UAV-borne Short-wave Infrared Hyperspectral Measurement System for Uranium Resource Exploration

Abstract

The present invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to an airborne short-wave infrared hyperspectral measurement system for uranium resource exploration. In this system: The airborne GPS is wirelessly connected to the GPS ground station, and the airborne GPS obtains the position information of the exterior orientation elements of the single-line image data row by row through real-time differential; The airborne GPS is connected to the high-precision IMU, and the airborne GPS triggers the high-precision IMU to obtain the exterior orientation angle element information of the single-line image data; The high-precision IMU is connected to the short-wave infrared hyperspectral imager, and the high-precision IMU triggers the short-wave infrared hyperspectral imager to synchronously obtain the differential GPS information, the high-precision IMU, as well as the spectral row data and the exterior orientation element information; The high-precision IMU and the short-wave infrared hyperspectral imager are respectively connected to the industrial control computer, and the exterior orientation elements and the spectral row data information of the obtained single-line image data are stored in the industrial control computer. The present invention can identify the ore-forming alteration zone and the rock mass, which is beneficial to the uranium resource exploration work.

Description

Technical Field

[0001] The present invention belongs to the technical field of unmanned aerial vehicles, and particularly relates to an unmanned aerial vehicle-borne short-wave infrared hyperspectral measurement system for uranium resource exploration. Background Art

[0002] Uranium resources, as an indispensable strategic reserve resource of the country, are the "grain" for the development of China's nuclear military industry and nuclear power. As a strategic mineral resource, it occupies an extremely important position in national defense construction and the national economy. The rapid development of China's nuclear power and the construction of strategic nuclear forces in the new era have put forward new major and long-term demands for uranium resource security.

[0003] Since the United Kingdom successfully developed the world's first unmanned aerial vehicle in 1917, the development and progress of unmanned aerial vehicle technology have been closely related to strong military needs. Therefore, unmanned aerial vehicles are very richly used in the military and have played an increasingly important role in wars. Compared with the rich military applications, the development of unmanned aerial vehicles in the civilian field is slightly behind. The development of unmanned aerial vehicles in China started in the 1950s, and substantial progress began in the 1990s. In recent years, it has achieved rapid development, providing new technical means for uranium resource exploration in "blank areas", "difficult areas", and "areas with inconvenient transportation".

[0004] Spectral imaging technology can simultaneously obtain the spectral and spatial information of ground targets. Manned airborne hyperspectral remote sensing has played an important role in national economic construction and has achieved a series of important application results in recent years. However, manned airborne hyperspectral remote sensing, due to the large size of the aircraft body, taking into account the safety of the crew members, cannot fly low or slowly, and it is very difficult to fly along complex trajectories (such as canyons with huge height differences). At the same time, manned airborne hyperspectral remote sensing is affected by factors such as difficult airspace application, poor timeliness, high cost, and poor mobility, severely restricting the application and development of airborne hyperspectral remote sensing in national economic construction.

[0005] Currently, hyperspectral sensors such as CASI / SASI / TASI and HyMAP, which are currently applied to uranium resource exploration, can only be carried on manned aircraft, with high flight costs, poor flexibility, and demanding weather conditions. During the operation of wide-band sensors such as HyMAP, continuous addition of liquid nitrogen is required for refrigeration control, and the on-board operation process is cumbersome, greatly restricting the popularization and application of hyperspectral technology. In recent years, technologies for near-surface detection using unmanned aerial vehicles (UAVs), unmanned airships, hot air balloons and other unmanned aircraft carrying aerial remote sensing equipment have made great progress. Currently, the sensors applied to UAV remote sensing information acquisition platforms mainly consist of digital cameras and lightweight multispectral cameras. Based on the diverse selection of UAV types and remote sensing sensor types, the developed remote sensing sensor systems at home and abroad also present a variety of multi-purpose forms. The technology of flight stability and safety is the prerequisite and foundation for ensuring the successful acquisition of remote sensing information, and the payload of UAVs is the key factor affecting the safety of UAV remote sensing systems. Given the limited payload of UAVs, the current lightweight hyperspectral measurement systems based on UAVs have become a research hotspot in the industry.

[0006] In recent years, with the rapid development of technologies such as 3S technology, microcomputers, and communication equipment, it has become possible to acquire and transmit UAV hyperspectral remote sensing information, which has been rapidly developed. UAV-borne hyperspectral remote sensing technology has the characteristics of easy platform construction, low operation and maintenance costs, small size, light weight, simple operation, high flexibility, and short operation cycle. It can make up for the deficiencies of existing spaceborne, airborne remote sensing, and ground hyperspectral remote sensing systems, and improve the sky-ground-depth integrated hyperspectral remote sensing monitoring technology system. However, currently, the response bands of the lightweight hyperspectral imaging systems suitable for UAVs on the market are all 400 - 1000 nm, while the spectral characteristic bands of the metallogenic elements related to uranium mineralization are all located in the range of 1000 - 2500 nm. Therefore, the development of a short-wave infrared hyperspectral measurement system can significantly promote the progress of green exploration technology for uranium resources.

[0007] Currently, UAV-borne hyperspectral imagers adopt a push-broom imaging mode, and the images are recorded sequentially according to the number of rows. The matching of POS data and the number of image rows depends on time difference, with a cumbersome operation process, high error rate, and low accuracy, bringing many difficulties to geometric correction processing.

[0008] Therefore, the development of a lightweight imaging spectral data and POS data synchronous acquisition trigger device is of great significance for promoting the development of UAV hyperspectral remote sensing technology. Summary of the Invention

[0009] The object of the present invention is to provide an airborne short-wave infrared hyperspectral measurement system for uranium resource exploration. This system aims at the problems in the current uranium resource exploration field, such as the weak ability to identify metallogenic elements, the harsh natural environment in the areas to be explored, and the need to strengthen the exploration ability in areas such as "blank areas", "unmanned areas", and "difficult areas". By using the airborne short-wave infrared hyperspectral measurement system, it realizes the identification of minerals related to uranium mineralization, thereby predicting the prospective areas for uranium ore exploration, delineating the favorable areas for uranium mineralization, and identifying the ore-forming alteration zones and rock masses.

[0010] The technical solution for achieving the object of the present invention:

[0011] An airborne short-wave infrared hyperspectral measurement system for uranium resource exploration, the system includes: a short-wave infrared hyperspectral imager, a POS system, and an industrial control computer. The POS system includes a high-precision IMU, an airborne GPS, and a GPS ground station; the airborne GPS is wirelessly connected to the GPS ground station, and the airborne GPS and the GPS ground station communicate with each other to obtain high-precision differential GPS information for spectral scan line data. Based on the GPS ground station, the airborne GPS obtains the position information of the exterior orientation elements of the single-line image data through real-time differential. The airborne GPS is connected to the high-precision IMU, and the airborne GPS triggers the high-precision IMU to obtain the exterior orientation angle element information of the single-line image data. The high-precision IMU is connected to the short-wave infrared hyperspectral imager, and the high-precision IMU triggers the short-wave infrared hyperspectral imager to synchronously obtain the differential GPS information, the high-precision IMU, and the exterior orientation element information of the spectral line data. The high-precision IMU and the short-wave infrared hyperspectral imager are respectively connected to the industrial control computer. The exterior orientation element information of the single-line image data obtained by the high-precision IMU is stored in the industrial control computer, and the exterior orientation element information of the spectral line data obtained by the short-wave infrared hyperspectral imager is stored in the industrial control computer. The spectral data of the high-precision IMU and the short-wave infrared hyperspectral imager are synchronously obtained line by line through a synchronous trigger method to obtain high-quality short-wave infrared hyperspectral imaging data, which is finally stored in the industrial control computer.

[0012] The GPS ground station includes: a ground differential station, a ground control system, and a ground data transmission radio; the ground differential station outputs the differential GPS information; the ground control system is used to send control commands to the ground data transmission radio and receive the position information of the STM32 single-chip microcomputer at the data acquisition moment; the ground data transmission radio packs the ground differential GPS data and the ground station control commands and sends them to the airborne end, and at the same time receives the data returned by the airborne end.

[0013] The airborne GPS includes: an airborne data radio, an airborne data processing module, an airborne GPS calibration module, and an airborne inertial navigation system; the airborne data radio is used to receive data sent by the ground data radio; the airborne data processing module is used to process the data received by the airborne data radio and send the data to the STM32 single-chip microcomputer; the airborne GPS calibration module is used to receive the GPS information sent by the airborne data processing module, calibrate it through the RTK algorithm, and send the calibrated GPS information to the airborne inertial navigation system and then back to the airborne data processing module; the airborne inertial navigation system processes the GPS data packet to obtain high-precision inertial navigation data.

[0014] The response band range of the short-wave infrared hyperspectral imager is 1000 - 2500 nm.

[0015] The short-wave infrared hyperspectral imager adopts a push-broom imaging mode, and the spectroscopic system adopts a prism-grating-prism dispersion spectroscopy method.

[0016] The short-wave infrared hyperspectral imager includes a short-wave infrared spectroscopic module, a short-wave infrared lens, and a short-wave infrared focal plane detector. The short-wave infrared spectroscopic module, the short-wave infrared lens, and the short-wave infrared focal plane detector are installed through alignment and mechanical structure reinforcement.

[0017] The short-wave infrared focal plane detector has a high quantum efficiency at 2000 - 2500 nm, and this band is the main response band of uranium mineralization-related minerals.

[0018] The system further includes: a fixed-wing vertical takeoff and landing unmanned aerial vehicle and a stabilization platform. The stabilization platform is installed inside the fixed-wing vertical takeoff and landing unmanned aerial vehicle, and the short-wave infrared hyperspectral imager is connected to the fixed-wing vertical takeoff and landing unmanned aerial vehicle through the stabilization platform.

[0019] The system further includes air damping shock pads. Four air damping shock pads are placed at the base of the stabilization platform. The stabilization platform is installed inside the fixed-wing vertical takeoff and landing unmanned aerial vehicle through the air damping shock pads to achieve shock absorption during the data acquisition process, and a 5 cm rotational compensation space for the stabilization platform is reserved on each side.

[0020] The beneficial technical effects of the present invention are as follows:

[0021] 1. The uranium resource exploration unmanned aerial vehicle-borne short-wave infrared hyperspectral measurement system provided by the present invention collects short-wave infrared hyperspectral image data, and uses the POS synchronous triggering technology to realize the synchronous acquisition of spectral data and exterior orientation elements, changing the current technical status in the field of unmanned aerial vehicle hyperspectral that relies on time stamps to calculate exterior orientation elements by difference.

[0022] 2. The uranium resource exploration unmanned aerial vehicle-borne short-wave infrared hyperspectral measurement system provided by the present invention realizes the identification of key elements of short-wave infrared uranium mineralization, achieving the purpose of delineating uranium mineralization prospective areas. Brief Description of the Drawings

[0023] Figure 1 It is a block diagram of an airborne short-wave infrared hyperspectral measurement system for uranium resource exploration provided by the present invention;

[0024] Figure 2 It is a schematic diagram of synchronous triggering of the hyperspectral imager and the POS provided by the present invention;

[0025] Figure 3 It is a schematic structural diagram of a short-wave infrared hyperspectral imager in the payload compartment of an unmanned aerial vehicle short-wave infrared hyperspectral measurement system provided by the present invention;

[0026] Figure 4 It is a top view of the interior of the payload compartment of an unmanned aerial vehicle short-wave infrared hyperspectral measurement system provided by the present invention;

[0027] Figure 5 It is a three-dimensional view of the interior of the payload compartment of an unmanned aerial vehicle short-wave infrared hyperspectral measurement system provided by the present invention. Detailed Embodiment

[0028] The present invention will be further described in detail below with reference to the drawings and embodiments.

[0029] As Figure 1 shown, an airborne short-wave infrared hyperspectral measurement system for uranium resource exploration provided by the present invention includes: a wing vertical takeoff and landing unmanned aerial vehicle, a stable platform, a short-wave infrared hyperspectral imager, a POS system, and an industrial control computer. The POS system includes a high-precision IMU, an airborne GPS, and a GPS ground station.

[0030] The airborne GPS is connected to the GPS ground station, and the airborne GPS and the GPS ground station communicate with each other to obtain high-precision differential GPS information for spectral scan line data. Based on the GPS ground station, the airborne GPS obtains the exterior orientation element information of single-line image data through real-time differential.

[0031] The airborne GPS is connected to the high-precision IMU, and the airborne GPS triggers the high-precision IMU to obtain the exterior orientation element information of single-line image data.

[0032] The high-precision IMU is connected to the short-wave infrared hyperspectral imager, and the high-precision IMU triggers the short-wave infrared hyperspectral imager to synchronously obtain differential GPS information, high-precision IMU, and exterior orientation element information of spectral line data.

[0033] The high-precision IMU and the short-wave infrared hyperspectral imager are respectively connected to the industrial control computer. The exterior orientation element information of the single-line image data obtained by the high-precision IMU is stored in the industrial control computer, and the exterior orientation element information of the spectral line data obtained by the short-wave infrared hyperspectral imager is stored in the industrial control computer. In this embodiment, the hyperspectral image data is transmitted to the industrial control computer equipped with a Cameralink data acquisition card through a Cameralink data cable.

[0034] The spectral data of the high-precision IMU and the short-wave infrared hyperspectral imager are obtained line by line synchronously through a synchronous trigger method to obtain high-quality short-wave infrared hyperspectral imaging data, which is finally stored in the industrial control computer. Thus, spectral imaging data acquisition under the condition of no ground control points is realized, and the hyperspectral image data is stored in the industrial control computer. The ground control station communicates with the UAV through wireless communication, controls the route planning of the UAV, and intuitively displays information such as the flight time, speed, altitude, and azimuth angle of the aircraft.

[0035] As Figure 2 shown, the high-precision IMU, the on-board GPS, and the GPS ground station form a POS system. In order to reduce the weight and volume of the POS system, it is generally composed of an MB-TWO receiver, a BD982 receiver, an Ellipse 2-E inertial sensor, a radio, an STM32 single-chip microcomputer, etc. It is divided into a ground base station end (i.e., GPS ground) and an on-board end (on-board GPS).

[0036] The GPS ground station includes: a ground differential station (BD982), a ground control system (STM32 - mobile Internet), and a ground data radio (JZX9879); the ground differential station outputs the differential GPS information; the ground control system is used to send control commands to the ground data radio and receive the position information of the STM32 single-chip microcomputer at the data acquisition moment; the ground data radio packs the ground differential GPS data and the ground station control commands and sends them to the on-board end, and at the same time receives the data returned by the on-board end.

[0037] The on-board GPS includes: an on-board data radio, an on-board data processing module (STM32 - data integration), an on-board GPS calibration module (MB2), and an on-board inertial navigation system (SBG); the on-board data radio is used to receive the data sent by the ground data radio; the on-board data processing module (STM32) is used to process the data received by the on-board data radio and send the data to the STM32 single-chip microcomputer; the on-board GPS calibration module (MB2) is used to receive the GPS information sent by the on-board data processing module, calibrate it through the RTK algorithm, and send the calibrated GPS information to the on-board inertial navigation system (SBG), and then send it back to the on-board data processing module (STM32); the on-board inertial navigation system (SBG) processes the GPS data packet to obtain high-precision inertial navigation data.

[0038] AsFigure 3 As shown in the figure, the response band range of the short-wave infrared hyperspectral imager is 1000 - 2500 nm. The short-wave infrared hyperspectral imager adopts a push-broom imaging mode, and the spectroscopic system adopts a prism-grating-prism dispersion spectroscopy method. The short-wave infrared hyperspectral imager includes a short-wave infrared spectroscopic module 201, a short-wave infrared lens 202, and a short-wave infrared focal plane detector 203. The short-wave infrared spectroscopic module 201, the short-wave infrared lens 202, and the short-wave infrared focal plane detector 203 are installed through alignment and mechanical structure reinforcement. The short-wave infrared focal plane detector 203 has a high quantum efficiency at 2000 - 2500 nm, and this band is the main response band of uranium-related minerals. The short-wave infrared hyperspectral imager is small in volume and weight, can obtain airborne and ground hyperspectral images, achieving "one machine with two uses", and obtains image data by pushing and scanning line by line. At the same time, the airborne GPS board and the high-precision IMU on the aircraft are synchronously triggered to obtain the exterior orientation element information of a single-line image data, which is stored in the industrial control computer 204. The industrial control computer is fixedly connected to the UAV payload compartment through a ground aluminum ring. At the same time, a hyperspectral imaging scanning control software is developed to realize real-time monitoring of the imaging process.

[0039] As Figure 4 shown in the figure, the stabilization platform 302 is installed inside the fixed-wing vertical takeoff and landing UAV 303, and the short-wave infrared hyperspectral imager 301 is connected to the fixed-wing vertical takeoff and landing UAV 303 through the stabilization platform 302. Four air damping shock pads 304 are placed at the base of the stabilization platform 302. The stabilization platform is inside the fixed-wing vertical takeoff and landing UAV through the air damping shock pads to achieve shock absorption during the data acquisition process. A 5 cm rotational compensation space is reserved on each side of the stabilization platform. After the fixed-wing vertical takeoff and landing UAV is opened, it is encapsulated with a transparent acrylic hemisphere cover to maintain the integrity of the aircraft and reduce the influence of wind resistance on the pan-tilt head.

[0040] The internal structure of the payload compartment of the UAV short-wave infrared hyperspectral measurement system is as Figure 5 shown in the figure. The airborne GPS 401 is installed on the upper part of the industrial control computer, communicates with the GPS ground station through a data transmission antenna, obtains high-precision differential GPS information of the spectral scanning line data, and stores it in the industrial control computer. The high-precision IMU 402 is hard-connected to the short-wave infrared hyperspectral imager. The short-wave infrared hyperspectral imager uses an STM32 control board to synchronously obtain differential GPS information, high-precision IMU, and exterior orientation elements of the spectral line data.

[0041] In the initial state, the deflection attitude information is obtained in real time through the inertial navigation, and the output message mode can be set, such as the GGA mode, to adjust the stabilization platform to the horizontal. During the data acquisition process, the stabilization platform controls the motor through the control board to correct the deflection angle in real time, so that the attitude of the hyperspectral imager is always in the vertical state, thereby obtaining high-quality short-wave infrared hyperspectral imaging data.

[0042] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present invention within the scope of knowledge possessed by those of ordinary skill in the art. Contents not described in detail in the present invention can all adopt the prior art.

Claims

1. An airborne short-wave infrared hyperspectral measurement system for uranium resource exploration by unmanned aerial vehicle, characterized in that, the system includes: a short-wave infrared hyperspectral imager, a POS system, and an industrial control computer. The POS system includes a high-precision IMU, an airborne GPS, and a GPS ground station; the airborne GPS is connected to the GPS ground station, and the airborne GPS and the GPS ground station communicate with each other to obtain high-precision differential GPS information for spectral scan line data. Based on the GPS ground station, the airborne GPS obtains the exterior orientation position element information of each single-line image data through real-time differential; the airborne GPS is connected to the high-precision IMU, and the airborne GPS triggers the high-precision IMU to obtain the exterior orientation angle element information of the single-line image data; the high-precision IMU is connected to the short-wave infrared hyperspectral imager, and the high-precision IMU triggers the short-wave infrared hyperspectral imager to synchronously obtain differential GPS information, high-precision IMU, and exterior orientation element information of spectral line data; the high-precision IMU and the short-wave infrared hyperspectral imager are respectively connected to the industrial control computer. The exterior orientation element information of the single-line image data obtained by the high-precision IMU is stored in the industrial control computer, and the exterior orientation element information of the spectral line data obtained by the short-wave infrared hyperspectral imager is stored in the industrial control computer; the spectral data of the high-precision IMU and the short-wave infrared hyperspectral imager are synchronously obtained line by line through a synchronous trigger method to obtain high-quality short-wave infrared hyperspectral imaging data, and finally stored in the industrial control computer.

2. The airborne short-wave infrared hyperspectral measurement system for uranium resource exploration according to claim 1, characterized in that, the GPS ground station includes: a ground differential station, a ground control system, and a ground data transmission radio; the ground differential station outputs differential GPS information; the ground control system is used to send control commands to the ground data transmission radio and receive the position information of the STM32 single-chip microcomputer at the data acquisition moment; the ground data transmission radio packs the ground differential GPS data and the ground station control commands and sends them to the airborne end, and at the same time receives the data returned by the airborne end.

3. The airborne short-wave infrared hyperspectral measurement system for uranium resource exploration according to claim 2, characterized in that, the airborne GPS includes: an airborne data transmission radio, an airborne data processing module, an airborne GPS calibration module MB2, and an airborne inertial navigation system; the airborne data transmission radio is used to receive the data sent by the ground data transmission radio; the airborne data processing module is used to process the data received by the airborne data transmission radio and send the data to the STM32 single-chip microcomputer; the airborne GPS calibration module is used to receive the GPS information sent by the airborne data processing module, calibrate it through the RTK algorithm, and send the calibrated GPS information to the airborne inertial navigation system and then back to the airborne data processing module; the airborne inertial navigation system processes the GPS data packet to obtain high-precision inertial navigation data.

4. The airborne short-wave infrared hyperspectral measurement system for uranium resource exploration according to claim 3, characterized in that, the response band range of the short-wave infrared hyperspectral imager is 1000 - 2500 nm.

5. The airborne short-wave infrared hyperspectral measurement system for uranium resource exploration according to claim 4, characterized in that, The short-wave infrared hyperspectral imager adopts a push-broom imaging mode, and the spectroscopic system adopts a prism-grating-prism dispersion spectroscopy method.

6. A uranium resource exploration unmanned aerial vehicle (UAV)-borne short-wave infrared hyperspectral measurement system according to claim 5, characterized in that the short-wave infrared hyperspectral imager includes a short-wave infrared spectroscopic module, a short-wave infrared lens, and a short-wave infrared focal plane detector, and the short-wave infrared spectroscopic module, the short-wave infrared lens, and the short-wave infrared focal plane detector are installed through alignment and mechanical structure reinforcement.

7. A uranium resource exploration UAV-borne short-wave infrared hyperspectral measurement system according to claim 6, characterized in that the short-wave infrared focal plane detector has a high quantum efficiency at 2000 - 2500 nm, and this band is the main response band of uranium mineralization-related minerals.

8. A uranium resource exploration UAV-borne short-wave infrared hyperspectral measurement system according to claim 7, characterized in that the system further includes: a fixed-wing vertical takeoff and landing UAV and a stabilization platform. The stabilization platform is installed inside the fixed-wing vertical takeoff and landing UAV, and the short-wave infrared hyperspectral imager is connected to the fixed-wing vertical takeoff and landing UAV through the stabilization platform.

9. A uranium resource exploration UAV-borne short-wave infrared hyperspectral measurement system according to claim 8, characterized in that the system further includes air damping shock pads. Four air damping shock pads are placed at the base of the stabilization platform, and the stabilization platform is inside the fixed-wing vertical takeoff and landing UAV through the air damping shock pads to achieve shock absorption during the data acquisition process, and a 5 cm rotational compensation space for the stabilization platform is reserved on each side.

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