A single pulse and angle measurement method for low-altitude unmanned aerial vehicle

Abstract

The present invention discloses a single pulse angle measurement method for a low-altitude unmanned aerial vehicle. In a microwave communication system, the antenna array and difference beam angle measurement technology are used to calculate the azimuth deflection of a distant target emitting electromagnetic waves. Based on this technology, a ground station microwave communication tracking system is designed. When a distant flying target moves horizontally, the antenna array receives the radio signal emitted by the flying target to form a sum signal and a difference signal. After filtering and amplification, the sum and difference signals are collected respectively, and the amplitude value ratio and phase ratio of the two signals are calculated. The deflection angle θ is calculated according to a formula using the ratio, thereby obtaining the deflection angle θ information of the distant target relative to the normal of the antenna array, and then the deflection angle information is fed back to the servo turntable, which is rotated by the servo turntable to always keep the antenna array pointing to the target, and finally the tracking communication function of the target is realized.

Description

Technical Field

[0001] The invention relates to the technical field of microwave communications, and in particular to a single-pulse angle measurement method for a low-altitude unmanned aerial vehicle. Background Art

[0002] Unmanned aerial vehicles (UAVs) often fly at low altitudes. When a low-altitude flying target communicates with a ground station in the microwave frequency band, GPS signals are usually used for positioning to guide the ground station antenna to point to the target. However, when the GPS signal is weak or lost, the GPS position information of the target may be lost, resulting in the ground station antenna array being unable to aim at the target and the communication effect between the ground station and the target cannot be guaranteed. Therefore, a single-pulse angle measurement method for low-altitude UAVs is proposed. Summary of the invention

[0003] The purpose of the present invention is to provide a single-pulse angle measurement method for low-altitude unmanned aerial vehicles, which utilizes antenna arrays and difference beam angle measurement technology to calculate and determine the azimuth deviation angle between the target and the antenna array in real time, thereby controlling the servo turntable to drive the antenna array to align with the target, achieving tracking and communication effects on the target, and solving the problems raised in the above-mentioned background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a single pulse angle measurement method for a low-altitude UAV, comprising the following steps:

[0005] S1. Yagi antenna array receives signals: The Yagi antenna array is divided into left and right arrays from the center line. The radio signals transmitted by distant flying targets are received by the antenna array of the ground station.

[0006] S2, sum and difference signal dual-channel signal output: half of the signals of the left and right arrays are superimposed in phase in the sum and difference device, and then output from the sum channel, and the other half of the signals of the left and right arrays are reversely offset in the sum and difference device, and then output from the difference channel;

[0007] S3, calculating the deflection angle θ: after the sum signal and the difference signal are filtered and amplified, the sum and difference signals are collected respectively, and the amplitude ratio and phase ratio of the two signals are calculated, and the deflection angle θ is calculated according to the formula using the ratio;

[0008] S4, servo turntable rotation tracking: The deflection angle θ information is fed back to the servo turntable. The servo turntable continuously adjusts the direction of the antenna array according to the θ value, so that the antenna array is always pointed directly at the communication target, thereby realizing the function of tracking communication.

[0009] Preferably, the Yagi antenna array is mainly composed of a half-wave dipole, a balun, a reflector, and a director, and the Yagi antenna array consists of eight antenna units arranged at intervals of half a wavelength.

[0010] Preferably, the antenna unit comprises a connecting piece and a plurality of antenna poles, a plurality of arc grooves matching the antenna poles are provided on one side of the connecting piece, a first groove is provided on both sides of the arc groove, a clamping assembly is provided inside the two first grooves, an arc block is movably sleeved on the outer side of the antenna pole, plug blocks are fixedly connected at both ends of the arc block, and the plug blocks are inserted into the inside of the first grooves.

[0011] Preferably, both sides of the antenna rod are fixedly connected with blocks, one side of the block is provided with a through hole, the inner side wall of the first groove is provided with two through grooves, a straight rod is slidably inserted into the through groove, one end of the straight rod is provided with a conical groove adapted to the plug block, and one end of the plug block passes through the through hole and is inserted into the conical groove.

[0012] Preferably, the clamping assembly comprises a cross bar, one side of which is fixedly connected to one end of the two straight bars, one side of the connecting piece is provided with a second groove, an inner side wall of the second groove is fixedly connected with a spring, one end of the spring is fixedly connected to one side of the cross bar.

[0013] Preferably, a pull ring is fixedly connected to one side of the cross bar, a plurality of spikes are fixedly connected to the inner wall of the arc-shaped groove, one side of the spikes is fitted with the outer side of the antenna pole, a plurality of anti-slip protrusions are fixedly connected to the inner wall of the conical groove, the outer side of the anti-slip protrusions is fitted with one end of the plug-in block, one end of the plug-in block is an arc-shaped end, two arc-shaped spring sheets are fixedly connected to the outer side of the plug-in block, the outer side of the arc-shaped spring sheets is fitted with the inner wall of the through hole, and two supporting members are fixedly connected to the bottom of the connecting member.

[0014] Preferably, the outer side of the servo turntable in S4 is fixedly sleeved with a shell, the inner side of the shell is provided with a support assembly and a buffer assembly, the support assembly includes a plurality of L-shaped steel plates and special-shaped spring clips, the L-shaped steel plates are movably sleeved on the outer side of the shell, the inner side of the L-shaped steel plates are fixedly connected with a moving rod, the two sides of the moving rods are fixedly connected with push rods, four slots are opened on the outer side of the servo turntable, the special-shaped spring clips are slidably connected to the inside of the slots, the outer side of the servo turntable is fixedly connected with a plurality of support rods, one end of the support rod is in contact with one side of the special-shaped spring clip.

[0015] Preferably, the above-mentioned buffer assembly includes a plurality of airbags, a plurality of fixed blocks are fixedly connected to one side of the airbags, a plurality of fixed grooves adapted to the fixed blocks are opened on the inner side wall of the shell, the fixed blocks are fixedly inserted into the inside of the fixed grooves, and a plurality of limit blocks are fixedly connected to the outer side of the servo turntable.

[0016] Preferably, a plurality of guide grooves are provided on the inner side of the shell, the movable rod is slidably connected to the inside of the guide grooves, a plurality of support columns are fixedly connected to the bottom of the servo turntable, and a base is fixedly connected to the bottom of the support columns.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention designs a microwave communication tracking system of a ground station based on antenna array and difference beam angle measurement technology. When a distant communication target moves horizontally, the tracking system of the ground station continuously collects sum and difference signals, and performs ratio operation to calculate the deflection angle θ of the target. The servo turntable continuously adjusts the pointing direction of the antenna array according to the θ value, so that the antenna array is always pointed directly at the communication target, thereby realizing the function of tracking communication, and thus ensuring the communication effect between the ground station and the target even when the GPS position information of the target is lost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of the present invention;

[0020] Figure 2 A schematic diagram of the location of the target and antenna array of the present invention;

[0021] Figure 3 It is a structural schematic diagram of the antenna rod of the present invention;

[0022] Figure 4 is a schematic cross-sectional structural diagram of a connecting piece of the present invention;

[0023] Figure 5 for Figure 4 A schematic diagram of the enlarged structure of area A;

[0024] Figure 6 It is a schematic cross-sectional structural diagram of a straight rod of the present invention;

[0025] Figure 7 It is a schematic cross-sectional structural diagram of the housing of the present invention;

[0026] Figure 8 for Figure 7 Schematic diagram of the enlarged structure of area B;

[0027] Fig. 9 It is a schematic structural diagram of the housing of the present invention.

[0028] In the figure: 100, antenna unit; 101, antenna rod; 102, connector; 103, arc groove; 104, first groove; 105, through groove; 106, second groove; 107, block; 108, through hole; 109, arc block; 110, plug block; 111, straight rod; 112, tapered groove; 113, cross bar; 114, spring; 115, pull ring; 116, stab; 117, arc spring piece; 11 8. Anti-slip protrusion; 119. Support member; 200. Dual channels for sum and difference signals; 300. Servo turntable; 301. Shell; 302. Slot; 303. Moving rod; 304. Guide groove; 305. Special-shaped spring piece; 306. Support rod; 307. Push rod; 308. L-shaped steel plate; 309. Airbag; 310. Fixing block; 311. Fixing groove; 312. Limiting block; 313. Support column; 314. Base. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] Example 1

[0031] See also Figure 1-8 The present invention provides a technical solution: a single pulse angle measurement method for a low-altitude UAV, comprising the following steps:

[0032] S1. Yagi antenna array receives signals: The Yagi antenna array is divided into left and right arrays from the center line. The radio signals transmitted by distant flying targets are received by the antenna array of the ground station.

[0033] S2, sum and difference signal dual channel 200 signal output: half of the signals of the left and right arrays are superimposed in phase in the sum and difference device, and then output from the sum channel, and the other half of the signals of the left and right arrays are reversely offset in the sum and difference device, and then output from the difference channel;

[0034] S3, calculating the deflection angle θ: after the sum signal and the difference signal are filtered and amplified, the sum and difference signals are collected respectively, and the amplitude ratio and phase ratio of the two signals are calculated, and the deflection angle θ is calculated according to the formula using the ratio;

[0035] S4, the servo turntable 300 rotates and tracks: the deflection angle θ information is fed back to the servo turntable 300, and the servo turntable 300 continuously adjusts the direction of the antenna array according to the θ value, so that the antenna array is always pointed directly at the communication target, thereby realizing the function of tracking communication.

[0036] The Yagi antenna array is mainly composed of a half-wave dipole, a balun, a reflector, and a director. The Yagi antenna array consists of eight antenna units 100 arranged at intervals of half a wavelength. The half-wave dipole is a classic radiator form, which radiates the electromagnetic wave energy fed into the free space. It has two arms, one of which is grounded. A balun is usually designed to eliminate the imbalance of the grounded arm. The director and reflector are used to guide the directional radiation of electromagnetic waves. The reflector is usually slightly longer than the dipole, and the director is usually slightly shorter. The closer the director is to the front end, the shorter it is.

[0037] Working principle or structural principle:

[0038] 1.1 Yagi antenna array receiving signal

[0039] The Yagi antenna array is mainly composed of a half-wave oscillator, a balun, a reflector, and a director. Eight such antenna units 100 are arranged at intervals of half a wavelength to form a Yagi antenna array. The radio signals transmitted by distant flying targets are received by the antenna array of the ground station.

[0040] 1.2 Sum and difference signal dual channel 200 signal output

[0041] The line array is divided into the left and right planes from the center line, and the left and right planes are connected to the left and right power dividers respectively. The left and right power dividers synthesize the signal energy received from the left and right planes respectively, and then feed them into the two receiving ports of the summator. In the summator, half of the signals of the left and right planes are superimposed in phase and then output from the sum channel, and the other half of the signals of the left and right planes are reversely offset and then output from the difference channel. Thus, a dual channel that can form a sum signal and a difference signal at the same time is formed, forming a sum signal and a difference signal, and after filtering and amplification, the sum and difference signals are collected respectively.

[0042] 1.3 Calculate the deflection angle θ

[0043] The amplitude ratio and phase ratio of the two difference signals are calculated, and the deflection angle θ is calculated using the ratio according to the formula. In the antenna array, when all units are fed with equal-amplitude and in-phase signals, the beam will synthesize a single peak sum beam in the normal direction. When the units on the left and right planes are fed with equal-amplitude and inverted signals respectively, the antenna beam will form a difference beam with zero depth. The antenna array units (number n) are as follows: Figure 2 It is arranged as shown, and it is assumed that the antenna units 100 are all ideal half-wave oscillators.

[0044] Normalize the amplitude and phase of antenna unit 1001 to: E1=1;

[0045] The second unit is: E2=1*exp(-1j*2πdsinθ* / λ);

[0046] And so on, the nth unit is: En=1*exp(-(n-1)j*2πdsinθ* / λ).

[0047] When designing, n is an even number, and the antenna array can be divided into two symmetrical array planes according to the central normal.

[0048] For the left matrix: PL=E1+E2+...+En / 2;

[0049] For the right matrix: PR=En / 2+1+En / 2+2+...+En;

[0050] Let P difference = PL-PR, P sum = PL+PR, then: |P difference / P sum| = |tan(nπdsinθ / λ)| and P difference / P sum = -jtan(nπdsinθ / λ).

[0051] Where d is the distance between two units. As shown above, the magnitude of the deflection angle |θ| can be calculated by the ratio of the sum and difference beam amplitudes, and whether θ is on the left or right side of the normal can be determined by the sum and difference beam phase ratio, thus obtaining the deflection angle θ of the distant target relative to the normal of the antenna array.

[0052] 1.4 Servo turntable 300 rotation tracking

[0053] The servo turntable 300 continuously adjusts the direction of the antenna array according to the θ value, so that the antenna array is always pointed directly at the communication target, thereby realizing the function of tracking communication. Finally, the deflection angle information is fed back to the servo turntable 300, and the turntable is controlled to perform corresponding tracking rotation, thus completing the tracking and control of the servo turntable 300.

[0054] The antenna unit 100 includes a connector 102 and a plurality of antenna rods 101. A plurality of arc grooves 103 matching the antenna rods 101 are provided on one side of the connector 102. First grooves 104 are provided on both sides of the arc grooves 103. Clamping assemblies are provided inside the two first grooves 104. An arc block 109 is movably sleeved on the outer side of the antenna rod 101. Insertion blocks 110 are fixedly connected to both ends of the arc block 109. The insertion blocks 110 are inserted into the first grooves 104. The antenna rod 101 is inserted into the arc groove 103, the arc block 109 is clamped on one side of the antenna rod 101, and the insertion block 110 is inserted into the first groove 104, so that the antenna rod 101 is fixed to the connector 102. The assembly and disassembly is quick, convenient and simple.

[0055] Blocks 107 are fixedly connected to both sides of the antenna rod 101. A through hole 108 is provided on one side of the block 107. Two through grooves 105 are provided on the inner side wall of the first groove 104. A straight rod 111 is slidably inserted into the through groove 105. A conical groove 112 adapted to the plug block 110 is provided at one end of the straight rod 111. One end of the plug block 110 passes through the through hole 108 and is inserted into the conical groove 112. One end of the plug block 110 passes through the through hole 108 and is inserted into the conical groove 112, thereby being fixed to one end of the straight rod 111 to prevent the block 107 from freely escaping from the first groove 104.

[0056] The clamping assembly includes a cross bar 113, one side of which is fixedly connected to one end of two straight rods 111, a second groove 106 is opened on one side of the connecting piece 102, and a spring 114 is fixedly connected to the inner side wall of the second groove 106, and one end of the spring 114 is fixedly connected to one side of the cross bar 113; when the insert 110 is inserted into the straight rod 111, the spring 114 pulls the straight rod 111 to reset through the cross bar 113 to prevent the straight rod 111 from shaking in the first groove 104.

[0057] A pull ring 115 is fixedly connected to one side of the cross bar 113, a plurality of thorns 116 are fixedly connected to the inner wall of the arc groove 103, one side of the thorns 116 is in contact with the outer side of the antenna rod 101, a plurality of anti-skid protrusions 118 are fixedly connected to the inner wall of the conical groove 112, the outer side of the anti-skid protrusions 118 is in contact with one end of the plug block 110, one end of the plug block 110 is an arc-shaped end, and two arc-shaped spring pieces 117 are fixedly connected to the outer side of the plug block 110, and the outer side of the arc-shaped spring piece 117 is in contact with the through hole 110. 08, and the bottom of the connecting piece 102 is fixedly connected with two supporting pieces 119; the cross bar 113 is pulled to move by the pull ring 115, the spur 116 increases the friction between the antenna rod 101 and the arc groove 103, the anti-slip protrusion 118 increases the friction between the conical groove 112 and the plug 110, and the arc-shaped spring piece 117 is stuck on one side of the through hole 108. After the straight rod 111 passes through the through hole 108, the through hole 108 is blocked to prevent the plug 110 from freely escaping from the through hole 108.

[0058] The outer side of the servo turntable 300 in S4 is fixedly sleeved with a shell 301, and the inner side of the shell 301 is provided with a support assembly and a buffer assembly. The support assembly includes a plurality of L-shaped steel plates 308 and special-shaped spring pieces 305. The L-shaped steel plates 308 are movably sleeved on the outer side of the shell 301, and the inner side of the L-shaped steel plates 308 is fixedly connected with a moving rod 303, and both sides of the moving rod 303 are fixedly connected with push rods 307. Four slots 302 are opened on the outer side of the servo turntable 300, and the special-shaped spring pieces 305 are slidably connected to the inside of the slots 302. The outer side of the servo turntable 300 is fixedly connected with a plurality of support rods 306, and one end of the support rod 306 is connected to the special-shaped spring piece 305. The shell 301 protects the servo turntable 300 and prevents the servo turntable 300 from being damaged by external impact. When the servo turntable 300 is hit, the first L-shaped steel plate 308 moves relative to the shell 301 due to the external impact, driving the moving rod 303 to move relative to the servo turntable 300. The push rod 307 squeezes the special-shaped spring piece 305 and cooperates with the support rod 306. The special-shaped spring piece 305 is deformed, which expands the force-bearing area of ​​the servo turntable 300, preventing the servo turntable 300 from being damaged due to the fulcrum point being too small and the pressure being too high. The servo turntable 300 is effectively protected.

[0059] The buffer assembly includes a plurality of airbags 309, a plurality of fixing blocks 310 are fixedly connected to one side of the airbags 309, a plurality of fixing grooves 311 adapted to the fixing blocks 310 are opened on the inner wall of the shell 301, the fixing blocks 310 are fixedly inserted into the inside of the fixing grooves 311, and a plurality of limit blocks 312 are fixedly connected to the outside of the servo turntable 300; when the servo turntable 300 is impacted on all sides, the airbags 309 buffer and dissipate the external impact force to prevent damage to the servo turntable 300, and the fixing blocks 310 are fixedly inserted into the inside of the fixing grooves 311, thereby fixing the airbags 309 to the inside of the shell 301.

[0060] A plurality of guide grooves 304 are provided on the inner side of the shell 301, and the moving rod 303 is slidably connected to the inside of the guide groove 304. A plurality of support columns 313 are fixedly connected to the bottom of the servo turntable 300, and a base 314 is fixedly connected to the bottom of the support column 313. The guide groove 304 guides the moving rod 303, and the support column 313 supports the servo turntable 300. The base 314 expands the force-bearing area of ​​the support column 313.

[0061] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A single pulse angle measurement method for low-altitude UAV, characterized by: The following steps are involved: S1. Yagi antenna array receives signals: The Yagi antenna array is divided into left and right arrays from the center line. The radio signals transmitted by distant flying targets are received by the antenna array of the ground station. S2, sum and difference signal dual channel (200) signal output: half of the signals of the left and right arrays are added in phase in the sum and difference device, and then output from the sum channel, and the other half of the signals of the left and right arrays are reversely offset in the sum and difference device, and then output from the difference channel; S3, calculating the deflection angle θ: after the sum signal and the difference signal are filtered and amplified, the sum and difference signals are collected respectively, and the amplitude ratio and phase ratio of the two signals are calculated, and the deflection angle θ is calculated according to the formula using the ratio; S4, the servo turntable (300) rotates and tracks: the deflection angle θ information is fed back to the servo turntable (300), and the servo turntable (300) continuously adjusts the direction of the antenna array according to the θ value, so that the antenna array is always pointed directly at the communication target, thereby realizing the function of tracking communication; The Yagi antenna array is mainly composed of a half-wave dipole, a balun, a reflector, and a director. The Yagi antenna array is composed of eight antenna units (100) arranged at intervals of half a wavelength. The antenna unit (100) comprises a connecting piece (102) and a plurality of antenna rods (101); a plurality of arc-shaped grooves (103) adapted to the antenna rods (101) are provided on one side of the connecting piece (102); first grooves (104) are provided on both sides of the arc-shaped groove (103); clamping assemblies are provided inside the two first grooves (104); an arc-shaped clamping block (109) is movably sleeved on the outside of the antenna rod (101); plug-in blocks (110) are fixedly connected to both ends of the arc-shaped clamping block (109); and the plug-in block (110) is inserted into the inside of the first groove (104); Both sides of the antenna rod (101) are fixedly connected to a block (107), one side of the block (107) is provided with a through hole (108), the inner side wall of the first groove (104) is provided with two through slots (105), a straight rod (111) is slidably inserted into the interior of the through slot (105), one end of the straight rod (111) is provided with a conical slot (112) adapted to the plug block (110), and one end of the plug block (110) passes through the through hole (108) and is inserted into the interior of the conical slot (112); The clamping assembly comprises a cross bar (113), one side of the cross bar (113) is fixedly connected to one end of the two straight bars (111), one side of the connecting member (102) is provided with a second groove (106), an inner side wall of the second groove (106) is fixedly connected to a spring (114), and one end of the spring (114) is fixedly connected to one side of the cross bar (113); A pull ring (115) is fixedly connected to one side of the cross bar (113); a plurality of spikes (116) are fixedly connected to the inner wall of the arc-shaped groove (103); one side of the spikes (116) is in contact with the outer side of the antenna rod (101); a plurality of anti-slip protrusions (118) are fixedly connected to the inner wall of the conical groove (112); the outer side of the anti-slip protrusions (118) is in contact with one end of the plug-in block (110); one end of the plug-in block (110) is an arc-shaped end; two arc-shaped spring sheets (117) are fixedly connected to the outer side of the plug-in block (110); the outer side of the arc-shaped spring sheets (117) is in contact with the inner wall of the through hole (108); and the bottom of the connector (102) is fixedly connected to two support members (119); The outer side of the servo turntable (300) in S4 is fixedly sleeved with a shell (301), the inner side of the shell (301) is provided with a support assembly and a buffer assembly, the support assembly comprises a plurality of L-shaped steel plates (308) and special-shaped spring pieces (305), the L-shaped steel plates (308) are movably sleeved on the outer side of the shell (301), the inner side of the L-shaped steel plates (308) is fixedly connected with a moving rod (303), both sides of the moving rod (303) are fixedly connected with push rods (307), the outer side of the servo turntable (300) is provided with four slots (302), the special-shaped spring pieces (305) are slidably connected to the inside of the slots (302), the outer side of the servo turntable (300) is fixedly connected with a plurality of support rods (306), one end of each support rod (306) is in contact with one side of each special-shaped spring piece (305); The buffer assembly comprises a plurality of air bags (309), a plurality of fixing blocks (310) are fixedly connected to one side of the air bags (309), a plurality of fixing grooves (311) adapted to the fixing blocks (310) are formed on the inner side wall of the shell (301), the fixing blocks (310) are fixedly inserted into the fixing grooves (311), and a plurality of limit blocks (312) are fixedly connected to the outer side of the servo turntable (300).

2. The single pulse angle measurement method for a low-altitude UAV according to claim 1 is characterized in that: A plurality of guide grooves (304) are provided on the inner side of the shell (301), the movable rod (303) is slidably connected to the inside of the guide groove (304), a plurality of support columns (313) are fixedly connected to the bottom of the servo turntable (300), and a base (314) is fixedly connected to the bottom of the support column (313).

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