse shaping circuit (19); the pulse shaping circuit (19) performs shaping processing on the electrical signal; the logic operation unit uses a diode logic network, including a first fast recovery diode (29) and a second fast recovery diode (30), and generates a square wave characteristic waveform with a pulse width proportional to the time difference Δt between the transmitted pulse and the received pulse through different conduction states; The linear conversion module is used to extract the DC component of the square wave characteristic waveform and convert it into a current signal that is linearly related to the time difference, thereby achieving quantitative output of flight time information.

7. The laser radar ranging system based on digital logic according to claim 1, characterized in that: The linear conversion module includes an RC low-pass filter and a voltage-controlled current source (4). The RC low-pass filter is used to extract the DC component V0 of the characteristic waveform v0, establish a linear mathematical model between the output node V0 and the flight time variable τ to analyze the time difference; and the voltage-controlled current source is used to convert the DC component V0 into a current signal that is linearly mapped with the delay time τ, thereby realizing the quantitative output of the flight time information.

8. The laser radar ranging system based on digital logic according to claim 1, characterized in that: The distance calculation unit includes a signal acquisition module (20), a digital processing module (21), a mode selection module (22) and a microprocessor (23); Among them, the signal acquisition module is used to receive the transmission trigger signal and the receiving pulse signal output by the signal processing unit; The digital processing module is used to extract the flight time difference; The mode selection module is used to select an appropriate mode, which includes a continuous wave mode and a pulse mode; The microprocessor is used to calculate the distance through a temperature compensation algorithm and output the distance to a display terminal (26).

9. The ranging method of a laser radar ranging system based on digital logic according to claim 1, characterized in that: The specific steps include: Step 1: Initialize the configuration and select continuous wave mode or pulse mode; Step 2: Continuous wave mode: emit continuous laser light, capture the reflected light and generate a standardized electrical signal with phase difference; Pulse mode: emits light pulses, captures reflected pulses and generates time difference electrical signals; Step 3: Continuous Wave Mode: A staircase waveform is synthesized through a diode logic network, and its level characteristics are linearly related to the phase difference; Pulse mode: The transmit trigger signal and the receive pulse signal are logically operated through the diode logic network to generate a square wave characteristic waveform with a pulse width proportional to the time difference Δt; Step 4: Calculate the target distance based on the phase difference or time difference using the following formula:

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