An aircraft navigation light communication system and method

Abstract

The application discloses an airplane navigation light communication system and method, wherein the navigation communication light is used as a transceiving carrier of a navigation communication transceiving unit, and FPGA master control, signal processing and communication protocol control are integrated. The navigation communication transceiving unit realizes time-sharing switching of transceiving through a link switching switch, and the communication performance is improved by combining multi-path parallel high-speed A / D conversion and MPAM, and a special half-duplex protocol is built-in to guarantee the order of communication. The application realizes integration of warning and communication, adapts to extreme working conditions of aviation, solves the pain points of the prior art, fills the blank of a special bidirectional optical communication system for aviation navigation communication lights, and is suitable for scenes such as airplane air collision avoidance communication, airport ground-air communication, anti-interference communication and aircraft auxiliary communication, and belongs to the technical field of wireless optical communication.

Description

Technical Field

[0001] This invention relates to the fields of aviation communication and visible light communication technology, specifically to an aircraft navigation light communication system and method. Background Technology

[0002] Currently, aviation communication primarily relies on radio frequency (RF) communication, which has significant drawbacks in scenarios such as close-range aircraft interaction and dense airport takeoffs and landings: RF communication has a limited spectrum, is susceptible to electromagnetic interference, and is prone to signal interruption due to crosstalk; signals are easily intercepted, resulting in poor security; and communication equipment needs to be added, increasing aircraft load and wiring complexity. Visible light communication (VLC) offers advantages such as no electromagnetic interference, free spectrum, and high security, which can compensate for the shortcomings of RF communication. Aircraft navigation lights, as standard equipment, can carry optical communication signals to achieve data transmission without affecting their warning function. However, existing VLC technology is mostly concentrated in indoor and vehicle applications, and dedicated systems for aviation scenarios have shortcomings: they are mostly one-way communication, unable to meet the needs of two-way interaction; the receiving end relies on dedicated photodetectors, making it impossible to achieve integrated transmission and reception for a single light; and the communication rate is low, with a high bit error rate, making it unsuitable for aviation conditions. Summary of the Invention

[0003] The present invention aims to solve the problems of traditional visible light communication, such as unidirectional transmission, transmission and reception separation, and lack of aviation adaptation, and provides an aircraft navigation light communication system and method.

[0004] To solve the above problems, the present invention is achieved through the following technical solution:

[0005] An aircraft navigation light communication system includes two or more communication terminals. Each communication terminal includes an independent power supply, an FPGA main control unit, a navigation communication transceiver unit, and a signal processing unit connected to the independent power supply. The navigation communication transceiver unit includes a navigation communication light, a link switching switch, a drive circuit, and an I / V conversion circuit. The navigation communication light is connected to the common terminal of the link switching switch. One contact of the link switching switch is connected to the drive circuit, and the other contact of the link switching switch is connected to the I / V conversion circuit. The link switching switch, the drive circuit, and the I / V conversion circuit are connected to the FPGA main control unit. The signal processing unit includes a signal modulation and demodulation circuit and an A / D conversion circuit. The signal modulation and demodulation circuit is connected to the drive circuit of the navigation communication transceiver unit. The A / D conversion circuit is connected to the I / V conversion circuit of the navigation communication transceiver unit. The modulation and demodulation circuit and the A / D conversion circuit are connected to the FPGA main control unit.

[0006] In the above scheme, the normally open contact of the link switching switch is connected to the drive circuit, and the normally closed contact of the link switching switch is connected to the I / V conversion circuit.

[0007] In the above scheme, the communication protocol control unit is integrated within the FPGA main control unit.

[0008] The aircraft navigation light communication method implemented by the above system includes the following steps:

[0009] Before communication is initiated, the sending end sends a connection request frame containing a unique pseudo-random frame header code. After the receiving end verifies that the frame header is correct, it returns a connection confirmation frame. After the sending end receives the confirmation signal, the two parties formally establish an encrypted half-duplex communication link.

[0010] The FPGA main control unit at the transmitting end switches the control link switching switch to the drive circuit, and the navigation communication light switches to the forward transmission mode; the modulation and demodulation circuit at the transmitting end uses the distance-level MPAM adaptive modulation algorithm to modulate and load the data to be transmitted onto the visible light signal of the navigation communication light, and the drive circuit drives the navigation communication light to transmit the visible light signal loaded with the data to be transmitted.

[0011] The receiving end utilizes the reverse photoelectric detection characteristic of the navigation communication light to collect the visible light signal carrying the data to be transmitted emitted by the transmitting end and generate an induced current. The I / V conversion circuit converts the induced current into a voltage signal and sends it to the A / D conversion circuit. The A / D conversion circuit uses a multi-channel parallel amplitude fusion decision algorithm to complete multi-channel synchronous sampling quantization and then transmits it to the FPGA main control unit. The FPGA main control unit restores the data to be transmitted based on the sampled and quantized signal.

[0012] In the above scheme, the modulation and demodulation circuit of the transmitting end adopts the distance-level MPAM adaptive modulation algorithm to adaptively and hierarchically match the modulation parameters according to the real-time communication distance between the two parties. That is, MPAM high-order modulation is enabled in close-range scenarios, MPAM medium-order modulation is enabled in medium-range scenarios, and MPAM low-order modulation is enabled in close-range scenarios.

[0013] In the above scheme, the modulation and demodulation circuit of the transmitting end also embeds an adaptive optical signal compensation algorithm, namely: for the high-altitude strong light conditions of aviation, an ultra-narrowband filtering mechanism is used to accurately match the exclusive center wavelength of the navigation light and synchronously and dynamically improve the modulation amplitude; for the conditions of rain, fog and cloud cover and signal attenuation, low-order MPAM modulation is locked.

[0014] In the above scheme, after the transmitter completes the transmission of a visible light signal with data to be transmitted in a single load, the FPGA main control unit of the transmitter controls the link switching switch to the I / V conversion circuit, and the navigation communication light switches back to the reverse reception mode.

[0015] In the above scheme, the multi-channel parallel amplitude fusion decision algorithm used in the A / D conversion circuit of the receiving end first performs mean filtering on the high, medium and low amplitude data acquired by the three parallel A / D converters, and then dynamically corrects the level decision deviation based on the high-frequency real-time sampling data to obtain the sampled quantization signal.

[0016] Compared with the prior art, the present invention has the following characteristics:

[0017] 1. Integrated Functionality: No additional communication light source is required. It can reuse optical communication functions on the basis of airborne navigation light warning and illumination functions, reducing equipment costs and aircraft load. The load is reduced by 80% and the installation cost is reduced by 60%.

[0018] 2. Strong anti-interference and confidentiality: It adopts visible light transmission, has no electromagnetic radiation, is not affected by radio frequency interference, and combines dedicated frame header verification before communication, so that the illegal signal access rate is ≤0.01%, which improves the confidentiality by 99% compared with radio frequency communication and solves communication security risks.

[0019] 3. Superior communication performance: Combining multi-channel parallel A / D conversion with MPAM adaptive modulation anti-interference method, the maximum downlink rate of communication is increased by 433%, and the bit error rate is reduced by 1000 times, solving the defects of low rate, high bit error rate and weak anti-interference.

[0020] 4. Strong airborne adaptability: Specially improved for special aviation operating conditions, adaptable to mainstream civil aircraft models, and the multi-aircraft time slot allocation mechanism improves communication efficiency by more than 30%, avoids signal collisions, and improves landing feasibility. Attached Figure Description

[0021] Figure 1 This is a block diagram of the overall architecture of an aircraft navigation light communication system. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific examples.

[0023] An aircraft navigation light communication system, such as Figure 1 As shown, the system includes two or more communication terminals. Each terminal has an independent power supply, an FPGA main control unit, a navigation communication transceiver unit, and a signal processing unit connected to the independent power supply. The communication terminals employ a three-layer isolation structure of independent power supply partitioning, signal-to-ground separation, and metal shielding potting. This structure independently partitions the transmission drive circuit, photoelectric receiving circuit, and signal processing circuit. Oxygen-free copper electromagnetic shielding partitions are installed between each circuit to completely isolate cross-link electromagnetic crosstalk generated by airborne high-frequency power supplies and avionics equipment. This solves the inherent signal leakage defects of traditional single-lamp time-division transceiver architectures, improving the system's transceiver isolation to over 40dB, far exceeding the 15dB isolation index of conventional visible light communication systems, and perfectly adapting to the dense electromagnetic working environment of aviation.

[0024] The navigation communication transceiver unit includes a navigation communication light, a link switching switch, a drive circuit, and an I / V conversion circuit. The navigation communication light is connected to the common terminal of the link switching switch, one contact of the link switching switch is connected to the drive circuit, and the other contact of the link switching switch is connected to the I / V conversion circuit. The link switching switch, the drive circuit, and the I / V conversion circuit are connected to the FPGA main control unit.

[0025] The navigation communication light has both transmitting and receiving functions. It operates in transmitting mode under forward operating voltage and in receiving mode under reverse operating voltage. The navigation communication light, as a carrier of optical signals, is installed at the location of the original aircraft navigation lights, such as the nose, wing, or tail. Because the navigation communication light has an emitting function, it can directly replace the original aircraft navigation lights at that location, but it needs to have the same emitting color as the original aircraft navigation lights; for example, a red navigation communication light for the nose, a green navigation communication light for the wing, and a white navigation communication light for the tail. In this embodiment, the navigation communication light is a monochrome high-brightness LED navigation light. The forward operating voltage of this LED is 115VAC / 380–800Hz, 4W, with a minimum horizontal luminous intensity exceeding 120 cd and a minimum vertical luminous intensity ≥40 cd. In reverse detection mode, it has a voltage greater than 10V DC and a built-in bidirectional switching circuit for emitting / detecting. Under reverse voltage, it has excellent photoelectric detection performance, with its photoelectric detection spectrum peak covering its own emission spectrum, enabling integrated and efficient adaptation of visible light signal transmission and reception. Furthermore, to overcome the limitations of traditional single-lamp communication, the navigation communication light adopts a multi-lamp spatial diversity redundancy communication hardware structure, supporting spatial diversity collaborative transmission and reception of red, green, and white navigation lights. A hardware timing selection structure enables parallel acquisition and optimal output of multi-lamp signals. When a single light fails, the hardware can automatically switch redundant links without program jumps, with a link switching delay ≤25ns. This meets the high reliability and high redundancy safety design specifications for aviation communications, is highly compatible with civil aviation standard multi-lamp layouts, and has strong practical applicability. Since the navigation communication light cannot simultaneously transmit and receive optical signals, the system employs a time-division multiplexing control strategy to switch operating states in a time-division manner: independently configuring the navigation communication light's operating mode in different time slots to ensure that only the transmitting or receiving circuit is active at any given time. Simultaneously, the navigation communication light integrates an aviation-grade temperature drift hardware calibration and compensation structure, along with a patch-type thermal acquisition and hardware voltage divider calibration and compensation network, integrated with the navigation light's LED body. This allows for real-time hardware acquisition of device operating temperatures, providing accurate data support for subsequent circuit dynamic compensation and offsetting device performance drift issues caused by the ultra-wide temperature range of aviation applications.

[0026] The link switching switch is used to switch the transmit and receive modes of the navigation light. In this embodiment, the link switching switch adopts a single-pole double-throw analog switch with a typical on-time (tON) of 20ns and a typical off-time (tOFF) of 15ns. It has an enable terminal control function, and the FPGA main control unit outputs high and low levels to control the switch switching, realizing selective connection between the drive circuit and the I / V conversion circuit, physically isolating the transmit and receive links, and eliminating signal crosstalk. The GPIO port of the FPGA main control unit is connected to the enable terminal of the link switching switch. The overall mode switching of the navigation communication light is completed by the link switching switch to complete the link selection control: when the switch is on the drive circuit, the navigation communication light works in the forward direction, in the light signal transmission mode, and normally lights up and modulates the output of visible light; when the switch is switched to the I / V conversion circuit, the navigation communication light is reverse biased and used as a photodetector to realize photoelectric acquisition of ambient light and the light signal from the other end, and complete the signal reception function. In this embodiment, the normally open contact of the link switching switch is connected to the driving circuit, and the normally closed contact of the link switching switch is connected to the I / V conversion circuit. That is, the navigation communication light is in the receiving mode by default, and monitors the visible light communication signal in the air in real time.

[0027] The driving circuit is used to drive the navigation light to emit modulated light signals. In this embodiment, the driving circuit adopts a constant current driving topology and consists of a DC / DC boost module, a MOSFET switching circuit, and a current-limiting feedback resistor. The input terminal of the DC / DC boost module is connected to an independent power supply, and the output terminal of the DC / DC boost module is electrically connected to the drain pin of the MOSFET switching circuit. The source pin of the MOSFET switching circuit is connected in series with the current-limiting feedback resistor and then connected to the positive terminal of the navigation communication light, while the negative terminal of the navigation communication light is grounded. Simultaneously, the current-limiting feedback resistor collects real-time loop current signals and feeds them back to the current sampling pin of the FPGA main control unit, forming a closed-loop constant current control loop. The gate pin of the MOSFET switching circuit is connected to the modulation signal output terminal of the FPGA main control unit. The FPGA outputs the MPAM modulation level to control the switching on and off of the MOSFET, realizing the modulation loading of the light signal. The driving circuit input is adapted to the airborne 115VAC / 28VDC power supply, and the output constant driving current is 200-350mA, ensuring that the brightness of the LED navigation light meets civil aviation standards while carrying the MPAM modulation signal.

[0028] The I / V conversion circuit converts the current signal generated by the light received by the navigation light into a voltage signal. In this embodiment, the I / V conversion circuit adopts a transimpedance amplifier topology and consists of an operational amplifier, a 100kΩ-1MΩ adjustable feedback resistor, and a filter capacitor. The non-inverting input of the operational amplifier is directly grounded, and the inverting input is connected to the photocurrent output of the navigation communication light through a signal line to collect the weak photocurrent generated by the reverse bias of the LED. The adjustable feedback resistor is connected between the inverting input and the signal output of the operational amplifier to form a negative feedback loop. The resistance value is adjusted to adapt to different photocurrent input intensities. The filter capacitor is connected in parallel with the adjustable feedback resistor to effectively filter out airborne high-frequency power supply noise and space clutter interference. The overall circuit stably converts the nA-level photocurrent generated by the reverse bias of the LED into a standard voltage signal of 0-3.3V, with a bandwidth covering 1-10MHz. It has high signal conversion accuracy and strong noise suppression capability. The single-pole double-throw link switch is an analog switch with a turn-on delay ≤20ns, a turn-off delay ≤15ns, and a bandwidth ≥100MHz. The switching is controlled by the output level of the FPGA main control unit to achieve physical isolation between the transmit and receive links and avoid signal interference.

[0029] The signal processing unit includes a signal modulation and demodulation circuit and an A / D conversion circuit; the signal modulation and demodulation circuit is connected to the drive circuit of the navigation communication transceiver unit; the A / D conversion circuit is connected to the I / V conversion circuit of the navigation communication transceiver unit; the modulation and demodulation circuit and the A / D conversion circuit are connected to the FPGA main control unit.

[0030] The signal modulation and demodulation circuit employs MPAM (Multi-Pulse Amplitude Modulation) technology to achieve high-speed optical signal modulation and demodulation. In this example, the signal modulation and demodulation circuit supports 4 / 8 / 16 levels of modulation and can adaptively adjust the modulation format according to the aviation communication distance and operating conditions to ensure communication stability.

[0031] The A / D conversion circuit is a multi-channel parallel high-speed A / D conversion circuit, adapted to multi-amplitude modulation signals, improving signal decision accuracy and reducing system bit error rate. The multi-channel parallelism is limited to 2-4 channels, and the number of parallel channels can be adjusted within this range according to communication rate requirements. In this example, the multi-channel parallel high-speed A / D conversion circuit preferably uses a three-channel parallel design, employing high-speed, high-precision A / D chips, all with a sampling rate of 20MSPS and a resolution of 12 bits, to complete the rapid acquisition and quantization of analog optical signals, improving signal decision accuracy and reducing system bit error rate. The A / D conversion circuit has a sampling rate ≥10MSPS, a resolution ≥10 bits, and an upper limit of 50MSPS (to adapt to airborne power consumption and space limitations), corresponding to the high / medium / low amplitude channels of MPAM multi-amplitude signals, respectively. After parallel quantization, the data is merged by the FPGA main control unit to improve signal decision accuracy, with an acquisition delay ≤50ns.

[0032] The FPGA main control unit is used to control the link switching switch to achieve transmit / receive mode switching, handle signal modulation and demodulation, data encoding and decoding, clock synchronization, and communication timing control to ensure orderly half-duplex communication. In this example, the FPGA main control unit uses an aerospace-grade FPGA chip that meets the DO-178C airborne software standard, has a vibration resistance level of 10-2000Hz, and an operating temperature of -55℃ to +85℃, exhibiting strong anti-interference capabilities and stability. The FPGA main control unit integrates a communication protocol control unit, which incorporates a dedicated half-duplex communication protocol to achieve full-process control of communication link establishment, data transmission, and link disconnection, avoiding signal conflicts and ensuring the reliability of aviation communication. The communication protocol control module is integrated into the FPGA's internal logic, incorporating a time-division multiplexing communication protocol to standardize the communication initiation, response, transmission, and disconnection processes, avoiding signal conflicts, and simultaneously setting up a dedicated check frame to enhance communication security. The protocol frame format is: frame header (16 bits) + address bits (8 bits) + data bits (64 bits) + check bit (16-bit CRC) + frame trailer (8 bits), with a single frame length of 112 bits. The frame header uses a dedicated 16-bit pseudo-random code (0x7E7E) for identity verification and link identification. Communication is established only if the frame header matches. Timing synchronization uses the FPGA's built-in 100MHz clock for synchronization. The transmit and receive time slots are fixed as 1ms for transmit, 1ms for receive, and 0.1ms for guard. The transmit / receive switching delay is ≤35ns.

[0033] In summary, through the aforementioned integrated and multi-layered hardware structure innovation design, this system addresses the structural shortcomings of traditional visible light communication equipment in adapting to the extreme and complex operating conditions of aviation from four core dimensions: electromagnetic isolation, dynamic gain adjustment, wide-temperature accuracy compensation, and multi-machine redundancy and fault tolerance. All innovative structures are deeply integrated with the original navigation light hardware, requiring no additional modifications to the airframe structure. While meeting civil aviation airworthiness standards and retaining the original navigation light warning function, it significantly improves the stability, accuracy, and reliability of aviation optical communication. The system demonstrates strong structural creativity and high feasibility.

[0034] Based on the above system architecture, the present invention provides an aircraft navigation light communication method, comprising the following steps:

[0035] S1. System Initialization:

[0036] During the initialization phase, the system automatically completes independent power supply status detection, hardware module connectivity self-test, and ambient light intensity acquisition. Simultaneously, it completes 100MHz high-precision clock synchronization and MPAM modulation (multi-level amplitude modulation) parameter initialization, temperature drift compensation parameter calibration, and gain level adaptive preset. The overall initialization time is ≤100ms.

[0037] Compared to the traditional VLC system which only performs simple power-on initialization, the initialization phase integrates a hardware parameter pre-adaptation mechanism, which links the front-end temperature drift compensation network and gain adjustment module to complete the hardware parameter pre-configuration based on real-time ambient temperature and light intensity, thus avoiding initial communication deviations under aviation conditions from the source.

[0038] S2, Link Pre-detection:

[0039] Before communication is initiated, the sending end sends a connection request frame containing a unique 16-bit pseudo-random frame header code. Unlike the traditional public frame header structure, the unique encrypted frame header can realize the unique identity verification of the device. If the frame header verification fails, the access of unauthorized devices will be rejected. After the receiving end verifies that the frame header is correct, it returns a connection confirmation frame. After the sending end receives the confirmation signal, the two parties formally establish an encrypted half-duplex communication link, ensuring the security of aviation communication from the link handshake stage.

[0040] S3, Signal transmission from the transmitting end:

[0041] The FPGA main control unit at the transmitting end switches the control link switching switch to the drive circuit, and the navigation communication light switches to the forward transmission mode. The modulation and demodulation circuit at the transmitting end uses the distance-level MPAM adaptive modulation algorithm to modulate and load the data to be transmitted onto the visible light signal of the navigation communication light, and the drive circuit drives the navigation communication light to transmit the visible light signal loaded with the data to be transmitted.

[0042] In this embodiment, since the navigation communication transceiver unit defaults to receive mode, when transmitting a signal, the FPGA main control unit needs to first control the link switching switch to the drive circuit, allowing the navigation communication light to switch to forward transmission mode. Then, the modulation and demodulation circuit at the transmitting end modulates the data to be transmitted (including aircraft position, speed, heading collision avoidance data, and airport ground temperature commands, etc.) using a distance-level MPAM adaptive modulation algorithm. This completely solves the shortcomings of traditional fixed-level modulation, which cannot adapt to dynamic aviation communication distances and suffers from severe signal attenuation. The drive circuit then drives the navigation communication light to transmit a visible light signal loaded with the data to be transmitted. After the transmitting end completes a single signal transmission, the FPGA main control unit at the transmitting end controls the link switching switch to the I / V conversion circuit, and the navigation communication transceiver unit switches back to standby receive mode.

[0043] The aforementioned distance-graded MPAM adaptive modulation algorithm adaptively matches modulation parameters according to the real-time communication distance threshold. For close-range scenarios (≤300m), high-order MPAM modulation (16 levels) is enabled to maximize communication speed; for medium-range scenarios (300–800m), mid-order MPAM modulation (8 levels) is enabled to balance speed and stability; and for close-range scenarios (800m–2km, including the 1.5–2km limit line-of-sight distance), low-order MPAM modulation (4 levels) is enabled. Furthermore, to reduce inter-symbol interference, a 4-level gain reduction mode is also used in close-range scenarios.

[0044] In addition, the modulation and demodulation circuit at the transmitting end also embeds an adaptive optical signal compensation algorithm, namely: for the high-altitude strong light (light intensity ≥ 50,000 lux) conditions of aviation, a 10-20nm ultra-narrowband filtering mechanism is adopted to accurately match the exclusive center wavelength of the navigation light, filter out more than 99% of solar stray light interference, and synchronously and dynamically increase the modulation amplitude by 0.3-0.5V, thereby increasing the signal recognition rate in strong light environments from the traditional 60% to more than 99%; for the severe conditions of rain, fog and cloud cover and signal attenuation ≥ 10dB, it automatically locks the 4-level MPAM low-order modulation to improve signal penetration and ensure uninterrupted communication under extreme weather conditions.

[0045] S4, Signal reception at the receiving end

[0046] The receiving end utilizes the reverse photoelectric detection characteristic of the navigation communication light to collect the visible light signal carrying the data to be transmitted emitted by the transmitting end and generate an induced current. The I / V conversion circuit converts the induced current into a voltage signal and sends it to the A / D conversion circuit. The A / D conversion circuit uses a multi-channel parallel amplitude fusion decision algorithm to complete multi-channel synchronous sampling quantization and then transmits it to the FPGA main control unit. The FPGA main control unit restores the data to be transmitted based on the sampled and quantized signal.

[0047] In this embodiment, the receiving end utilizes the reverse photoelectric detection characteristic of the navigation communication light to collect the visible light signal emitted by the other end and generate an nA-level induced current. After amplification and filtering by the I / V conversion circuit, it is converted into a 0-3.3V standard voltage signal, completing the precise conversion of the photoelectric signal. The converted voltage signal is input to the A / D conversion circuit of the signal processing circuit. The A / D conversion circuit uses a multi-channel parallel amplitude fusion decision algorithm to complete multi-channel synchronous sampling and quantization before transmitting it to the FPGA main control unit, thus overcoming the technical defects of traditional single-channel sampling and fixed threshold demodulation.

[0048] The aforementioned three-digit multi-channel parallel amplitude fusion decision algorithm first performs mean filtering on the high, medium, and low amplitude data acquired by the three parallel A / D converters. Then, it dynamically corrects the level decision deviation based on the high-frequency real-time sampling data, adapting to real-time fluctuations in aviation lighting and temperature, and completes signal decoding to obtain the sampled quantized signal. Compared to the traditional single-level decision method, this method can significantly reduce the decision error of MPAM multi-amplitude signals.

[0049] After decoding, the FPGA main control unit verifies data integrity using a 16-bit CRC redundancy check mechanism. For abnormal data that fails the check, a tiered retransmission mechanism is automatically triggered: minor anomalies are retransmitted as a single frame, while severe anomalies require link reset. Compared to the traditional method of directly discarding data, this significantly improves the integrity of aviation communication data and effectively reduces the bit error rate. For normal data that passes the check, the FPGA main control unit reconstructs the data to be transmitted based on the sampled quantized signal.

[0050] The performance of the present invention will be illustrated below through a specific example:

[0051] The system maintains stable communication in unobstructed scenarios with a line-of-sight distance of ≤2km. The communication rate and bit error rate at different distances strictly adhere to the standards shown in Table 1, with a bit error rate of ≤ 0.5% across all scenarios. It is free from electromagnetic interference, highly secure, and suitable for the short-range, high-real-time communication needs of civil aviation and various application scenarios; the specific test raw data and parameter calibration methods are as follows:

[0052] 1. Raw test data (selecting 3 typical scenarios): Airport taxiing scenario (200m, illumination 100,000 lux), using red light communication, downlink rate 7.98 Mbit / s, uplink rate 6.95 Mbit / s, bit error rate... Near-field flight scenario (500m, illumination 50000 lux), downlink rate 4.97 Mbit / s, uplink rate 4.48 Mbit / s, bit error rate... Mid-range obstacle avoidance scenario (aerial formation avoidance, 1.2km, illumination 60000 lux): Communication is achieved using taillights with white light, downlink rate 2.48 Mbit / s, uplink rate 1.95 Mbit / s, and bit error rate... In extreme line-of-sight scenarios (2km, 8dB attenuation due to rain and fog, 20000 lux illumination), using green light communication, the downlink rate is 1.18 Mbit / s, the uplink rate is 0.98 Mbit / s, and the bit error rate is [missing information]. .

[0053] 2. Parameter calibration methods: A / D conversion circuit calibration: sampling accuracy is calibrated every hour of power-on, and quantization error is calibrated using a standard signal source (amplitude 0-3.3V, frequency 1MHz) to ensure error ≤0.01V; MPAM modulation calibration: amplitude level is calibrated in real time according to ambient light intensity to ensure decision threshold deviation ≤0.05V; vibration fault tolerance algorithm calibration: vibration offset coefficient is calibrated every 3 hours of flight to ensure time delay jitter ≤5ns.

[0054] Table 1

[0055]

[0056] The physical parameters of the aircraft navigation light communication system are as follows: total weight ≤150g, volume ≤100mm×80mm×20mm (excluding the navigation light body), suitable for narrow airborne installation space; specific compatible aircraft models and installation locations: compatible with Boeing 737 (installed in the reserved mounting position of the wing navigation light, space size 105mm×85mm×25mm, matching the reserved mounting holes, the system volume and weight are 5% and 10% smaller than the reserved space respectively, no modification to the mounting position is required), Airbus A320 (installed in the tail navigation light assembly, space size 98mm×78mm×22mm, compatible with the original fixed structure, the system volume and weight are within the installation space limit); the heat dissipation adopts passive patch heat dissipation, fanless design, suitable for airborne scenarios without additional heat dissipation space; vibration resistance level 10-2000Hz, operating temperature -55℃~+85℃, fully compatible with aviation flight conditions; system compatibility test details with other airborne electronic equipment: compatible with airborne navigation system (model: Garmin) The G1000 and communication system (model: Collins VHF-250) were jointly tested. The test items included data interaction latency, electromagnetic interference, and link stability. The test results showed that the data interaction latency was ≤3ms, there was no electromagnetic interference, and there was no link interruption for 72 hours of continuous testing, and the compatibility met the standards (test report number: HK-20260416-01).

[0057] Therefore, this system fully complies with the mandatory CAAC / FAA navigation light standards, as evidenced by the following: 1. Compliance Testing: The system's performance meets CCAR-25, FAR-25, and DO-160G standards. The communication mode does not affect the navigation light warning logic and can be directly applied to civil aircraft. 2. Key Test Items: These include navigation light brightness testing, electromagnetic compatibility testing, and vibration adaptation testing, all completed using corresponding professional equipment and methods. 3. Parameter Compliance: The brightness of red, green, and white navigation lights all comply with the relevant provisions of CCAR-25.1387 and FAR-25.1387. 4. Electromagnetic Compatibility: It complies with the DO-160G standard, with electromagnetic radiation ≤20dBμV / m, no electromagnetic interference, no impact on the navigation light warning function, and no safety hazards.

[0058] In summary, this invention discloses an aircraft navigation light communication system and method. The navigation communication light serves as the transceiver carrier for the navigation communication transceiver unit (acting as both a light source and a photodetector with reverse bias), integrating FPGA main control, signal processing, and communication protocol control. The navigation communication transceiver unit achieves time-division switching of transmission and reception through a link switching switch, combining multi-channel parallel high-speed A / D conversion and MPAM to improve communication performance, and incorporating a dedicated half-duplex protocol to ensure orderly communication. This invention achieves integrated warning and communication, adapts to extreme aviation conditions, solves the pain points of existing technologies, fills the gap in dedicated two-way optical communication systems for aviation navigation lights, and is applicable to scenarios such as aircraft air-to-air collision avoidance communication, airport ground-to-air communication, anti-interference communication, and aircraft auxiliary communication, falling within the scope of wireless optical communication application technology.

[0059] It should be noted that although the embodiments described above are illustrative, they are not intended to limit the invention. Therefore, the invention is not limited to the specific embodiments described above. Any other embodiments obtained by those skilled in the art under the guidance of this invention without departing from its principles are considered to be within the protection scope of this invention.

Claims

1. An aircraft navigation light communication system, characterized in that, It includes two or more communication terminals, each of which includes an independent power supply, an FPGA main control unit, a navigation communication transceiver unit, and a signal processing unit connected to the independent power supply; The navigation communication transceiver unit includes a navigation communication light, a link switching switch, a drive circuit, and an I / V conversion circuit. The navigation communication light is connected to the common terminal of the link switching switch. One contact of the link switching switch is connected to the drive circuit, and the other contact of the link switching switch is connected to the I / V conversion circuit. The link switching switch, the drive circuit, and the I / V conversion circuit are connected to the FPGA main control unit. The signal processing unit includes a signal modulation and demodulation circuit and an A / D conversion circuit; the signal modulation and demodulation circuit is connected to the drive circuit of the navigation communication transceiver unit; the A / D conversion circuit is connected to the I / V conversion circuit of the navigation communication transceiver unit; the modulation and demodulation circuit and the A / D conversion circuit are connected to the FPGA main control unit.

2. The aircraft navigation light communication system according to claim 1, characterized in that, The normally open contact of the link switching switch is connected to the drive circuit, and the normally closed contact of the link switching switch is connected to the I / V conversion circuit.

3. The aircraft navigation light communication system according to claim 1, characterized in that, The FPGA main control unit integrates a communication protocol control unit.

4. An aircraft navigation light communication method implemented by the aircraft navigation light communication system of claim 1, characterized in that, The steps include the following: Before communication is initiated, the sending end sends a connection request frame containing a unique pseudo-random frame header code. After the receiving end verifies that the frame header is correct, it returns a connection confirmation frame. After the sending end receives the confirmation signal, the two parties formally establish an encrypted half-duplex communication link. The FPGA main control unit at the transmitting end switches the control link switching switch to the drive circuit, and the navigation communication light switches to the forward transmission mode; the modulation and demodulation circuit at the transmitting end uses the distance-level MPAM adaptive modulation algorithm to modulate and load the data to be transmitted onto the visible light signal of the navigation communication light, and the drive circuit drives the navigation communication light to transmit the visible light signal loaded with the data to be transmitted. The receiving end utilizes the reverse photoelectric detection characteristic of the navigation communication light to collect the visible light signal carrying the data to be transmitted emitted by the transmitting end and generate an induced current. The I / V conversion circuit converts the induced current into a voltage signal and sends it to the A / D conversion circuit. The A / D conversion circuit uses a multi-channel parallel amplitude fusion decision algorithm to complete multi-channel synchronous sampling quantization and then transmits it to the FPGA main control unit. The FPGA main control unit restores the data to be transmitted based on the sampled and quantized signal.

5. The aircraft navigation light communication method according to claim 1, characterized in that, The modulation and demodulation circuit at the transmitting end uses a distance-graded MPAM adaptive modulation algorithm to adaptively and hierarchically match modulation parameters according to the real-time communication distance between the two parties. That is, MPAM high-order modulation is enabled in close-range scenarios, MPAM medium-order modulation is enabled in medium-range scenarios, and MPAM low-order modulation is enabled in close-range scenarios.

6. The aircraft navigation light communication method according to claim 1, characterized in that, The modulation and demodulation circuit at the transmitting end also embeds an adaptive optical signal compensation algorithm, namely: for high-altitude strong light conditions in aviation, an ultra-narrowband filtering mechanism is used to accurately match the exclusive center wavelength of the navigation light and synchronously and dynamically improve the modulation amplitude; for rain, fog, cloud cover and signal attenuation conditions, low-order MPAM modulation is locked.

7. The aircraft navigation light communication method according to claim 1, characterized in that, After the transmitter completes the transmission of a visible light signal loaded with data to be transmitted, the FPGA main control unit of the transmitter controls the link switching switch to the I / V conversion circuit, and the navigation communication light switches back to the reverse reception mode.

8. The aircraft navigation light communication method according to claim 1, characterized in that, The A / D conversion circuit at the receiving end uses a multi-channel parallel amplitude fusion decision algorithm to first perform mean filtering on the high, medium and low amplitude data acquired by the three parallel A / D converters, and then dynamically correct the level decision deviation based on the high-frequency real-time sampling data to obtain the sampled quantized signal.

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