Unmanned aerial vehicle terrain matching ground-imitating flight method based on DEM data
Technical Field
The invention belongs to the technical field of unmanned aerial vehicle ground-imitating flight, and particularly relates to an unmanned aerial vehicle terrain matching ground-imitating flight method based on DEM data.
Background
In order to complete land survey, monitoring and statistics systems, strengthen land resource informatization services and meet the requirements of economic and social development and national and local resource management work, local on-site survey is required to identify map spots with inconsistent land types and internal interpretation land types, and new added land features of the local additional survey, which cannot be reflected by images, need to be proved all on-site, so that real and accurate external survey data such as the map spot land types, the map spot boundaries and the like are obtained, and the method is an important source and a key link for obtaining the data by the national and local survey.
The method is characterized in that field investigation evidence-raising needs to be carried out, investigation equipment with a satellite positioning sensor and a direction sensor is used, internet and evidence-raising software issued by national or provincial third-level dispatching is utilized, an encrypted evidence-raising data packet containing comprehensive information such as map spot ground satellite positioning coordinates, a shooting azimuth angle, shooting time, ground photos and evidence-raising instructions is shot and uploaded to a unified evidence-raising platform, the internet and the evidence-raising software which are researched and developed in a unified mode by national or provincial third-level dispatching can only be installed on an android smart phone or a flat plate for manual investigation evidence-raising, and the difficulty is brought to investigation work of evidence-raising aiming at investigation evidence-raising tasks, particularly areas which are inconvenient in traffic and difficult to reach by workers in investigation. This dilemma can be solved to utilize unmanned aerial vehicle technique, but unmanned aerial vehicle still has some problems at the process of proving.
Unmanned aerial vehicle demonstrates photo because the reason at high altitude visual angle, when the photo of proving is examined and examined, the checker need utilize the peripheral scenery of photo to judge the pattern spot scope, if ground scenery changes comparatively greatly, then be difficult to make quick judgement to the achievement of proving, the efficiency is examined in the influence, simultaneously, the photo of proving that utilizes unmanned aerial vehicle to obtain has the problem of being difficult to fix a position the pattern spot border.
In the field test process, it is found that in a mountain area with fluctuating terrain, the flying height setting of the unmanned aerial vehicle needs to be adjusted correspondingly according to the fluctuation of the terrain, so that the unmanned aerial vehicle can fly in a simulated terrain manner, otherwise, the quality of the shot pictures is uneven (the higher the relative height difference from the ground, the worse the quality of the pictures, and the difficulty in identifying secondary terrains). In addition, in places crossing a mountain or across a gully, the difficulty in setting the relative height difference is high, and the situation that the unmanned aerial vehicle is in a mountain collision or falls into a tree to be hung can occur if the relative height difference is not reasonable. Therefore, an unmanned aerial vehicle terrain matching ground-imitating flight method based on DEM data is provided.
Disclosure of Invention
The invention aims to solve the defects in the prior art, and provides a terrain matching ground-imitating flying method of an unmanned aerial vehicle based on DEM data.
In order to achieve the purpose, the invention adopts the following technical scheme:
an unmanned aerial vehicle terrain matching ground-imitating flight method based on DEM data is designed,
the method comprises the following steps:
step one, importing open-source DEM data in a ground station, and performing terrain matching of a flight area;
setting an unmanned aerial vehicle flying point by the ground station, and automatically planning an unmanned aerial vehicle route;
thirdly, referring to the high-precision DEM data of the flying area imported in the first step, automatically setting the relative flying height of the unmanned aerial vehicle relative to the flying starting point according to the height of each flying point, and generating a ground-imitating flying route;
correcting flight navigation in real time by using a front route correction device of the unmanned aerial vehicle, ensuring fixed flight height difference between the unmanned aerial vehicle and the three-dimensional terrain, and generating a real-time ground-imitating flight route;
when the value measured by the unmanned aerial vehicle preposed flight path correcting device exceeds the altitude allowable error threshold value of the waypoint, correcting the ground imitating flight path to generate a new ground imitating flight path;
otherwise, not correcting;
collecting positive photos at the photo taking points by the unmanned aerial vehicle, correcting by adopting an algorithm according to flight attitude parameters of the unmanned aerial vehicle, superposing the photos on the pattern spot range line in an orthoscopic image mode, and drawing to obtain proof-proving photos;
a. when the photo is shot, the course angle y, the pitch p and the roll r of the unmanned aerial vehicle and the geographic coordinates L and B when the photo is shot can be obtained simultaneously;
b. inputting ground elevation fluctuation correction numbers by using the imported DEM data and the unmanned aerial vehicle preposed route correction device to determine the ground relative height difference H of the photographing point;
c. and roughly calculating the geographic coordinates of the four corners of the proof photo by adopting a three-dimensional coordinate conversion method, and then overlaying and drawing the image spots to obtain the proof photo.
Further, in the second step, the ground station and the unmanned aerial vehicle transmit image data through a 4G/5G wireless transmission technology and in an asymmetric photo encryption mode.
Further, the asymmetric photo encryption method comprises the following steps:
a. firstly, shooting photo content by an unmanned aerial vehicle to generate a 128-bit MD5 code, and then forming a character string with shooting seven-element information, wherein the seven elements comprise: personnel, time, location, orientation, altitude, pitch angle, and photo content;
b. acquiring a check code by using a public key by adopting an RSA algorithm, and simultaneously aiming at the multi-level check of the state, province, city and county and checking requirements;
and c, when the local natural resource department submits the proof achievement to provincial or national level inspection, the proof achievement is decrypted by using the private key and verified, and the proof photo passing the verification can be used for auditing.
Furthermore, in the fourth step, the positive shot picture is shot by adopting a shooting interface in the SDK, the resolution of the shot picture is more than 500 ten thousand pixels, and the pixels are 1-3cm, so that the current situation can be clearly fed back and investigated on the spot.
Further, in step five, leading course line correcting unit of unmanned aerial vehicle, including the end of pegging graft, the end of pegging graft sets up the one side at unmanned aerial vehicle flight direction, peg graft and serve and install telescopic machanism with the detachable mode, range unit is installed to telescopic machanism's tip, range unit links to each other with unmanned aerial vehicle's wireless communication module.
Furthermore, the distance measuring device comprises a laser emitting end and a laser receiving end.
Furthermore, telescopic machanism adopts multisection flat structure telescopic link, all is equipped with spacing buckle at the tip of every section telescopic link.
Further, one side of the unmanned aerial vehicle, which is far away from the unmanned aerial vehicle front course correcting device, is provided with a counterweight rod.
The invention provides an unmanned aerial vehicle terrain matching ground-imitating flying method based on DEM data, which has the beneficial effects that:
(1) according to the invention, by referring to high-precision DEM data of a flight area, the relative flight height of each flying point is automatically set according to the elevation of each flight point, an unmanned aerial vehicle front course correcting device is additionally arranged for real-time correction on the spot, corresponding adjustment is carried out according to the fluctuation of the terrain, the fixed height difference between the unmanned aerial vehicle and the three-dimensional terrain is kept, the unmanned aerial vehicle flies in a simulated manner, the quality of shot photos is improved, and the situations of 'mountain collision' or 'falling into a forest and hanging up' of the unmanned aerial vehicle and the like can be effectively avoided.
(2) According to the method, real-time correction is carried out on the ground-imitating flight route by adopting the DEM data auxiliary correction and the unmanned aerial vehicle front route correction device, the fixed flight height difference between the unmanned aerial vehicle and the three-dimensional terrain is ensured, the pattern spot range is restored by adopting an algorithm according to the flight attitude parameters of the unmanned aerial vehicle, and the picture can be superimposed on vector data in an orthographic image mode, so that the picture becomes a picture with a coordinate system, technical support is provided for quick verification, reference can be provided for verification personnel well, and the verification efficiency is improved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic structural diagram of the invention relating to the generation of a ground imitating flight course and a real-time ground imitating flight course by an unmanned aerial vehicle;
FIGS. 2-3 are schematic diagrams of the structure of the invention relating to the overlay of the pattern spots onto the proof photo
Fig. 4 is a schematic diagram of the structure of the unmanned aerial vehicle.
Labeled as: 1. an unmanned aerial vehicle; 2. a weight lever; 3. a plug end; 4. a telescoping mechanism; 5. distance measuring device, 51, laser emission end, 52, laser receiving end.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. These examples are intended to illustrate the invention and are not intended to limit the scope of the invention. In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted", "provided" and "connected" are to be interpreted broadly, e.g. as a fixed connection, a detachable connection or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
The structural features of the present invention will now be described in detail with reference to the accompanying drawings.
An unmanned aerial vehicle terrain matching ground-imitating flight method based on DEM data comprises the following steps:
(1) and importing 30 m DEM data with an open source in the ground station to perform terrain matching of the flight area.
(2) The ground station sets the unmanned aerial vehicle flying starting point, and automatically plans the unmanned aerial vehicle air route, and the ground station and the unmanned aerial vehicle carry out image data transmission through 4G/5G wireless transmission technology and by adopting an asymmetric photo encryption mode.
The asymmetric photo encryption method comprises the following steps:
a. firstly, shooting photo content by an unmanned aerial vehicle to generate a 128-bit MD5 code, and then forming a character string with shooting seven-element information, wherein the seven elements comprise: personnel, time, location, orientation, altitude, pitch angle, and photo content;
b. acquiring a check code by using a public key by adopting an RSA algorithm, and simultaneously aiming at the multi-level check of the state, province, city and county and checking requirements;
and c, when the local natural resource department submits the proof achievement to provincial or national level inspection, the proof achievement is decrypted by using the private key and verified, and the proof photo passing the verification can be used for auditing.
(3) And (3) referring to the high-precision DEM data of the flight area imported in the step (1), automatically setting the relative flight height of the unmanned aerial vehicle relative to the flying starting point according to the height of each flight point, and generating the ground-imitating flight route.
(4) Correcting flight navigation in real time by using a front route correction device of the unmanned aerial vehicle, ensuring the fixed flight height difference between the unmanned aerial vehicle and the three-dimensional terrain, and obtaining a corrected real-time ground-imitating flight route; otherwise, no correction is made (see fig. 1).
(5) The unmanned aerial vehicle collects positive photos at the photo taking point, the positive photos are taken by a photo taking interface in the SDK, the resolution of the shot photos is more than 500 ten thousand pixels, the pixels are 1-3cm, the current situation of field investigation can be clearly fed back, the photos are superimposed on a pattern spot range line in an orthoscopic image mode by adopting algorithm correction according to flight attitude parameters of the unmanned aerial vehicle, and proof-taking photos are obtained by drawing (see fig. 2-3);
a. when the photo is shot, the course angle y, the pitch p and the roll r of the unmanned aerial vehicle and the geographic coordinates L and B when the photo is shot can be obtained simultaneously;
b. inputting ground elevation fluctuation correction numbers by using the imported DEM data and the unmanned aerial vehicle preposed route correction device to determine the ground relative height difference H of the photographing point;
c. and roughly calculating the geographic coordinates of the four corners of the proof photo by adopting a three-dimensional coordinate conversion method, and then overlaying and drawing the image spots to obtain the proof photo.
Referring to fig. 4, for further explanation, the invention further provides a device for correcting a leading flight path of an unmanned aerial vehicle, which comprises an insertion end 3, wherein the insertion end 3 is arranged on one side of the unmanned aerial vehicle 1 in the flight direction, a telescopic mechanism 4 is detachably mounted on the insertion end 3, the telescopic mechanism 4 is a plurality of sections of telescopic rods with flat structures, and the end part of each section of telescopic rod is provided with a limit buckle 41. Distance measuring device 5 is installed to telescopic machanism 4's tip, and distance measuring device links to each other with unmanned aerial vehicle's wireless communication module. The ranging apparatus includes a laser emitting end 51 and a laser receiving end 52. One side of unmanned aerial vehicle 1, which is far away from the leading course line correcting device of unmanned aerial vehicle, is provided with a counterweight rod 2.
Referring to fig. 1, specifically, when the leading flight path correction device of the unmanned aerial vehicle is used, the telescopic mechanism 4 is stretched out, so that the distance between the distance measuring device 5 and the unmanned aerial vehicle 1 is kept at a certain distance, the distance can enable the unmanned aerial vehicle 1 to complete flight height adjustment before flying to a detection point of the distance measuring device 5, when an actual distance detected by the distance measuring device 5 is greater than or less than 30 meters, error judgment is performed, after an absolute error of an actual measurement value greater than or less than 30 meters exceeds 0.5 meter, flight path adjustment is performed, and an adjustment value is an absolute error, so that a new flight path is formed.
The invention relates to an unmanned aerial vehicle terrain matching ground-imitating flying method based on DEM data, which automatically sets the relative flying height relative to a flying point according to the elevation of each navigation point by referring to high-precision DEM data of a flying area, is additionally provided with an unmanned aerial vehicle preposed flight path correcting device for real-time correction on the spot, carries out corresponding adjustment according to the relief of the terrain, keeps the fixed altitude difference between the unmanned aerial vehicle and a three-dimensional terrain, leads the unmanned aerial vehicle to carry out ground-imitating flying, improves the quality of shot photos, can effectively avoid the occurrence of the situations of collision or hanging of the unmanned aerial vehicle in a forest and the like, on the other hand, adopts DEM data auxiliary correction and the unmanned aerial vehicle preposed flight path correcting device to carry out real-time correction on a ground-imitating flight path, ensures the fixed flying altitude difference between the unmanned aerial vehicle and the three-dimensional terrain, adopts an algorithm to restore a pattern range according to flight attitude parameters of the unmanned aerial vehicle, and can superpose the photos on vector data in an orthographic image mode, the photo is changed into a photo with a coordinate system, so that technical support is provided for quick examination and verification, reference can be provided for inspectors well, and the inspection efficiency is improved.
Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.