CN104833343B - System and method for complex terrain boundary and area estimation based on multi-rotor aircraft - Google Patents

Abstract

The present invention provides a kind of complicated landform border based on multi-rotor aerocraft and Class area estimation System and method for, and system includes multi-rotor aerocraft, strapdown inertial navigation system, gps antenna, GPS navigation data reception board, PC end ground control system；The flight control of multi-rotor aerocraft, strapdown inertial navigation system receive the overlapping rotor support intersection being placed on multi-rotor aerocraft of board with GPS navigation data；Strapdown inertial navigation system, GPS navigation data are received board and are connected with the flight control of multi-rotor aerocraft respectively, gps antenna outfan connects GPS navigation data and receives board input, and multi-rotor aerocraft is set up with PC end ground control system and is wirelessly connected.The present invention realizes multi-rotor aerocraft remotely control, and real time imaging is obtained with flight attitude, and location information returns in real time；Integrated navigation system is constituted using double GPS pseudo range difference relative localization technology and inertial navigation technology, realizes being accurately positioned of multi-rotor aerocraft and landform boundary point to be estimated.

Description

System and method for complex terrain boundary and area estimation based on multi-rotor aircraft

technical field

The present invention relates to the fields of control engineering technology, information engineering technology and precision agriculture, in particular to a system and method for estimating complex terrain boundaries and areas based on multi-rotor aircraft.

Background technique

Due to the constraints of my country's current agricultural production environment and the non-centralized and scattered management of land, my country's agricultural production is still in an extensive mode, for example: in agricultural production, the use of water resources is low, pesticides and fertilizers are excessively used, and human and material labor intensity is high. Wait for the status quo. According to relevant data in 2012, the effective utilization coefficient of farmland irrigation water in my country is far lower than the world's advanced level; the grain output per unit of water is less than 2.4 catties/cubic meter; the water consumption for producing 1 kg of grain is as high as 800 kg. Excessive use of pesticides and fertilizers has led to extreme lack of land nutrients, environmental deterioration, ecological environment imbalance, and the consequences of substandard crop products. In view of the above problems, it is imperative to realize precise agricultural water irrigation, soil fertilization and pesticide spraying in my country's agricultural production. Precision agriculture is a modern agricultural production model with interdisciplinary application of information technology and engineering technology. It optimizes many agricultural production factors such as irrigation water, soil fertilization and pesticide spraying to the greatest extent, so as to obtain the greatest economic benefits and realize benign ecological agriculture. The premise of realizing precise agricultural water irrigation, soil fertilization and pesticide spraying is the accurate measurement of the terrain boundary and area of the land to be used. In addition, complex terrain boundary and area measurement can also be used in important links such as forest land measurement and land survey.

At present, commonly used methods for obtaining terrain boundaries and areas include: 1) Obtaining terrain images by using satellite or aircraft remote aerial photography. It has the advantages of wide coverage and high spatial resolution. However, this method has defects such as high operation and maintenance costs and poor real-time performance; 2) using software such as Google Earth or Google Map. However, this method needs to manually confirm the terrain boundary points, and the terrain area estimation accuracy is low; 3) Pix4UAV and Agisoft commercial aerial photography software are used. It needs to use aerial photography of aircraft or aircraft to obtain 2D or 3D images of terrain, and use the acquired images to generate DOM or DEM format files; then use aerial photography to obtain the positioning data of terrain boundary points in advance or manually input terrain boundary point position information, and Finally, the boundary and area estimates of the terrain are obtained. This method needs to know the definite location information of the terrain boundary points to be estimated in advance, and the estimation process is cumbersome, and online estimation cannot be realized; 4) Use equipment for field measurement. This method is easily affected by many factors such as terrain, geographical environment, and weather conditions, and the equipment cost is high. If the terrain to be estimated is complex, manual field operations cannot be realized at all, and with the increase of complex terrain conditions, the estimation accuracy decreases sharply.

Contents of the invention

Aiming at the problems existing in the prior art, the present invention provides a complex terrain boundary and area estimation system and method based on a multi-rotor aircraft.

Technical scheme of the present invention is:

A complex terrain boundary and area estimation system based on multi-rotor aircraft, including:

Multi-rotor aircraft: work according to the control commands of the ground control system on the PC side, obtain the front-view image and the bottom-view image in real time, and combine the acquired front-view image and the bottom-view image with the real-time positioning information and pseudo-range of the multi-rotor aircraft obtained through calculation The pseudo-range rate is transmitted back to the PC-side ground control system;

Strapdown inertial navigation system: used to obtain the instantaneous inertial navigation data of the multi-rotor aircraft, and transmit the data to the main flight control system of the multi-rotor aircraft through the SPI interface;

GPS antenna: used to receive the instantaneous GPS navigation data of the multi-rotor aircraft and transmit it to the GPS navigation data receiving board;

GPS navigation data receiving board: used to calculate instantaneous GPS navigation data and transmit it to the main flight control system of the multi-rotor aircraft through the COM interface;

PC-side ground control system: used for remote control of the multi-rotor aircraft, according to the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image acquired in real time, the real-time positioning information returned, the pseudo-range and the pseudo-range rate to estimate the terrain Boundary drawing and area estimation; the PC-side ground control system determines the boundary points of the terrain to be estimated according to the front-view image and the down-view image acquired in real time, and realizes the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudo-range and pseudo-range rate; using The determined boundary points of the terrain to be estimated and the flight attitude of the multi-rotor aircraft perform boundary drawing and area estimation of the terrain to be estimated;

The main flight control system of the multi-rotor aircraft, the strapdown inertial navigation system and the GPS navigation data receiving board are overlapped and placed at the intersection of the rotor bracket of the multi-rotor aircraft, which is the theoretical center of mass of the multi-rotor aircraft; the strap-down inertial navigation system is connected through the SPI interface Connect with the main flight control system of the multi-rotor aircraft, the GPS navigation data receiving board is connected with the main flight control system of the multi-rotor aircraft through the COM interface, the output end of the GPS antenna is connected with the input end of the GPS navigation data receiving board, the multi-rotor aircraft Establish a wireless connection with the PC-side ground control system.

The method for estimating complex terrain boundaries and areas using the complex terrain boundary and area estimation system includes the following steps:

Step 1. The PC-side ground control system sends a take-off control command to the multi-rotor aircraft;

Step 2. The multi-rotor aircraft obtains the flight attitude, front-view image and down-view image in real time and wirelessly transmits them to the PC-side ground control system;

Step 3, the GPS antenna receives the instantaneous GPS navigation data of the multi-rotor aircraft in real time and transmits it to the GPS navigation data receiving board;

Step 4, the strapdown inertial navigation system obtains the instantaneous inertial navigation data of the multi-rotor aircraft in real time, and transmits the data to the main flight control system of the multi-rotor aircraft through the SPI interface;

Step 5, the GPS navigation data receiving board solves the instantaneous GPS navigation data and transmits it to the main flight control system of the multi-rotor aircraft through the COM interface;

Step 6, the main flight control system of the multi-rotor aircraft calculates the instantaneous inertial navigation data and the instantaneous GPS navigation data, obtains the real-time positioning information, pseudo-range and pseudo-range rate of the multi-rotor aircraft and transmits them to the PC-side ground control system;

Step 7. Based on the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image obtained in real time, the real-time positioning information, pseudorange and pseudorange rate, the PC-side ground control system performs boundary drawing and area estimation of the terrain to be estimated: according to the real-time acquisition The front-view image and the bottom-view image determine the boundary points of the terrain to be estimated; realize the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudo-range and pseudo-range rate; use the determined boundary points of the terrain to be estimated and the flight attitude of the multi-rotor aircraft Boundary drawing and area estimation for estimated terrain.

Described step 7 comprises the steps:

Step 7-1. Select the boundary point of the terrain to be estimated according to the front-view image and the bottom-view image acquired in real time;

Step 7-2, the PC-side ground control system remotely controls the multi-rotor aircraft to obtain positioning information at the current boundary point, and sends it back to the PC-side ground control system;

Step 7-3. The PC-side ground control system processes the obtained current boundary point positioning information: use the Pauta criterion to eliminate abnormal positioning information and use the EKPF method to improve the positioning information accuracy;

Step 7-4, judging whether the current boundary point is in an arc segment: if yes, execute step 7-5; otherwise execute step 7-8;

Step 7-5. The multi-rotor aircraft flies along the arc segment. At a fixed time interval, the multi-rotor aircraft automatically hovers to obtain the positioning information of the boundary points, and sends it back to the PC-side ground control system for processing: use the Pauta criterion to eliminate abnormalities Positioning information and using the EKPF method to improve the accuracy of positioning information;

Step 7-6. If the current boundary point is the end point of the arc segment, execute step 7-7, otherwise return to step 7-5;

Step 7-7, divide the obtained arc segment starting point, arc segment end point and all boundary points on the arc segment into groups of 3, if there are remaining boundary points on the arc segment, then combine the remaining boundary points with the previous Boundary points are combined to complete the grouping; the area of the arc is calculated by the segmented quadratic interpolation method; 5 interpolation points are interpolated between two adjacent boundary points; the inclination α of the straight line formed from the starting point of the arc to the end point of the arc is set; The middle point of the straight line formed from the start point of the arc segment to the end point of the arc segment is the middle point of the x _{line and the middle point} of the y _{line; the middle point} of the arc is the middle point of the x _{arc segment and the middle point} of the y _{arc segment} . If the point is an even number, the average of the two middle boundary points is taken as the middle point of the arc segment; if 0≤α≤90°y _{arc segment middle} point≥y _{straight line middle point} , the arc segment is a convex arc segment, otherwise it is a concave arc segment ; If 90<α≤180°, _{the middle point of the x arc segment} ≥ _{the middle point of the x straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 180<α≤270° _{, the middle point of the y arc segment} ≤ the middle point of the y _{straight line point} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 270<α<360°, the middle point of the x _{arc segment ≤ the middle point} of the x _{straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; definition The area of a convex arc is positive, and the area of a concave arc is negative;

Step 7-8, judging whether the current boundary point is the first two boundary points of the terrain to be estimated: if yes, then perform step 7-9, otherwise perform step 7-10;

Step 7-9. If the current boundary point is the first boundary point of the terrain to be estimated, set the boundary point as a convex point and return to step 7-2; if the current boundary point is the second boundary point of the terrain to be estimated point, then set the boundary point as a convex point, and after determining the initial rotation trend by the relationship between the yaw angle and the position of the first two boundary points of the terrain to be estimated, return to step 7-2;

Step 7-10, determine the concave-convex property of the current boundary point: if the current boundary point rotation trend is inconsistent with the initial rotation trend, then the boundary point is a concave point, and perform steps 7-11; if the current boundary point rotation trend is consistent with the initial rotation trend, Then the boundary point is a convex point, perform steps 7-12;

Step 7-11, if there is a convex point adjacent to the current boundary point, the ground control system at the PC side calculates the current boundary point, the convex point adjacent to the current boundary point, and the previous A triangular area formed by a boundary point, obtain the convex point area and remove the convex point adjacent to the current boundary point from the terrain to be estimated; otherwise, the PC-side ground control system retains the current boundary point in the terrain to be estimated;

Steps 7-12. Determine whether the multi-rotor aircraft has returned to the starting point: if yes, the ground control system on the PC side generates a pre-estimated terrain, and determines the final rotation trend of the terrain to be estimated and the pre-estimated terrain according to the current arc boundary point rotation trend Concave-convex property of the terrain boundary point; otherwise, the multi-rotor aircraft flies to the next boundary point, and returns to step 7-1;

Step 7-13: Determination of the secondary concave point of the pre-estimated terrain boundary point: If the rotation trend of the boundary point in the pre-estimated terrain is different from the final rotation trend of the terrain to be estimated, then the boundary point is a secondary concave point, go to step 7 -14; if the rotation trend of the boundary point in the pre-estimated terrain is the same as the final rotation trend of the terrain to be estimated, then the boundary point is a convex point, then the ground control system on the PC end retains the current boundary point in the terrain to be estimated, and execute step 7 -15;

Step 7-14. Determine whether the currently processed pre-estimated terrain boundary point is a continuous secondary concave point: if yes, the PC-side ground control system will calculate the current boundary point, the previous concave point and the next adjacent convex point. The area of the triangle is obtained from the area of the secondary concave point, and the current boundary point is eliminated from the estimated terrain; otherwise, the PC-side ground control system calculates the area of the triangle formed by the current boundary point and the first two convex points adjacent to the current boundary point to obtain the second The area of the second concave point, and remove the current boundary point from the pre-estimated terrain;

Step 7-15, judging whether to completely eliminate the secondary concave point in the pre-estimated terrain; if not completely eliminated, then judge the next boundary point, and return to step 7-13; if completely eliminated, then execute step 7-16;

Steps 7-16. The PC-side ground control system generates the second estimated terrain and calculates the area of the second estimated terrain, and completes the boundary drawing and area estimation of the terrain to be estimated according to the second estimated terrain: if the final rotation trend of the terrain to be estimated Clockwise: the final estimated terrain area estimation result = secondary pre-estimated terrain area - secondary concave point area + convex point area - arc area; if the final rotation trend of the estimated terrain is counterclockwise: the final estimated terrain area Terrain area estimation result = secondary pre-estimated terrain area - secondary concave point area - convex point area + arc section area.

Beneficial effect:

The invention adopts the combined navigation of dual GPS pseudo-range differential relative positioning and inertial navigation to realize the online estimation of complex terrain boundary and area, has the advantages of low cost, high precision, remote control, and can complete the accurate estimation of boundary and area of any terrain at any time Etc. After testing and verification, the estimation accuracy of the terrain boundary and area estimation system reaches ±1%.

The invention relates to a system and method for realizing online estimation of boundaries and areas of complicated terrains by using a multi-rotor aircraft as a measurement carrier. It realizes the remote control of the multi-rotor aircraft through the PC-side ground control system, real-time image and flight attitude acquisition, and real-time feedback of positioning information; the dual GPS pseudo-range differential relative positioning technology and inertial navigation technology are used to form a combined navigation system to realize multi-rotor aircraft. Precise positioning of the boundary points of the terrain to be estimated; using the Pauta criterion (3σ criterion) to remove abnormal data in the positioning information; using the Extended Kalman Particle Filter (EKPF) method to locate the boundary points after removing the abnormal positioning information The information is filtered and the positioning accuracy is further improved; the system and method have the advantages of low cost, high precision, good real-time performance, remote control, and easy operation.

Description of drawings

Fig. 1 is a block diagram of the overall structure of the complex terrain boundary and area estimation system based on multi-rotor aircraft according to an embodiment of the present invention;

Fig. 2 is a flow chart of a complex terrain boundary and area estimation method based on a multi-rotor aircraft according to an embodiment of the present invention;

Fig. 3 is an example diagram of the terrain boundary and area in the clockwise direction of an embodiment of the present invention;

(a) is a schematic diagram of the terrain to be estimated;

(b) is a schematic diagram of the terrain after the concave-convex points are judged;

(c) is a schematic diagram of the estimated terrain;

(d) is a schematic diagram of the secondary pre-estimated terrain;

Fig. 4 is an example diagram of terrain boundary and area in the counterclockwise direction of an embodiment of the present invention;

(a) is a schematic diagram of the terrain to be estimated;

(b) is a schematic diagram of the terrain after the concave-convex points are judged;

(c) is a schematic diagram of the estimated terrain;

(d) is a schematic diagram of the secondary pre-estimated terrain.

detailed description

Embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

As shown in Figure 1, a complex terrain boundary and area estimation system based on multi-rotor aircraft includes:

Multi-rotor aircraft: work according to the control commands of the ground control system on the PC side, obtain the front-view image and the bottom-view image in real time, and combine the acquired front-view image and the bottom-view image with the real-time positioning information and pseudo-range of the multi-rotor aircraft obtained through calculation The pseudo-range rate is sent back to the ground control system on the PC side.

Strapdown inertial navigation system: used to obtain the instantaneous inertial navigation data of the multi-rotor aircraft, and transmit the data to the main flight control system of the multi-rotor aircraft through the SPI interface; the instantaneous inertial navigation data includes instantaneous flight attitude, speed and position.

Two IGO ESmart GPS antennas with pseudo-range measurement function: used to receive the instantaneous GPS navigation data of the multi-rotor aircraft and transmit it to the GPS navigation data receiving board.

OEMStarGPS navigation data receiving board: It is used to solve the instantaneous GPS navigation data and transmit it to the main flight control system of the multi-rotor aircraft through the COM interface.

PC-side ground control system: used for remote control of the multi-rotor aircraft, according to the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image acquired in real time, the real-time positioning information returned, the pseudo-range and the pseudo-range rate to estimate the terrain Boundary drawing and area estimation; the PC-side ground control system determines the boundary points of the terrain to be estimated according to the front-view image and the down-view image acquired in real time, and realizes the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudo-range and pseudo-range rate; using The determined boundary points of the terrain to be estimated and the flight attitude of the multi-rotor aircraft perform boundary drawing and area estimation of the terrain to be estimated.

The main flight control system of the multi-rotor aircraft, the strapdown inertial navigation system and the GPS navigation data receiving board are overlapped and placed at the intersection of the rotor bracket of the multi-rotor aircraft, which is the theoretical center of mass of the multi-rotor aircraft; the strapdown inertial navigation system is connected through the SPI interface. Connect with the main flight control system of the multi-rotor aircraft, the GPS navigation data receiving board is connected with the main flight control system of the multi-rotor aircraft through the COM interface, the output end of the GPS antenna is connected with the input end of the GPS navigation data receiving board, the multi-rotor aircraft Establish a wireless connection with the PC-side ground control system through WIFI, 3G network, remote control, etc., to realize the remote control of the multi-rotor aircraft.

The main flight control system of the multi-rotor aircraft uses an ARM9 processor and runs the Linux 2.6.32 operating system. It is mainly used to realize multi-rotor aircraft control, attitude control, etc.; the strapdown coherent navigation system consists of a barometer and a 9-degree-of-freedom inertial measurement unit (3-axis gyroscope, 3-axis accelerometer, and 3-axis magnetometer); The GPS pseudo-range differential relative positioning system is composed of IGO ESmart GPS antenna with pseudo-range measurement function and OEMStar GPS navigation data receiving board; the strapdown continuous navigation system is combined with the dual GPS differential relative positioning system to form an integrated navigation system.

The method for complex terrain boundary and area estimation using the complex terrain boundary and area estimation system, as shown in Figure 2, comprises the following steps:

Step 1. The PC-side ground control system sends a take-off control command to the multi-rotor aircraft;

Step 2. The multi-rotor aircraft obtains the flight attitude, front-view image and down-view image in real time and wirelessly transmits them to the PC-side ground control system;

Step 3, the GPS antenna receives the instantaneous GPS navigation data of the multi-rotor aircraft in real time and transmits it to the GPS navigation data receiving board;

Step 4, the strapdown inertial navigation system obtains the instantaneous inertial navigation data of the multi-rotor aircraft in real time, and transmits the data to the main flight control system of the multi-rotor aircraft through the SPI interface;

Step 5, the GPS navigation data receiving board solves the instantaneous GPS navigation data and transmits it to the main flight control system of the multi-rotor aircraft through the COM interface;

Step 6, the main flight control system of the multi-rotor aircraft calculates the instantaneous inertial navigation data and the instantaneous GPS navigation data, obtains the real-time positioning information, pseudo-range and pseudo-range rate of the multi-rotor aircraft and transmits them to the PC-side ground control system;

Step 7. Based on the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image obtained in real time, the real-time positioning information, pseudorange and pseudorange rate, the PC-side ground control system performs boundary drawing and area estimation of the terrain to be estimated: according to the real-time acquisition The front-view image and the bottom-view image determine the boundary points of the terrain to be estimated; realize the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudo-range and pseudo-range rate; use the determined boundary points of the terrain to be estimated and the flight attitude of the multi-rotor aircraft Boundary drawing and area estimation for estimated terrain.

The format of the position data defining the boundary point is pdi=( _xi , y _i , yaw _i , mark _i ), i=0, 1..., n. x _i and y _i are the positions in the Gaussian plane coordinate system (the initial position defaults to the coordinate origin); yaw _i is the yaw angle of the multi-rotor aircraft from the boundary point pdi to the next boundary point (the range of the yaw angle is -179 °～180°, the yaw angle of the multi-rotor aircraft is 0° when it is flying forward); mark _i is the concave and convex mark of the boundary point pdi;

Step 7-1. Select the boundary points of the terrain to be estimated according to the front-view image and the bottom-view image acquired in real time; pd0-pd8 in Fig. 3(a) and pd0-pd9 in Fig. 4(a);

Step 7-2. The multi-rotor aircraft hovers at the selected boundary point for 1 minute, and the PC-side ground control system remotely controls the multi-rotor aircraft to obtain positioning information at the current boundary point, and sends it back to the PC-side ground control system;

Step 7-3. The PC-side ground control system processes the obtained current boundary point positioning information: use the Pauta criterion (3σ criterion) to eliminate abnormal positioning information and use the Extended Kalman Particle Filter (EKPF) method to improve the positioning information precision;

The position and velocity information of the multi-rotor aircraft after removing the abnormal positioning information is used as the input state variable of the EKPF method; the output of the EKPF method is used as the final positioning information of the current boundary point;

Step 7-4, judging whether the current boundary point is in an arc segment: if yes, execute step 7-5; otherwise execute step 7-8;

The arc start point and arc end point are determined by observing the front view image and the bottom view image:

The starting point of the arc segment is pd5 in Fig. 3(b), and pd8 in Fig. 4(b).

The end point of the arc segment is pd6 in Fig. 3(b), and pd9 in Fig. 4(b).

Step 7-5: The multi-rotor aircraft flies along the arc, and every 15 seconds, the multi-rotor aircraft hovers automatically to obtain 300 positioning information of the boundary points, and sends them back to the PC-side ground control system for processing: using the Pauta criterion ( 3σ criterion) to eliminate abnormal positioning information and use the Extended Kalman Particle Filter (EKPF) method to improve the accuracy of positioning information;

Step 7-6. If the current boundary point is the end point of the arc segment, execute step 7-7, otherwise return to step 7-5;

Step 7-7, divide the obtained arc segment starting point, arc segment end point and all boundary points on the arc segment into groups of 3, if there are remaining boundary points on the arc segment, then combine the remaining boundary points with the previous Combining boundary points to complete the grouping; adopting the segmented quadratic interpolation method to calculate the arc area; interpolating 5 interpolation points between two adjacent boundary points;

Set the inclination angle α of the straight line formed from the starting point of the arc segment to the ending point of the arc segment; the middle point position of the straight line formed from the starting point of the arc segment to the ending point of the arc segment is the middle point of the x _{straight line and the middle point} of the y _{straight line} ; the middle point position of the arc segment It is the middle point of the x _{arc segment and the middle point} of the y _{arc segment} . If the boundary point of the arc segment is an even number, the mean value of the two middle boundary points is taken as the middle point of the arc segment; if 0≤α≤90° _{, the middle point of the y arc} segment≥y If _{the middle point of the straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 90<α≤180°, x _{arc segment middle point} ≥ x _{straight line middle point} , the arc segment is a convex arc segment, otherwise it is a concave arc segment ; If 180<α≤270°, the _{middle point of the y arc segment} ≤ the middle point of the y _{straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 270<α<360°, the middle point of the x _{arc segment ≤ the middle point of the} x _{straight line point} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; the area of a convex arc segment is defined as positive, and the area of a concave arc segment is negative;

The arc area is shown as saa in Fig. 3(b) and Fig. 4(b).

Step 7-8, judging whether the current boundary point is the first two boundary points of the terrain to be estimated: if yes, then perform step 7-9, otherwise perform step 7-10;

Step 7-9. If the current boundary point is the first boundary point of the terrain to be estimated, set the boundary point as a convex point and return to step 7-2; if the current boundary point is the second boundary point of the terrain to be estimated point, then set the boundary point as a convex point, determine the initial rotation trend (clockwise or counterclockwise) according to the relationship between the yaw angle and position of the first two boundary points (pd1 and pd2) of the terrain to be estimated, and return to the execution step 7-2;

Step 7-10, determine the concave-convex property of the current boundary point: if the current boundary point rotation trend is inconsistent with the initial rotation trend, then the boundary point is a concave point, and perform steps 7-11; if the current boundary point rotation trend is consistent with the initial rotation trend, Then the boundary point is a convex point (such as pd1 and pd3 in Fig. 3 and Fig. 4), perform steps 7-12;

Step 7-11, if there is a convex point adjacent to the current boundary point (such as pd2 and pd4 in Figure 3 and Figure 4), the PC-side ground control system calculates the current boundary point, the convex point adjacent to the current boundary point point, the triangle area formed by the previous boundary point of the convex point adjacent to the current boundary point (as shown in Fig. point adjacent salient points; otherwise, the ground control system on the PC side will retain the current boundary point in the terrain to be estimated;

Steps 7-12. Determine whether the multi-rotor aircraft has returned to the starting point: if yes, then the ground control system on the PC side generates a pre-estimated terrain (as shown in Figure 3(c) and Figure 4(c)), and based on the boundary points of the current arc segment The rotation trend determines the final rotation trend of the terrain to be estimated (clockwise as shown in Figure 3, and counterclockwise in Figure 4) and determines the concave-convex property of the boundary point of the pre-estimated terrain; otherwise, the multi-rotor aircraft flies to the next boundary point and returns to the execution step 7-1;

Step 7-13: Determination of the secondary concave point of the pre-estimated terrain boundary point: If the rotation trend of the boundary point in the pre-estimated terrain is different from the final rotation trend of the terrain to be estimated, then the boundary point is a secondary concave point, go to step 7 -14; if the rotation trend of the boundary point in the pre-estimated terrain is the same as the final rotation trend of the terrain to be estimated, then the boundary point is a convex point, then the ground control system on the PC end retains the current boundary point in the terrain to be estimated, and execute step 7 -15;

Steps 7-14, judging whether the currently processed pre-estimated terrain boundary point is a continuous secondary concave point: yes, the currently processed pre-estimated terrain boundary point is a continuous secondary concave point (as shown in pd4 in Figure 3), then the PC terminal The ground control system will calculate the area of the triangle formed by the current boundary point, the previous concave point and the adjacent subsequent convex point to obtain the area of the secondary concave point (the area scpa of the vertical shaded part in Fig. Eliminate the current boundary point; otherwise, the currently processed pre-estimated terrain boundary point is a discontinuous secondary concave point (as shown in pd2 in Figure 3 and Figure 4), and the PC-side ground control system calculates the current boundary point, adjacent to the current boundary point The triangular area formed by the first two salient points of the first two convex points of the first two points obtains the area of the secondary concave point (the area scpa of the vertical shaded part in Fig. 4), and removes the current boundary point from the pre-estimated terrain;

Step 7-15, judging whether to completely eliminate the secondary concave point in the pre-estimated terrain; if not completely eliminated, then judge the next boundary point, and return to step 7-13; if completely eliminated, then execute step 7-16;

Steps 7-16. The ground control system at the PC end generates the second estimated terrain and calculates the area of the second estimated terrain, completes the boundary drawing and area estimation of the terrain to be estimated according to the second estimated terrain, and obtains the final estimation of the area of the terrain to be estimated Result (fa, as shown in Figure 3 (d) and Figure 4 (d)): If the final rotation trend of the terrain to be estimated is clockwise: the final estimation result of the terrain area to be estimated fa=secondary estimated terrain area spta-secondary Concave point area scpa+convex point area cpa-arc area ssa; if the final rotation trend of the terrain to be estimated is counterclockwise: the final estimation result of the terrain area to be estimated fa=secondary pre-estimated terrain area spta-secondary concave point area scpa -Bump area cpa+arc area ssa.

Claims (4)

1. A complex terrain boundary and area estimation system based on multi-rotor aircraft, characterized in that it comprises: Multi-rotor aircraft: work according to the control commands of the ground control system on the PC side, obtain the front-view image and the bottom-view image in real time, and combine the acquired front-view image and the bottom-view image with the real-time positioning information and pseudo-range of the multi-rotor aircraft obtained through calculation The pseudo-range rate is transmitted back to the PC-side ground control system; Strapdown inertial navigation system: used to obtain the instantaneous inertial navigation data of the multi-rotor aircraft, and transmit the data to the main flight control system of the multi-rotor aircraft through the SPI interface; GPS antenna: used to receive the instantaneous GPS navigation data of the multi-rotor aircraft and transmit it to the GPS navigation data receiving board; GPS navigation data receiving board: used to solve the instantaneous GPS navigation data and transmit it to the main flight control system of the multi-rotor aircraft through the COM interface; PC-side ground control system: used for remote control of the multi-rotor aircraft, according to the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image acquired in real time, the real-time positioning information returned, the pseudo-range and the pseudo-range rate to estimate the terrain Boundary drawing and area estimation; The main flight control system of the multi-rotor aircraft, the strapdown inertial navigation system and the GPS navigation data receiving board are overlapped and placed at the intersection of the rotor bracket of the multi-rotor aircraft, which is the theoretical center of mass of the multi-rotor aircraft; the strap-down inertial navigation system is connected through the SPI interface Connect with the main flight control system of the multi-rotor aircraft, the GPS navigation data receiving board is connected with the main flight control system of the multi-rotor aircraft through the COM interface, the output end of the GPS antenna is connected with the input end of the GPS navigation data receiving board, the multi-rotor aircraft Establish a wireless connection with the PC-side ground control system. 2. the complex terrain boundary and area estimation system based on multi-rotor aircraft according to claim 1, is characterized in that, The PC-side ground control system determines the boundary points of the terrain to be estimated according to the front-view image and the down-view image acquired in real time, and realizes the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudorange and pseudorange rate; The boundary points and the flight attitude of the multi-rotor aircraft are used to draw the boundary and estimate the area of the terrain to be estimated. 3. adopt the method for complex terrain boundary and area estimation system to carry out complex terrain boundary and area estimation according to claim 1, it is characterized in that, comprise the following steps: Step 1. The PC-side ground control system sends a take-off control command to the multi-rotor aircraft; Step 2. The multi-rotor aircraft obtains the flight attitude, front-view image and down-view image in real time and wirelessly transmits them to the PC-side ground control system; Step 3, the GPS antenna receives the instantaneous GPS navigation data of the multi-rotor aircraft in real time and transmits it to the GPS navigation data receiving board; Step 4, the strapdown inertial navigation system obtains the instantaneous inertial navigation data of the multi-rotor aircraft in real time, and transmits the data to the main flight control system of the multi-rotor aircraft through the SPI interface; Step 5, the GPS navigation data receiving board solves the instantaneous GPS navigation data and transmits it to the main flight control system of the multi-rotor aircraft through the COM interface; Step 6, the main flight control system of the multi-rotor aircraft calculates the instantaneous inertial navigation data and the instantaneous GPS navigation data, obtains the real-time positioning information, pseudo-range and pseudo-range rate of the multi-rotor aircraft and transmits them to the PC-side ground control system; Step 7. Based on the flight attitude of the multi-rotor aircraft, the front-view image and the down-view image obtained in real time, the real-time positioning information, pseudorange and pseudorange rate, the PC-side ground control system performs boundary drawing and area estimation of the terrain to be estimated: according to the real-time acquisition The front-view image and the bottom-view image determine the boundary points of the terrain to be estimated; realize the positioning of the multi-rotor aircraft according to the real-time positioning information, pseudo-range and pseudo-range rate; use the determined boundary points of the terrain to be estimated and the flight attitude of the multi-rotor aircraft Boundary drawing and area estimation for estimated terrain. 4. complex terrain boundary and area estimation method according to claim 3, is characterized in that, described step 7 comprises the steps: Step 7-1. Select the boundary point of the terrain to be estimated according to the front-view image and the bottom-view image acquired in real time; Step 7-2, the PC-side ground control system remotely controls the multi-rotor aircraft to obtain positioning information at the current boundary point, and sends it back to the PC-side ground control system; Step 7-3. The PC-side ground control system processes the obtained current boundary point positioning information: use the Pauta criterion to eliminate abnormal positioning information and use the EKPF method to improve the positioning information accuracy; Step 7-4, judging whether the current boundary point is in an arc segment: if yes, execute step 7-5; otherwise execute step 7-8; Step 7-5. The multi-rotor aircraft flies along the arc segment. At a fixed time interval, the multi-rotor aircraft automatically hovers to obtain the positioning information of the boundary points, and sends it back to the PC-side ground control system for processing: use the Pauta criterion to eliminate abnormalities Positioning information and using the EKPF method to improve the accuracy of positioning information; Step 7-6. If the current boundary point is the end point of the arc segment, execute step 7-7, otherwise return to step 7-5; Step 7-7, divide the obtained arc segment starting point, arc segment end point and all boundary points on the arc segment into groups of 3, if there are remaining boundary points on the arc segment, then combine the remaining boundary points with the previous Boundary points are combined to complete the grouping; the area of the arc is calculated by the segmented quadratic interpolation method; 5 interpolation points are interpolated between two adjacent boundary points; the inclination α of the straight line formed from the starting point of the arc to the end point of the arc is set; The middle point of the straight line formed from the start point of the arc segment to the end point of the arc segment is the middle point of the x _{line and the middle point} of the y _{line; the middle point} of the arc is the middle point of the x _{arc segment and the middle point} of the y _{arc segment} . If the point is an even number, the average of the two middle boundary points is taken as the middle point of the arc segment; if 0≤α≤90°, the middle point of the y _{arc segment≥the middle point of} the y _line , the arc segment is a convex arc segment, otherwise it is a concave arc segment segment; if 90<α≤180°, the middle point of the x _{arc segment ≥ the middle point} of the x _{straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 180<α≤270°, _{the middle point} of the y arc segment ≤ y _{The middle point of the straight line} , the arc segment is a convex arc segment, otherwise it is a concave arc segment; if 270<α<360°, x _{arc segment middle point} ≤ x _{straight line middle point} , the arc segment is a convex arc segment, otherwise it is a concave arc segment ;Define the area of the convex arc segment in the graph as positive, and the area of the concave arc segment as negative; Step 7-8, judging whether the current boundary point is the first two boundary points of the terrain to be estimated: if yes, then perform step 7-9, otherwise perform step 7-10; Step 7-9. If the current boundary point is the first boundary point of the terrain to be estimated, set the boundary point as a convex point and return to step 7-2; if the current boundary point is the second boundary point of the terrain to be estimated point, then set the boundary point as a convex point, and after determining the initial rotation trend by the relationship between the yaw angle and the position of the first two boundary points of the terrain to be estimated, return to step 7-2; Step 7-10, determine the concave-convex property of the current boundary point: if the current boundary point rotation trend is inconsistent with the initial rotation trend, then the boundary point is a concave point, and perform steps 7-11; if the current boundary point rotation trend is consistent with the initial rotation trend, Then the boundary point is a convex point, perform steps 7-12; Step 7-11, if there is a convex point adjacent to the current boundary point, the ground control system at the PC side calculates the current boundary point, the convex point adjacent to the current boundary point, and the previous A triangular area formed by a boundary point, obtain the convex point area and remove the convex point adjacent to the current boundary point from the terrain to be estimated; otherwise, the PC-side ground control system retains the current boundary point in the terrain to be estimated; Steps 7-12. Determine whether the multi-rotor aircraft has returned to the starting point: if yes, the ground control system on the PC side generates a pre-estimated terrain, and determines the final rotation trend of the terrain to be estimated and the pre-estimated terrain according to the current arc boundary point rotation trend Concave-convex property of the terrain boundary point; otherwise, the multi-rotor aircraft flies to the next boundary point, and returns to step 7-1; Step 7-13: Determination of the secondary concave point of the pre-estimated terrain boundary point: If the rotation trend of the boundary point in the pre-estimated terrain is different from the final rotation trend of the terrain to be estimated, then the boundary point is a secondary concave point, go to step 7 -14; if the rotation trend of the boundary point in the pre-estimated terrain is the same as the final rotation trend of the terrain to be estimated, then the boundary point is a convex point, then the ground control system on the PC end retains the current boundary point in the terrain to be estimated, and execute step 7 -15; Step 7-14. Determine whether the currently processed pre-estimated terrain boundary point is a continuous secondary concave point: if yes, the PC-side ground control system will calculate the current boundary point, the previous concave point and the next adjacent convex point. The area of the triangle is obtained from the area of the secondary concave point, and the current boundary point is eliminated from the estimated terrain; otherwise, the PC-side ground control system calculates the area of the triangle formed by the current boundary point and the first two convex points adjacent to the current boundary point to obtain the second The area of the second concave point, and remove the current boundary point from the pre-estimated terrain; Step 7-15, judging whether to completely eliminate the secondary concave point in the pre-estimated terrain; if not completely eliminated, then judge the next boundary point, and return to step 7-13; if completely eliminated, then execute step 7-16; Steps 7-16. The PC-side ground control system generates the second estimated terrain and calculates the area of the second estimated terrain, and completes the boundary drawing and area estimation of the terrain to be estimated based on the second estimated terrain: if the final rotation trend of the terrain to be estimated Clockwise: the final estimation result of terrain area to be estimated = quadratic estimated terrain area - quadratic concave point area + convex point area - arc area; if the final rotation trend of the estimated terrain is counterclockwise: the final estimated terrain area Terrain area estimation result = secondary pre-estimated terrain area - secondary concave point area - convex point area + arc segment area.