A UAV-borne full-circle multi-target laser communication system and method

Abstract

The present invention relates to an all-around multi-target laser communication system carried by an unmanned aerial vehicle, and relates to the field of laser communication technology. It is used to solve the demand for cluster formation command interaction of unmanned aerial vehicles in a strong electromagnetic interference environment, as well as the problem that traditional laser communication is difficult to achieve multi-target simultaneous communication, and the system is complex, and the volume and weight are not suitable for the unmanned aerial vehicle hanging environment. The system consists of a communication module, a main control terminal, a heat dissipation module and a structural support. The communication module includes a communication codec circuit board, a laser emitting unit and a laser receiving unit. The main control terminal includes a host computer, a master control circuit board and a communication interface board. The heat dissipation module includes a heat dissipation fan and a heat sink. The circumferential array of the communication module realizes the ability of multi-channel simultaneous communication in 360° azimuth and within a certain pitch angle range, and has the advantages of small size, light weight, and low power consumption.

Description

Technical Field

[0001] The present invention relates to the field of laser communication technology, and in particular to an unmanned aerial vehicle-borne all-around multi-target laser communication system and method. Background Art

[0002] With the expansion of the application field of unmanned aerial vehicles, drones, as high-tech equipment in the new era, play a vital role in changing the combat style and winning future wars. Due to the increase in military combat requirements and the specific needs of social development, the application of drone formations has attracted extensive research. Compared with a single independent drone, drone formation flight presents great advantages in terms of payload, detection field of view, and multi-task execution.

[0003] Traditional radio frequency communications are susceptible to electromagnetic field interference, making it difficult to communicate in real time and efficiently, affecting the coordinated combat effectiveness of drone clusters. In addition, the broadcast characteristics of radio frequency communications are prone to co-channel interference and information leakage problems, which restricts the safety and concealment performance of drones.

[0004] Free-space laser communication refers to the communication between free-space channels using laser beams as information carriers. Laser communication has many advantages, such as high propagation directionality, large transmission capacity, strong confidentiality, no need for spectrum authorization, and outstanding anti-interference ability. Therefore, drone-borne laser communication is an effective solution for the construction of anti-interference, large-capacity airborne communication networks.

[0005] At present, laser communication usually uses a tracking and aiming mechanism to achieve point-to-point communication. Although the signal rate is high, it is difficult to achieve simultaneous communication with multiple targets. At the same time, due to the tracking and aiming mechanism, the system is complex, and the size, weight and power consumption are relatively high, which limits its use for drones with limited load capacity. Summary of the invention

[0006] The present invention provides an unmanned aerial vehicle-borne all-around multi-target laser communication system and method to solve the problems existing in existing space laser communication terminals in unmanned aerial vehicle formation communication.

[0007] An unmanned aerial vehicle-mounted all-around multi-target laser communication system comprises a main control terminal, a heat dissipation module and a plurality of communication modules arranged in a circumferential array;

[0008] Each communication module includes a laser emitting unit, a laser receiving unit and a signal encoding and decoding circuit, and the laser emitting unit and the laser receiving unit are connected to the signal encoding and decoding circuit through a cable;

[0009] The laser emitting unit includes a driving circuit, a VCSEL laser, an array substrate and a beam shaping lens. A plurality of VCSEL lasers inlaid with beam shaping lenses are welded on the array substrate and powered by a circuit in the array substrate. The driving circuit converts the digital signal in the signal encoding and decoding circuit into a current pulse to drive the VCSEL laser to emit a laser pulse signal.

[0010] The laser receiving unit includes a filter component, a Fresnel lens, a photoelectric sensor and a pre-signal amplifier. The photoelectric sensor converts the laser signal that passes through the filter component and is focused by the Fresnel lens into an electrical signal, which is amplified by the pre-signal amplifier and transmitted to the signal encoding and decoding circuit.

[0011] The signal encoding and decoding circuit encodes the information data transmitted by the main control end and transmits it to the driving circuit of the laser emitting unit, and decodes the electrical signal received from the laser receiving unit into a digital signal;

[0012] The main control end is used to control each communication module to perform adaptive communication, and at the same time process the data uploaded by each communication module to realize information interaction with each communication module;

[0013] The multiple VCSEL lasers in the array in the laser emitting unit emit shaped and optimized laser beams, covering an area within a certain azimuth angle range and a pitch angle range. At the same time, the Fresnel lens and the photoelectric sensor in the laser receiving unit complete the reception of the laser signal in the area, so that the communication module covers a communication area within a certain azimuth angle range and a pitch angle range; the multiple communication modules arranged in a circumferential array are used to realize full-circle communication within a 360° azimuth angle range.

[0014] A method for all-around multi-target laser communication onboard an unmanned aerial vehicle is implemented by the following steps:

[0015] Step S1: Before the communication starts, the laser receiving units in the communication modules of the UAV cluster leader and the wingman are in a normally open state. The UAV cluster leader sends a communication command, and the laser emitting units in the communication modules of the leader emit laser signals in a polling manner.

[0016] Step S2: After the receiving unit in the communication module of each wingman drone receives the laser signal, the laser emitting unit in the corresponding regional communication module emits the laser signal to the leader drone of the drone cluster. After the communication module of the leader drone of the drone cluster receives the laser signal of the wingman drone, the laser emitting unit in the corresponding regional communication module is selected to emit the laser signal to the wingman drone to achieve initial alignment.

[0017] Step S3, the leader and wingman of the UAV cluster send an identification code, decode the signal and perform identity recognition, and start information transmission after successful identity recognition;

[0018] Step S4, adaptive communication, the leader of the UAV cluster maintains communication with each communication module that has been successfully identified, while the remaining communication modules continue to scan in turn until all wingmen in the cluster formation are contacted and the scanning stops, the laser emission unit in the non-working communication module is turned off, and the corresponding communication module is switched according to the changes in the azimuth position of each wingman during the communication process to maintain smooth and uninterrupted communication.

[0019] Beneficial effects of the present invention:

[0020] 1. The unmanned aerial vehicle-borne all-around multi-target laser communication system of the present invention adopts a circumferential array configuration of multiple communication modules, avoiding the problem of complex tracking and aiming mechanism system and difficulty in achieving multi-target simultaneous communication in traditional space laser communication, and has the ability to communicate with multiple targets simultaneously within the communication coverage range of 360° in azimuth and a certain pitch angle; there are no moving parts, the entire system is simpler and more reliable, thereby reducing the size, weight, power consumption and cost of the entire system, and better matching the unmanned aerial vehicle hanging environment with limited carrying capacity and high maneuverability.

[0021] 2. The UAV-borne all-around multi-target laser communication method described in the present invention adopts a scanning method in which each communication module performs polling in the all-around range. Compared with mechanical scanning, it greatly shortens the time for target capture. The adaptive communication working mode during the communication process ensures smooth communication links while reducing system power consumption. It can realize safe, confidential, and anti-interference information and command transmission and interaction between multiple machines in a UAV cluster formation under radio silence or strong electromagnetic interference environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a principle block diagram of an unmanned aerial vehicle-mounted all-around multi-target laser communication system according to the present invention;

[0023] Figure 2 This is a schematic structural diagram of an unmanned aerial vehicle-mounted all-around multi-target laser communication system according to the present invention;

[0024] Figure 3 The present invention provides a flow chart of a method for all-around multi-target laser communication onboard an unmanned aerial vehicle. DETAILED DESCRIPTION

[0025] Specific implementation method 1. Combination Figure 1 and Figure 2To illustrate the present embodiment, an unmanned aerial vehicle-mounted all-around multi-target laser communication system includes a communication module 1, a main control terminal 2, a heat dissipation module 3 and a structural support 4; 24 of the communication modules 1 are arranged in a circumferential array and connected to the main control terminal 2, each communication module 1 transmits and receives laser signals within the range of 18° in azimuth and 18° in pitch, and there is an overlapping area of ​​1.5° between adjacent communication modules 1 to ensure coverage of targets within the range of 360° in azimuth and 15° in pitch within the spatial range.

[0026] The communication module includes a signal encoding and decoding circuit 1-1, a laser emitting unit 1-2, and a laser receiving unit 1-3; wherein the laser emitting unit 1-2 includes: a driving circuit 1-2-1, an array substrate 1-2-2, a VCSEL laser (vertical cavity surface emitting laser) 1-2-3 and a beam shaping lens 1-2-4; the laser receiving unit 1-3 includes: a filter component 1-3-1, a Fresnel lens 1-3-2, a photodetector 1-3-3 and a pre-signal amplification circuit 1-3-4, and the filter component 1-3-1 is composed of an optical cutoff filter and a narrow-band filter.

[0027] The signal encoding and decoding circuit 1-1 is connected to the laser emitting unit 1-2 and the laser receiving unit 1-3 through cables. In the laser emitting unit: 8 VCSEL lasers 1-2-3 inlaid with beam shaping lenses 1-2-4 are welded on the array substrate 1-2-2, and the driving circuit 1-2-1 is connected to the signal encoding and decoding circuit 1-1 and the array substrate 1-2-2; in the laser receiving unit 1-3: the preamplifier 1-3-4 is connected to the photoelectric sensor 1-3-3 and the signal encoding and decoding circuit 1-1, and the filter component 1-3-1 and the Fresnel lens 1-3-2 are arranged at the front end of the photoelectric sensor 1-3-3.

[0028] In this embodiment, the information encoding and decoding circuit 1-1 is controlled by an STM32F407ZGT6 chip to control the laser emission and reception within a 15° range of the corresponding communication module 1, and encode and decode it at the same time. The VCSEL laser 1-2-3 uses a 940nm near-infrared band, and its beam divergence angle is 27°. After the optical shaping lens 1-2-4 is optimized for beam shrinkage, the beam divergence angle is 18°. The array substrate 1-2-2 is a copper substrate, and multiple VCSEL lasers 1-2-3 are welded on the array substrate 1-2-2 with a power supply circuit to ensure the emission intensity of the laser signal and to dissipate heat for the VCSEL laser 1-2-3.

[0029] The narrowband filter parameters in the filter assembly 1-3-1 are 940nm±5nm. According to the size and lightweight requirements of the system receiving unit, the Fresnel lens 1-3-2 has a diameter of 40mm, a focal length of 21mm, and a transmittance of 98% for a laser with a wavelength of 940nm. It is made of acrylic material and can focus light within the range of ±7.5° of the field of view angle onto the 10mmх10mm target surface of the photoelectric sensor.

[0030] In this embodiment, the preamplifier 1-3-4 is designed as a transimpedance preamplifier (TIA) with a minimum current resolution of 10nA and a bandwidth of 100K. The front end of this module uses an AD825 chip, and the module power supply voltage is ±5V; the output voltage is 20Vpp (MAX), and the output current is ±20mA (MAX).

[0031] In this embodiment, the main control terminal 2 includes a host computer, a master control circuit board 2-1 and a communication interface board 2-2. The master control circuit board 2-1 is connected to the host computer and the communication interface board 2-2 via an RS422 interface, and the communication interface board 2-2 is connected to the signal encoding and decoding circuit 1-1 in each communication module 1 via a USART interface. The master control circuit board 2-1 is controlled by an STM32F407ZGT6 chip to control the subordinate 24 communication modules 1 to perform adaptive communication.

[0032] In this embodiment, the heat dissipation module 3 includes a heat sink 3-1 and a heat dissipation fan 3-2; the heat sink 3-1 is attached to the array substrate 1-2-3 in the laser emitting unit to dissipate heat for the VCSEL laser 1-2-3, and the heat dissipation fan 3-2 is arranged above each heat sink 3-1 to assist the heat sink 3-1 in dissipating heat.

[0033] In this embodiment, the structural support member 4 is made of magnesium-aluminum alloy to ensure the lightness and miniaturization of the entire system and the stability of the optical system under strong vibration and maneuvering conditions of the airborne platform.

[0034] In this embodiment, at least two communication systems are used in coordination, one of which is designated as the leader communication terminal and the others are wingman communication terminals, wherein the leader communication terminal can communicate in formation with multiple wingman terminals that are not in the same position.

[0035] Specific implementation method 2: Combination Figure 3 This embodiment describes a method for all-around multi-target laser communication onboard an unmanned aerial vehicle. The working process is as follows:

[0036] S1, scanning. Before the communication starts, the laser receiving units in the communication modules of the leader and wingman of the UAV cluster are in a normally open state. The leader of the UAV cluster sends a communication command, and the laser transmitting units in the communication modules of the leader transmit laser signals in a polling manner.

[0037] S2, alignment. After the receiving unit in the communication module of the wingman receives the laser signal, the laser emitting unit in the corresponding regional communication module emits a laser to the leader of the drone cluster. After the leader of the drone cluster receives the laser signal of the wingman, it selects the laser emitting unit in the corresponding regional communication module to emit a laser to provide feedback to the wingman to achieve initial alignment.

[0038] S3, identification, the leader and wingman of the drone cluster send identification codes, decode the signals and perform identification, and start information transmission after successful identification;

[0039] S4, adaptive communication. While the leader of the UAV cluster maintains communication with each communication module that has been successfully identified, the other communication modules continue to scan in turn until all wingmen in the cluster formation are contacted, then the scanning stops, the laser emission unit in the non-working communication module is turned off, and the corresponding communication module is switched according to the changes in the azimuth and position of each wingman during the communication process to maintain smooth and uninterrupted communication.

[0040] In this implementation, S1 specifically includes: the host computer of the UAV cluster leader communication terminal issues a communication command, and the laser emitting unit in each module cyclically emits laser signals in a full 360° range in sequence. At the same time, each receiving unit of the UAV leader communication terminal and the wingman communication terminal are in standby mode, waiting for feedback signals from each wingman.

[0041] In steps S2-S3, the actions of other wingman communication terminals participating in the cluster formation are consistent with the wingman communication terminals described in S2-S3 above.

[0042] In this embodiment, in order to solve the problem of communication interference caused by the overlapping area existing in the S2-S3 process and the laser signal emitted by the same wingman being simultaneously received by multiple receiving units during the communication process, the communication interface board selects the optimal data to be received and specifies this communication module according to the signal strength received by each communication module.

Claims

1. An unmanned aerial vehicle-mounted all-around multi-target laser communication system, characterized by: The communication system includes a main control terminal, a heat dissipation module and a plurality of communication modules arranged in a circumferential array; Each communication module includes a laser emitting unit, a laser receiving unit and a signal encoding and decoding circuit, and the laser emitting unit and the laser receiving unit are connected to the signal encoding and decoding circuit through a cable; The laser emitting unit includes a driving circuit, a VCSEL laser, an array substrate and a beam shaping lens. A plurality of VCSEL lasers inlaid with beam shaping lenses are welded on the array substrate and powered by a circuit in the array substrate. The driving circuit converts the digital signal in the signal encoding and decoding circuit into a current pulse to drive the VCSEL laser to emit a laser pulse signal. The laser receiving unit includes a filter component, a Fresnel lens, a photoelectric sensor and a pre-signal amplifier. The photoelectric sensor converts the laser signal that passes through the filter component and is focused by the Fresnel lens into an electrical signal, which is amplified by the pre-signal amplifier and transmitted to the signal encoding and decoding circuit. The signal encoding and decoding circuit encodes the information data transmitted by the main control end and transmits it to the driving circuit of the laser emitting unit, and decodes the electrical signal received from the laser receiving unit into a digital signal; The main control end is used to control each communication module to perform adaptive communication, and at the same time process the data uploaded by each communication module to realize information interaction with each communication module; The multiple VCSEL lasers arrayed in the laser emitting unit emit laser beams that have been shaped and optimized to cover an area within a certain azimuth angle range and a pitch angle range. At the same time, the Fresnel lens and the photoelectric sensor in the laser receiving unit complete the reception of the laser signal in the area, so that the communication module covers a communication area within a certain azimuth angle range and a pitch angle range; multiple communication modules arranged in a circumferential array are used to achieve full-circle communication within an azimuth angle range of 360°. Specifically: 24 communication modules are arranged in a circumferential array and connected to the main control end, each communication module transmits and receives laser signals within an azimuth angle range of 18° and a pitch angle range of 18°, and there is an overlapping area of ​​1.5° between adjacent communication modules to ensure coverage of targets within an azimuth angle range of 360° and a pitch angle range of 15° in the space range; The main control end includes a host computer, a master control circuit board and a communication interface board. The master control circuit board is connected to the host computer and the communication interface board, converts the control commands received from the host computer into digital signals for transmission, and feeds back the information received by the communication module to the host computer, and communicates with the subordinate communication modules. The communication interface board is connected to the signal encoding and decoding circuits in each communication module.

2. The unmanned aerial vehicle-mounted all-around multi-target laser communication system according to claim 1 is characterized in that: It also includes a heat dissipation module, which includes a heat sink and a heat dissipation fan. The heat sink is attached to the array substrate in each communication module, and the heat dissipation fan is arranged above each heat sink to dissipate heat for the VCSEL laser.

3. The unmanned aerial vehicle-borne all-around multi-target laser communication system according to claim 1 is characterized in that: It also includes a structural support member, which provides mechanical structural support for each device.

4. The unmanned aerial vehicle-borne all-around multi-target laser communication system according to claim 1 is characterized in that: The filter assembly is composed of a narrowband filter and an optical cutoff filter, which filters the incident light and only transmits light of a specified wavelength. The Fresnel lens focuses the filtered light within the corresponding azimuth and elevation angle range onto the target surface of the photoelectric sensor.

5. A method for all-around multi-target laser communication onboard an unmanned aerial vehicle, the communication method being implemented based on an all-around multi-target laser communication system onboard an unmanned aerial vehicle according to any one of claims 1 to 4, and characterized in that: The steps of this method are as follows: Step S1: Before the communication starts, the laser receiving units in the communication modules of the UAV cluster leader and the wingman are in a normally open state. The UAV cluster leader sends a communication command, and the laser emitting units in the communication modules of the leader emit laser signals in a polling manner. Step S2: After the receiving unit in the communication module of each wingman drone receives the laser signal, the laser emitting unit in the corresponding regional communication module emits the laser signal to the leader drone of the drone cluster. After the communication module of the leader drone of the drone cluster receives the laser signal of the wingman drone, the laser emitting unit in the corresponding regional communication module is selected to emit the laser signal to the wingman drone to achieve initial alignment. Step S3, the leader and wingman of the UAV cluster send an identification code, decode the signal and perform identity recognition, and start information transmission after successful identity recognition; Step S4, adaptive communication, the leader of the UAV cluster maintains communication with each communication module that has been successfully identified, while the remaining communication modules continue to scan in turn until all wingmen in the cluster formation are contacted and the scanning stops, the laser emission unit in the non-working communication module is turned off, and the corresponding communication module is switched according to the changes in the azimuth position of each wingman during the communication process to maintain smooth and uninterrupted communication.

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