Method and system for detecting and compensating light decay of navigation signal lamp

Abstract

The invention discloses a method and system for detecting and compensating light decay of a navigation signal lamp, and relates to the technical field of navigation signal lamps and control of the navigation signal lamps, and the system comprises a photosensitive sensor module, an LED driving module and a navigation signal lamp control device. The photosensitive sensor module is used for detecting the illumination intensity of the navigation signal lamp and the scattered light intensity of the light of the signal lamp at different angles, the LED driving module is used for driving the LED lamp string to emit light, and the navigation signal lamp control device is used for carrying out light attenuation detection according to the illumination intensity and the scattered light intensity at different measurement angles. The driving current of the LED driving module is increased by adjusting the duty ratio of the PWM signal, so that light attenuation compensation is carried out on the LED lamp string, and the visibility of the navigation signal lamp is maintained; according to the technical scheme, light attenuation compensation of the photosensitive sensor module can be realized, so that the navigation signal lamp maintains constant brightness in different light attenuation stages or in an extreme environment, and the stability and reliability of the brightness of the navigation signal lamp are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of navigation signal light and its control, in particular to a method and system for navigation signal light light decay detection and compensation. BACKGROUND

[0002] In the traditional navigation signal light system, the brightness state of the LED lamp is usually judged by artificial naked eye observation. When the brightness of the LED light source decreases, the maintenance personnel judges whether the lamp bead needs to be replaced by experience. This judgment method has obvious limitations: 1) inaccurate judgment: artificial naked eye judgment is affected by environmental light, observation angle and human subjective factors, it is difficult to accurately judge the real light intensity and light decay degree of the LED lamp, and the remaining life of the LED light source cannot be scientifically evaluated; 2) lack of light decay compensation mechanism: after discovering the light decay of the LED, the traditional control circuit usually directly replaces the lamp bead, and does not provide the function of compensating and adjusting the driving current or brightness of the LED light. This not only increases the maintenance cost and material waste, but also may cause the performance of the system before the light decay to be not fully utilized; 3) unable to automatically adjust the light intensity to maintain visibility: the traditional system cannot monitor the light intensity in real time and automatically adjust the LED driving current to realize light decay compensation, so as to ensure the visibility and reliability of the navigation signal light under any environmental conditions. Since the environmental factors such as the change of underwater turbidity affect the scattered light intensity, the traditional system fails to make appropriate automatic compensation adjustment for these changes. Therefore, the existing LED light control system has problems of inaccurate light decay monitoring, lack of intelligent compensation adjustment, resource waste and high maintenance cost, and an intelligent control system capable of monitoring the light intensity in real time and automatically adjusting the LED driving current to realize light decay compensation is needed. SUMMARY

[0003] The purpose of the present application is to provide a method and system for navigation signal light light decay detection and compensation, which accurately detects the light intensity of the LED light string and the scattered light intensity of the light emitted by the navigation signal light in different directions, and automatically adjusts the current output by the LED driving module according to the light decay condition, realizes light decay compensation of the LED light string, maintains the visibility of the navigation signal light under the current environment, reduces human error and maintenance cost, and avoids resource waste.

[0004] The technical solution of the present application is to provide a method for navigation signal light light decay detection and compensation, which comprises:

[0005] A first photosensitive sensor, a second photosensitive sensor, a third photosensitive sensor and an LED driving module, the LED driving module is used for driving the LED light string to emit light according to the PWM signal emitted by the navigation signal light control device, and the method comprises:

[0006] S1: Use the first photosensitive sensor to obtain the light intensity of the LED string within the current time period and calculate the average light intensity within the current time period, wherein the first photosensitive sensor is located inside the lampshade where the LED string is located;

[0007] S2: Preset light intensity threshold. If the average light intensity is greater than or equal to the light intensity threshold, it is determined that the LED string has no light decay. If the average light intensity is less than the light intensity threshold, it is determined that the LED string has light decay. The adjustment duty cycle of the PWM signal is calculated based on the difference between the light intensity threshold and the average light intensity.

[0008] S3: The intensity of the scattered light emitted by the navigation signal light is collected from the first measurement angle and the second measurement angle using the second photosensitive sensor and the third photosensitive sensor respectively. The intensity of the scattered light is corrected according to the measurement angle of each sensor. The second photosensitive sensor and the third photosensitive sensor are symmetrically arranged outside the lamp cover, and the optical axes of the second photosensitive sensor and the third photosensitive sensor intersect with the optical axis directly in front of the navigation signal light.

[0009] S4: Calculate the ratio of scattered light intensity in different directions, construct a function model of the ambient light attenuation intensity around the navigation signal light with respect to the ratio, use the function model to calculate the light attenuation intensity of the current environment, calculate the compensation duty cycle of the PWM signal based on the light attenuation intensity of the current environment, and superimpose the compensation duty cycle on the adjustment duty cycle to adjust the current PWM signal. When the duty cycle of the PWM signal reaches its maximum value and the light intensity of the LED string is still less than the preset light intensity threshold, turn off the LED driver chip and control the alarm to sound.

[0010] Furthermore, S2 specifically includes: averaging the light intensity over the current time period. With light intensity threshold If a comparison is made, ≥ If the LED string shows no light decay, the duty cycle D1 of the PWM signal is set to 0. < If the LED string shows signs of light decay, the duty cycle of the PWM signal is calculated based on the difference between the light intensity threshold and the average light intensity, expressed as:

[0011] ;

[0012] In the formula, D1 is the adjustment duty cycle of the PWM signal, k1 and k2 are proportional coefficients, and D max To determine the maximum allowable duty cycle, D max =1, Δ1 and Δ2 are the exponential adjustment coefficients and the error interval thresholds.

[0013] Further, S3 specifically comprises: obtaining the scattering function by experimental data fitting , and taking 0° as the reference angle to bring into the scattering function to calculate the reference scattering function value f ref , constructing a light intensity correction function based on the scattering function and the reference scattering function value f ref , denoted as

[0014] ;

[0015] In the formula, I act is the corrected actual scattering light intensity, I meas is the collected scattering light intensity, is the measurement angle; the first measurement angle corresponding to the second light-sensitive sensor is brought into the light intensity correction function to calculate the corrected first actual scattering light intensity I act ( ), and the second measurement angle corresponding to the third light-sensitive sensor is brought into the light intensity correction function to calculate the corrected second actual scattering light intensity I act ( ).

[0016] Further, in S3, the scattering function is obtained by experimental data fitting, specifically comprising:

[0017] An experimental scene for simulating the current environment is arranged, a plurality of measurement angles are set in the range of 0° to 90°, a light source is placed in the experimental scene, and the scattering light intensity is measured at each measurement angle by using a sensor, the measured scattering light intensity and the corresponding measurement angle are recorded, a plurality of experimental data are obtained, and based on the plurality of experimental data, the scattering function is fitted in a preset sinusoidal function form, the scattering function is denoted as:

[0018] ;

[0019] In the formula, A and B are constants to be fitted; the least square method is used to fit the scattering function , A and B are continuously adjusted so that the error between the output of the scattering function and the scattering light intensity data at each measurement angle is minimized, and finally A and B are obtained.

[0020] Further, S4 specifically comprises: calculating the ratio I act ( ) / I act( ), a function model of the ambient light attenuation intensity around the navigation signal light about the ratio is constructed, which is expressed as:

[0021] ;

[0022] In the formula, T is the ambient light attenuation intensity around the navigation signal light, is the attenuation coefficient, d1 is the distance from the intersection point of the optical axis of the second photosensitive sensor and the optical axis of the navigation signal light to the navigation signal light, d2 is the distance from the intersection point of the optical axis of the third photosensitive sensor and the optical axis of the navigation signal light to the navigation signal light, and n is the power index, 0

[0023] The compensation duty cycle of the PWM signal is calculated based on the light attenuation intensity T of the current environment, and the compensation duty cycle is limited in the range of [0, 1], which is expressed as:

[0024] ;

[0025] In the formula, D2 is the compensation duty cycle, I tar,0 is the preset standard light intensity of the navigation signal light, I max is the maximum light intensity of the navigation signal light, is an empirical adjustment coefficient.

[0026] Further, S4 further comprises: superimposing the compensation duty cycle D2 on the adjustment duty cycle D1, and adjusting the PWM signal by using the superimposed duty cycle to increase the driving current of the LED light string, and the driving current of the LED light string is expressed as:

[0027] ;

[0028] In the formula, V OUT(VIN) is the reference voltage provided by the voltage reference pin OUT (VIN) in the LED driving chip, V CSN is the voltage provided by the current detection pin CSN in the LED driving chip, R Sence is the resistance value of the LED current detection resistor R1.

[0029] If the current duty cycle is equal to 1 and the illumination intensity of the LED light string is still less than the preset illumination intensity threshold, the navigation signal light control device inputs a fixed low level to the enable input pin EN of the LED driving chip to turn off the current LED driving chip.

[0030] The technical scheme of the present application further provides a system for navigation signal light attenuation detection and compensation, which comprises: a photosensitive sensor module, an MCU module, an LED driving module and a navigation signal light control device.

[0031] The photosensitive sensor module includes a first photosensitive sensor, a second photosensitive sensor, and a third photosensitive sensor. The first photosensitive sensor is used to detect the light intensity of the LED light string. The second photosensitive sensor is used to detect the intensity of scattered light in a first direction, and the angle between its optical axis and the optical axis directly in front of the navigation signal light is the first measurement angle. The third photosensitive sensor is used to detect the intensity of scattered light in a second direction, and the angle between its optical axis and the optical axis directly in front of the navigation signal light is the second measurement angle. The second measurement angle is greater than the first measurement angle.

[0032] The MCU module is used to feed back the illumination intensity of the LED string detected by the first photosensitive sensor, as well as the intensity of scattered light in different directions detected by the second and third photosensitive sensors, to the navigation signal light control device.

[0033] The LED driver module is used to drive the LED string to emit light according to the PWM signal issued by the navigation signal light control device. Specifically, the LED driver module uses an adjustable buck-boost constant current driver chip as the LED driver chip. The LED driver chip is connected to the PWM output terminal of the navigation signal light control device through its enable input pin to receive the PWM signal. When the PWM signal is high, the LED driver chip is turned on, and its internal MOSFET is periodically turned on and off. The LED string receives a constant current and emits light continuously. When the PWM signal is low, the LED driver chip is turned off, its internal MOSFET is completely turned off, the LED string stops receiving current, and stops emitting light.

[0034] The navigation signal light control device is used to detect light decay based on the illumination intensity of the LED light string and the intensity of scattered light emitted by the navigation signal light from different directions. It also increases the drive current output by the LED driver module by adjusting the duty cycle of the PWM signal to compensate for the light decay of the LED light string and maintain the visibility of the navigation signal light.

[0035] Furthermore, the LED driver module includes an energy storage inductor, a freewheeling diode, and an LED current sensing resistor. The positive terminal of the energy storage inductor is connected to the power input terminal, and the negative terminal of the energy storage inductor is divided into a first branch and a second branch. The first branch is directly connected to the switching node pin of the LED driver chip, and the second branch is connected to the LED string in sequence through the freewheeling diode and the LED current sensing resistor.

[0036] Furthermore, the LED driver module also includes an input filter capacitor C1, a power supply decoupling capacitor C2, and resistors R2 and R3. The LED driver chip also includes a voltage reference pin OUT (VIN), a current detection pin CSN, and an output overvoltage protection pin VOP.

[0037] The input filter capacitor C1 is placed in the feedback branch between the power input terminal VIN and the voltage reference pin OUT(VIN) to stabilize the reference voltage and suppress output ripple. The power decoupling capacitor C2 is connected between the power input terminal VIN and GND to filter and decouple the input power supply. R2 is connected between the voltage reference pin OUT(VIN) and the output overvoltage protection pin VOP, and R3 is connected between the output overvoltage protection pin VOP and GND. The two form an output voltage divider network, which is used to provide output overvoltage protection for the LED driver chip.

[0038] Furthermore, the system also includes an input module, a power conversion module, and a 485 communication module;

[0039] The input module converts external AC power into 24V DC power and supplies it to the power conversion module and the LED driver module respectively; the power conversion module converts 24V DC power into 3.3V DC power and supplies it to the photosensitive sensor module, the MCU module and the 485 communication module respectively; the 485 communication module is used to realize the communication connection between the MCU module and the navigation signal light control device.

[0040] The beneficial effects of this application are:

[0041] First, the technical solution in this application detects light decay by real-time monitoring of the average illuminance of the LED string. Based on the difference between the average illuminance and a preset illuminance threshold, it calculates the adjustment duty cycle of the PWM signal and uses the PWM signal to adjust the LED drive current. Furthermore, the technical solution incorporates environmental variation factors into the adjustment of the LED drive current. By measuring the intensity of scattered light at different angles, it calculates the ambient light attenuation intensity and then calculates the compensation duty cycle based on this intensity. The compensation duty cycle is then used to correct the adjustment duty cycle, thereby achieving precise adjustment of the LED drive current. This technical solution combines light decay compensation with environmental adaptation compensation, utilizing changes in the illuminance of the LED string and environmental variations to jointly compensate for and adjust the brightness of the navigation signal lights. This improves the accuracy of light decay compensation and the system's anti-interference capability, enabling the navigation signal lights to maintain optimal operating conditions even under slight light decay or extreme environments. This ensures the reliability and visibility of the navigation signal lights, significantly improving their stability and adaptability, and providing greater assurance for navigation safety.

[0042] Secondly, the technical solution in this application, when detecting light decay in the LED string, first increases the output current of the LED driver module by adjusting the duty cycle of the PWM signal, so that the light intensity of the LED string returns to the preset threshold, without the need to immediately replace the LED beads. When the duty cycle reaches its maximum value and the light intensity is still insufficient, the current LED driver chip is turned off and an alarm is triggered, extending the LED lifespan and reducing maintenance costs and resource waste. The LED driver module uses an adjustable buck-boost constant current driver chip as the LED driver chip. The LED driver module can form a closed-loop feedback with the navigation signal light control device, and the PWM duty cycle adjustment can quickly respond to changes in light decay, so that the navigation signal light maintains a constant light intensity at different stages of light decay, avoiding local dimness or overbrightness and improving signal recognizability.

[0043] Third, the technical solution in this application uses a photosensitive sensor module to detect the light intensity of the LED light string in real time and calculates the average light intensity according to a preset time period. By comparing the detected light intensity with a preset light intensity threshold, the light decay of the LED light string is detected, thus quantifying the light intensity change process. This allows for accurate judgment of whether the LED light string has experienced light decay, avoiding the inaccuracy of traditional manual judgment and improving the scientificity and reliability of LED light decay detection. At the same time, setting a period avoids judgment errors. Attached Figure Description

[0044] The advantages of the above and / or additional aspects of this application will become apparent and readily understood in the description of the embodiments in conjunction with the following drawings, wherein:

[0045] Figure 1 This is a schematic flowchart of a method for detecting and compensating for the attenuation of navigation signal lights according to an embodiment of this application;

[0046] Figure 2 This is a schematic diagram of the overall structure of a system for detecting and compensating for the attenuation of navigation signal lights according to an embodiment of this application;

[0047] Figure 3 This is a circuit design diagram of an LED driver module according to an embodiment of this application;

[0048] Figure 4 This is a circuit design diagram of a photosensitive sensor module and an MCU module according to an embodiment of this application;

[0049] Figure 5 This is a circuit design diagram of an input module according to an embodiment of this application;

[0050] Figure 6 This is a circuit design diagram of a power conversion module according to an embodiment of this application;

[0051] Figure 7 This is a circuit design diagram of a 485 communication module according to an embodiment of this application. Detailed Implementation

[0052] To better understand the above-mentioned objectives, features, and advantages of this application, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.

[0053] In the following description, many specific details are set forth in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0054] like Figures 2 to 7 As shown, this embodiment provides a system for detecting and compensating for the attenuation of navigation signal lights. The system includes: an input module, a power conversion module, a photosensitive sensor module, an MCU module, a 485 communication module, an LED driver module, and a navigation signal light control device.

[0055] The input module is used to convert external AC power into 24V DC power and supply it to the power conversion module and the LED driver module respectively.

[0056] The power conversion module converts 24V DC to 3.3V DC and supplies power to the photosensitive sensor module, MCU module and 485 communication module respectively.

[0057] The photosensitive sensor module includes a first photosensitive sensor, a second photosensitive sensor, and a third photosensitive sensor. The first photosensitive sensor is disposed inside the lampshade containing the LED light string and is used to detect the light intensity of the LED light string. The second and third photosensitive sensors are respectively disposed symmetrically on both sides of the outside of the lampshade. The second photosensitive sensor is used to detect the intensity of scattered light in a first direction, and the angle between its optical axis and the optical axis directly in front of the navigation signal light is the first measurement angle. The third photosensitive sensor is used to detect the intensity of scattered light in a second direction, and the angle between its optical axis and the optical axis directly in front of the navigation signal light is the second measurement angle. The second measurement angle is greater than the first measurement angle, and the optical axes of the second and third photosensitive sensors and the optical axis directly in front of the navigation signal light are located in the same plane.

[0058] It should be noted that when navigation lights emit light, if there are opaque materials around them, these materials will cause the light to scatter, thus weakening the light intensity and making the emitted light weaker, making it difficult to detect effectively and potentially causing a hazard. The scattered light travels in different directions. Second and third photosensors are installed on both sides of the lamp cover, respectively, to capture the intensity of scattered light from different directions. This provides the system with crucial information about the transparency or turbidity of the surrounding environment, assisting the system in adjusting the intensity of the navigation lights and preventing hazards.

[0059] The MCU module communicates with the navigation signal light control device via the 485 communication module. The MCU module is used to feed back the illumination intensity of the LED string detected by the first photosensitive sensor, as well as the intensity of scattered light in different directions detected by the second and third photosensitive sensors, to the navigation signal light control device via the 485 communication module.

[0060] The LED driver module is used to drive the LED string to emit light according to the PWM signal issued by the navigation signal light control device. Specifically, the LED driver module uses an adjustable buck-boost constant current driver chip as the LED driver chip. When the PWM signal is high, the LED driver chip is turned on, and its internal MOSFET is periodically turned on and off. The LED string receives a constant current and emits light continuously. When the PWM signal is low, the LED driver chip is turned off, its internal MOSFET is completely turned off, the LED string stops receiving current, and stops emitting light.

[0061] Specifically, the LED driver module includes an energy storage inductor L1, a freewheeling diode D1, and an LED current sensing resistor R1. The power input terminal VIN of the LED driver module is connected to 24V DC. The positive terminal of the energy storage inductor L1 is connected to the power input terminal VIN. The negative terminal of the energy storage inductor L1 is divided into a first branch and a second branch. The first branch is directly connected to the switching node pin SW of the LED driver chip. The second branch is connected to the LED string in sequence through the freewheeling diode D1 and the LED current sensing resistor R1.

[0062] When the PWM signal is high, the LED driver chip is turned on, and its internal MOSFET periodically turns on and off. Specifically, when the switch node pin SW is grounded, the internal MOSFET of the LED driver chip is turned on, and the energy storage inductor L1 is charged through the circuit formed by the MOSFET and VIN. When the switch node pin SW is floating, the internal MOSFET of the LED driver chip is turned off, and the energy storage inductor L1 supplies power to the LED string through the freewheeling diode D1 and the LED current sensing resistor R1. The MOSFET rapidly turns on and off periodically to achieve constant current output to the LED string, and the LED string lights up. When the PWM signal is low, the LED driver chip is turned off, its internal MOSFET is completely turned off, the LED string stops receiving current, and no longer lights up.

[0063] The LED driver chip connects to the PWM output of the navigation signal light control device via its enable input pin EN. This allows it to receive the PWM signal from the navigation signal light control device and thus control the brightness of the LED string.

[0064] The LED driver module also includes an input filter capacitor C1 and a power decoupling capacitor C2. The LED driver chip also includes a voltage reference pin OUT (VIN) and a current detection pin CSN. The input filter capacitor C1 is set in the feedback branch between the power input terminal VIN and the voltage reference pin OUT (VIN) to stabilize the reference voltage, suppress output ripple, and improve the stability of the internal reference circuit of the chip. The power decoupling capacitor C2 is connected between the power input terminal VIN and GND to filter and decouple the input power supply, absorb high-frequency noise and transient spikes on the input side, and prevent interference from affecting the normal operation of the LED driver chip.

[0065] It should be noted that the voltage reference pin OUT (VIN) provides a stable reference voltage V. OUT(VIN) For the LED driver chip, the current sensing pin CSN is used to monitor the current of the LED string. The current of the LED string flows through the LED current sensing resistor R1, generating a voltage V across the CSN pin. CSN V CSN =I LED ×R Sence R Sence The resistance value of R1 is used to internally control the voltage V of the LED driver chip. CSN With reference voltage V OUT(VIN) Comparison, if V CSN <V OUT(VIN) If the current to the LED string is insufficient, increase the switching duty cycle to allow more current to flow through the LED string. If V CSN >VV OUT(VIN)If the current of the LED string is too high, reduce the switching duty cycle (by adjusting the MOSFET on-time to reduce or increase the duty cycle) to lower the LED string current. The LED string current is then stabilized at the value determined by OUT(VIN) and R1, achieving constant current output.

[0066] The LED driver module also includes resistors R2 and R3. The LED driver chip also includes an output overvoltage protection pin VOP. R2 is connected between the voltage reference pin OUT (VIN) and the output overvoltage protection pin VOP, and R3 is connected between the output overvoltage protection pin VOP and GND. These two components form an output voltage divider network, which is used to protect the LED driver chip from output overvoltage damage, preventing the LED chips from disconnecting and damaging the chip. Specifically, the typical trigger point voltage of the output overvoltage protection pin OVP is set to 1V, and the recovery point voltage is set to 0.9V. The output overvoltage protection threshold is set according to the number of LED chips in the LED string, and the ratio of resistors R2 and R3 is adjusted according to the output overvoltage protection threshold so that the output overvoltage protection threshold corresponds to the typical trigger point voltage, expressed as:

[0067]

[0068]

[0069] In the formula, V OUT_OVP The output overvoltage protection threshold is set, where N is a preset multiple (1.3 to 1.5 times), and V... LED_total This is the normal operating voltage of a single LED (obtained from the component datasheet), V OVP_trig The typical value of the trigger point voltage, V OVP_trig =1V;

[0070] When the output voltage rises due to a disconnection or abnormality of the LED string, and the voltage drop detected by the output overvoltage protection pin OVP exceeds the typical trigger point voltage of 1V, the actual output voltage of the LED driver module (i.e., the voltage across the LED string) exceeds the output overvoltage protection threshold V. OUT_OVP The LED driver chip automatically enters overvoltage protection mode, stopping the switching drive to prevent damage to the chip and peripheral components due to output overvoltage. When the voltage drop detected by the output overvoltage protection pin OVP decreases to the recovery point voltage of 0.9V, the actual output voltage of the LED driver module is lower than the output overvoltage protection threshold V. OUT_OVP The LED driver chip has resumed normal operation.

[0071] The LED driver module also includes a resistor R4, which is connected between the enable input pin EN and GND of the LED driver chip. R4 is used to provide a pull-down potential when the PWM signal is not connected, so that the LED driver chip is in the off state by default and to prevent accidental start-up when the system is powered on.

[0072] In this embodiment, the optimal value range for the energy storage inductor L1 is 10uH-47uH. However, for the best loop stability and efficiency curve, the manual-recommended inductance value of 10uH is selected.

[0073] In this embodiment, the LED driver chip's enable input pin EN has two independent thresholds. When the rising threshold is greater than 0.5V, it enables the output (PWM signal); when the falling threshold is lower than 0.4V, it shuts down the regulator output and enters a low-power sleep mode. To avoid LED instability caused by the EN pin being left floating, an external pull-down resistor R4 is added, and R4 is set to 10K.

[0074] The navigation signal light control device is used to detect light decay based on the illumination intensity of the LED light string and the intensity of scattered light emitted by the navigation signal light from different directions. It also increases the drive current output by the LED driver module by adjusting the duty cycle of the PWM signal to compensate for the light decay of the LED light string and maintain the visibility of the navigation signal light (i.e., the actual brightness that can be observed externally under different environmental backgrounds).

[0075] It should be noted that the first photosensitive sensor is set inside the lamp cover of the navigation signal light and is located around the LED light string. The input module, power conversion module, MCU module, 485 communication module and LED driver module are set in the base of the navigation signal light. This system can be applied to the navigation signal light of underwater vehicles. This type of navigation signal light has a relatively compact structure, and the photosensitive sensor module cannot be arranged in the base.

[0076] Specifically, the circuit design of the first photosensor is as follows: Figure 4As shown, it consists of a photosensitive sensor GDI-1006T72, a filter capacitor C38, and pull-up resistors R19 and R20. The photosensitive sensor GDI-1006T72 is connected to a 3.3V input power supply. The filter capacitor C38 is connected in parallel between the 3.3V power supply and GND to decouple / filter power supply ripple and suppress high-frequency interference, stabilizing the sensor's power supply voltage. The two output pins of the photosensitive sensor GDI-1006T72 are connected to the PA6 and PA7 pins of the microcontroller U4 in the MCU module via the I²C bus (a communication channel composed of the SDA and SCL lines) for communication with the microcontroller U4. The light intensity information collected by the photosensitive sensor GDI-1006T72 is output to the microcontroller U4 through SCL and SDA. The pull-up resistors R19 and R20 are connected to the two output pins of the photosensitive sensor (i.e., connecting SDA and SCL). Pulling it high provides a pull-up bias for the I²C bus, ensuring it is high when idle, which helps suppress interference and provide current limiting protection (typical values ​​are 2–6.8kΩ in the diagram). The circuit designs for the second and third photosensors are the same as the first photosensor, and both are connected to other receive pins of the microcontroller U4 in the MCU module via the I²C bus. This explanation will only use the first photosensor as an example and will not elaborate further.

[0077] It should be noted that the photosensitive sensor exhibits a clear directionality when acquiring light signals. However, to reduce interference from non-target light such as ambient light, a lens structure can be added to the receiving end of the second and third photosensitive sensors in this embodiment. The collimation or light-limiting effect of the lens allows the sensor to receive only scattered light signals from a predetermined direction, thereby improving the reliability of light signal acquisition. Furthermore, although the photosensitive sensor itself does not have an optical axis, a lens structure is provided in its receiving section in this application, enabling it to receive only scattered light signals from a predetermined direction. Therefore, the axis at the center of its detection range can be used as the optical axis.

[0078] In this embodiment, a photosensitive sensor is used in the navigation signal light to detect the light decay of the LED string. The photosensitive sensor uses serial two-wire digital output, is minimally affected by infrared light, and its internal clock circuit uses an RC oscillator with extremely low temperature drift, achieving an accuracy of 0.1% and a measurement range of 1-1,000,000 Lx.

[0079] Specifically, the circuit design of the MCU module is as follows: Figure 4As shown, it consists of a microcontroller U4 (using a GED32F103ARBT). Microcontroller U4 is connected to 3.3V DC power. Pins PA6 and PA7 of microcontroller U4 are connected to a photosensitive sensor via SCL and SDA. Pins PA9 and PA10 of microcontroller U4 are connected to a 485 communication module via RS485_RX and RS485_TX. After the photosensitive sensor transmits the collected light intensity information to the microcontroller, the microcontroller feeds it back to the navigation signal light control device via the 485 communication module. The GED32F103ARBT microcontroller has a maximum operating frequency of 72MHz and features wide voltage range, single-wire debugging, and low power consumption. Furthermore, its small package and simple peripheral circuitry save space and simplify the design.

[0080] The MCU module also includes decoupling capacitors (C18, C22, C23, C25), a power supply filter network (L6, C20, C21), and a ferrite bead resistor (R22), covering the microcontroller pins VDD, VDDA, VSS, and VSSA. These are used to ensure stable power supply to the MCU and prevent power ripple and noise from affecting the microcontroller's performance. The decoupling capacitors are placed near each VDD or VBAT pin to filter out high-frequency noise. In the power supply filter network, inductor L6 is used to suppress high-frequency interference, and capacitors C20 and C21 are used to filter out bypass noise, making the 3.3V power supply cleaner. The ferrite bead resistor R22 is used to isolate high-frequency interference between digital ground and analog ground.

[0081] The MCU module also includes a reset circuit (R13, C24, R21, C19), a clock crystal circuit (U3, C16, C17, C19), and a debug and download interface J1 (Header4). In the reset circuit, R13 and C24 are connected in parallel. R13 is a pull-up resistor to maintain a default high level, and C24 is a power-on delay reset capacitor, forming an RC delay with R13 to ensure the reset signal is released only after the power supply stabilizes. R21 and C19 are connected in parallel (resistor pull-up, capacitor pull-down) for power-on reset. In the clock crystal circuit, U3 (8 MHz crystal) provides the clock source for the microcontroller U4. C16 and C17 are crystal load capacitors, connected in parallel with U3 to match the crystal frequency and stabilize oscillation. The debug and download interface J1 connects to the microcontroller via SWDIO and SWCLK lines, enabling firmware burning, online debugging, register monitoring, and other functions. It is the main interface for MCU debugging and upgrades.

[0082] Specifically, the circuit design of the input module is as follows: Figure 5As shown, it includes input terminal PI, 1A slow-blow fuse F1, varistor R1, common-mode / differential-mode filter network (including common-mode inductors L7 and L8 and filter capacitors C1, C3, and C4), power frequency transformer and rectifier preamp (including UU9.8-30m2H transformer and capacitors C5, C26, and C27), AC-DC module U1, output filter capacitors C28 and C29, and transient voltage suppression diode (SMBJ30CA) D1;

[0083] The input terminal PI is the module's AC input interface (including Live line L1 and Neutral line N1), used to connect to an external 220V AC power supply; the 1A slow-blow fuse F1 provides input overcurrent protection, blowing when a short circuit or excessive overload current occurs to prevent downstream components from burning out; the varistor R1 absorbs overvoltage, conducting and absorbing energy when the input voltage spikes instantaneously, protecting the circuit; common-mode inductors L7 and L8 suppress common-mode interference (i.e., high-frequency noise from the L and N lines changing in phase); filter capacitors C1, C3, and C4 are connected between the L and N lines to absorb differential-mode interference; the UU9.8-30m²H transformer provides electrical isolation between the input and output, ensuring a 3000Ω gap between them. Vac isolation voltage; capacitors C5, C26, and C27 form a high-frequency bypass and absorption network to filter out leakage inductance spikes from the transformer; AC-DC module U1 converts the input AC (after filtering and isolation) into a stable DC output; output filter capacitors C28 and C29 (i.e., a 100 µF / 50 V electrolytic capacitor and a 1 µF / 50 V film capacitor in parallel) work together to smooth the output voltage and reduce ripple; transient voltage suppression diode (SMBJ30CA) D1 is used for output overvoltage protection to protect the load.

[0084] In this embodiment, the navigation signal light hardware circuit is powered by single-phase AC220V 50Hz AC power, with the power supply voltage being +20% to -20% of the rated voltage and the frequency being +5% to -5% of the rated frequency, ensuring reliable operation.

[0085] Specifically, the circuit design of the power conversion module is as follows: Figure 6 As shown, it includes a step-down DC-DC converter chip FHT3550A, an input filter network (including capacitors C39 and C40), an output filter network (including capacitors C41 and C42), a frequency setting resistor R23 (27 kΩ), and an internal feedback resistor divider (upper voltage divider resistor R24 ​​with a voltage divider of 23.2 kΩ and lower voltage divider resistor R25 with a voltage divider of 10 kΩ).

[0086] The FHT3550A chip features high efficiency, low ripple, high linear regulation, and high load regulation. This module enables or disables the FHT3550A via an external voltage signal. The module operates normally when the enable signal is high. The typical threshold for the enable pin EN is 1.22V, and the maximum withstand voltage is 24V. Connecting an external 24V DC voltage to raise the enable pin EN enables the module to operate normally. The module uses an internal feedback resistor divider to set the output voltage to 3.3V by default, with an upper divider resistor of 23.2kΩ and a lower divider resistor of 10kΩ. Parallel capacitors C39 (22 µF) and C40 (0.1 µF) in the input filter network are used for input filtering and decoupling. Parallel capacitors C41 (0.1 µF) and C42 (22 µF) in the output filter network are used for... µF is used for output filtering and stabilizing the output voltage; the RFREQ pin of the FHT3550A chip is connected to GND through resistor R23 to set the internal switching frequency. R23=27kΩ usually corresponds to a typical switching frequency (such as 400 kHz to 1 MHz).

[0087] Specifically, the circuit design of the 485 communication module is as follows: Figure 7 As shown, the GLb2582 high-speed RS-485 transceiver is used. This device integrates a three-channel isolator (for isolating the TXD, RXD, and RE / DE pin control signals), a tri-state differential line driver, a differential input receiver, and an isolated DC / DC converter. The device operates from a single 3.3V DC power supply, achieving a fully integrated 485 signal and power isolation scheme. The driver has a high-level active enable characteristic, and the receiver has a low-level active enable characteristic. When disabled, the receiver can enter a high-impedance state. With the GLb2582, the 485 communication module circuit has current limiting and thermal shutdown characteristics, and supports bus pin protection exceeding ±8kV ESD, as well as signal and power isolation.

[0088] The TXD and RXD pins of the GLb2582 are connected to pins PA10 and PA9 of the microcontroller U4, respectively, for communication with the microcontroller U4 (RS485_RX, RS485_TX). The A / Y pins and B / Z pins of the GLb2582 form a common pin for communication with the navigation signal light control device (RS485_A, RS485_B). The RXD pin of the GLb2582 is pulled up to 3.3V through a 10kΩ resistor R14 for circuit failure protection. The RE / DE pins are directly connected together to form a common control pin, which is connected to the PA1 pin of the microcontroller U4 to receive the RD_Ctrl signal (RS-485 Direction Control, a signal used by the microcontroller to control the data direction) output by the microcontroller U4. When the RD_Ctrl signal is high, it is in transmit mode, enabling the 485 driver, and the microcontroller sends data to the 485 communication module. When the Ctrl signal is low, it is in receive mode, enabling the 485 receiver. The microcontroller receives data from the 485 communication module. This shared control pin is also connected to GND through a 10kΩ resistor R15 to enter receive mode. Capacitors C30~C35 are power supply filter capacitors used to stabilize the power supply and reduce noise. The 485 communication module also includes bias resistors R6 and R18, a termination matching resistor R17, and transient voltage suppressors D11 (SM712) and D12. Bias resistors R6 and R18 are used to form a bias network to ensure that the bus outputs a stable logic level when idle, disconnected, or without drive, preventing false triggering. The termination matching resistor R17 is used to match the characteristic impedance of the RS-485 bus. Transient voltage suppressors D11 and D12 protect the RS-485 transceiver from damage by high voltage.

[0089] like Figure 1 As shown, this embodiment provides a method for detecting and compensating for the attenuation of navigation signal lights. This method is applied to the above-mentioned system and specifically includes the following steps:

[0090] S1: Use the first photosensitive sensor to obtain the light intensity of the LED string within the current time period, and calculate the average light intensity within the current time period.

[0091] S2: Preset light intensity threshold. If the average light intensity is greater than or equal to the light intensity threshold, the LED string is determined to have no light decay. If the average light intensity is less than the light intensity threshold, the LED string is determined to have light decay. The adjustment duty cycle of the PWM signal is calculated based on the difference between the light intensity threshold and the average light intensity.

[0092] Specifically, the average light intensity within the current time period. With light intensity threshold If a comparison is made, ≥ If the LED string shows no light decay, the duty cycle D1 of the PWM signal is set to 0. < If the LED string shows signs of light decay, the duty cycle of the PWM signal is calculated based on the difference between the light intensity threshold and the average light intensity, expressed as:

[0093]

[0094] In the formula, D1 is the adjustment duty cycle of the PWM signal, k1 and k2 are proportional coefficients (constant), and D... max To determine the maximum allowable duty cycle, D max =1, Δ is the exponential adjustment coefficient used to control the steepness of the compensation curve, e is the base of the natural logarithm, and Δ1 and Δ2 are two error interval thresholds (i.e., the threshold of the difference) used to divide different intervals of light decay.

[0095] It should be noted that by dividing the light decay level into different intervals and using compensation functions in linear, square, and exponential forms in each interval, the duty cycle can be avoided from being over-adjusted when the light decay is slight. At the same time, the compensation strength under moderate to severe light decay is significantly enhanced, making the brightness adjustment process both smooth and fast, and effectively improving the accuracy, stability, and anti-interference ability of light decay compensation.

[0096] S3: The intensity of the scattered light emitted by the navigation signal light is collected from the first measurement angle and the second measurement angle using the second and third photosensitive sensors, respectively, and the intensity of the scattered light is corrected according to the measurement angle of each sensor.

[0097] Specifically, the scattering function is obtained by fitting experimental data. This allows for the correction of scattered light intensity at different angles, with 0° as the reference angle substituted into the scattering function. In the middle, calculate the reference scattering function value f ref Based on scattering function and reference scattering function value f ref Construct a light intensity correction function, expressed as:

[0098]

[0099] In the formula, I act I represents the corrected actual scattered light intensity. meas The intensity of the collected scattered light. To measure the angle; the first measurement angle corresponding to the second photosensitive sensor. Substituting this into the light intensity correction function, we can calculate the corresponding corrected first actual scattered light intensity I. act ( The second measurement angle corresponding to the third photosensor. Substituting this into the light intensity correction function, we can calculate the corresponding corrected second actual scattered light intensity I. act ( ).

[0100] The scattering function was obtained by fitting experimental data. Specifically, it includes:

[0101] An experimental scenario simulating an underwater environment is set up. A sample with fixed turbidity (such as suspended particles of standard concentration) is used as the scattering medium. Several measurement angles are set within the range of 0° to 90°. A light source is placed in the experimental scenario, and the intensity of scattered light is measured at each measurement angle using sensors. The measured scattered light intensity and the corresponding measurement angle are recorded to obtain multiple sets of experimental data. Based on these multiple sets of experimental data, a scattering function is fitted according to a preset sine function form. Represented as:

[0102]

[0103] In the formula, A and B are constants to be fitted; the least squares method is used to fit the scattering function. By fitting the data and continuously adjusting A and B, the scattering function is optimized. By minimizing the error between the output and the scattered light intensity data at each measurement angle, A and B are finally obtained.

[0104] S4: Calculate the ratio of scattered light intensity in different directions, construct a function model of the ambient light attenuation intensity (i.e., the attenuation intensity of the light emitted by the navigation signal light) around the navigation signal light with respect to this ratio, use this function model to calculate the light attenuation intensity of the current environment, calculate the compensation duty cycle of the PWM signal based on the light attenuation intensity of the current environment, and superimpose this compensation duty cycle on the adjustment duty cycle to adjust the current PWM signal to maintain the visibility of the navigation signal light in the current environment. When the duty cycle of the PWM signal reaches its maximum value and the light intensity of the LED string is still less than the preset light intensity threshold, turn off the current LED driver chip, control the alarm to sound, and start the control circuit of the backup LED string.

[0105] Specifically, the ratio of scattered light intensity in different directions is calculated and expressed as I. act ( ) / I act ( Construct a functional model of the ambient light attenuation intensity around the navigation signal light with respect to this ratio, expressed as:

[0106]

[0107] In the formula, T represents the ambient light attenuation intensity around the navigation signal light. Here, d1 is the distance from the navigation signal light to the point where the optical axis of the second photosensitive sensor intersects with the optical axis directly in front of the navigation signal light, and d2 is the distance from the point where the optical axis of the third photosensitive sensor intersects with the optical axis directly in front of the navigation signal light. Both d1 and d2 can be obtained through trigonometric functions, where n is the power exponent, 0. <n<1。

[0108] The compensation duty cycle of the PWM signal is calculated based on the light attenuation intensity T of the current environment, and the compensation duty cycle is restricted to the range [0,1], expressed as:

[0109]

[0110] In the formula, D2 is the compensation duty cycle, I tar,0 For the preset standard light intensity of navigation signal lights, I max This is the maximum light intensity of the navigation signal light (the light intensity when the duty cycle is 1 under normal conditions). This is an empirical adjustment coefficient, ranging from 0.3 to 1.0.

[0111] Finally, the compensation duty cycle D2 is superimposed on the adjustment duty cycle D1. The superimposed duty cycle is used to adjust the PWM signal to increase the driving current of the LED string, thereby compensating for the light decay of the LED string and maintaining the visibility of the navigation signal lights under the current environmental conditions. The driving current of the LED string (i.e., the output current of the LED driver module) is expressed as:

[0112]

[0113] In the formula, V OUT(VIN) The reference voltage provided to the voltage reference pin OUT(VIN) in the LED driver chip, V CSN The voltage supplied to the current sensing pin CSN in the LED driver chip, R Sence The value of LED current sensing resistor R1 is given. If, after the duty cycle increases, the average light intensity in the next time period is greater than the preset light intensity threshold, then the LED string will not experience light decay and will resume normal operation.

[0114] It should be noted that V OUT(VIN) -V CSN The typical value is 0.2V. According to the LED chip product manual, the maximum output current is set as the LED forward current, and its maximum parameter value is 1200mA. At this time, IOUT The maximum output current is set to the peak output current of the LED as 1.2A, and R1 is calculated to be 166mΩ.

[0115] The navigation signal light control device can obtain the current duty cycle of the output PWM signal from the PWM output terminal. If the current duty cycle is equal to 1 and the light intensity of the LED string is still less than the preset light intensity threshold, the current duty cycle equal to 1 means that the MOSFET in the LED driver chip is fully turned on, the LED string is already working at maximum current (maximum brightness), and the duty cycle cannot be adjusted further. The navigation signal light control device inputs a fixed low level (duty cycle 0%) to the enable input pin EN of the LED driver chip to turn off the current LED driver chip and control the alarm to sound. At this time, the navigation signal light control device can switch the circuit of the backup LED string. After the faulty LED is replaced, the product is powered on again, the duty cycle of the LED driver circuit becomes the initial preset value, and the cycle detection is performed again.

[0116] In this embodiment, a preset time interval of 1 minute can be set, meaning the illuminance value is read once per minute, and a single time period of 30 minutes can be set to avoid misjudgment. Taking the anchor lamp as an example, the initial current of the LED driver circuit is set to 700mA, at which point the PWM duty cycle is approximately 0.6. A light decay threshold is set, and the illuminance is read periodically by the product's MCU module, with 10 illuminance values ​​read every 10 minutes. When the average illuminance detected over 30 minutes is greater than the product threshold of 20769 lx, there is no light decay in the LED, and the product operates normally. When the average illuminance detected over 30 minutes is less than the product threshold of 20769 lx, the PWM duty cycle is adjusted to 0.7, the LED driver current is 840mA, and the LED light intensity increases.

[0117] The steps in this invention can be adjusted, combined, or deleted according to actual needs.

[0118] The units in the device of the present invention can be merged, divided, or reduced according to actual needs.

[0119] In this invention, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; "linking" can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0120] The shapes of the components in the accompanying drawings are schematic and may differ from their actual shapes. The drawings are only used to illustrate the principles of the present invention and are not intended to limit the present invention.

[0121] Although the invention has been disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and not intended to limit the application of the invention. The scope of protection of the invention is defined by the appended claims and may include various modifications, alterations, and equivalents made to the invention without departing from the scope and spirit of the invention.

Claims

1. A method for navigation light fade detection and compensation, characterized in that, The method is applied to a system comprising a first photosensitive sensor, a second photosensitive sensor, a third photosensitive sensor, and an LED driving module for driving an LED light string to emit light according to a PWM signal emitted by a navigation signal light control device, and the method comprises: S1: acquiring the light intensity of the LED light string in a current time period by using the first photosensitive sensor, and calculating the average light intensity in the current time period, wherein the first photosensitive sensor is located in a lampshade where the LED light string is located; S2: presetting a light intensity threshold value, if the average light intensity is greater than or equal to the light intensity threshold value, it is determined that the LED light string has no light decay, if the average light intensity is less than the light intensity threshold value, it is determined that the LED light string has light decay, and the adjustment duty cycle of the PWM signal is calculated based on the difference between the light intensity threshold value and the average light intensity; S3: collecting the scattered light intensity of the light emitted by the navigation signal light from a first measurement angle and a second measurement angle by using the second photosensitive sensor and the third photosensitive sensor respectively, and correcting the scattered light intensity corresponding to each sensor according to the measurement angle of the sensor, wherein the second photosensitive sensor and the third photosensitive sensor are symmetrically arranged outside the lampshade, and the optical axes of the second photosensitive sensor and the third photosensitive sensor respectively intersect with the optical axis in front of the navigation signal light; S4: calculating the ratio of the scattered light intensity in different directions, constructing a function model of the light attenuation intensity of the environment around the navigation signal light with respect to the ratio, calculating the light attenuation intensity of the current environment by using the function model, calculating the compensation duty cycle of the PWM signal based on the light attenuation intensity of the current environment, and superimposing the compensation duty cycle on the adjustment duty cycle to adjust the current PWM signal, wherein when the duty cycle of the PWM signal reaches the maximum value and the light intensity of the LED light string is still less than the preset light intensity threshold value, the LED driving chip is turned off and the alarm is controlled to alarm.

2. The method for navigation light fade detection and compensation of claim 1, wherein, The S2 specifically comprises: comparing the average of the light intensity in the current time period with a light intensity threshold value comparing the average of the light intensity in the current time period with a light intensity threshold value if ≥ , it is determined that the LED light string has no light decay, and the adjustment duty cycle D1 of the PWM signal is set to 0, if < , it is determined that the LED light string has light decay, and the adjustment duty cycle of the PWM signal is calculated according to the difference between the light intensity threshold value and the average of the light intensity, which is represented as: ； In the formula, D1 is the adjusted duty ratio of the PWM signal, k1 and k2 are proportional coefficients, D max is the maximum allowed duty ratio, D max = 1, is the exponential adjustment coefficient, and Δ1 and Δ2 are error interval thresholds.

3. The method for navigation light falloff detection and compensation of claim 1, wherein, The S3 specifically comprises: Obtaining the scattering function by fitting experimental data The 0° angle is taken as the reference angle to calculate the reference scattering function value f ref Based on the scattering function and the reference scattering function value f ref , a light intensity correction function is constructed, expressed as​ ； In the formula, I act is the corrected actual scattering light intensity, I meas is the collected scattering light intensity, is the measurement angle; the first measurement angle corresponding to the second photosensitive sensor is brought into the light intensity correction function, and the corrected first actual scattering light intensity I act ( ) corresponding thereto is calculated. The second measurement angle corresponding to the third photosensitive sensor is brought into the light intensity correction function, and the corrected second actual scattering light intensity I act ( ) corresponding thereto is calculated.

4. The method for navigation light falloff detection and compensation of claim 3, wherein, In the S3, the scattering function is obtained by fitting experimental data , and specifically comprises: An experimental scene for simulating a current environment is arranged, a plurality of measurement angles are set in a range of 0° to 90°, a light source is placed in the experimental scene, and scattered light intensities are measured at the respective measurement angles by using sensors, respectively, measured scattered light intensities and corresponding measurement angles are recorded, a plurality of experimental data are obtained, based on the plurality of experimental data, a scattering function is fitted according to a preset sinusoidal function form, and the scattering function is represented as: ； In the formula, A, B are constants to be fitted; the scattering function is fitted by using the least square method, and A, B are constantly adjusted so that the error between the output of the scattering function and the scattering light intensity data at each measurement angle is minimized, and finally A, B are obtained.

5. The method for navigation light falloff detection and compensation of claim 3, wherein, The S4 specifically comprises: The ratio I of the scattered light intensity in different directions act act The function model of the ambient light attenuation intensity of the navigation signal light around the ratio is constructed, which is expressed as:​​​ ； In the formula, T is the ambient light attenuation intensity of the navigation light, is the attenuation coefficient, d1 is the distance from the intersection point of the optical axis of the second photosensitive sensor and the optical axis of the front of the navigation light to the navigation light, d2 is the distance from the intersection point of the optical axis of the third photosensitive sensor and the optical axis of the front of the navigation light to the navigation light, and n is the power index, 0 The compensation duty cycle of the PWM signal is calculated based on the light attenuation intensity T of the current environment, and the compensation duty cycle is limited in the range of [0, 1], which is represented as: ； In the formula, D2 is the compensation duty cycle, I tar,0 is the preset standard light intensity of the navigation signal light, I max is the maximum light intensity of the navigation signal light, is the empirical adjustment coefficient.

6. The method for navigation light falloff detection and compensation of claim 5, wherein, The S4 further comprises: The compensation duty cycle D2 is superimposed on the adjustment duty cycle D1, and the PWM signal is adjusted by using the superimposed duty cycle to increase the driving current of the LED light string, and the driving current of the LED light string is represented as: ； In the formula, V OUT(VIN) Vref is the reference voltage provided for the voltage reference pin OUT (VIN) in the LED driving chip, CSN R is the voltage provided for the current detection pin CSN in the LED driving chip, Sence R1 is the resistance value of the LED current detection resistor If the current duty cycle is equal to 1 and the light intensity of the LED light string is still less than the preset light intensity threshold value, the navigation signal light control device inputs a fixed low level to the enable input pin EN of the LED driving chip to turn off the current LED driving chip.

7. A system for navigation light fade detection and compensation, comprising: The system is used to execute the method for navigation signal light light decay detection and compensation as claimed in any one of claims 1-6, and the system comprises a photosensitive sensor module, an MCU module, an LED driving module, and a navigation signal light control device. The photosensitive sensor module comprises a first photosensitive sensor, a second photosensitive sensor and a third photosensitive sensor, the first photosensitive sensor is used for detecting the light intensity of the LED light string, the second photosensitive sensor is used for detecting the scattered light intensity in the first direction, and the included angle between the optical axis of the second photosensitive sensor and the optical axis of the front of the navigation signal light is a first measurement angle, and the third photosensitive sensor is used for detecting the scattered light intensity in the second direction, and the included angle between the optical axis of the third photosensitive sensor and the optical axis of the front of the navigation signal light is a second measurement angle, wherein the second measurement angle is greater than the first measurement angle; The MCU module is used for feeding back the light intensity of the LED light string detected by the first photosensitive sensor and the scattered light intensity in different directions detected by the second photosensitive sensor and the third photosensitive sensor to the navigation signal light control device; The LED driving module is used for driving the LED light string to emit light according to the PWM signal sent by the navigation signal light control device, specifically, the LED driving module adopts an adjustable step-up / step-down constant current driving chip as an LED driving chip, the LED driving chip is connected with the PWM output end of the navigation signal light control device through an enable input pin, and is used for receiving the PWM signal, when the PWM signal is at a high level, the LED driving chip is turned on, the internal MOSFET of the LED driving chip is periodically turned on and turned off, the LED light string receives a constant current and continuously emits light, and when the PWM signal is at a low level, the LED driving chip is turned off, the internal MOSFET of the LED driving chip is completely turned off, and the LED light string stops receiving current and no longer emits light. The navigation signal light control device is used for detecting light attenuation according to the light intensity of the LED light string and the scattered light intensity of the light emitted by the navigation signal light in different directions, and increasing the driving current output by the LED driving module in the form of adjusting the duty cycle of the PWM signal to compensate for the light attenuation of the LED light string and maintain the visibility of the navigation signal light.

8. The system for light degradation detection and compensation of a navigation light of claim 1, wherein, The LED driving module comprises an energy storage inductor, a freewheeling diode and an LED current detection resistor, the positive pole of the energy storage inductor is connected to a power input end, the negative pole of the energy storage inductor is divided into a first branch and a second branch, the first branch is directly connected to a switch node pin of the LED driving chip, and the second branch is connected to the LED light string through the freewheeling diode and the LED current detection resistor in sequence.

9. The optical decay detection and compensation system for navigation lights as claimed in claim 2, wherein, The LED driving module further comprises an input filter capacitor C1 and a power decoupling capacitor C2, resistors R2 and R3, and the LED driving chip further comprises a voltage reference pin OUT(VIN), a current detection pin CSN and an output overvoltage protection pin VOP; The input filter capacitor C1 is arranged in a feedback branch between the power input end VIN and the voltage reference pin OUT(VIN), and is used for stabilizing the reference voltage and suppressing the output ripple, the power decoupling capacitor C2 is connected between the power input end VIN and GND, and is used for filtering and decoupling the input power; R2 is connected between the voltage reference pin OUT(VIN) and the output overvoltage protection pin VOP, and R3 is connected between the output overvoltage protection pin VOP and GND, and the two form an output voltage dividing network, which is used for output overvoltage protection of the LED driving chip.

10. The system for light degradation detection and compensation of a navigation light of claim 1, wherein, The system also comprises an input module, a power conversion module and a 485 communication module; The input module is used for converting the external input AC power into 24V DC power, and supplying the power conversion module and the LED driving module respectively; the power conversion module is used for converting the 24V DC power into 3.3V DC power, and supplying the photosensitive sensor module, the MCU module and the 485 communication module respectively; and the 485 communication module is used for realizing the communication connection between the MCU module and the navigation signal lamp control device.

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