A navigation method and system based on pseudo-satellite networking of unmanned aerial vehicles

Abstract

The present invention relates to the field of satellite navigation technology, and specifically discloses a navigation method and system based on unmanned aerial vehicle pseudo-satellite networking, including modeling a GNSS denied area as a square area, determining the flight path of the unmanned aerial vehicle pseudo-satellite based on the networking of unmanned aerial vehicle pseudo-satellite in the GNSS denied area; determining the navigation service coverage area of ​​the unmanned aerial vehicle pseudo-satellite networking based on the flight path, flight altitude and antenna beam angle of the unmanned aerial vehicle pseudo-satellite; and providing navigation services to users based on the navigation service coverage area of ​​the unmanned aerial vehicle pseudo-satellite networking. The method can provide navigation services in the GNSS denied area, and can ensure the accuracy of the unmanned aerial vehicle pseudo-satellite's self-positioning in the GNSS satellite signal denied area by controlling the flight parameters of the unmanned aerial vehicle pseudo-satellite.

Description

Technical Field

[0001] The present invention relates to the field of satellite navigation technology, and in particular to a navigation method and system based on unmanned aerial vehicle pseudo-satellite networking. Background Art

[0002] The Global Navigation Satellite System (GNSS) can provide navigation services around the clock and in all weather conditions, but the landing signal is extremely susceptible to electromagnetic interference. When GNSS performance is degraded or denied, various navigation alternatives and enhanced assistance systems are constantly being developed; among them, pseudo-satellites (Pseudolite or Pseudo-Satellite, PL) are a low-cost, easy-to-deploy regional navigation enhancement platform that can emit strong GNSS-like signals and have been widely studied and applied; pseudo-satellite systems (Pseudolite System, PLS) can be divided into two categories: air-based and ground-based (sea-based) according to their deployment locations. Ground-based pseudo-satellite signals have good quality but limited coverage; existing air-based pseudo-satellites have a larger coverage range, but cannot work completely under denied conditions and are often used as a means of GNSS signal enhancement.

[0003] Moreover, the high-precision positioning of the pseudo-satellite itself is the basis for achieving high-precision positioning of the overall system. If the position of the pseudo-satellite is not accurate enough, it will directly affect the accuracy of the navigation information it provides. In a dynamic environment, most studies have focused on the networking solutions, formation control and route planning of near-space airships, using them as aerial relay base stations for communication functions. Few studies have used drones as pseudo-satellite carrier platforms and relied on GNSS satellites for combined navigation. Therefore, in view of the shortcomings of current research, it is urgent to explore the independent networking of drone pseudo-satellites to provide navigation and positioning services and power enhancement under GNSS denial conditions. Summary of the invention

[0004] In view of the above problems, an object of the present invention is to provide a navigation method based on UAV pseudo-satellite networking, which can provide high-precision navigation services even in an environment with severe electromagnetic interference, that is, it can provide navigation services in GNSS denied areas, and can ensure the accuracy of the UAV pseudo-satellite's own positioning in the GNSS satellite signal denied area by controlling the flight parameters of the UAV pseudo-satellite.

[0005] The second object of the present invention is to provide a navigation system based on UAV pseudo-satellite networking.

[0006] The first technical solution adopted by the present invention is: a navigation method based on pseudo-satellite networking of unmanned aerial vehicles, comprising the following steps:

[0007] S100: Model the GNSS denial area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denial area;

[0008] S200: Determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite;

[0009] S300: Providing navigation services to users based on the navigation service coverage area of ​​the drone pseudo-satellite network.

[0010] Preferably, the step S100 includes:

[0011] The midpoints of the four sides of the square area are respectively used as the starting positions of the four UAV pseudo-satellites. The four UAV pseudo-satellites fly toward the center of the square area along a straight line respectively, and return to the starting position in a straight line after reaching the extreme position. The four UAV pseudo-satellites continuously travel back and forth between the starting position and the extreme position in a straight line. The speeds of the four UAV pseudo-satellites are constant and consistent, and the network presents a square shape.

[0012] Preferably, the navigation service coverage area of ​​the drone pseudo-satellite network in step S200 is expressed by the following formula:

[0013] S=4R 2 θ-2(h+l)x-2lh (10)

[0014] Where S is the area of ​​the navigation service coverage area; R is the radius of the navigation service coverage area; θ is the central angle of the two sectors in the quarter of the navigation service coverage area; h is the length between point D and point E; x is the x-axis coordinate of point A; l is the center of the circle L i and the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1,2,3,4) is the center of the circle covered by the GPS signals of the four drone pseudo-satellites; point D is L 1 The point where A intersects the y-axis.

[0015] Preferably, the central angles of the two sectors in the quarter navigation service coverage area are expressed by the following formula:

[0016]

[0017] Where θ is the central angle of the two sectors in the quarter navigation service coverage area; x is the x-axis coordinate of point A; y is the y-axis coordinate of point A; l is the center of the circle L iand the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1, 2, 3, 4) is the center of the circle covered by the GPS signals of the four UAV pseudo-satellites.

[0018] Preferably, the radius of the navigation service coverage area is expressed by the following formula:

[0019] R=Htanα(1)

[0020] Where R is the radius of the navigation service coverage area; H is the flight altitude of the UAV pseudo-satellite; and α is the antenna beam angle.

[0021] Preferably, the step S200 further includes:

[0022] The side length of the GNSS denied area is estimated and restored based on the flight altitude of the UAV pseudo-satellite; the flight time of the UAV pseudo-satellite in the GNSS denied area is determined based on the restored side length of the GNSS denied area, thereby ensuring the accuracy of the UAV pseudo-satellite's self-positioning in the GNSS satellite signal denied area.

[0023] Preferably, the side length of the restored GNSS denied area is expressed by the following formula:

[0024]

[0025] Where a is the side length of the restored GNSS denied area; r is the distance between the UAV pseudo-satellite and the center of the GPS signal coverage area; and H is the flight altitude of the UAV.

[0026] Preferably, the relationship between the accuracy of the self-positioning of the UAV pseudo-satellite in the GNSS denied area and its flight time in the GNSS denied area is expressed by the following formula:

[0027] y=0.4673t 2 -3.3466t(20)

[0028] Where y is the error accuracy; t is the flight time of the UAV pseudo-satellite in the GNSS denied area.

[0029] Preferably, the step S300 includes:

[0030] In the navigation service coverage area of ​​the drone pseudo-satellite network, the drone pseudo-satellite broadcasts GPS signals, and the user end receives the GPS signals for navigation, thereby providing navigation services to users in the GNSS denied area.

[0031] The second technical solution adopted by the present invention is: a navigation system based on pseudo-satellite networking of unmanned aerial vehicles, including a networking module, a computing module and a navigation service module;

[0032] The networking module is used to model the GNSS denied area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denied area;

[0033] The calculation module is used to determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite;

[0034] The navigation service module is used to provide navigation services to users based on the navigation service coverage area of ​​the UAV pseudo-satellite network.

[0035] Beneficial effects of the above technical solution:

[0036] (1) The present invention provides a navigation method based on UAV pseudo-satellite networking for a GNSS completely denied environment, which can provide high-precision navigation services even in an environment with severe electromagnetic interference.

[0037] (2) An object of the present invention is to provide a navigation method based on UAV pseudo-satellite networking, which method can provide navigation services in GNSS denied areas and can ensure the accuracy of the UAV pseudo-satellite's own positioning in GNSS satellite signal denied areas by controlling the flight parameters of the UAV pseudo-satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A flowchart of a navigation method based on pseudo-satellite networking of unmanned aerial vehicles provided by an embodiment of the present invention;

[0039] Figure 2 A top view of a pseudo-satellite networking scenario of a UAV provided by an embodiment of the present invention;

[0040] Figure 3 A schematic diagram of the pseudo-satellite signal coverage area of ​​four UAVs provided in one embodiment of the present invention;

[0041] Figure 4 A schematic diagram of adjusting the antenna beam angle provided by an embodiment of the present invention;

[0042] Figure 5 A schematic diagram of a navigation service coverage area provided by an embodiment of the present invention;

[0043] Figure 6 A schematic diagram of positional relationships provided for an embodiment of the present invention;

[0044] Figure 7A schematic structural diagram of a navigation system based on pseudo-satellite networking of unmanned aerial vehicles is provided for one embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following detailed description of the embodiments of the present invention is further described in detail in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the preferred embodiments described, and the scope of the present invention is defined by the claims.

[0046] In the description of the present invention, it should be noted that, unless otherwise specified, “plurality” means two or more than two; the terms “first”, “second”, etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0047] Embodiment 1

[0048] like Figure 1 As shown, an embodiment of the present invention provides a navigation method based on drone pseudo-satellite networking, comprising the following steps:

[0049] S100: Model the GNSS denial area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denial area;

[0050] The GNSS denial area has arbitrary shapes in reality. For the purpose of simplifying the model, such as Figure 2 As shown in the figure, the GNSS denial area is modeled as a square area, and normal satellite navigation signals can be received outside the square area. Since the ground receiver needs to observe at least 4 pseudo-satellites at the same time, inside the GNSS denial area, the starting positions of the four UAVs carrying navigation payloads (i.e., UAV pseudo-satellites) are located at the midpoints of the four sides of the square area. The four UAV pseudo-satellites fly along a straight line toward the center of the square area, relying only on inertial navigation to calculate their own positions. However, the time for maintaining positioning accuracy by inertial navigation alone is limited, and it is believed that the UAV pseudo-satellite cannot reach the center of the square, so there is a deep limit position L. In order to update the positioning error accumulated by the inertial navigation, the UAV pseudo-satellite needs to return to the starting position.

[0051] The flight paths of the four drone pseudo-satellites are: the midpoints of the four sides of the square area are used as the starting positions of the four drone pseudo-satellites. The four drone pseudo-satellites fly in a straight line toward the center of the square area, and return to the starting position in a straight line after reaching the extreme position L. The four drone pseudo-satellites keep going back and forth between the starting position and the extreme position L. The speed of the four drone pseudo-satellites is constant and consistent, and the network presents a square shape, which is conducive to shortening the flight range and minimizing the distance between drone pseudo-satellites. Figure 3 As shown, Figure 3 The shaded part in the figure is the overlapping area of ​​the GPS signals of the four UAV pseudo-satellites, that is, the navigation service area provided by the network formed by the four UAV pseudo-satellites.

[0052] To ensure that the networked UAV pseudo-satellite can provide continuous navigation services, when the UAV pseudo-satellite is repositioned outside the GNSS denied area, such as Figure 4 As shown in the figure, the UAV pseudo-satellite needs to continuously adjust the antenna beam angle to keep the beam in the power enhancement area (ignoring the deformation of the area from circular to elliptical); when the UAV pseudo-satellite flies outside the GNSS denial area, although the landing signal power will decrease with the increase of signal transmission distance, the coverage area is guaranteed to be constant, thereby providing continuity of navigation and positioning services.

[0053] S200: Determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite;

[0054] The GPS signal coverage of a single UAV pseudo-satellite is approximately circular, and the radius R is determined by the UAV pseudo-satellite flight altitude H and the antenna beam angle. For example, the antenna beam angle is set to 60°. The signal coverage of a network of four UAV pseudo-satellites is as follows: Figure 5 As shown, E is the origin with coordinates (0, 0), L i (i=1,2,3,4) are the centers of the four circles, D is L 1 The intersection of A and the y-axis; Figure 5 The middle shaded area is one quarter of the navigation service coverage area, which can be divided into two parts: 1 :DEBA and S 2 :DAC, each part is the difference between the area of ​​a sector and a triangle (Formulas 8 and 9), and the two sectors are L 1 AB and L 2 CA, a triangle is a right triangle with two right-angled sides of length l and length h. 1 ED, the other is an obtuse triangle L with the sum of the lengths of h and l as the base and x as the height 2DA. The two sectors have the same area. The central angle θ of the sector can be obtained according to the coordinates of one of the intersection points of the four circles closest to the origin, A(x, y). Combined with the radius R, the areas of the two sectors can be obtained. The UAV pseudo-satellite can penetrate as far as 2.2 km from the center of the denial area, that is, the position of the center L of the four circles (the extreme position L). The distance between the center L and the origin E is l = 2.2 km, and h is obtained according to the ratio of similar triangles.

[0055] The specific derivation process of the size of the navigation service coverage area of ​​the UAV pseudo-satellite network is as follows:

[0056] Taking the first quadrant as an example, it is known that the centers of the two circles are L 1 (-l, 0) and L 2 (0, -l), the radius is R:

[0057] R=Htanα(1)

[0058] Where R is the radius of the navigation service coverage area; H is the flight altitude of the UAV pseudo-satellite; α is the antenna beam angle, and α is 60°, for example.

[0059] Solve the equations of the two circles:

[0060] (x+l) 2 +y 2 =R 2

[0061] x 2 +(y+l) 2 =R 2 (2)

[0062] Where x is the x-axis coordinate of point A; y is the y-axis coordinate of point A; l is the center of the circle L i and the origin E; R is the radius of the navigation service coverage area; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1, 2, 3, 4) is the center of the circle covered by the GPS signals of the four UAV pseudo-satellites.

[0063] The horizontal and vertical coordinates of the intersection point A(x, y) closest to the origin are:

[0064]

[0065] Thus we can get two sectors L 1 AB and L 2 The central angle of CA is:

[0066]

[0067] Where θ is the central angle of the two sectors in the quarter navigation service coverage area; x is the x-axis coordinate of point A; y is the y-axis coordinate of point A; l is the center of the circle L i and the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1, 2, 3, 4) is the center of the circle covered by the GPS signals of the four UAV pseudo-satellites.

[0068] According to L 1 ED and A, L 1 , the similarity between the triangles whose three vertices are the intersection of the perpendicular line through point A and parallel to the y-axis and the x-axis, combined with x=y, we get:

[0069]

[0070] Where h is the length between point D and point E; x is the x-axis coordinate of point A; y is the y-axis coordinate of point A; l is the center of the circle L i and the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1,2,3,4) is the center of the circle covered by the GPS signals of the four drone pseudo-satellites; point D is L 1 The point where A intersects the y-axis.

[0071] Then the length h of DE is:

[0072]

[0073] Where S is the area covered by the navigation service; S 1 A portion of the area covered by one quarter of the navigation service; S 2 Another part of the area within the quarter navigation service coverage area.

[0074] The shaded part S 1 :DEBA is:

[0075]

[0076] Shaded area S 2 :DAC is:

[0077]

[0078] In the formula, S 1 A portion of the area covered by one quarter of the navigation service; S 2is the other part of the area in the quarter of the navigation service coverage area; R is the radius of the navigation service coverage area; θ is the central angle of the two sectors in the quarter of the navigation service coverage area; h is the length between point D and point E; x is the x-axis coordinate of point A; l is the center of the circle L i and the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1,2,3,4) is the center of the circle covered by the GPS signals of the four drone pseudo-satellites; point D is L 1 The point where A intersects the y-axis.

[0079] The service coverage area of ​​the four UAV pseudo-satellite network is:

[0080] S=4R 2 θ-2(h+l)x-2lh (10)

[0081] Where S is the area of ​​the navigation service coverage area; R is the radius of the navigation service coverage area; θ is the central angle of the two sectors in the quarter of the navigation service coverage area; h is the length between point D and point E; x is the x-axis coordinate of point A; l is the center of the circle L i and the distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i (i=1,2,3,4) is the center of the circle covered by the GPS signals of the four drone pseudo-satellites; point D is L 1 The point where A intersects the y-axis.

[0082] To simplify the formula, let

[0083]

[0084] make Substituting l=2.2km into formula (10) yields:

[0085] S=12H 2 θ-2(h+2.2)x-4.4h(12)

[0086] After R and l are substituted into formula (3), formulas (4) and (6) are rearranged in combination with x and l in formula (3) to obtain θ and h. Moreover, θ, h and x are substituted into formula (12), and H′ in formula (11) is rearranged to obtain the mathematical model of the navigation service coverage area size of the UAV pseudo-satellite network:

[0087]

[0088] The navigation service coverage rate η is the ratio of the common coverage area S of the pseudo-satellite signals of the four UAVs to the area of ​​the entire GNSS denial area:

[0089]

[0090] Where η is the coverage rate of navigation service; S is the area of ​​navigation service coverage area; a 2 is the area of ​​the GNSS denied area; a is the side length of the GNSS denied area.

[0091] When the side length a of the denied area is 57.8014 km, according to formula (13), the mathematical model of the UAV flight altitude and network navigation service coverage can be obtained as follows:

[0092]

[0093] In the formula, η is the navigation service coverage rate; H is the flight altitude of the drone;

[0094] Furthermore, it also includes: restoring the side length of the GNSS denied area based on the flight altitude estimation of the UAV pseudo-satellite; determining the flight time of the UAV pseudo-satellite in the GNSS denied area based on the restored side length of the GNSS denied area, thereby ensuring the accuracy of the UAV pseudo-satellite's own positioning in the GNSS satellite signal denied area.

[0095] Generally, the transmission power of the air-based platform antenna is between tens and hundreds of watts. Therefore, the present invention sets the transmission power of the pseudo-satellite P TX is set to 50W; currently, the receiving power of the navigation terminal (i.e., the user end) cannot be lower than -127 to -130dBw; due to electromagnetic interference, terrain shielding and other factors, the GNSS denial area appears, so the specific performance indicators of the satellite navigation receiver allowed in practice need to be higher; in order to ensure a certain power enhancement effect, the present invention sets the lower limit of the signal strength received by the user end to -110dBw, i.e. 10 -11 W.

[0096] 1) Recover the side length of the GNSS denial area based on the flight altitude estimation of the UAV pseudo-satellite;

[0097] When the drone pseudo-satellite is located above the midpoint of the square side at a flight altitude H (for example, the maximum flight altitude is 18km), the transmission distance of the GPS signal broadcast by the drone pseudo-satellite is the longest and the attenuation multiple is the largest. The size of the GNSS denial area that can be recovered in this case can ensure the normal provision of navigation and positioning services under other flight altitude and position conditions. The specific derivation process is as follows:

[0098] The signal attenuation factor Lbf is calculated by calculating the ratio of the UAV pseudo-satellite transmission power to the GNSS user end receiving power. The unit is unified to dB to facilitate subsequent calculations. The signal attenuation factor is expressed by the following formula:

[0099]

[0100] Where Lbf is the attenuation factor of GPS signal propagation; P TX is the transmission power of the UAV pseudo-satellite; P RX It is the receiving power of the GNSS user terminal.

[0101] Lbf is calculated according to the following free space electromagnetic wave power attenuation formula:

[0102] Lbf=32.4+20lgf+20lgr (17)

[0103] Where Lbf is the attenuation multiple of GPS signal propagation; f is the center frequency of the GPS signal L1 band, 1575.42 MHz; r is the distance between the UAV pseudo-satellite and the center of the GPS signal coverage area.

[0104] Then r can be derived as follows:

[0105]

[0106] Where r is the distance between the UAV pseudo-satellite and the center of the GPS signal coverage area (i.e., the signal propagation distance); Lbf is the GPS signal attenuation multiple; and f is the center frequency of the GPS signal L1 band, 1575.42 MHz.

[0107] like Figure 6 As shown in the figure, half of the side length of the GNSS denial area that can be recovered is approximately the base of a right triangle with the signal propagation distance r as the hypotenuse and the flight altitude H as a right angle side; the signal propagation distance r is 34.0478 km, and the attenuation multiple of the signal propagation is calculated to be 126.9897 db according to formula (17), so the side length a of the GNSS denial area to be recovered is set to 57.8014 km;

[0108] The side length of the restored GNSS denied area is expressed by the following formula:

[0109]

[0110] Where a is the side length of the restored GNSS denied area; r is the distance between the UAV pseudo-satellite and the center of the GPS signal coverage area; and H is the flight altitude of the UAV.

[0111] 2) determining the flight time of the UAV pseudo-satellite in the GNSS denied area based on the flight speed of the UAV pseudo-satellite and the side length of the restored GNSS denied area;

[0112] The positioning accuracy of the UAV pseudo-satellite in the GNSS satellite signal denial area decreases over time, which directly leads to the decrease of the positioning accuracy of the ground receiver. When the inertial navigation error exceeds 10m, the positioning accuracy is low. Ignoring the initial error, a binomial fitting is performed with 120m / 20min and 0.8 nautical miles / h, and the model of the inertial navigation error accumulation over time is obtained as shown in the following formula:

[0113] y=0.4673t 2 -3.3466t(20)

[0114] Where y is the error accuracy; t is the flight time of the UAV pseudo-satellite in the GNSS denial area. When y = 10m, t = 9.425mins (negative values ​​are discarded).

[0115] Therefore, in order to achieve a positioning accuracy of UAV pseudo-satellite higher than 10m, the flight time of UAV pseudo-satellite in the GNSS denied area cannot exceed 9.425 minutes.

[0116] When the UAV pseudo-satellite flies at a speed of 340km / h, the flight distance of the UAV pseudo-satellite in the GNSS denied area cannot exceed 52.4km, that is, the one-way flight distance is 26.7km. Therefore, the UAV pseudo-satellite can penetrate as far as 2.2km from the center of the GNSS denied area.

[0117] S300: Providing navigation services to users based on the navigation service coverage area of ​​the drone pseudo-satellite network.

[0118] In the navigation service coverage area of ​​the drone pseudo-satellite network, the drone pseudo-satellite broadcasts GPS signals, and the user end receives the GPS signals for navigation, thereby providing navigation services to users in the GNSS denied area.

[0119] Embodiment 2

[0120] like Figure 7 As shown, an embodiment of the present invention provides a navigation system based on UAV pseudo-satellite networking, including a networking module, a computing module and a navigation service module;

[0121] The networking module is used to model the GNSS denied area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denied area;

[0122] The calculation module is used to determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite;

[0123] The navigation service module is used to provide navigation services to users based on the navigation service coverage area of ​​the UAV pseudo-satellite network.

[0124] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the embodiments of the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0125] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0126] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0127] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0128] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, ROM, RAM, magnetic disks, or optical disks.

[0129] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A navigation method based on pseudo-satellite networking of unmanned aerial vehicles, characterized in that: The following steps are involved: S100: Model the GNSS denial area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denial area; S200: Determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite; S300: providing navigation services to users based on the navigation service coverage area of ​​the pseudo-satellite network of the unmanned aerial vehicle; The navigation service coverage area of ​​the pseudo-satellite network of the UAV in step S200 is expressed by the following formula: S=4R 2 θ-2(h+l)x-2lh (10) Where S is the area of ​​the navigation service coverage area; R is the radius of the navigation service coverage area; θ is the central angle of the two sectors in the quarter of the navigation service coverage area; h is the length between point D and point E; x is the x-axis coordinate of point A; l is the center of the circle L i The distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i ,i=1,2,3,4 are the centers of the circles covered by the GPS signals of the four UAV pseudo-satellites; point D is the intersection of L1A and the y-axis; The central angle of the two sectors in the quarter navigation service coverage area is expressed by the following formula: Where y is the y-axis coordinate of point A; The radius of the navigation service coverage area is expressed by the following formula: R=Htanα (1) Where R is the radius of the navigation service coverage area; H is the flight altitude of the UAV pseudo-satellite; and α is the antenna beam angle.

2. The navigation method according to claim 1, characterized in that: The step S100 includes: The midpoints of the four sides of the square area are respectively used as the starting positions of the four UAV pseudo-satellites. The four UAV pseudo-satellites fly toward the center of the square area along a straight line, and return to the starting position in a straight line after reaching the extreme position. The four UAV pseudo-satellites continuously travel back and forth between the starting position and the extreme position in a straight line. The speeds of the four UAV pseudo-satellites are constant and consistent, and the network presents a square shape. The limit position is the position reached by the UAV pseudo-satellite within the time period during which the inertial navigation maintains the positioning accuracy.

3. The navigation method according to claim 1, characterized in that: The step S200 further includes: The side length of the GNSS denied area is estimated and restored based on the flight altitude of the UAV pseudo-satellite; the flight time of the UAV pseudo-satellite in the GNSS denied area is determined based on the restored side length of the GNSS denied area, thereby ensuring the accuracy of the UAV pseudo-satellite's self-positioning in the GNSS satellite signal denied area.

4. The navigation method according to claim 3, characterized in that: The side length of the restored GNSS denied area is expressed by the following formula: Where α is the side length of the restored GNSS denied area; r is the distance between the UAV pseudo-satellite and the center of the GPS signal coverage area; and H is the flight altitude of the UAV.

5. The navigation method according to claim 3, characterized in that: The relationship between the accuracy of the UAV pseudo-satellite's self-positioning in the GNSS denied area and its flight time in the GNSS denied area is expressed by the following formula: <h2 style=";text-align:left;direction:ltr">y = 0.4673t<h2 style=";text-align:left;direction:ltr"> 2 <h2 style=";text-align:left;direction:ltr"> -3.3466t (20) Where y is the error accuracy; t is the flight time of the UAV pseudo-satellite in the GNSS denied area.

6. The navigation method according to claim 1, characterized in that: The step S300 includes: In the navigation service coverage area of ​​the drone pseudo-satellite network, the drone pseudo-satellite broadcasts GPS signals, and the user end receives the GPS signals for navigation, thereby providing navigation services to users in the GNSS denied area.

7. A navigation system based on pseudo-satellite networking of unmanned aerial vehicles, characterized in that: Including networking module, computing module and navigation service module; The networking module is used to model the GNSS denied area as a square area, and determine the flight path of the UAV pseudo-satellite based on the networking of the UAV pseudo-satellite in the GNSS denied area; The calculation module is used to determine the navigation service coverage area of ​​the UAV pseudo-satellite network based on the flight path, flight altitude and antenna beam angle of the UAV pseudo-satellite; the navigation service coverage area of ​​the UAV pseudo-satellite network is expressed by the following formula: S=4R 2 θ-2(h+l)x-2lh (10) Where S is the area of ​​the navigation service coverage area; R is the radius of the navigation service coverage area; θ is the central angle of the two sectors in the quarter of the navigation service coverage area; h is the length between point D and point E; x is the x-axis coordinate of point A; l is the center of the circle L i The distance from the origin E; Point A is the intersection of the GPS signal coverage circles of the four drone pseudo-satellites closest to the coordinate origin; Point E is the coordinate origin (0, 0); L i ,i=1,2,3,4 are the centers of the circles covered by the GPS signals of the four UAV pseudo-satellites; point D is the intersection of L1A and the y-axis; The central angle of the two sectors in the quarter navigation service coverage area is expressed by the following formula: Where y is the y-axis coordinate of point A; The radius of the navigation service coverage area is expressed by the following formula: R=Htanα (1) Where R is the radius of the navigation service coverage area; H is the flight altitude of the UAV pseudo-satellite; α is the antenna beam angle; The navigation service module is used to provide navigation services to users based on the navigation service coverage area of ​​the UAV pseudo-satellite network.

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