Aerial Exploration Research Articles

A Mars quadcopter capable of autonomous flight and sample collection: Structure and avionics

The Mars rotorcraft is an aerial exploration platform capable of repeated take-offs and landings to extend the range of rover explorations. NASA’s Ingenuity helicopter is a full y functioning coaxial helicopter for technology demonstration. Increasing the rotor diameter or the number of blades can enhance the load capacity of the coaxial helicopter but would make it difficult to be folded. A more suitable configuration for Mars exploration is the multi-rotor aircraft, which has a stronger load capacity with the same rotor diameter. Although the aerodynamic performance and operational capabilities of the Mars multi-rotor aircraft have been partially considered, mechatronic system design and autonomous flight control have not been fully addressed. Harbin Institute of Technology and China Academy of Space Technology jointly proposed a deployable Mars quadcopter for air patrol and sampling with a sample mass of 100 g. This paper presents a concept for a Mars quadcopter and its mission operations, including operational procedures and flight modes, to provide a framework for future Mars flight sampling missions. We describe the structure and avionics architecture of the Mars quadcopter. Then, we present the hardware and software design of the guidance, navigation, and control (GNC) system to illustrate the autonomous flight control method. Finally, we introduce the deployment mechanism of the Mars quadcopter.

Modeling and experimental study on orientation dynamics of a Mars rotorcraft with swashplate mechanism

The Mars rotorcraft is an auxiliary aerial exploration platform to expand the rovers' patrol range. Attitude control is a fundamental aspect of autonomous flight control. So far, there has been no detailed investigation of the orientation dynamics of the rotor in the Martian atmosphere. A swashplate mechanism for manipulating isolated rotors is proposed to control the blade pitch angle, whose kinematics equation is established based on the closed condition of space vectors. Considering the blade as a rigid beam flapping around a central hinge, the flapping equation of the hingeless rotor is established to analyze the aerodynamic load for orientation adjusting. The Mars rotorcraft orientation dynamics model is constructed to develop an attitude control algorithm by combining the swashplate kinematics equation and the rotor flapping equation. The orientation experiment is conducted to verify the theoretical model and investigate the response law of the body's heading angle to the cyclic pitch input. The experimental results indicate that the attitude response is more sensitive to the blade pitch angle input under a smaller collective pitch angle or a higher rotor speed. The rigid rotor hypothesis may be unsuitable for the case where the collective pitch angle is smaller than 22°. The hovering flight tests prove that the orientation dynamics model proposed in this paper can effectively support the development of the Mars rotorcraft attitude control system.

Oil & Gas Operations are Taking Off with Drone Technology

Drones have redefined the way the oil & gas businesses is doing aerial exploration, surveys, inspections and a multitude of tasks by providing a swifter and safer operations that are saving the industry millions of dollars in extended shutdowns.

Fast Active Aerial Exploration for Traversable Path Finding of Ground Robots in Unknown Environments

This article proposes an autonomous aerial exploration framework for traversable path finding of ground robots in unknown environments to achieve a fast response in search and rescue (SAR) missions. Different from existing works, our method provides a task-oriented active exploration strategy that makes the aerial robot fully autonomous during the exploration and does not require human intervention. To identify the candidate regions which ground robots can go through, a fast incremental traversability estimation algorithm is presented, which can evaluate the traversability of the region of interest (ROI) efficiently. Based on the traversability map, we propose a highly efficient frontier detection algorithm that can guarantee both reachability and safety of the extracted frontiers. To reduce the total response time of the whole robot system, a new cost function considering both the time costs of the aerial and ground robots is designed that aims to avoid back-and-forth motion behavior during aerial exploration. The performance of our approach is evaluated in both simulation and real-world experiments. The results show that the proposed method outperforms existing methods in terms of traversability estimation and frontier detection time (about one order of magnitude faster) as well as the response time (at least 13% shorter on average).

Дослідження методів стабілізації відео та будови гіростабілізованих підвісів відеокамер для безпілотних літальних пристроїв

The goal of this paper was to research the construction of gyro-stabilized video camera suspensions for drones used for mechanical video stabilization during video monitoring or aerial exploration. The quality of the image received from the drone depends on the quality of the video stabilization, and therefore the amount of useful information received. There are two main groups of video stabilization methods: optical-mechanical and digital stabilization. In order to maximize the quality of the image from the video camera of the unmanned aerial vehicle and to minimize the effects of camera shake, it is necessary to first perform mechanical-optical video stabilization, and then, if necessary, supplement it with digital stabilization. Only digital stabilization without mechano-optical is performed only for the purpose of making the drone cheaper. Optical-mechanical stabilization is usually based on gyroscope readings. In this work, comparative research of the following methods of mechanical stabilization of video from drones was conducted: based on 3-axis and 2-axis gyro-stabilized suspensions with one microcontroller and based on gyro-stabilized suspensions with encoders and several microcontrollers. Mechanical stabilization, in addition to leveling the position of the camera when maneuvering the drone, allows you to turn the camera to a convenient viewing angle for the operator of a drone. 2-axis and 3-axis suspensions with one microcontroller have become the most popular because of their convenience and practicality. 1-axis suspensions or rigidly fixed cameras are used less often. Rigidly fixed cameras are used as course guides for orientation in space by the operator of a drone. That is, such a camera makes it possible to understand the deviation of the drone from the horizon and to adjust the command to the operator for correct flight. Rigid cameras are also used on drones for drone racing competitions. A modular system based on magnetic encoders and several microcontrollers is just beginning to develop, but such a system has a number of advantages, although it is more complicated and expensive. The system provides high accuracy and reliability of stabilization. Each module of the system performs its task. In this way, the resources of microcontrollers are distributed. But its main feature is maintaining the position of the axis rotors relative to the encoder readings. This makes it possible to react very precisely to dynamic actions on the system during active maneuvering of the drone.

A Three Dimensional MIMO Channel Model for Unmanned Aerial Vehicle in Urban Environments

Increasing the availability of Unmanned Aerial Vehicles (UAV's) platforms leads to a variety of applications for aerial exploration, surveillance, and transport. Many of these applications rely on the communication between the UAV and the ground receiver which is subjected to high mobility that may lead to restrictions on link connectivity and throughput. In order to design high throughput and efficient communication schemes for these scenarios, a deep understanding of the communication channel behavior is required, especially taking into account measurement data from flight experiments. Channel propagation in urban environments involves diffraction effects which modify the Line-of-Sight (LoS) contribution of the total received signal, especially when the receiver is located on the ground. This process leads to scenarios where Multiple-Input Multiple-Output (MIMO) signal processing can take advantage from this situation. In this context, the goal of this paper is to study the diffraction effects of the LoS component through spatial correlation metrics of the signal. To accomplish this, we propose the use of a geometric stochastic technique to model the channel behavior which lies between High Altitude Platforms (HAP) and terrestrial link communications.

Path Planning for Indoor UAV Using A* and Late Acceptance Hill Climbing Algorithms Utilizing Probabilistic Roadmap

The main objective of an unmanned aerial vehicle (UAV) path planning is to generate a flight path that links a start point to an endpoint in an indoor space avoiding obstacles. Path planning is essential for many real-life applications such as an autonomous car, surveillance mission, farming robots, unmanned aerial vehicles package delivery, space exploration, and many others. To create an optimal path, we need to adopt a specific criterion to minimize the distance the UAV must travel such as the Euclidean distance. In this paper, we provide our initial idea of creating an optimal path for indoor UAV using both A* and the Late Acceptance Hill Climbing (LAHC) algorithms. We are adopting an indoor search environment with various complexity and utilize the Probabilistic Roadmap algorithm (PRM) as a search space for both algorithms. The basic idea following PRM is to generate random sample points in the space and search these points for an optimal path. The developed results show that the LAHC algorithm outperforms the A* algorithm.

Analysis of Primary Field Shielding Stability for the Weak Coupling Coil Designs

As an electromagnetic field conversion tool in the transient electromagnetic method (TEM), the weak coupling coils reduce the mutual inductance of its transmitter and receiver coils by special structural optimization, so the detection signal can be protruded from the primary field interference generated by the transmitter coil; thus, this kind of coil design can significantly improve the signal-to-noise ratio. However, with the popularity of drag or aerial TEM exploration, the structural stability problem caused by bumps or windage leads to non-negligible primary field leakages, thereby reducing the detection reliability. This paper incorporates the primary field shielding stability as a key indicator of the weak coupling designs and proposes a calibration scheme for this stability assessment, based on which the shielding stability of five typical weak coupling coil designs is quantitatively compared, and the relationship between the primary field density and the shielding stability explored in this study may contribute to the selection and improvement of TEM coils.

High-Level Teleoperation System for Aerial Exploration of Indoor Environments.

Exploration of challenging indoor environments is a demanding task. While automation with aerial robots seems a promising solution, fully autonomous systems still struggle with high-level cognitive tasks and intuitive decision making. To facilitate automation, we introduce a novel teleoperation system with an aerial telerobot that is capable of handling all demanding low-level tasks. Motivated by the typical structure of indoor environments, the system creates an interactive scene topology in real-time that reduces scene details and supports affordances. Thus, difficult high-level tasks can be effectively supervised by a human operator. To elaborate on the effectiveness of our system during a real-world exploration mission, we conducted a user study. Despite being limited by real-world constraints, results indicate that our system better supports operators with indoor exploration, compared to a baseline system with traditional joystick control.

Active Autonomous Aerial Exploration for Ground Robot Path Planning

We address the problem of planning a path for a ground robot through unknown terrain, using observations from a flying robot. In search and rescue missions, which are our target scenarios, the time from arrival at the disaster site to the delivery of aid is critically important. Previous works required exhaustive exploration before path planning, which is time-consuming but eventually leads to an optimal path for the ground robot. Instead, we propose active exploration of the environment, where the flying robot chooses regions to map in a way that optimizes the overall response time of the system, which is the combined time for the air and ground robots to execute their missions. In our approach, we estimate terrain classes throughout our terrain map, and we also add elevation information in areas where the active exploration algorithm has chosen to perform 3-D reconstruction. This terrain information is used to estimate feasible and efficient paths for the ground robot. By exploring the environment actively, we achieve superior response times compared to both exhaustive and greedy exploration strategies. We demonstrate the performance and capabilities of the proposed system in simulated and real-world outdoor experiments. To the best of our knowledge, this is the first work to address ground robot path planning using active aerial exploration.

Localization of Suborbital Vehicle Using On-Board Map and Camera Image

Recently, unmanned aerial exploration of planets is an emerging field of interest for researchers all over the world. One of the major challenges that lie in the exploration aircraft is its localization in an environment where there is no useful navigation system like GPS. Although several localization algorithms were proposed, like SURF and SIFT, they suffer from premature convergence in an unknown and harsh terrain atmosphere (using satellite image mapping). The aim of this research is to develop a localization algorithm to detect the optimum features from the video, obtained onboard, and performs fast feature mapping of the features with the satellite image. The features are then mapped to the exact location on the database image and the path of the kite plane is obtained on the database image using RANSAC. The localization algorithm was evaluated in flight experiments using a kite plane. The experimental result of the algorithm showed localization of the aircraft using OpenCV (using CPP Console). The experimental results showed that the proposed algorithm (LAIGDE) outperforms the traditional mapping techniques like SURF with high accuracy and robustness.

Medieval and Ottoman period (14th–17th c.) Archaeology in the Drava River region, Hungary

The paper is a short summary of the main archaeological outcomes of an interdisciplinary project in a section of the Drava river crossing the territory of Somogy county, in Hungary. One of the study areas is the vicinity of Berzence where medieval settlement patterns, land use and economy have been reconstructed on the basis of historical sources and an archaeological field survey. A comprehensive review of architectural history and material culture of the Ottoman Period stronghold in Barcs was the other area under investigation. Research there was based on written sources and the archaeological assemblage recovered from the palisaded fort. Zooarchaeological research at this site revealed some significant culture historical aspects of this stronghold. Underwater archaeological investigations carried out in the Drava river itself and aerial exploration of the study areas also supplied valuable archaeological results.

Ethanol Perinatal Exposure Induces Behavioral Alterations and Ethanol Preference in Adolescent Wistar Rats

Ethanol-perinatally-exposed (EPE) Wistar rats show central nervous system morphological alterations that persist until adulthood. The aim of this work was to study whether adolescent EPE rats present alterations in behavior and develop ethanol (EtOH) preference. For behavioral analyses, locomotor and exploratory activity, anxiety and long-term memory standardized tests were performed on 40 to 45 day- old male rats. Another group of rats chose to drink between EtOH and water using the model of preference between two bottles, one with EtOH 6% v/v and the other with water. During eight weeks, the volume of EtOH consumed/kg/day was registered and blood EtOH concentration was determined at the end of the experiment. Results in EPE rats show a decrease in aerial exploration and anxiety, while locomotor activity and long-term memory were not affected. Both male and female EPE rats preferred EtOH earlier than control rats, showing a highest level of blood EtOH concentration.

Gas source localization with a micro-drone using bio-inspired and particle filter-based algorithms

Gas source localization (GSL) with mobile robots is a challenging task due to the unpredictable nature of gas dispersion, the limitations of the currents sensing technologies, and the mobility constraints of ground-based robots. This work proposes an integral solution for the GSL task, including source declaration. We present a novel pseudo-gradient-based plume tracking algorithm and a particle filter-based source declaration approach, and apply it on a gas-sensitive micro-drone. We compare the performance of the proposed system in simulations and real-world experiments against two commonly used tracking algorithms adapted for aerial exploration missions.

Using Clustering and Metric Learning to Improve Science Return of Remote Sensed Imagery

Current and proposed remote space missions, such as the proposed aerial exploration of Titan by an aerobot, often can collect more data than can be communicated back to Earth. Autonomous selective downlink algorithms can choose informative subsets of data to improve the science value of these bandwidth-limited transmissions. This requires statistical descriptors of the data that reflect very abstract and subtle distinctions in science content. We propose a metric learning strategy that teaches algorithms how best to cluster new data based on training examples supplied by domain scientists. We demonstrate that clustering informed by metric learning produces results that more closely match multiple scientists’ labelings of aerial data than do clusterings based on random or periodic sampling. A new metric-learning strategy accommodates training sets produced by multiple scientists with different and potentially inconsistent mission objectives. Our methods are fit for current spacecraft processors (e.g., RAD750) and would further benefit from more advanced spacecraft processor architectures, such as OPERA.

Mission Planning and Modeling Analysis for Unmanned Aerial Exploration Vehicle on Mars

With the development of socio-economy and technology,more and more people from various countries pay more attention to deep-space exploration.Mars is the closest planet where life is possible.So,Mars exploration is a hot issue on international deep space exploration in recent years.There are many advantages for the use of unmanned aerial exploration vehicles on Mars, including the wide range of exploration,the visualization of terrain changes,etc.In this paper, the overall mission planning is described for unmanned aerial exploration vehicle on Mars,and the difference between flight on earth and on Mars is discussed.Then the longitudinal nonlinear model is established for unmanned aerial exploration vehicle on Mars,and Taylor expansion is applied to the nonlinear model at the trim point,hence to obtain the linear model.By further analysis of the linear model,the stable performance and flight characteristics have been grasped for unmanned aerial exploration vehicle on Mars.These work will provide the platform for the follow-up research for Mars Unmanned Aerial Vehicle(UAV) navigation and control method.

Remote sensing activities in Japan

Abstract Remote sensing activities in Japan are reviewed under three sectors; the government, private and universities. International activities are also reviewed. The largest governmental activity is the launch of earth observation satellite by National Space Development Agency (NASDA). Apart from that, remote sensing technology is utilized in many government research institutes. The first level activities in private companies are research, design and development of rockets, spacecrafts, sensors and receiving stations which are carried out by five big electronic companies. Aerial survey companies and oil exploration companies are presently utilizing technology of remote sensing. University professors are bearing the responsibility for research and education as well as advising the government and private companies.

A espectrometria de raios gama na prospeccao de sulfetos em rochas alteradas hidrotermalmente

Potassium is added in the hydrothermally altered rocks by the percolating solutions, in a sufficient quantity to be detected by surface or aerial spectrometry. The current models for alteration zoning explain the high potassium content. The Gamma-Ray Spectrometry is an useful geophysical method in the aerial exploration for disseminated or massive sulphide deposits of hydrothermal origin, as it was again proved in Camaqua area, South Brazil.

A ESPECTROMETRIA DE RAIOS GAMA NA PROSPECÇÃO DE SULFETOS EM ROCHAS ALTERADAS HIDROTERMALMENTE

Potassium is added in the hydrothermally altered rocks by the percolating solutions, in a sufficient quantity to be detected by surface or aerial spectrometry. The current models for alteration zoning explain the high potassium content. The Gamma-Ray Spectrometry is an useful geophysical method in the aerial exploration for disseminated or massive sulphide deposits of hydrothermal origin, as it was again proved in Camaquã area, South Brazil.

Air-Borne Magnetometers for Search and Survey

Air-borne magnetometers developed during the war for the detection of submerged enemy submarines now have become important tools for aerial geophysical exploration. The instruments described utilize the second harmonic outputs produced by the magnetic field in saturated core inductors for field measurement and for control of servo stabilizing systems acting around two axes to maintain the measuring element in alignment with the earth's field. The field to be measured is compared continuously with that produced in the measuring inductor, winding by an accurately controlled direct current. The sensitive element usually is towed in a bombshaped bird sufficiently removed from the airplane to escape the effects of its magnetic field. A continuous record is produced which, when keyed with position records obtained by photography or shoran, may be used in the preparation of maps of total magnetic field intensity.