Lightning protection device of photoelectric navigation equipment

Abstract

The invention provides a thunder and lightning protection device for photoelectric navigation equipment, the photoelectric navigation equipment comprises an outboard device and an in-cabin device, the outboard device and the in-cabin device are connected through a connecting cable, and the thunder and lightning protection device comprises an outboard device thunder and lightning suppression module and an in-cabin device thunder and lightning protection module; the outboard equipment lightning suppression module is installed inside the outboard equipment, the in-cabin equipment lightning protection module is connected to the connecting cable in series, and the in-cabin equipment lightning protection module is grounded through an independent current loop. The outboard equipment lightning suppression module serves as a first defense line for lightning protection, is installed in outboard equipment (such as a photoelectric sensor, an antenna, an external detector and the like which are exposed in a complex electromagnetic environment), and preferentially suppresses lightning indirect effects (such as inductive lightning surge and electrostatic discharge) entering from outboard cable coupling. And surge energy is prevented from being directly transmitted into the connecting cable.

Description

Technical Field

[0001] This invention relates to the field of analog-to-digital conversion application equipment technology, specifically to a lightning protection device for photoelectric navigation equipment. Background Technology

[0002] Optical and photoelectric navigation equipment is widely used in outdoor environments and is inevitably exposed to lightning fields, facing the dual threats of direct and indirect lightning effects. Direct lightning effects can cause physical damage such as surface breakdown and structural deformation, while indirect lightning effects generate surge voltages and currents through coupling, interfering with or damaging the internal electrical performance of the equipment, leading to signal disturbances, erroneous command outputs, or even equipment shutdown. Since the core safety requirement for optical and photoelectric navigation equipment lies in resisting indirect lightning effects, existing protective measures mainly involve installing protective modules at the external connectors, using gas discharge tubes at the front end to discharge surge currents, and supplementing the back end with filtering or current limiting methods to suppress surge voltages.

[0003] However, existing protection solutions have significant shortcomings: the electrical signals of optoelectronic navigation equipment include DC voltage signals, differential signals, and AC voltage signals. The characteristics of different types of signals are significantly different (such as power, frequency, transmission mode, etc.), but existing protection modules are not precisely designed for signal types, resulting in insufficient protection targeting. At the same time, protection modules are mostly concentrated in a single link (such as only set at the connector), failing to form a collaborative protection system between external and internal equipment. The lightning current discharge path is not independent or continuous, the residual voltage suppression effect is limited, and it is difficult to ensure the stable operation of the equipment in complex lightning environments. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention proposes a lightning protection device for an optoelectronic navigation device. The optoelectronic navigation device includes an external device and an internal device, which are connected by a connecting cable. The lightning protection device includes a lightning suppression module for the external device and a lightning protection module for the internal device. The lightning suppression module for the external equipment is installed inside the external equipment. The lightning protection module for the equipment inside the cabin is connected in series with the connecting cable, and the lightning protection module for the equipment inside the cabin is grounded through an independent current loop.

[0005] Preferably, the lightning suppression module for the external equipment includes a first lightning suppression module and a second lightning suppression module; The lightning protection module for the in-cabin equipment includes a first lightning protection module, a second lightning protection module, a third lightning protection module, a fourth lightning protection module, a fifth lightning protection module, a sixth lightning protection module, and a seventh lightning protection module; The connecting cables include a first connecting cable, a second connecting cable, a third connecting cable, a fourth connecting cable, a fifth connecting cable, a sixth connecting cable, and a seventh connecting cable; The first lightning protection module is connected to the first lightning suppression module via the first connecting cable; the second lightning protection module is connected to the first lightning suppression module via the second connecting cable; the third lightning protection module is connected to the first lightning suppression module via the third connecting cable; the fourth lightning protection module is connected to the first lightning suppression module via the fourth connecting cable; and the fifth lightning protection module is connected to the first lightning suppression module via the fifth connecting cable. The sixth lightning protection module is connected to the second lightning suppression module via the sixth connecting cable, and the seventh lightning protection module is connected to the second lightning suppression module via the seventh connecting cable.

[0006] Preferably, the first lightning suppression module, the first lightning protection module, the second lightning protection module, the third lightning protection module, the fourth lightning protection module, and the fifth lightning protection module are DC voltage signal protection modules; The second lightning suppression module, the sixth lightning protection module, and the seventh lightning protection module are differential signal protection modules.

[0007] Preferably, the DC voltage signal protection module includes a first gas discharge tube, a common-mode inductor, and a first TVS diode; The differential signal protection module includes a second gas discharge tube, a second TVS diode, a current-limiting resistor, and a common-mode inductor connected in series.

[0008] Preferably, in the DC voltage signal protection module, the first gas discharge tube includes gas discharge tube G1 and gas discharge tube G2, and the first TVS diode includes TVS diode D2, TVS diode D3, TVS diode D4, and TVS diode D5. Gas discharge tubes G1 and G2 are connected in parallel between the positive and negative terminals of the input power supply and ground, respectively. The input side of the common-mode inductor is connected to the output terminals of gas discharge tubes G1 and G2, and the output side is connected to the first TVS diode. The positive terminal of TVS diode D2 is connected to the output terminal of the common-mode inductor, and the negative terminal is grounded; the negative terminal of TVS diode D3 is connected to the output terminal of the common-mode inductor, and the positive terminal is grounded; the positive terminal of TVS diode D4 is connected to the output terminal of the common-mode inductor, and the negative terminal is grounded; the negative terminal of TVS diode D5 is connected to the output terminal of the common-mode inductor, and the positive terminal is grounded.

[0009] Preferably, the DC voltage signal protection module further includes a diode D1, which is connected in series in the positive power output line.

[0010] Preferably, in the differential signal protection module, the second gas discharge tube includes gas discharge tube G3 and gas discharge tube G4; the second TVS diode includes TVS diode D5, TVS diode D6, TVS diode D7, and TVS diode D8; the current limiting resistor includes resistor R1, resistor R2, resistor R3, and resistor R4; and the common mode inductor includes inductor L1 and inductor L3. One end of the gas discharge tube G3 is directly connected to the 422 RX+ signal, and the other end is grounded; one end of the TVS diode D5 is connected to the 422 RX+ signal, and the other end is grounded; one end of the TVS diode D6 is connected to the 422 RX+ signal, and the other end is connected to the 422 RX- signal; resistors R1 and R2 are connected in series in the 422 RX+ signal link after TVS diodes D5 and D6; common mode inductor L1 is connected in series after resistor R2, outputting the 422 RX+_OUT signal; One end of the gas discharge tube G4 is directly connected to the 422 RX- signal, and the other end is grounded; TVS diode D7 is connected between the 422 RX- signal and ground, and TVS diode D8 is connected between the 422 RX- signal and the 422 RX+ signal; resistors R3 and R4 are connected in series after TVS diodes D7 and D8 to limit current; inductor L3 is connected in series after resistor R4, outputting 422 RX-_OUT.

[0011] Preferably, it also includes an AC voltage signal protection module, which is located at the external equipment interface and at the AC signal inlet of the internal equipment. The AC voltage signal protection module includes a third gas discharge tube, a varistor, a common-mode inductor, and a third TVS diode.

[0012] In summary, the lightning protection device for photoelectric navigation equipment provided by the present invention has the following beneficial effects: The system employs a three-tiered protection architecture to precisely suppress surge energy: a gas discharge tube (discharge) → TVS diode (clamping) → current-limiting resistor / common-mode inductor (filtering and current limiting). The front-end gas discharge tube rapidly discharges large-current surges, the mid-end TVS clamps the residual voltage to the device's tolerance value, and the back-end resistor / inductor further weakens high-frequency interference and current surges, preventing single-stage device overload failure. Different protection parameters are configured for different types of signals, such as DC voltage, differential signal, and AC voltage (e.g., common-mode inductor filtering for DC and line-to-line TVS protection for differential signals) to ensure that protection does not affect normal signal transmission (e.g., differential signal insertion loss <1dB). By combining gas discharge tubes (common mode bleed), bidirectional TVS (line-to-ground + line-to-line clamping), and common mode inductors (high-frequency common mode suppression), common mode interference (such as sudden voltage changes between cables and ground) and differential mode interference (such as sudden voltage differences between signal lines) caused by lightning are suppressed simultaneously, thus avoiding distortion of navigation data transmission (such as IMU attitude data bit error rate <0.1%).

[0013] Devices such as gas discharge tubes and TVS diodes automatically return to a high-resistance state after a surge (a non-destructive action), preventing continuous short circuits from causing power outages or fires, and ensuring the safe operation of the photoelectric navigation system. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the lightning protection device structure of the photoelectric navigation equipment according to an embodiment of the present invention.

[0016] Figure 2 The structure of the DC voltage signal protection module is shown in this embodiment of the invention.

[0017] Figure 3 This is a structural block diagram of the differential signal protection module according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] See Figure 1 The present invention provides a lightning protection device for an optoelectronic navigation device, the optoelectronic navigation device including an external device and an internal device, the external device and the internal device being connected by a connecting cable, and the lightning protection device including an external device lightning suppression module and an internal device lightning protection module; The lightning suppression module for the external equipment is installed inside the external equipment. The lightning protection module for the equipment inside the cabin is connected in series with the connecting cable, and the lightning protection module for the equipment inside the cabin is grounded through an independent current loop.

[0020] Specifically, the lightning suppression module for external equipment serves as the "first line of defense" against lightning. It is installed inside external equipment (such as photoelectric sensors, antennas, external detectors, and other equipment exposed to complex electromagnetic environments) to prioritize suppressing indirect lightning effects (such as induced lightning surges and electrostatic discharges) coupled in from external cables, thus preventing surge energy from being directly transmitted to the connecting cables.

[0021] The lightning protection module for the equipment inside the cabin serves as the "second line of defense" against lightning. It is connected in series on the connecting cable between the equipment outside the cabin and the equipment inside the cabin (such as the interface end of the cable near the equipment inside the cabin). It provides secondary protection against residual surges weakened by the suppression module outside the cabin and completely discharges surge energy through an independent grounding circuit to prevent it from intruding into the core equipment inside the cabin (such as the navigation host and data processing unit).

[0022] Based on the above embodiments, as a preferred implementation method, such as Figure 1 As shown, the external equipment lightning suppression module includes a first lightning suppression module and a second lightning suppression module; The lightning protection module for the in-cabin equipment includes a first lightning protection module, a second lightning protection module, a third lightning protection module, a fourth lightning protection module, a fifth lightning protection module, a sixth lightning protection module, and a seventh lightning protection module; The connecting cables include a first connecting cable, a second connecting cable, a third connecting cable, a fourth connecting cable, a fifth connecting cable, a sixth connecting cable, and a seventh connecting cable (corresponding to...). Figure 1 (Connecting cables W01 to W07 in the middle). The first lightning protection module is connected to the first lightning suppression module via the first connecting cable; the second lightning protection module is connected to the first lightning suppression module via the second connecting cable; the third lightning protection module is connected to the first lightning suppression module via the third connecting cable; the fourth lightning protection module is connected to the first lightning suppression module via the fourth connecting cable; and the fifth lightning protection module is connected to the first lightning suppression module via the fifth connecting cable. The sixth lightning protection module is connected to the second lightning suppression module via the sixth connecting cable, and the seventh lightning protection module is connected to the second lightning suppression module via the seventh connecting cable.

[0023] Specifically, the W01-W07 cables corresponding to the connecting cables integrate 7 independent protection channels, each matching the signal type of the external suppression module. Channels 1-5 (DC voltage signals): The structure is the same as the DC sub-circuit of the external suppression module, but the device parameters are enhanced (e.g., lower TVS clamping voltage, higher common-mode inductor filtering accuracy) to ensure that the residual surge voltage is ≤ the withstand voltage of the internal equipment interface (e.g., ≤15V). Channels 6-7 (differential signals): The structure is the same as the differential circuit of the external suppression module, and ferrite beads can be added to further filter out high-frequency interference, ensuring that the differential signal-to-noise ratio is ≥40dB.

[0024] The first lightning suppression module is used for DC voltage signal protection, responsible for handling high-power DC signals (such as 15-30V power supplies and drive signals transmitted via connecting cables W01-W05). These signals are characterized by high current and stable voltage, but lightning surges can easily cause overvoltage / overcurrent damage to downstream circuits (such as motor drives and sensor power supplies). Therefore, the first lightning suppression module needs to focus on "high current discharge + voltage smoothing". The second lightning suppression module is responsible for differential signal protection and processing digital differential signals (such as the 422 communication signals transmitted via connecting cables W06-W07). These signals are characterized by low voltage, high frequency, and sensitivity to interference (lightning surges can easily cause signal errors and communication interruptions). Therefore, the second lightning suppression module needs to focus on "high-frequency filtering + precise clamping".

[0025] Taking W01 DC signal as an example, external suppression (first lightning suppression module): First, 80%-90% of the surge current (such as the large current induced by lightning) is discharged through a gas discharge tube. Then, a common-mode inductor is used to filter voltage fluctuations. Finally, a TVS diode is used to clamp the residual voltage (such as reducing a 30V surge voltage to below 15V). This coarse-filtering of the surge protects the output terminals of the external equipment and prevents large-energy surges from directly impacting the connecting cables.

[0026] Internal protection (first lightning protection module): Secondary fine protection is provided for the "residual surge" after external suppression: the voltage is clamped again with TVS diodes (e.g., from 15V to 10V), and high-frequency interference (e.g., MHz-level noise from lightning coupling) is filtered out through a common-mode inductor.

[0027] Taking the W06 differential signal as an example, external suppression (second lightning suppression module): First, the surge current is discharged through the gas discharge tube. Then, the bidirectional TVS diode is used to protect against both "line-to-ground surge" (signal to ground overvoltage) and "line-to-line surge" (signal line-to-line overvoltage). Finally, a ferrite bead is used to filter high-frequency noise (such as high-frequency interference in the 422 signal).

[0028] Coarse surge filtering and differential mode interference immunity ensure that the differential signal output from outside the cabin is "identifiable" (bit error rate ≤ 0.1%).

[0029] Internal protection (sixth lightning protection module): The signal suppressed outside the cabin is finely clamped again with a TVS diode and filtered more effectively with a common-mode inductor to ensure that the differential signal entering the cabin can be accurately identified (bit error rate ≤ 0.01%).

[0030] Surge filtering and common-mode interference suppression protect the communication interfaces of equipment inside the cabin (such as serial port chips).

[0031] Based on the above embodiments, as a preferred implementation, the first lightning suppression module, the first lightning protection module, the second lightning protection module, the third lightning protection module, the fourth lightning protection module, and the fifth lightning protection module are DC voltage signal protection modules; The second lightning suppression module, the sixth lightning protection module, and the seventh lightning protection module are differential signal protection modules.

[0032] Specifically, the electrical signals of optoelectronic navigation equipment can be divided into DC voltage signals, differential signals, and AC voltage signals. Based on the type of electrical signal, this embodiment can classify the protection scheme into DC voltage signal lightning indirect effect protection, differential signal lightning indirect effect protection, and AC voltage signal lightning indirect effect protection.

[0033] Furthermore, the aforementioned protection against the indirect effects of lightning on DC voltage signals employs a combination of lightning protection and filtering. Lightning protection is implemented at the front end, while filtering is implemented at the back end. Gas discharge tubes are used for lightning protection at the front end. At the back end, a common-mode inductor is used for power smoothing, followed by voltage clamping via a TVS diode to further limit the lightning voltage.

[0034] The aforementioned differential signal lightning indirect effect protection employs a combination of lightning protection and current limiting, with lightning protection at the front end and current limiting at the back end. The front-end lightning protection device uses a gas discharge tube. The back end uses a combination of TVS diodes and resistors to limit voltage and current, further restricting the lightning voltage. A ferrite bead is connected to the output terminal to filter out high-frequency interference generated during lightning strikes, ensuring the signal is not affected by noise.

[0035] The aforementioned AC voltage signal lightning indirect effect protection employs a combination of lightning protection and current limiting, with lightning protection at the front end and current limiting at the back end. The front-end lightning protection device uses a gas discharge tube. The back end uses a series resistor for current limiting, while simultaneously controlling the insertion loss between 0.5dB and 1.0dB to achieve the best lightning protection effect.

[0036] Based on the above embodiments, as a preferred implementation, the DC voltage signal protection module includes a first gas discharge tube, a common mode inductor, and a first TVS diode; The differential signal protection module includes a second gas discharge tube, a second TVS diode, a current-limiting resistor, and a common-mode inductor connected in series.

[0037] A gas discharge tube is a lightning protection device. When the voltage across its terminals reaches a certain threshold (breakdown voltage), the internal gas ionizes and conducts, which can quickly discharge large current.

[0038] A common-mode inductor is a filtering device that can suppress common-mode interference signals and has little impact on differential-mode signals. It can perform filtering processes such as "smoothing" on power signals after passing through a gas discharge tube.

[0039] TVS diodes are transient voltage suppressor diodes that can clamp excessively high voltages to a safe value in a very short time, protecting downstream circuits.

[0040] Based on the above embodiments, as a preferred implementation method, such as Figure 2 As shown in the figure, in the DC voltage signal protection module, the first gas discharge tube includes gas discharge tube G1 and gas discharge tube G2, and the first TVS diode includes TVS diode D2, TVS diode D3, TVS diode D4 and TVS diode D5. Gas discharge tubes G1 and G2 are connected in parallel between the positive and negative terminals of the input power supply and ground, respectively; the two gas discharge tubes G1 and G2 are connected in parallel between the positive and negative terminals of the input 15-30V power supply and ground (GND), forming the first-level lightning protection discharge channel, which is used to initially discharge lightning surge current.

[0041] The input side of the common-mode inductor is connected to the output terminals of gas discharge tubes G1 and G2, and the output side is connected to the first TVS diode. In the main power supply circuit after the gas discharge tube, the input side is connected to the output terminal of the gas discharge tube, and the output side is connected to the subsequent TVS diode circuit, which is used to perform preliminary filtering and stabilize voltage fluctuations of residual voltage from lightning surges.

[0042] The anode of TVS diode D2 is connected to the output terminal of the common-mode inductor, and the cathode is grounded; the cathode of TVS diode D3 is connected to the output terminal of the common-mode inductor, and the anode is grounded; the anode of TVS diode D4 is connected to the output terminal of the common-mode inductor, and the cathode is grounded; the cathode of TVS diode D5 is connected to the output terminal of the common-mode inductor, and the anode is grounded. These diodes are connected in parallel between the common-mode inductor output and ground to clamp the residual surge voltage passing through the common-mode inductor, further limiting the voltage amplitude and protecting the downstream circuitry.

[0043] Based on the above embodiments, as a preferred implementation, the DC voltage signal protection module further includes a diode D1, which is connected in series in the positive power output line. Connected in series in the positive power output line, it ensures a positive output of 15-30V voltage, preventing reverse voltage surges and other issues (it can also assist in providing some overvoltage and overcurrent protection logic), ultimately outputting 15-30V voltage to the load or subsequent circuits.

[0044] Based on the above embodiments, as a preferred implementation method, such as Figure 3 As shown in the diagram, in the differential signal protection module, the second gas discharge tube includes gas discharge tube G3 and gas discharge tube G4; the second TVS diode includes TVS diode D5, TVS diode D6, TVS diode D7, and TVS diode D8; the current limiting resistor includes resistor R1, resistor R2, resistor R3, and resistor R4; and the common mode inductor includes inductor L1 and inductor L3. One end of the gas discharge tube G3 is directly connected to the 422 RX+ signal, and the other end is grounded. During a lightning surge, G1 breaks down and conducts, and the lightning current is discharged through G1→ground, initially weakening the surge. One end of the TVS diode D5 is connected to the 422 RX+ signal, and the other end is grounded. One end of the TVS diode D6 is connected to the 422 RX+ signal, and the other end is connected to the 422 RX- signal. When the residual surge voltage exceeds the TVS threshold (e.g., 7.5V), D5 and D6 conduct and clamp, locking the voltage at a safe value to protect the downstream circuit. Resistors R1 and R2 are connected in series in the 422 RX+ signal link after TVS diodes D5 and D6. Common-mode inductor L1 is connected in series after resistor R2, outputting the 422RX+_OUT signal. One end of the gas discharge tube G4 is directly connected to the 422 RX- signal, and the other end is grounded; TVS diode D7 is connected between the 422 RX- signal and ground, and TVS diode D8 is connected between the 422 RX- signal and the 422 RX+ signal; resistors R3 and R4 are connected in series after TVS diodes D7 and D8 to limit current; inductor L3 is connected in series after resistor R4, outputting 422 RX-_OUT.

[0045] Based on the above embodiments, as a preferred implementation, it further includes an AC voltage signal protection module, which is located at the external equipment interface and at the AC signal inlet of the internal equipment. The AC voltage signal protection module includes a third gas discharge tube, a varistor, a common-mode inductor, and a third TVS diode.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightning protection device for an optoelectronic navigation equipment, the optoelectronic navigation equipment comprising an external device and an internal device, the external device and the internal device being connected by a connecting cable, characterized in that, The lightning protection device includes an external equipment lightning suppression module and an internal equipment lightning protection module. The lightning suppression module for the external equipment is installed inside the external equipment. The lightning protection module for the equipment inside the cabin is connected in series with the connecting cable, and the lightning protection module for the equipment inside the cabin is grounded through an independent current loop.

2. The lightning protection device for the photoelectric navigation equipment according to claim 1, characterized in that, The lightning suppression module for the external equipment includes a first lightning suppression module and a second lightning suppression module; The lightning protection module for the in-cabin equipment includes a first lightning protection module, a second lightning protection module, a third lightning protection module, a fourth lightning protection module, a fifth lightning protection module, a sixth lightning protection module, and a seventh lightning protection module; The connecting cables include a first connecting cable, a second connecting cable, a third connecting cable, a fourth connecting cable, a fifth connecting cable, a sixth connecting cable, and a seventh connecting cable; The first lightning protection module is connected to the first lightning suppression module via the first connecting cable; the second lightning protection module is connected to the first lightning suppression module via the second connecting cable; the third lightning protection module is connected to the first lightning suppression module via the third connecting cable; the fourth lightning protection module is connected to the first lightning suppression module via the fourth connecting cable; and the fifth lightning protection module is connected to the first lightning suppression module via the fifth connecting cable. The sixth lightning protection module is connected to the second lightning suppression module via the sixth connecting cable, and the seventh lightning protection module is connected to the second lightning suppression module via the seventh connecting cable.

3. The lightning protection device for the photoelectric navigation equipment according to claim 2, characterized in that, The first lightning suppression module, the first lightning protection module, the second lightning protection module, the third lightning protection module, the fourth lightning protection module, and the fifth lightning protection module are DC voltage signal protection modules; The second lightning suppression module, the sixth lightning protection module, and the seventh lightning protection module are differential signal protection modules.

4. The lightning protection device for the photoelectric navigation equipment according to claim 3, characterized in that, The DC voltage signal protection module includes a first gas discharge tube, a common-mode inductor, and a first TVS diode; The differential signal protection module includes a second gas discharge tube, a second TVS diode, a current-limiting resistor, and a common-mode inductor connected in series.

5. The lightning protection device for the photoelectric navigation equipment according to claim 4, characterized in that, In the DC voltage signal protection module, the first gas discharge tube includes gas discharge tube G1 and gas discharge tube G2, and the first TVS diode includes TVS diode D2, TVS diode D3, TVS diode D4, and TVS diode D5. Gas discharge tubes G1 and G2 are connected in parallel between the positive and negative terminals of the input power supply and ground, respectively. The input side of the common-mode inductor is connected to the output terminals of gas discharge tubes G1 and G2, and the output side is connected to the first TVS diode. The positive terminal of TVS diode D2 is connected to the output terminal of the common-mode inductor, and the negative terminal is grounded; the negative terminal of TVS diode D3 is connected to the output terminal of the common-mode inductor, and the positive terminal is grounded; the positive terminal of TVS diode D4 is connected to the output terminal of the common-mode inductor, and the negative terminal is grounded; the negative terminal of TVS diode D5 is connected to the output terminal of the common-mode inductor, and the positive terminal is grounded.

6. The lightning protection device for the photoelectric navigation equipment according to claim 5, characterized in that, The DC voltage signal protection module also includes a diode D1, which is connected in series in the positive power output line.

7. The lightning protection device for the photoelectric navigation equipment according to claim 4, characterized in that, In the differential signal protection module, the second gas discharge tube includes gas discharge tube G3 and gas discharge tube G4; the second TVS diode includes TVS diode D5, TVS diode D6, TVS diode D7, and TVS diode D8; the current limiting resistor includes resistor R1, resistor R2, resistor R3, and resistor R4; and the common mode inductor includes inductor L1 and inductor L3. One end of the gas discharge tube G3 is directly connected to the 422 RX+ signal, and the other end is grounded; one end of the TVS diode D5 is connected to the 422 RX+ signal, and the other end is grounded; one end of the TVS diode D6 is connected to the 422 RX+ signal, and the other end is connected to the 422 RX- signal; resistors R1 and R2 are connected in series in the 422 RX+ signal link after TVS diodes D5 and D6; common-mode inductor L1 is connected in series after resistor R2, outputting the 422 RX+_OUT signal; One end of the gas discharge tube G4 is directly connected to the 422 RX- signal, and the other end is grounded; TVS diode D7 is connected between the 422 RX- signal and ground, and TVS diode D8 is connected between the 422 RX- signal and the 422 RX+ signal; resistors R3 and R4 are connected in series after TVS diodes D7 and D8 to limit current; inductor L3 is connected in series after resistor R4, outputting 422 RX-_OUT.

8. The lightning protection device for the photoelectric navigation equipment according to claim 3, characterized in that, It also includes an AC voltage signal protection module, which is located at the external equipment interface and at the AC signal inlet of the internal equipment. The AC voltage signal protection module includes a third gas discharge tube, a varistor, a common-mode inductor, and a third TVS diode.

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