A UAV swarm networking measurement and control communication link and communication method

Abstract

The present invention provides a drone swarm networking measurement and control communication link and communication method, including airborne equipment and local equipment, the airborne equipment includes an airborne data terminal host and an omnidirectional antenna, and the local equipment includes a local data terminal host, a positioning module, and an omnidirectional and directional integrated antenna. The present invention adopts a time division multiple access, time division duplex system, a single-hop network, and a single-channel form of communication equipment. The measurement and control communication link and the inter-machine communication link work at the same frequency point, and the inter-machine communication, telemetry, remote control, and mission load information are compositely transmitted. In addition, the command and control node adopts a measurement and control communication form that combines directional antennas and omnidirectional antennas and works in time and stage, which simplifies the design of airborne communication equipment, realizes the remote transmission of telemetry, remote control, and mission load information, and maintains the inter-machine communication function.

Description

Technical Field

[0001] The present invention belongs to the field of communication technology, and relates to a networking measurement and control communication link and a communication method, in particular to a networking measurement and control communication link and a communication method for a swarm of unmanned aerial vehicles. Background Art

[0002] It is generally believed that a drone swarm refers to a group of small drones that carry out unified combat missions through autonomous networking and formation coordination under the command or supervision of operators (in the air, on the ground or at sea). The swarm system has outstanding characteristics such as a large number of drones, a large coverage area, strong anti-destruction capability, low unit cost, strong combat flexibility, and excellent coordination ability, and is highly advanced. The basis for the autonomous networking and formation coordination of drone swarms is that each drone node can be interconnected through inter-machine communication links, and the premise for operators to effectively command or supervise drone swarms is to have a robust measurement and control communication link. The data transmitted by inter-machine communication includes the location, status, target data and coordination information of drones, while the data transmitted by measurement and control communication includes the uplink remote control information of the operator (command and control node), the downlink telemetry information of drones and mission payload information. For a single UAV, inter-machine communication, telemetry and remote control have relatively low link bandwidth requirements (generally 1 to 10 kbps), while mission payload information transmission involving images or high-definition pictures has relatively high link bandwidth requirements (generally 500 Kbps to 2 Mbps). In addition, inter-machine communication, telemetry and remote control need to cover all current UAVs at any time, while mission payload information only needs to be transmitted in the mission area.

[0003] There are currently several main ways to achieve multi-machine measurement and control and inter-machine communication: (1) Broadband services and narrowband services use independent links and work simultaneously. For narrowband services, both the sender and the receiver use omnidirectional antennas to form omnidirectional links to cover all drones, while for broadband services, directional antennas are used on the sender or receiver to form directional links to cover a single drone in a certain direction (when there are multiple drones in multiple directions with broadband service requirements, multiple directional antennas with different directions are used to achieve this). For example, the utility model patent "A drone measurement and control device" (patent number: CN 206249086 U) and the invention patent "A drone-borne low-altitude emergency communication self-organizing radio device and networking method" (patent number: CN 110602638A) use the characteristics of omnidirectional antennas with a large coverage angle range and narrow bandwidth for long-distance communication and the characteristics of high-gain directional antennas with a long range, high link bandwidth but narrow beam coverage and poor adaptability for short-distance communication. It should be pointed out that the load capacity of swarm drones is very limited, the transmission power of airborne communication equipment is small, and the dynamics of drones are relatively large. In order to achieve reliable communication in any direction, only lightweight airborne omnidirectional antennas can be used. In addition, in a swarm system, the number of drones N is usually large (N can reach 50 to 100, or even more). The link bandwidth requirements for inter-machine communication and telemetry are N times that of a single machine, and the link bandwidth requirements for remote control are also increased accordingly. At this time, the effective range of the omnidirectional link is very limited and cannot meet the actual combat needs. In addition, the communication equipment needs to adopt a dual-channel form, which will increase the complexity of the equipment and the cost of use. The size, weight and power consumption of dual-channel equipment are larger than those of single-channel equipment, and the adaptability to small drones is poor. (2) The measurement and control communication link and the inter-machine communication link operate at different frequencies, and they work simultaneously without interfering with each other. There is a machine in the swarm as a relay node, which has both inter-machine communication link equipment and measurement and control communication link equipment. When working, the relay node receives the remote control information uploaded by the command and control node where the operator is located through the measurement and control communication link, and then forwards it to the drone swarm through the inter-machine communication link. At the same time, it receives the telemetry information and mission load information transmitted by the drone swarm through the inter-machine communication link, and then forwards it to the command and control node through the measurement and control communication link. The operator can use a high-gain self-tracking directional antenna to achieve remote communication with the relay node, and indirectly achieve remote telemetry, remote control and mission load information transmission of the swarm. Its advantage is that the command and control node has a long range of action on the swarm, and its disadvantage is that the measurement and control information needs to be forwarded twice through the relay node using the inter-machine communication link, that is, multi-hop transmission is required, which increases the communication delay, and the system needs to backup multiple relay nodes. After the current relay node fails, a new relay node must be quickly elected, otherwise the measurement and control communication link will be paralyzed, and the operator will lose the command and supervision of the drone swarm. In addition, the communication equipment on the relay node must also have a dual-channel mode.(3) The measurement and control communication link and the inter-machine communication link operate at the same frequency. Inter-machine communication, telemetry, remote control, and mission payload information are transmitted in a composite manner to form a single-hop communication network. The airborne single-channel communication equipment is more adaptable to small UAVs than dual-channel communication equipment. The command and control node can communicate directly with each swarm of UAVs without any transit, and the communication delay is short. However, in order to achieve coverage of all UAVs, the command and control node uses an omnidirectional antenna. Therefore, the communication distance is limited, which is also difficult to meet actual combat needs. Summary of the invention

[0004] The purpose of the present invention is to provide a networking measurement and control communication link and communication method for unmanned aerial vehicle swarms, adopting time division multiple access, time division duplex system (TDD-TDMA), single-hop network, communication equipment adopting single-channel form, measurement and control communication link and inter-machine communication link working at the same frequency, inter-machine communication, telemetry, remote control and mission load information composite transmission, and command and control node adopts measurement and control communication form that combines directional antenna and omnidirectional antenna and works in time and stage, simplifies the design of airborne communication equipment, realizes remote transmission of telemetry, remote control and mission load information while maintaining inter-machine communication function.

[0005] In order to achieve the above-mentioned purpose, the present invention provides a drone swarm networking measurement and control communication link, including airborne equipment and local equipment, the airborne equipment includes an airborne data terminal host and an omnidirectional antenna, the local equipment includes a local data terminal host, a positioning module and an omnidirectional and directional integrated antenna; the omnidirectional and directional integrated antenna includes an omnidirectional antenna, a directional antenna, an antenna base, a servo tracking mechanism, a servo control module, and an electronic switch, the omnidirectional antenna is installed on the upper part of the directional antenna, the directional antenna is installed on the antenna base, the positioning module, the servo control module, and the servo tracking mechanism are installed on the back of the directional antenna, and the RF front end of the local data terminal host is connected to the omnidirectional antenna or the directional antenna through an electronic switch.

[0006] Furthermore, the airborne data terminal host and the local data terminal host both include a radio frequency front-end module, a channel module and a baseband module; the radio frequency front end is used to receive antenna signals, which are sent to the channel module after filtering and amplification, and at the same time receive radio frequency signals from the channel module after up-conversion, and send them to the antenna after amplification; the channel module receives the signal preliminarily amplified by the radio frequency front end, and sends it to the baseband module after down-conversion, amplification and filtering, and at the same time, receives the modulated signal sent by the baseband module, and sends it to the radio frequency front end after up-conversion, amplification and filtering; the baseband module receives the down-converted signal sent by the channel module, and sends it to the airborne flight control system after processing, and at the same time, receives the business data of the flight control system and the mission payload, and sends it to the channel module after processing; the baseband module of the local data terminal host is also used to provide a network port and control an electronic switch.

[0007] Furthermore, the power amplifier transmission power of the RF front end is 0.5W to 2W; the airborne data terminal host adopts a single-board integrated airborne data terminal, which is installed on the surface of the body and adopts an external thin and lightweight heat sink.

[0008] Furthermore, the omnidirectional antenna of the omnidirectional and directional integrated antenna is in the form of a dipole, the directional antenna is in the form of a flat antenna, a parabola, a horn or a phased array, and the directional antenna has a 3dB beam angle width θ in the azimuth direction. E 15~25°, 3dB beam angle width θ in elevation H It is 10~15°.

[0009] Furthermore, the omnidirectional antenna of the airborne equipment is a dipole vertically polarized antenna with an antenna gain of 0 dB, an antenna radiation pattern with full coverage of 360° in azimuth, and a 3dB beam angle coverage range of not less than ±30° in elevation.

[0010] Furthermore, the communication link operating frequency band adopts the L-band low frequency band 1350-1450MHz, and adopts a time division multiple access + time division duplex system.

[0011] The present invention also provides a drone swarm networking measurement and control communication method, comprising the following steps:

[0012] S1. The local device starts up for self-test, selects the omnidirectional antenna, and the positioning module calculates the location information of the local device. The servo control module controls the servo tracking mechanism to point the directional antenna to the azimuth zero position and pitch zero position of the local device by default, and performs north correction;

[0013] S2, the onboard equipment starts self-test and wirelessly networks with local equipment;

[0014] S3, the communication link dynamically sets the time slot to sparse mode or dense mode according to whether the service transmission demand of the current node in the network contains broadband task load information, and each node in the network transmits service data according to the agreed time slot;

[0015] S4. The local device obtains valid drone location information. The servo control module calculates the azimuth and pitch angles of all powered drones relative to the directional antenna of the local device in real time through the location information of the local device and the valid drone location information, and adjusts the servo tracking mechanism to control the main lobe of the directional antenna to align with the azimuth AZ and the pitch angle EL.

[0016] S5. The local device selects a directional antenna or an omnidirectional antenna according to the current situation;

[0017] S6. Determine whether the communication task is completed. If not, return to S3. If completed, end the workflow.

[0018] Furthermore, the calculation method of the main lobe alignment azimuth angle AZ of the directional antenna in step S4 is as follows:

[0019] If | AZ max –AZ min |≤θ E , then AZ=(AZ max +AZ min ) / 2;

[0020] If | AZ max –AZ min |>θ E , then AZ=1 / N*Σ(AZ1, AZ2,...AZ N );

[0021] The calculation method of the main lobe of the directional antenna to the elevation angle EL is as follows

[0022] If |EL max –EL min |≤θ H , then EL=(EL max +EL min ) / 2;

[0023] If |EL max –EL min |>θ H , then EL=1 / N*Σ(EL1, EL2,...EL N );

[0024] Among them, AZ1, AZ2, ... AZ N The azimuth of the directional antenna of all powered-on drones relative to the local device, EL1, EL2, ... EL N is the pitch angle of all powered-on drones relative to the local device’s directional antenna, [AZ min , A.Z. max ] is the range of azimuth angles of all powered-on drones relative to the directional antenna of the local device, [EL min , E.L. max ] is the range of the pitch angles of all powered-on drones relative to the directional antenna of the local device, and N represents the number of swarm drones currently acquired; θ E θ is the 3dB beam angle width of the directional antenna in azimuth; H It is the 3dB beam angle width of the directional antenna in the elevation direction.

[0025] Furthermore, the method for selecting an antenna in step S5 is as follows:

[0026] Extract the maximum distance d between each node of the current drone swarm and the ground station max With the reliable coverage radius R1 of the omnidirectional link,

[0027] If d max ≤R1, select omnidirectional antenna;

[0028] If R1 <d max ≤1.5R1,|AZ max –AZ min |≤θ E , and |EL max –EL min |≤θ H , select a directional antenna;

[0029] If R1 <d max ≤1.5R1, and AZ max –AZ min |>θ E or |EL max –EL min |>θ H , select an omnidirectional antenna;

[0030] If d max >1.5R1, select a directional antenna.

[0031] Furthermore, the step S1 also includes the servo control module acquiring the current mission planning information from the control node; and the step S4 also includes judging the validity of the drone position information according to the mission planning information.

[0032] Beneficial effects of the present invention:

[0033] The present invention provides a drone swarm networking measurement and control communication link and communication method, which has the following advantages:

[0034] 1) The present invention combines the characteristics of short single-hop network communication delay and relatively simple system. Compared with the mode of relying on relay nodes for networking measurement and control, it saves spectrum resources, improves the real-time performance of measurement and control communication, and simplifies the design of airborne equipment.

[0035] 2) The present invention combines the characteristics of high-gain directional self-tracking antennas in collecting space electromagnetic signals. Compared with the networking measurement and control mode of omnidirectional antennas, the communication distance is increased by about an order of magnitude, which is more in line with the actual combat scenario requirements.

[0036] 3) The present invention adopts a combination of directional and omnidirectional antennas in the local equipment, making full use of omnidirectional antennas to achieve wide-beam omnidirectional coverage measurement and control communications in the take-off and landing stages, and using directional antennas to achieve high-gain directional remote measurement and control communications in the cruise and mission stages. The two antennas work in time and stage to achieve reliable telemetry, remote control, mission payload information transmission and inter-machine communication for swarm drones.

[0037] 4) Use sparse and dense time slot modes as needed to dynamically allocate link bandwidth, maximize link level margin, and achieve reliable communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The included drawings are used to provide a further understanding of the embodiments of the present invention, which constitute a part of the specification, are used to illustrate the embodiments of the present invention, and together with the text description, explain the principles of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0039] Figure 1 An overall working block diagram of a drone swarm networking measurement and control communication link provided by a specific embodiment of the present invention;

[0040] Figure 2 A block diagram of a drone swarm networking measurement and control communication link device provided in a specific embodiment of the present invention;

[0041] Figure 3 A schematic diagram of a local directional omnidirectional integrated antenna structure for measurement and control of a drone swarm network provided by a specific embodiment of the present invention, wherein (a) is a front view of the antenna, and (b) is a side view of the antenna;

[0042] Figure 4 A schematic diagram of a time slot mode of a UAV swarm networking measurement and control communication link provided by a specific embodiment of the present invention;

[0043] Figure 5 A flow chart of a communication method for measurement and control communication link of a drone swarm networking provided by a specific embodiment of the present invention. DETAILED DESCRIPTION

[0044] The technical solution of the present invention is described in detail below through implementation modes in conjunction with the accompanying drawings.

[0045] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. Unless otherwise specifically stated, the relative arrangement of the components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention.

[0046] The networked measurement and control communication link of the drone swarm proposed by the present invention adopts the time division multiple access and time division duplex system (TDD-TDMA), the network within the swarm system is a single-hop mode, the communication equipment adopts a single-channel form, the measurement and control communication link and the inter-machine communication link operate at the same frequency, and the inter-machine communication, telemetry, remote control and mission load information are compositely transmitted. Networked measurement and control communication airborne equipment is installed on each swarm drone, and networked measurement and control communication local equipment is installed on the command and control node. The airborne equipment includes an airborne data terminal host and an airborne omnidirectional antenna. The local equipment includes a local data terminal host, a positioning module, and an omnidirectional and directional integrated antenna. The command and control node adopts a measurement and control communication form that combines omnidirectional and directional antennas and works in time and stages. In the take-off and landing section, the drone swarm is close to the command and control node, but the distribution angle range in azimuth and pitch is large, and the advantages of the omnidirectional antenna beam width are used to realize short-range omnidirectional measurement and control communication. During the cruise and mission phases, the drone swarm is far away from the command and control node, but the distribution angle range in azimuth and pitch becomes smaller. At this time, the system uses a high-gain tracking directional antenna to achieve remote directional measurement and control communication for the swarm drones. The command and control node and the drone swarm are both nodes in the single-hop communication network. While achieving measurement and control communication, the swarm drones can also communicate with each other. The overall working block diagram of the communication link is shown in the figure below. Figure 1 shown.

[0047] (1) Hardware equipment

[0048] The drone swarm networking measurement and control communication link provided by the present invention is as follows: Figure 2 As shown, it includes airborne equipment and local equipment. The airborne equipment includes an airborne data terminal host and an airborne omnidirectional antenna. The local equipment includes a local data terminal host, a positioning module, and an omnidirectional and directional integrated antenna.

[0049] For the swarm measurement and control communication airborne equipment, its airborne data terminal host includes three functional modules: RF front end, channel and baseband. Among them, the RF front end receives the weak electromagnetic signals of other nodes sent by the antenna, and sends them to the channel module after filtering and amplification by low noise amplifier (LNA) devices. At the same time, the RF front end receives the RF signal from the channel module after up-conversion, and sends it to the antenna after amplification by the power amplifier (PA). The power amplifier transmission power of the RF front end is preferably 0.5W~2W. The channel module receives the electromagnetic signals of other nodes initially amplified by the RF front end, and sends them to the baseband after down-conversion, amplification, filtering and other processes. At the same time, it receives the modulated signal sent by the baseband, and sends it to the RF front end after up-conversion, amplification, filtering and other processes. The baseband module receives the down-converted signal sent by the channel module, and sends it to the airborne flight control system after time slot synchronization, demodulation, deinterleaving, descrambling, decoding, deframing and other processes. At the same time, it receives the business data of the flight control system, mission payload, etc., and sends it to the channel after framing, encoding, scrambling, interleaving, time slot synchronization, modulation, etc. The RS422 asynchronous serial port is preferred for sending and receiving data with the flight control system, while the RS422 synchronous serial port is preferred for receiving mission payload information.

[0050] For the application scenarios of swarm drones, single-board integrated airborne data terminals are preferred. The size, weight and power consumption of this type of airborne data terminal are greatly reduced compared to traditional airborne data terminals. In order to further reduce the size, weight and power consumption of the equipment, the built-in air cooling can be eliminated, and the airborne data terminal can be installed on the surface of the fuselage, with a thin and lightweight heat sink attached tightly, and the relative flow of air when the drone swarm is flying can be used to automatically achieve device heat dissipation. The airborne data terminal needs to receive the drone satellite navigation positioning data, obtain the drone's location information, and share it with the swarm and the command and control node. The data can be forwarded to the airborne data terminal by the flight control system.

[0051] The antenna of the airborne equipment adopts an omnidirectional antenna, preferably a dipole vertically polarized antenna, with an antenna gain of about 0dB, an antenna pattern with full coverage of 360° in azimuth, and a 3dB beam angle coverage range of not less than ±30° in elevation. According to different application scenarios, a rod-shaped or thin sheet antenna shape can be selected as needed (for UAVs without vertical tails such as flying wing layout and rotor layout, a rod antenna is used, and for UAVs with vertical tails, a thin sheet antenna is designed in conformity with the tail wing). Unlike traditional large UAVs / manned aircraft / cruise missiles and other airborne / missile-borne measurement and control antennas, monopole antennas are not suitable. This is because in order to reduce their own weight, the body structure of swarm UAVs usually adopts composite materials, and the fuselage area is very small, and the fuselage cannot provide a sufficiently large metal reflective surface required for the normal operation of the L-band monopole antenna.

[0052] For the local equipment of swarm networking measurement and control communication, its data terminal generally also includes three functional modules: RF front-end, channel and baseband. Among them, the functions of RF front-end and channel are consistent with those of airborne equipment, and the basic functions of baseband are also consistent with those of airborne equipment. The difference is that the external communication interface module of baseband usually contains a network port, and the baseband has the ability to control electronic switches. The requirements of local equipment on volume, weight and power consumption are not as stringent as those of airborne equipment, and there is no carrier movement when the local equipment is placed on the ground, so the equipment can be designed to dissipate heat by itself, such as by increasing the thickness of the heat dissipation teeth or using a power supply fan for heat dissipation.

[0053] Another key to the local equipment of swarm measurement and control communication is the integrated omnidirectional and directional antenna, including omnidirectional antenna, directional antenna, "two-choice" electronic switch, servo tracking mechanism, servo control module, antenna bracket and base, etc. Figure 3 shown.

[0054] Structurally, the omnidirectional antenna is designed to be installed on top of the directional antenna. The RF front end is connected to the omnidirectional antenna or directional antenna as required through an electronic switch. The omnidirectional antenna is preferably in dipole form. Compared with the airborne antenna of the swarm drone, the number of array elements can be appropriately increased at the command and control node to obtain a certain gain. The optional forms of directional antennas include flat-panel antennas, parabolic antennas, horn antennas and phased array antennas. The present embodiment prefers a flat-panel antenna form, which has advantages in size and weight over the parabolic antenna and horn antennas, and has advantages in price over the phased array antenna. Directional antenna azimuth 3dB beam angle width θ E The preferred beam angle is 15-25°, and the 3dB beam angle width in the elevation direction is θ H The preferred angle is 10 to 15 degrees. In the L band, the directional antenna array width W of this performance indicator is generally 0.3 to 0.5 m, and the height H is generally 0.4 to 0.6 m, which is easy to carry, and the antenna gain is between 19 and 23 dB.

[0055] Behind the directional antenna is the servo tracking mechanism, which is controlled by the servo control module to point the directional antenna to the appropriate azimuth and elevation angles in real time.

[0056] Below the directional antenna is the antenna base, which includes an antenna bracket and a base, used to carry the antenna and servo tracking mechanism, etc. Depending on the usage scenario, the antenna base can be fixedly installed on a platform or supported by a stable tripod.

[0057] The satellite positioning module and servo control module are usually designed to be installed on the back of the directional antenna, with only the satellite receiving antenna extended. The servo control module can also be integrated with the data terminal host. Figure 3 As shown, the positioning module is located above the servo tracking mechanism on the back of the directional antenna, and the servo control module is located on the side of the servo tracking mechanism on the back of the directional antenna.

[0058] (2) Operating frequency band

[0059] The working frequency band of the drone swarm network measurement and control communication link adopts the L-band low frequency band of 1350-1450MHz. The use of this frequency band can not only avoid the electromagnetic interference of a large number of UHF (ultra-high frequency 300-3000MHz) military and civilian equipment, but also avoid the pressure on the equipment size, weight and power consumption caused by the increased spatial attenuation of electromagnetic waves and the decrease in power amplifier efficiency brought by higher frequency bands (such as S-band and C-band). At the same time, it avoids the satellite signal frequency points of the Beidou navigation system, GPS, GLONASS, etc., which is conducive to reducing the difficulty of electromagnetic compatibility design between the link and the airborne satellite navigation subsystem and reducing the complexity of the equipment.

[0060] (3) Multiple access mode

[0061] The measurement and control communication link of the UAV swarm networking adopts time division multiple access. Time division multiple access works in single-channel mode, which can avoid the problem of increased complexity of frequency division multiple access equipment. At the same time, the working principle of time division multiple access is that each swarm drone and command and control node transmits electromagnetic signals in its own time slot according to the allocated time slot, and only receives but does not transmit in the other time slots, realizing time division duplex. Time division multiple access + time division duplex (TDD+TDMA) avoids mutual interference within the swarm and circumvents the near-far effect. When the swarm system is working, remote control, telemetry and inter-machine communication data are transmitted periodically, while mission payload data is transmitted in bursts on demand. Such as Figure 4 As shown, when there is no task load data transmission demand, the system withdraws the bandwidth demand and transmits the signal according to the mode 1 time slot (sparse time slot) to obtain a larger link margin and improve communication stability. When there is a task load data transmission demand, the system transmits the signal according to the mode 2 time slot (dense time slot).

[0062] (4) Communication method

[0063] The specific communication workflow of the drone swarm networking measurement and control communication link of the present invention is as follows: Figure 5 shown.

[0064] S1. The local device starts self-test, and the "two-choice" electronic switch defaults to connect the omnidirectional antenna to the RF front end. The positioning module receives navigation satellite data and calculates the location information of the local device. The servo control module controls the servo tracking mechanism to point the directional antenna to the azimuth zero position and pitch zero position of the local device by default, and aligns the azimuth zero position of the local device with the true north direction or obtains the angle between the azimuth zero position of the local device and the true north direction through north correction. The servo control module obtains the mission planning information from the control node (the mission planning will give the approximate activity area, no-fly zone and other information of the swarm drone).

[0065] S2. The onboard device starts self-test and wirelessly networks with local devices.

[0066] S3. The communication link dynamically sets the time slot to sparse mode or dense mode according to whether the service transmission demand of the current node in the network contains broadband task load information, and each node in the network transmits service data according to the agreed time slot.

[0067] S4. The local device obtains valid drone location information and filters invalid drone location information. The servo control module calculates the azimuth angles (AZ1, AZ2, ... AZ 1, AZ 2, AZ 3, AZ 4, AZ 5, AZ 6, AZ 7, AZ 8, AZ 9, AZ 10, AZ 11, AZ 12, AZ 13, AZ 14, AZ 15, AZ N ) and elevation angle (EL1, EL2, ... EL N ), extract the azimuth range [AZ min , A.Z. max ] and elevation range [EL min , E.L. max ] and adjust the servo structure to control the main lobe of the directional antenna to align with the azimuth angle AZ and the elevation angle EL.

[0068] The calculation method of azimuth angle AZ is as follows:

[0069] If | AZ max –AZ min |≤θ E , then AZ=(AZ max +AZ min ) / 2;

[0070] If | AZ max –AZ min |>θ E , then AZ=1 / N*Σ(AZ1, AZ2,...AZ N ), N represents the number of swarm drones currently obtained.

[0071] The above formula means that if the azimuth dispersion range of the drone swarm relative to the directional antenna is not greater than the 3dB beam angle width θ of the directional antenna in azimuth E , then point the directional antenna to the middle position of the azimuth of the drone swarm in the azimuth direction. If the azimuth dispersion range relative to the directional antenna exceeds θ E , the azimuth direction of the directional antenna is determined by weighted averaging the azimuth angles of the drone swarm. The advantage of the weighted average method is that when the main lobe of the antenna cannot cover all drones, the main lobe of the antenna can cover as many drones as possible.

[0072] Similarly, the elevation angle EL is obtained using the same principle, and its specific calculation method is as follows:

[0073] If |EL max –EL min |≤θ H, then EL=(EL max +EL min ) / 2;

[0074] If |EL max –EL min |>θ H , then EL=1 / N*Σ(EL1, EL2,...EL N ).

[0075] After that, the servo control module of the directional antenna obtains the position of the drone swarm through telemetry parameters, calculates the azimuth angle AZ and the pitch angle EL, and controls the main lobe of the antenna to track the position in real time.

[0076] If the servo module does not receive any swarm drone positioning information or local positioning information within the agreed period, the direction of the directional antenna remains unchanged.

[0077] Unlike wired channels, wireless transmission channels inevitably have higher bit errors. In order to eliminate the impact of bit errors, a more complex CRC-32 check can be used to filter telemetry data frames containing bit errors; or a simpler checksum form can be used to filter most telemetry data frames, and the validity of the drone position information can be judged in combination with the mission planning information obtained in step S1, and invalid position information can be further filtered.

[0078] S5. The command node selects an antenna according to the current situation.

[0079] During the takeoff and landing phases of the drone swarm, the electronic switch should select the omnidirectional antenna. Because the drone swarm is close to the ground station during the takeoff and landing phases, the signal power is sufficient, and the main lobe of the omnidirectional antenna is very wide, which can achieve coverage of the drone swarm in any azimuth and most pitch directions. At this time, if a directional antenna is used, the main lobe of the directional antenna will often not cover the entire drone swarm, which is likely to cause communication data loss.

[0080] During the cruise and mission phases, the electronic switch should select the directional antenna to track the drone swarm, because when the spatial distribution pattern is maintained, the farther the drone swarm is from the ground station, the smaller the azimuth range and the pitch angle range. The directional antenna has a higher gain and its effective range is much longer than that of the omnidirectional antenna, which can reach more than 100km, which can meet the practical application of the swarm.

[0081] Specifically, for antenna gating, the general principles adopted are as follows:

[0082] Assume that the reliable coverage radius of the omnidirectional link is R1.

[0083] According to the obtained location information, determine the maximum distance d between each node of the current drone swarm and the ground station maxRelationship with R1 and relationship between drone coverage and directional antenna 3dB beam angle:

[0084] (1) If d max ≤R1, select omnidirectional antenna;

[0085] (2) If ①R1 <d max ≤1.5R1,②|AZ max –AZ min |≤θ E , and |EL max –EL min |≤θ H , select a directional antenna;

[0086] (3) If ①R1 <d max ≤1.5R1,②|AZ max –AZ min |>θ E or |EL max –EL min |>θ H , select an omnidirectional antenna;

[0087] (4) If d max >1.5R1, select a directional antenna.

[0088] S6. Determine whether the communication task is completed (as long as the local networking measurement and control equipment is not powered off, the communication task is considered not to be completed). If not, return to S3. If completed, end the workflow.

[0089] The following is a link level calculation for an implementation example of a UAV swarm networking measurement and control communication link design.

[0090] Formula (1) is an empirical calculation formula for directional antenna gain.

[0091] G=10*log 10 (32000 / θ E / θ H ) (1)

[0092] In this embodiment, θ E Take 20°, θ H Taking 10°, the calculated directional antenna gain is 22dB.

[0093] Formula (2) is the calculation formula of electromagnetic wave spatial attenuation Loss, R is the electromagnetic wave spatial transmission distance, unit is km, f is the electromagnetic wave operating frequency, unit is MHz.

[0094] Loss=20lg[f]+20lg[R]+32.45 (2)

[0095] Formula (3) is the calculation formula for the electromagnetic signal power Pr at the receiver. Pt is the transmitted signal power, in dBm; Gt is the transmit antenna gain, in dB; Lt is the total loss of the transmit channel, in dB; Gr is the receive antenna gain, in dB; Lr is the total loss of the receive channel, in dB;

[0096] Pr=Pt+Gt-Lt-Loss+Gr-Lr (3)

[0097] Link margin M = Pr-S, where S represents the link sensitivity under a certain signal bandwidth, in dBm. According to engineering experience, for air-to-ground and air-to-air communications, the link can be reliably established when M is not less than 10 dBm.

[0098] In this embodiment, the transmission power Pt of the airborne terminal and the ground terminal are both 2W (33dBm); the link operating frequency f is 1400MHz; the airborne omnidirectional antenna gain is 0dB; the ground omnidirectional antenna gain is 3dB, and the ground directional antenna gain is 22dB as described above; the total bandwidth of the network measurement and control link is designed to be 2Mbps (the number of swarm drone nodes is 100, the telemetry code rate is 1kpbs / frame, the remote control code rate is 10kpbs, the inter-machine communication code rate is 1kbps / frame, the mission load information is 1Mbps / frame, and at most one drone can be connected at any time. The UAV needs to transmit mission payload information, considering the overhead such as time slot protection, the total bandwidth is 2Mbps) or 1Mbps (the number of swarm UAV nodes is 100, the telemetry code rate is 1kpbs / frame, the remote control code rate is 10kpbs, the inter-machine communication code rate is 1kbps / frame, considering the overhead such as time slot protection, the total bandwidth is 1Mbps), the receiver sensitivity S is taken as -99dBm@2Mbps, -102dBm@1Mbps according to the current technical level; the transmission channel loss Lt is set to 1.5dB; the receiving channel energy loss Lr is set to 1.5dB. The link level calculation results of the machine-to-ground communication (directional antenna and omnidirectional antenna are used on the ground respectively) and machine-to-machine communication under the above parameter conditions are shown in the following table. It is generally believed that the link can operate reliably when the link level margin is not less than 10dB. It can be seen that the reliable communication distance between machines can reach 15km, and the reliable communication distance between machines and ground can reach 20km (omnidirectional antenna is used on the ground) and 190km (directional antenna is used on the ground).

[0099] Table 1 Calculation results of network measurement and control link level

[0100]

[0101] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0102] Parts of the present invention that are not described in detail are well known to those skilled in the art.

Claims

1. A drone swarm networking measurement and control communication method, characterized in that: The steps include: S1. The local device starts up for self-test, selects the omnidirectional antenna, and the positioning module calculates the location information of the local device. The servo control module controls the servo tracking mechanism to point the directional antenna to the azimuth zero position and pitch zero position of the local device by default, and performs north correction; S2, the onboard equipment starts self-test and wirelessly networks with local equipment; S3, the communication link dynamically sets the time slot to sparse mode or dense mode according to whether the service transmission demand of the current node in the network contains broadband task load information, and each node in the network transmits service data according to the agreed time slot; S4. The local device obtains valid drone location information. The servo control module calculates the azimuth and pitch angles of all powered drones relative to the directional antenna of the local device in real time through the location information of the local device and the valid drone location information, and adjusts the servo tracking mechanism to control the main lobe of the directional antenna to align with the azimuth AZ and the pitch angle EL. S5. The local device selects a directional antenna or an omnidirectional antenna according to the current situation; S6, determine whether the communication task is completed, if not, return to S3, if it is completed, end the workflow; The method for calculating the azimuth angle AZ of the main lobe of the directional antenna in step S4 is as follows: If| THE max – THE min |≤θ E ,then AZ=(AZ max + THE min ) / 2; If| AZ max – A-Z min |>θ E ,then AZ=1 / N*Σ(AZ1, AZ2,……AZ N ); The calculation method of the main lobe of the directional antenna to the elevation angle EL is as follows If |EL max – EL min | ≤ θ H , then EL = (EL max + EL min ) / 2; If |EL max –EL min |> θ H , then EL = 1 / N * Σ(EL1, EL2, …… EL N ); Among them, AZ1, AZ2, ... AZ N The azimuth of the directional antenna of all powered-on drones relative to the local device, EL1, EL2, ... EL N is the pitch angle of all powered-on drones relative to the local device’s directional antenna, [AZ min , A.Z. max ] is the range of azimuth angles of all powered-on drones relative to the directional antenna of the local device, [EL min , E.L. max ] is the range of the pitch angles of all powered-on drones relative to the directional antenna of the local device, and N represents the number of swarm drones currently acquired; θ E θ is the 3dB beam angle width of the directional antenna in azimuth; H The 3dB beam angle width of the directional antenna in the elevation direction; The method for selecting an antenna in step S5 is as follows: Extract the maximum distance d between each node of the current drone swarm and the ground station max With the reliable coverage radius R1 of the omnidirectional link, If d max ≤ R1, select omnidirectional antenna; If R1 <d max ≤1.5 R1, |AZ max – AZ min |≤θ E , and |EL max –EL min |≤θ H , select a directional antenna; If R1 <d max ≤1.5 R1, and AZ max – AZ min |>θ E or | EL max –EL min |>θ H , select an omnidirectional antenna; If d max > 1.5R1, select a directional antenna.

2. The drone swarm networking measurement and control communication method according to claim 1, characterized in that: The step S1 also includes the servo control module acquiring the current mission planning information from the control node; the step S4 also includes judging the validity of the drone position information according to the mission planning information.

3. A drone swarm networking measurement and control communication system, characterized in that: The drone swarm networking measurement and control communication method according to claim 1 or 2 is adopted, wherein the measurement and control communication system includes an airborne device and a local device, the airborne device includes an airborne data terminal host and an omnidirectional antenna, and the local device includes a local data terminal host, a positioning module, and an omnidirectional and directional integrated antenna; The omnidirectional and directional integrated antenna includes an omnidirectional antenna, a directional antenna, an antenna base, a servo tracking mechanism, a servo control module, and an electronic switch. The omnidirectional antenna is installed on the upper part of the directional antenna, the directional antenna is installed on the antenna base, the positioning module, the servo control module, and the servo tracking mechanism are installed on the back of the directional antenna, and the radio frequency front end of the local data terminal host is connected to the omnidirectional antenna or the directional antenna through an electronic switch.

4. The drone swarm networking measurement, control and communication system as claimed in claim 3, characterized in that: The airborne data terminal host and the local data terminal host both include a radio frequency front-end module, a channel module and a baseband module; The RF front end is used to receive antenna signals, and send them to the channel module after filtering and amplification, and at the same time receive the RF signals after up-conversion from the channel module, and send them to the antenna after amplification; The channel module receives the signal initially amplified by the RF front end, and sends it to the baseband module through down-conversion, amplification, and filtering. At the same time, it receives the modulated signal sent by the baseband module, and sends it to the RF front end through up-conversion, amplification, and filtering. The baseband module receives the down-converted signal sent by the channel module, and sends it to the airborne flight control system after processing. At the same time, it receives the business data of the flight control system and the mission payload, and sends it to the channel module after processing. The baseband module of the local data terminal host is also used to provide a network port and control an electronic switch.

5. The drone swarm networking measurement, control and communication system according to claim 4, characterized in that: The power amplifier transmission power of the radio frequency front end is 0.5W~2W; the airborne data terminal host adopts a single-board integrated airborne data terminal, which is installed on the surface of the body and adopts an external thin and lightweight heat sink.

6. The drone swarm networking measurement, control and communication system as claimed in claim 3, characterized in that: The omnidirectional antenna of the omnidirectional and directional integrated antenna is in the form of a dipole, the directional antenna is in the form of a flat antenna, a parabola, a horn or a phased array, and the 3dB beam angle width θ of the directional antenna in the azimuth direction is E 15~25°, 3dB beam angle width θ in elevation H It is 10~15°.

7. The drone swarm networking measurement, control and communication system as claimed in claim 3, characterized in that: The omnidirectional antenna of the airborne equipment is a dipole vertically polarized antenna with an antenna gain of 0 dB. The antenna radiation pattern has full coverage of 360° in azimuth and a 3dB beam angle coverage range of not less than ±30° in elevation.

8. The drone swarm networking measurement, control and communication system as claimed in claim 3, characterized in that: The communication system operates in the L-band low frequency band of 1350~1450MHz and adopts time division multiple access + time division duplex system.

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