JP2024040085A - Flying object collision avoidance device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that, in a case where a lot of flying objects fly in any directions in a narrow area, there is no simple means for detecting the presence/absence of possibility of collision by measuring a distance between any two flying objects of the flying objects being present in six directions of front, rear, right, left, upward and downward directions.

SOLUTION: Two flying objects transmit/receive GPS location information thereof and machine body identification numbers of the flying objects and calculate a distance between the two flying objects. Camera input images in six directions of front, rear, right, left, upward and downward directions are used for measuring an altitude difference between any two flying objects, a possibility of collision is detected while also taking a specular change of the altitude difference into consideration, and a collision avoiding operation is performed.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a device for avoiding collisions between two or more flying vehicles, which is equipped with a propulsion device that allows two or more aircraft to ascend, descend, move forward, retreat, and change directions to the left and right.

Currently, the number of flying vehicles known as drones is increasing, and flying taxis that can carry multiple people are also being considered and developed.

Currently, many drones are operated from the ground. However, in the near future, the number of autonomous and self-flying vehicles is expected to increase, as well as the number of large drones that carry people and heavy objects. It is predicted that we will see a coexistence of drones for transportation such as delivery, where flight routes can be determined, flying taxis for transporting people, drones for agriculture, forestry, or monitoring and inspection, and drones used by individuals for various purposes. A simplified collision avoidance and warning system under such conditions has not been realized.

Drones that fly only on predetermined routes, or transportation companies such as flying taxis and home delivery companies that fly to their destinations by selecting flight paths set in the air (elongated cylindrical or prismatic spaces). Accidents can be prevented by establishing a flight control center in each region and assigning collision-free routes and times to each drone. However, in cases such as agriculture, forestry, tourism, structure management, personal hobbies, etc., where the flight area is irregular and the flying area is irregular, the flying drone (hereinafter referred to as the own aircraft) and other drones (hereinafter referred to as other aircraft) ) must be equipped with devices that allow both sides to detect the other and automatically avoid collisions.

As a method for detecting the position of other aircraft, there is a position detection system for vehicles running on the ground. This method involves emitting millimeter waves from the own aircraft and measuring the reflection time to determine whether or not there is an approach. However, since the measurement is performed on the road, it mainly detects other vehicles within a narrow angle range in front of the vehicle in the direction of travel. can be detected. However, in the case of a drone, it is necessary to detect other aircraft in six directions: up and down, left and right, and front and rear.

JP 2021-121916 Publication

The problem to be solved is that it is not possible to detect the positions of other aircraft in five directions other than the forward direction.

The main feature of the present invention is to confirm the position information of another aircraft using the GPS position information transmitted by the other aircraft, and to detect the approach of another aircraft from the time-series changes in camera input images.

The GPS location information of the present invention is such that another device detects its own location using GPS location information, transmits it together with the ID information of the other device, detects this with its own device, and then uses the GPS location information of its own device. The distance to other aircraft is measured based on the difference between the two aircraft. Since it is difficult to accurately measure the altitude difference using GPS position information, the altitude difference between the aircraft and other aircraft is calculated from the camera input image and the possibility of collision with another aircraft is detected. Even for ultra-small drones that cannot detect GPS location information or transmit their own ID information, this system has the advantage of being able to detect the location of other aircraft from camera input images and avoid collisions.

FIG. 1 is an explanatory diagram showing an implementation device that detects the position of another aircraft using GPS position information. (Example 1) FIG. 2 is an explanatory diagram showing the position of another aircraft displayed on the display. (Example 1) FIG. 3 is an explanatory diagram showing the positions of the own aircraft and other aircraft as viewed from above. (Example 1) FIG. 4 is an explanatory diagram showing the contents of one packet representing an arrangement of aircraft identification information (ID), GPS position information, and other information. (Example 1) FIG. 5 is an explanatory diagram showing an example of measuring the distance between two aircraft. (Example 1) FIG. 6 is an explanatory diagram showing functional blocks of the aircraft. (Example 1) FIG. 7 is an explanatory diagram of the operation of a device that detects changes in the distance between the own aircraft and other aircraft only from camera input images. (Example 2) FIG. 8 is an explanatory diagram showing functional blocks of a device that detects changes in the distance between one's own aircraft and another aircraft only from camera input images. (Example 2) FIG. 9 is an explanatory diagram showing the horizontal input angle (field of view) of the camera. (Example 2) FIG. 10 is an explanatory diagram showing the vertical input angle (field of view) of the camera. (Example 2)

By acquiring the GPS location information of other aircraft along with the ID information of other aircraft, we have created a device that accurately measures the distance to other aircraft, detects the risk of collision, and avoids collisions.

FIG. 1 is a plan view of one embodiment of the device of the present invention, in which 1 is the own aircraft (drone), and 2A, 2B, 2C, and 2D are propulsion devices of the own aircraft 1. In this figure (example), there are four propulsion devices, but there may be more than that. 3F is a camera that photographs the front, 3B is a camera that photographs the rear, 3R is a camera that photographs the right direction, 3L is a camera that photographs the left, 3U is a camera that photographs upward, and 3D is a camera that photographs downward. It is. 4D is a display. 5 is a seat where an operator (pilot or driver) sits, and 6A, 6B, 6C, 6D, and 6E are seats where passengers sit.

FIG. 2 is a diagram showing the positional relationship between the own aircraft and other aircraft displayed on the display 4D. FIG. 2 shows images of the own device and other devices in the image memory, and shows the case where they are displayed on the display 4D. The vertical and horizontal directions of other aircraft and the own aircraft are displayed, and the difference in the longitudinal direction cannot be displayed. In the case of a large drone such as a flying taxi, this is a diagram (image) displayed on the display 4D in front of the cockpit.

FIG. 3 is a diagram showing a situation in which the own aircraft and other aircraft displayed on the display are viewed from above, and shows a two-dimensional positional relationship. Since 1 is the own aircraft and is at the same height as the other aircraft 21 flying in front, they are displayed overlapping each other on the display 4D (a broken line is drawn to indicate that the own aircraft and the other aircraft are displayed overlapping each other). ). If the other aircraft 21 is slower than the own aircraft 1, a warning will be displayed on the display 4D when it approaches, and a buzzer will sound at the same time. The other aircraft 22 moves in the opposite direction d2 to the own aircraft 1, but it is a little to the right from the own aircraft 1 in the horizontal direction, and there is no collision. They can safely pass each other. Since the other aircraft 24 moves in the right direction d2, it moves away from the own aircraft 1. The other aircraft 25 has already passed each other, and as shown in FIG. 2, the height is different from the own aircraft 1, and the direction of travel is d5, which is opposite to the own aircraft 1. Other aircraft 26 approaches own aircraft 1 from the left. The height is the same as own aircraft 1, and the traveling direction is d6. It intersects with the traveling direction d0 of own aircraft 1, but the time is different. After the own aircraft 1 moves (flights) forward (upwards in the paper of FIG. 3), the other aircraft 26 crosses the flight path of the own aircraft 1, so there is no collision.

The other aircraft 23 is diagonally ahead to the right, and its traveling direction is d3. As can be seen from FIG. 2, although the heights are different, if the own aircraft 1 and the other aircraft 23 are flying on the same plane, there is a possibility of a collision. Based on the time when the own aircraft and the other aircraft are at the positions shown by the solid line in Figure 3, if the aircraft moves to the position shown by the broken line in Figure 3 after T time has elapsed, then the position 1T of the broken line of own aircraft 1 and the broken line of the other aircraft 23 are Position 23T is quite close. If the distance between the own aircraft 1 and the other aircraft 23 is measured only using GPS horizontal position information, it will be determined that there is a risk of collision between the own aircraft 1 and the other aircraft 23.

If the information in the height direction shown in FIG. 2 is also used, it can be easily seen that there is no possibility of collision between the own aircraft 1 and the other aircraft 23. The current position of own aircraft 1 and the current position of other aircraft 23 are displayed using specific numerical examples. Own aircraft 1 is located at latitude 35°20'08.30 north and longitude 135°33'15.20 east. It is assumed that the other aircraft 23 is located at 35 degrees 20 minutes 48 seconds 30 north latitude and 135 degrees 33 minutes 53 seconds 97 east longitude. First, the horizontal distance between the own aircraft 1 and the other aircraft 21 is calculated from the GPS position information. One degree at 35 degrees north latitude is about 111 kilometers, so one minute is about 1.850 kilometers, and one second is about 30.83 meters. The latitude difference between the two is 40 seconds, or about 1233 meters. At latitude 35 north, one degree of longitude is approximately 91 kilometers, one minute is approximately 1.517 kilometers, and one second is approximately 25.28 meters. The difference in longitude is 48.77 seconds, which is approximately 1233 meters. The latitude and longitude values are chosen to be easy to calculate, but any value will do. The horizontal distance between own aircraft 1 and other aircraft 23 is the square root of "1233 squared + 1233 squared", which is approximately 1744 meters. From this distance and the angle between the own aircraft 1 and the other aircraft 23 photographed by the camera shown in FIG. 2, the altitude difference between the own aircraft 1 and the other aircraft 23 can be calculated. In other words, if the angle is 30 degrees, the height is approximately 1744Tan30 degrees = 1744 ÷ 1.732 = 1007
In other words, there is an altitude difference of 1007 m. Therefore, the possibility of collision is low.

In the above description, the following assumptions are made regarding the signals transmitted by each flying object. First, it is assumed that each flying object detects its position from a GPS signal and transmits it together with its ID. The ID is 16 digits, and the numerical value of each digit is 64 bits if expressed in BCD (4 bits). Latitude and longitude are expressed with 2 digits for minutes and 2 digits for seconds, and if you display up to 2 digits to the right of the second, you can express the position to a distance of 1 meter or less, so both latitude and longitude can be expressed by 6 digits or 12 digits to the right of the minute. Just express it. Even if the unit of degree is displayed, it is meaningless because it will not change every second unless you are far away. 48 bits are required to display 12 digits in BCD. The 16-digit 64-bit ID and 48-bit latitude and longitude are arranged as shown in FIG. In FIG. 4, only a part of the ID is illustrated. One packet consists of a total of 160 bits, including 16 bits of the header and 32 bits of other information such as error correction, and is transmitted with the same content 10 times per second.

If both aircraft 1 and other aircraft 23 are flying at 600 kilometers per hour, they will fly 10 kilometers per minute, or about 167 meters per second. Therefore, when the own aircraft 1 and the other aircraft 23 fly on the same plane, the distance between the own aircraft 1 and the other aircraft 23 is 1744 meters as described above. It is assumed that the angle between the own aircraft 1 and the other aircraft 23 at the reference time is 45 degrees as shown in FIG. 3B. If the speeds of both aircraft are the same, they will collide after flying 1233 meters, as shown in Figure 3B. The time to collision is approximately 7.38 seconds. If the position of the other aircraft 23 is detected within 1 second and the possibility of collision is calculated, there is a margin of 6 seconds or more to avoid a collision by changing the direction of travel and/or flight altitude. I can do it. The flying speed of so-called drones is slower than 600 kilometers per hour, and is thought to be less than half that in most cases, so the time margin will further increase.

The frequency used to transmit the ID and GPS location information is set in the gap between the frequency bands used for mobile phones, that is, in the 13 MHZ width between 1462.9 MHZ and 1475.9 MHZ. This is to keep costs low by sharing existing mobile phone parts, circuits, etc. for transmission/reception, signal processing, etc. The frequency used may be any frequency higher than about 100 MHz, for example. Control unit 7 in the functional block diagram shown in FIG. 6 is operated with a 1 GHZ clock. The clock of the MPU in 7 is also set to 1 GHZ. The unit time required to process one packet of 160 bits is 160 nanoseconds, and if we estimate the processing time to be 160 microseconds, which is 1000 times the processing time, the time required to process one packet of 160 bits is 160 microseconds. The processing time is 1.6 milliseconds, so there is plenty of time. Even if the data is sent 100 times per second, that is, every 10 milliseconds, the processing time is 16 milliseconds, which is sufficient time. The above examples are based on positions (distances) that are easy to calculate, but the distance between two aircraft in other positional relationships (including altitude difference) and the flight speed of the two aircraft can be used to calculate a certain amount of time. It is easy to calculate the positions of the latter two aircraft and determine whether there is a possibility of a collision. Since the flight speed is estimated to be less than 300 kilometers per hour in most cases, the time margin is more than twice that of 12 seconds.

To supplement the flight of own aircraft 1 and other aircraft 23 in Figure 3, as mentioned above, there is a 40 seconds difference in latitude between own aircraft 1 and other aircraft 23, so the north-south direction is approximately 1233 meters and the longitude is 48.77. Since there is a difference in seconds, the east and west directions are also approximately 1,233 meters apart. If the flight speed is 600 kilometers per hour, it will travel 10 kilometers in one minute and 167 meters in one second. Therefore, own aircraft 1 flies about 1233 meters northward (north is the top of the page in FIG. 3) in about 7.38 seconds. The other aircraft 23 flies about 1233 meters in the west direction (west is the left on the page of FIG. 3) in about 7.38 seconds. If own aircraft 1 and other aircraft 23 are flying on the same plane and have the positional relationship shown in Figure 5 at the reference time, then own aircraft 1 and other aircraft 23 will reach point K at the same time in about 7.38 seconds and collide. . Since it takes less than 1 second to receive GPS position information and the ID of the aircraft and calculate the distance between the two aircraft, there is approximately 6 seconds or more before collision, making collision avoidance easy. What you can do is as already mentioned. The distance between the own aircraft 1 and other flying objects can be calculated in the same way.

If the distance between the own aircraft 1 and the other aircraft 23 is expected to be less than 1 kilometer, the own aircraft 1 will ascend or descend in consideration of the traveling direction and altitude of the other aircraft 23. If the other aircraft 23 is at a different height from the own aircraft 1, as shown in FIG. 2, and the difference in altitude is 1007 meters as described above, there is no need to avoid collision. However, if the position after time T is the position indicated by the broken line in FIG. 3 and the altitude difference suddenly decreases to 500 meters, then the own aircraft 1 needs to lower its altitude while maintaining its flight direction. In any case, if the distance between the own aircraft 1 and the other aircraft 23 becomes less than a certain value, it is necessary to change the traveling direction and altitude of the own aircraft. If the other aircraft 23 changes its direction in the same way, the horizontal direction will move in opposite directions, but the vertical direction will move in the same direction. If you enter about 4 bits of information and notify the other party that it is going up or down, the other party can detect this and make the opposite movement. Alternatively, the operating rules may be such that if the direction of travel is north or east, the vehicle must ascend, and if the direction of travel is south or west, it must descend. The 32 bits include a plurality of digits allocated for such purposes such as error correction.

Next, consider the relationship between own aircraft 1 and other aircraft 22. In this case, because the heights are the same and the planes are traveling in opposite directions, there is a risk of a collision. As mentioned above, from the GPS position information of both aircraft, the distance between the two aircraft, that is, the vertical (north-south on the map) and left-right (east-west on the map) distances in FIG. 3 can be calculated. Therefore, if the distance from left to right (east to west on the map) is a certain distance or more, there is no need for collision avoidance action (operation). In the future, a cylindrical (cylindrical or prismatic) flight path will be determined in the air like a road on the ground, and the own aircraft 1, other aircraft 22, and other aircraft 25 will fly within that cylindrical space. There is no need to consider anything other than a rear-end collision. If the other aircraft 23 has an irregular flight area such as agriculture, forestry, tourism, structure management, or personal hobbies, the flight area of the other aircraft 23 may be determined from the GPS position information and camera input image as described above. It is necessary to detect whether there is a possibility of a collision and take action to avoid the collision. It is also necessary to emit an alarm sound to warn the operator (pilot or driver). Even if all operations of the own aircraft 1 are automated, if an operator (pilot or driver) is on board, it is desirable to issue a warning, switch to manual operation, and perform collision avoidance operations.

When the other aircraft 24 and the other aircraft 26 in FIG. 3 are flying in the same determined cylindrical space as the own aircraft 1, they will intersect with the cylindrical space in which the own aircraft 1 is flying. In this case, there is no need to avoid collision since the two cylindrical spaces intersect with a height difference of more than a certain level. In the example of Fig. 3, only the other aircraft 23 was considered to be an aircraft with irregular flight areas such as agriculture, forestry, tourism, structure management, and personal hobbies, but the other aircraft 21, 22, 24, 25, 26, or all of them can similarly detect the possibility of a collision using GPS position information and altitude difference information input from the camera, even if the flight is irregular and the flight area is undefined, and take evasive action. I can do it.

A device that performs the above-mentioned collision avoidance operation will be explained using the functional block diagram of FIG. In FIG. 6, 2 is a propulsion device for flight, such as a propeller. As shown in FIG. 1, the four pieces 2A, 2B, 2C, and 2D are the same. There can be as many as 4 or more. 3 is a camera, and as shown in FIG. 1, it consists of six cameras: 3F for front photography, 3B for rear photography, 3U for upward photography, 3D for downward photography, 3R for right photography, and 3L for left photography. 4D is a display, which is a liquid crystal panel that can be colored in two or more colors. 4K is a keyboard for operation. It is also possible to use a mouse and joystick together. 7 is a control unit including a CPU. It shall include memory, a chip dedicated to image processing, etc. 8R is a receiving antenna that receives GPS signals, IDs transmitted by other devices, and location information of other devices; 8S is a transmitting antenna that transmits its own ID and location information; 9 is an antenna 8R, 8S, and control unit 7; It is an interface between Reference numeral 10 denotes a battery that drives the power source and the control unit. Electric power is supplied from the battery 10 to the propulsion device 2 to generate propulsive force for flight. 3 is six cameras 3B, 3D, 3F, 3L, 3R, and 3U, and the input images are processed by the MPU of the control unit 7 and displayed on the display 4D. The display contents are shown in FIG.

Regarding the display of the own aircraft 1 and other aircraft 21 to 26 on the display 4D, those with a risk of collision are shown in red, those that require caution are shown in yellow, and those that are safe are shown in green. The other aircraft 21, 24, 25, and 26 are displayed in green, and the other aircraft 22 is displayed in yellow because it passes each other. The other aircraft 23 is displayed in green if the height difference is large, yellow if the difference in height is small, and red if the difference in height is minute. Since the other device 21 and the own device overlap, they are displayed, for example, by flashing green. The operator (pilot or driver) seated at 5 in Figure 1 looks at this display, and if there is no other aircraft displayed in red, he can wait in rest mode; if there is another aircraft displayed in yellow, Standby for collision avoidance maneuvers. If another aircraft appears in red, a warning sound is emitted and collision avoidance maneuvers are performed. If the vehicle is fully automated, there will be no need for an operator sitting in seat 5, allowing for an additional passenger. In the case of transportation such as home delivery, it is also possible for a delivery person who is not qualified to drive to board the vehicle instead of the operator sitting at seat 5, and to sit at seat 5 in FIG. It is also possible to carry luggage on all six seats.

The control unit 7 measures the distance between the two from the received GPS position information of the other aircraft and the GPS position information of the own aircraft 1, and determines whether the two are approaching or moving away. Furthermore, the relationship between the other aircraft and the own aircraft 1 is expressed in two dimensions based on the position information of the other aircraft and is displayed in FIG. FIG. 2 is the same as the display on the display 4d. It is also possible to display the ID of the other device when the cursor is placed on the image of the other device. When the keyboard 4K is operated, the contents (key operation signals) are interpreted by the control unit 7, and for example, whether the own aircraft 1 is to ascend or descend, or whether to change its course to the right or to the left. The signal is transmitted to the propulsion device 2. Although the battery 10 is of a rechargeable type, it may alternatively be a lightweight and small gasoline engine or a fuel cell. By configuring as described above, a collision avoidance device for an aircraft can be realized.

The embodiment shown in FIG. 2 is an example of a collision avoidance device for a small drone that does not have the function of transmitting ID information or GPS position information. A functional block in this case is shown in FIG. Since it is small, the camera 3 is only on the 3F for forward photography, and there is no display 4D, keyboard 4K, or transmitting antenna 8S. In this embodiment, collision avoidance with other aircraft is performed only from camera input. The method will be described below with reference to FIGS. 7, 8, 9, and 10. 9 and 10 show the input range (angle) of the camera 3F. The vertical direction is 30 degrees each, and the horizontal direction is 45 degrees each. Images of other aircraft 21, 22, and 23 in this range are displayed in FIG. 7 corresponds to FIG. 2 of the first embodiment, but in the second embodiment there is no display 4D, and FIG. 7 shows the state of the video memory that constitutes the control unit 7, and a virtual screen that displays it. It is. It is assumed that the positional relationship between own aircraft 1 and other aircraft 21, 22, and 23 is the same as in FIG. The lens of the camera 3F can be a small lens similar to that installed in a smartphone. When photographing with the camera 3F, only the other devices 21, 22, and 23 are displayed as shown in FIG. Other aircraft 24, 25, and 26 are outside the field of view of the lens of camera 3F. In Fig. 2, own machine 1 and other machine 21 are displayed overlappingly, but since Fig. 7 is a virtual screen that displays the input image of camera 3F recorded in the memory in control unit 7, own machine 1 is displayed. However, in this case, the own aircraft 1 is at the same position as the other aircraft 21.

The possibility of collision is determined from the size of the other aircraft 21, 22, 23 after time T and the position on the screen displayed in FIG. The positions of other aircraft 21, 22, and 23 at the reference time are represented by solid lines. The positions of other aircraft 21, 22, and 23 after T time are represented by broken lines. Since the other aircraft 21 becomes smaller, it can be seen that it is moving away. If the height of the own aircraft 1 is represented by XY in FIG. 7, the image of the other aircraft 22 is larger at the same altitude. If the distance between the own aircraft 1 and the other aircraft 22 is decreasing in FIG. 7, there is a possibility of a collision. This can be avoided by raising or lowering own aircraft 1. Since the image of the other aircraft 23 is larger and the height difference is smaller, there is a possibility of a collision. The flight directions of other aircraft 22 and 23 are detected from changes in images. It is also possible to use motion vector detection in digital image processing such as MPEG2 for this detection. Collision avoidance is carried out by raising or lowering the flight direction of the own aircraft 1, or changing the course to the left or right, or doing both at the same time, in response to the flight directions of the other aircraft 22 and 23. do. When the own aircraft 1 of the second embodiment is controlled from the ground, collision avoidance is performed by operations from the ground, but when the own aircraft 1 is in autonomous flight or automatic flight, the control unit 7 The system reads changes in the image, determines whether there is a possibility of a collision, controls the propulsion device 2, and automatically performs collision avoidance when the possibility of a collision is detected.

FIG. 8 is a functional block diagram of the second embodiment, in which the display 4D and keyboard 4K are removed from FIG. 5. However, 3 in FIG. 8 is only the lens 3F for front photography among the six lenses that constitute 3 shown in FIG. As mentioned above, the input range of 3F is 30 degrees vertically and 45 degrees horizontally. Although it is possible to set the vertical angle to 45 degrees, it is set to 30 degrees on the assumption that the possibility of collision when ascending or descending is lower than the possibility of collision on the same plane. In FIG. 8, blocks with the same numbers as in FIG. 5 have the same functions as blocks with the same numbers in FIG. In the above explanation, it is assumed that collision avoidance is performed when the possibility of a collision is detected, but by adding a distance measuring device such as the following distance measuring device installed in a car, collision avoidance It is also possible to delay implementation.

It can measure the distance between multiple flying objects, detect the possibility of collision from changes in distance, and take action to avoid collision.

1 Aircraft 2 Flight propulsion device 3 Camera 4 Display device 5 Pilot seat 6 Passenger seat 7 Control unit 8 Antenna 9 Interface 10 Power source

Claims (2)

A function to transmit the aircraft identification code (ID) and GPS position information of the own aircraft, a function to receive the aircraft identification code (ID) and GPS position information of the aircraft concerned transmitted by another aircraft, and 2. It has a function that calculates the horizontal distance between the two aircraft from the GPS position information of each aircraft, inputs an image of the aircraft, and simultaneously displays an image showing the position of the own aircraft on the display device. Equipped with a function to calculate the altitude difference between both aircraft from the image of An aircraft collision avoidance system characterized by starting a collision avoidance operation when the value falls below a numerical value. Images of other aircraft are inputted and displayed on a virtual display device without using the aircraft identification code or GPS position information, and other aircraft approach the own aircraft based on changes in the image size over time. An aircraft collision avoidance system characterized in that it determines whether or not the collision is occurring, and starts a collision avoidance operation.