Ground Reconnaissance Research Articles

Color-polarization synergistic target detection method considering shadow interference

Aiming at the problem of shadow interference in UAV's ground reconnaissance, a color and polarization synergistic target detection method is proposed for anti-shadow interference, based on the influence of two physical characteristics (wavelength and polarization) under different illuminations. A valid fusion strategy is proposed via integrating two separate detection results on color and polarization images. Moreover, a local enhancement and recognition module (LER) is introduced to boost the performance. Based on our built dataset, experimental results show that our method achieves mAP of 87.76%, and 12.37% higher than that of color image and 14.68% higher than that of polarization image.

Monitoring of simulated clandestine graves of victims using UAVs, GPR, electrical tomography and conductivity over 4-8 years post-burial to aid forensic search investigators in Colombia, South America

In Colombia there are estimated to be over 121,000 missing people and victims of forced disappearances. Forensic investigators therefore need assistance in determining optimal detection techniques for buried victims, to give victims’ families closure and for the wider community to see that justice is being served. Previous research has created 12 controlled simulated clandestine graves of typical Colombian murder victim scenarios at 0.5 m – 1.2 m depths in savannah and rainforest sites in Colombia. The 0–3 years of geophysical monitoring results of were published, with this paper reporting on 4–8 years monitoring of both UAV drone results and geophysical data. The UAV results from the year 8 survey, published for first time from Colombia, showed that the simulated graves could still be located using NDVI and NIR multi-spectral data, but not using optical or other multi-spectral data. The 0–3 years of geophysical data found the simulated clandestine graves could be detected with electrical resistivity and GPR methods, with the 4–8 year surveys evidencing that they could still be detected using bulk ground conductivity surveys, GPR horizontal time slice datasets and 2D ERT profiles. Research implications suggest initial use of UAV remote sensing technology to pinpoint likely search areas, before subsequent ground reconnaissance, geophysical surveys and their interpretation, before intrusive investigation methods are employed for detecting missing and disappeared persons in Colombia.

A spanning tree algorithm with adaptive pruning with low redundancy coverage rate

In reality, when UAV is used in region reconnaissance, the shape of region is usually irregular. Selecting an algorithm to find a complete coverage path with smaller coverage redundancy rate, lower path motion complexity and theoretical energy consumption has certain research significance for the complete coverage path planning (CCPP). In existing algorithms, there is always a high redundant coverage rate under irregularly shaped regions. The motion complexity and the theoretical energy consumption of the path also increase. In this paper, a kind of spanning tree with adaptive pruning (STAP) algorithm based on the grid map is proposed to solve the above problems: on the one hand, it uses a greedy growth strategy to determine the branching growth direction, and proposes an adaptive pruning method for self-optimization of the initial path; on the other hand, a kind of nearest neighbor sub-region connection rule of adjacent paths is proposed to reduce the complexity and the coverage redundancy rate. The STAP algorithm searches for all grid centers, grows, and optimizes the spanning tree by creating paths between the centers. At the end of the optimization, it creates a complete coverage path based on the distribution of the spanning tree. Experiments show that when the STAP algorithm is applied to unobstructed regions, it plans the path with the lowest redundant coverage rate, which reaches 2.6296% and 4.9402%; when it is applied to the regions include obstacles, the advantages of the algorithm are more significant: On the one hand, the path planned by STAP has the least total length, the lowest number of turning and turning back. On the other hand, the redundant coverage rate of the path is still the lowest, reaching 4.1362% and 2.7765%, respectively. The STAP is primarily suitable for situations about CCPP under grid maps formed by irregularly shaped regions, and it holds certain significance for ground reconnaissance of UAVs.

Image Stitching Based on Color Difference and KAZE with a Fast Guided Filter

Image stitching is of great importance for multiple fields such as moving object detection and tracking, ground reconnaissance and augmented reality. To ameliorate the stitching effect and alleviate the mismatch rate, an effective image stitching algorithm based on color difference and an improved KAZE with a fast guided filter is proposed. Firstly, the fast guided filter is introduced to reduce the mismatch rate before feature matching. Secondly, the KAZE algorithm based on improved random sample consensus is used for feature matching. Then, the color difference and brightness difference of the overlapping area are calculated to make an overall adjustment to the original images so as to improve the nonuniformity of the splicing result. Finally, the warped images with color difference compensation are fused to obtain the stitched image. The proposed method is evaluated by both visual effect mapping and quantitative values. In addition, the proposed algorithm is compared with other current popular stitching algorithms. The results show that the proposed algorithm is superior to other algorithms in terms of the quantity of feature point pairs, the matching accuracy, the root mean square error and the mean absolute error.

Active Disturbance Rejection Terminal Sliding Mode Control for Tele-Aiming Robot System Using Multiple-Model Kalman Observers

This study proposes a tele-aiming control strategy for the ground reconnaissance robot to track the maneuvering target rapidly in the presence of dynamic uncertainties, sensory measurement noises, and time-varying external disturbances. First, the tele-aiming control trajectory generated by human–computer interaction (HCI) device is filtered with a tracking differentiator and a recursive average filter. Second, the inertial impact force disturbance generated by maneuvering tele-aiming control jointly with the other uncertainties (e.g., internal friction, modeling error, etc.) is considered as a lumped disturbance, and then a novel multiple-model augmented-state extended Kalman observer (MEKO) is designed, capable of filtering out the joint measurement noises and estimating the lumped disturbance simultaneously. Lastly, a nonsingular terminal sliding mode controller is applied to eliminate the lumped disturbance and control the joints to track the corresponding desired joint trajectory. To verify the tele-aiming control performance, the random trajectory tracking experiments are designed to simulate the tele-aiming tracking control of maneuvering targets. As indicated from the experimental results, the proposed control strategy is capable of significantly suppressing the effect of inertial impact force disturbance and joint measurement noises, and achieving fast and stable tele-aiming control.

Analytical design and performance analysis of LEO mega chain satellite constellation

With the development of microsatellite technology and the growth of ground reconnaissance demand, the rapid design of a LEO constellation with minimum satellite number, low revisit time (within 10 minutes), and permanent inter-satellite links has become a hotspot and difficulty in constellation design. Aiming at the problem to use the minimum satellite number to achieve low revisit time coverage, a LEO (low earth orbit) Walker-chain constellation and its design method is proposed. The difference between the chain constellation and the classical Walker constellation is that it has one or more closed chain configurations. According to the coverage requirements and sensor field of view angle, the analytical design method is derived. A LEO chain constellation containing 132 satellites is designed for the ground reconnaissance mission. Comparing with the classical Walker-δ constellation and repeat ground track constellation, the chain constellation has fewer satellites, lower revisit time and the permanent inter-satellite links.

СТАРОВЛАШКЕ НАХИЈЕ БОБОЉ И ОСТАТИЈА (15–18. ВЕК) THE DISTRICTS OF BOBOLJ AND OSTATIJA IN STARI VLAH (15 TH - 18TH CENTURY)

The paper relies on a comparative study of Ottoman sources and archaeological ground reconnaissance. Owing to a multidisciplinary approach, old settlements were located, such as Bobolj and the largest settlement in Golija – Ravništa. The remains of several religious and economic buildings were also identified. The majority of churches were approximately dated, and the ktetor of the Pridvorica monastery was determined. The paper presents the development and characteristics of the mountain settlements, the origin and dynamics of the population, specific status of the Stari Vlah inhabitants, and the most commonplace economic activities. The rare defter of old and new estate owners from 1708 sheds more light on the rebellion in Golija from 1688, the scope of suffering and migration in the Great Migration, as well as the religious and social structure of new owners. A part of the paper is devoted to the found material remains.

Comparison of Flight Height Controlled UAV and Ground Vector Magnetometer Survey Data Covering an Urban Landfill

An autonomous UAV-mounted 3-axis fluxgate vector magnetometer (FVM) was flown over a Golden, Colorado landfill to test map buried ferromagnetic objects and infrastructure. The flights test terrain following flight control software using active GNSS positioning over a fixed 1-meter (m) resolution LiDAR control surface, at slung sensor clearances that approach ground survey sensor heights. The FVM was first walked over the landfill with the sensor at a constant 2 m above the surface, to provide a high-resolution ground survey dataset for comparison. Both the UAV and ground FVM data are scalar calibrated on the ground through a full sphere to return error corrected and 360⁰ maneuver compensated total magnetic intensity (TMI). The comparison also includes UAV downward and ground survey upward continuation filtered (DCF and UCF) TMI respectively, to put the two surveys on approximately the same levels, providing two inverse-distance-magnetic-source viewpoints for both surveys, one at ground level and one at UAV level. The UAV survey DCF results indicate that low level flights might be considered as a replacement for coarser reconnaissance ground TMI surveys in some mapping situations. Lastly, the ground and UAV survey calibration data statistics are reviewed, and the FVM survey TMI images are compared with each other. These in turn, are compared with a highresolution alkali-vapor scalar magnetometer (AVM) benchmark TMI survey, walked on the same lines as the FVM. The AVM provides a reference standard to compare with both FVM surveys.

Rapid characterisation of landslide heterogeneity using unsupervised classification of electrical resistivity and seismic refraction surveys

The characterisation of the subsurface of a landslide is a critical step in developing ground models that inform planned mitigation measures, remediation works or future early-warning of instability. When a landslide failure may be imminent, the time pressures on producing such models may be great. Geoelectrical and seismic geophysical surveys are able to rapidly acquire volumetric data across large areas of the subsurface at the slope-scale. However, analysis of the individual model derived from each survey is typically undertaken in isolation, and a robust, accurate interpretation is highly dependent on the experience and skills of the operator. We demonstrate a machine learning process for constructing a rapid reconnaissance ground model, by integrating several sources of geophysical data in to a single ground model in a rapid and objective manner. Firstly, we use topographic data acquired by a UAV survey to co-locate three geophysical surveys of the Hollin Hill Landslide Observatory in the UK. The data are inverted using a joint 2D mesh, resulting in a set of co-located models of resistivity, P-wave velocity and S-wave velocity. Secondly, we analyse the relationships and trends present between the variables for each point in the mesh (resistivity, P-wave velocity, S-wave velocity, depth) to identify correlations. Thirdly, we use a Gaussian Mixture Model (GMM), a form of unsupervised machine learning, to classify the geophysical data into cluster groups with similar ranges and trends in measurements. The resulting model created from probabilistically assigning each subsurface point to a cluster group characterises the heterogeneity of landslide materials based on their geophysical properties, identifying the major subsurface discontinuities at the site. Finally, we compare the results of the cluster groups to intrusive borehole data, which show good agreement with the spatial variations in lithology. We demonstrate the applicability of integrated geophysical surveys coupled with simple unsupervised machine learning for producing rapid reconnaissance ground models in time-critical situations with minimal prior knowledge about the subsurface.

Simulation and Analysis of a Snow Avalanche Accident in Lower Western Himalaya, India

In Western Himalaya, an average 49 person die every year due to snow avalanche activities and this death rate is very high as compared to other Asian countries. A snow avalanche accident was observed on 5 January 2018 on Chowkibal–Tangdhar (CT) road axis at avalanche site number CT-8 located near Chowkibal village in Kupwara district, union territory Jammu and Kashmir, India. In the present paper, we discuss snow avalanche simulation, the climatic condition, avalanche debris height and length, and suggested solutions to handle avalanche situations. Rapid Mass MovementS numerical model in combination with digital elevation model and potential release area has been used to simulate avalanche accident occurred on 5 January 2018 at CT-8. The analysis demonstrates maximum snow avalanche velocity, impact of pressure and height of flow to be ~ 25 ms−1, ~ 9.39 × 104 kgm−1 s−2, and ~ 3.0 m respectively on 5 January 2018 at CT-8. Further simulated avalanche debris height and length form road has been validated with ground observed data. Ground reconnaissance of the location was conducted by a team of Snow and Avalanche Study Establishment, Chandigarh and it has been observed that lack of ‘avalanche awareness and Standard Operating Procedures during movement in avalanche prone areas’ among the travellers on the road cause accident . The present paper seems to be first to investigate snow avalanche accident in Western Himalaya and recommend that proper campaigning of avalanche awareness among the people residing in avalanche prone areas of Himalaya could reduce such accidents significantly.

Дистанционное зондирование в изучении поселений позднего бронзового века в Северо-Западном Крыму

The article is devoted to the results of applying a comprehensive interdisciplinary methodology combining remote sensing methods, GIS, geophysical and archaeological research the Late Bronze for revealing and investigation of the Late Bronze Age settlements in the North-Western Crimea. The discovery of these settlements causes a certain difficulty, since they are buried under a layer of soil and do not have direct visual signs. A comprehensive step-by-step method of non-destructive remote sensing was developed, including the analysis of high-resolution satellite images in the Google Earth Pro resource, identifying promising areas by plant and landscape features, creating GPS routes for ground reconnaissance, geophysical surveys (magnetic and electromagnetic) on promising areas for identifying Late Bronze Age settlements, GPS mapping of surface material, point archaeological sounding. All the results obtained are placed in a special geo-information system, the substrate layers of which are detailed topographic, soil, geological, hydrogeological, digital relief maps. As a result, 48 new settlements of the Late Bronze Age were identified, including 19 settlements with double stone pens. These pens were first discovered only with help of remote sensing methods, especially magnetic surveying. The final answer about the existence and layout of the settlement of the Late Bronze Age before the archaeological excavations is given only by magnetic and electromagnetic surveys. The GIS created on the monuments of the Late Bronze Age in the North-Western Crimea will serve both scientific purposes and to preserve the cultural heritage of the Republic of Crimea, which is especially important in conditions of rapid economic development of land and the construction of trunk roads.

A New Disaster Information Sensing Mode: Using Multi-Robot System with Air Dispersal Mode.

This paper presents a novel sensing mode for using mobile robots to collect disaster ground information when the ground traffic from the rescue center to disaster site is disrupted. Traditional sensing modes which use aerial robots or ground robots independently either have limited ability to access disaster site or are only able to provide a bird’s eye view of the disaster site. To illustrate the proposed sensing mode, the authors have developed a Multi-robot System with Air Dispersal Mode (MSADM) by combining the unimpeded path of aerial robots with the detailed view of ground robots. In the MSADM, an airplane carries some minimal reconnaissance ground robots to overcome the paralyzed traffic problem and deploys them on the ground to collect detailed scene information using parachutes and separation device modules. In addition, the airplane cruises in the sky and relays the control and reported information between the ground robots and the human operator. This means that the proposed sensing mode is able to provide more reliable communication performance when there are obstacles between the human operators and the ground robots. Additionally, the proposed sensing mode can easily make use of different kinds of ground robots, as long as they have a compatible interface with the separation device. Finally, an experimental demonstration of the MSADM is presented to show the effectiveness of the proposed sensing mode.

Model of Optimal Cooperative Reconnaissance and its Solution using Metaheuristic Methods

<p>The model of optimal cooperative reconnaissance as a part of the tactical decision support system to aid commanders in their decision-making processes is presented. The model represents one of the models of military tactics implemented in the system to plan the ground reconnaissance operation for the commander optimally. The main goal of the model is to explore the area of interest by multiple military elements (scouts, UAVs, UGVs) as quickly as possible. A metaheuristic solution to this problem which combines two probabilistic methods: simulated annealing and the ant colony optimisation algorithm is proposed. In the first part of this study, the optimal cooperative reconnaissance problem is formulated. Then, metaheuristic solution, which is composed of three independent steps, is presented. Finally, experiments are conducted to verify the approach to this problem.</p>

Arquitectura troglodítica durante el siglo XX en Almería

The few studies on modern and contemporary housing in the province of Almeria have focused their interest on the most successful urban and building developments, having overshadowed other residential episodes without which the local reality is perceived misleading and incomplete, as the case of the underground architecture, which requires deepening its evolution and scope in the last century. The methodology followed is based on consulting census, inventories, registers, newspaper reports, files of Public Administrations, Rural Development Associations and other organizations, in addition to ground reconnaissance with an enough representative sampling of visits and interviews. Thus, after contextualizing the phenomenon, the results obtained allow to deduce both its territorial and social relevance as the slow, but progressive, change of consideration in recent decades in favour of a habitat that has been claimed as an intrinsic part of the heritage and cultural legacy.

Methods for monitoring land subsidence and earth fissures in the Western USA

Abstract. Depletion of groundwater resources in many deep alluvial basin aquifers in the Western USA is causing land subsidence, as it does in many regions worldwide. Land subsidence can severely and adversely impact infrastructure by changing the ground elevation, ground slope (grade) and through the development of ground cracks known as earth fissures that can erode into large gullies. Earth fissures have the potential to compromise the foundations of dams, levees, and other infrastructure and cause failure. Subsequent to an evaluation of the overall subsidence experienced in the vicinity of subsidence-impacted infrastructure, a detailed investigation to search for earth fissures, and design and/or mitigation of potentially effected infrastructure, a focused monitoring system should be designed and implemented. Its purpose is to provide data, and ultimately knowledge, to reduce the potential adverse impacts of land subsidence and earth fissure development to the pertinent infrastructure. This risk reduction is realized by quantifying the rate and distribution of ground deformation, and to detect ground rupture if it occurs, in the vicinity of the infrastructure. The authors have successfully designed and implemented monitoring systems capable of quantifying rates and distributions of ground subsidence and detection of ground rupture at multiple locations throughout the Western USA for several types of infrastructure including dams, levees, channels, basins, roadways, and mining facilities. Effective subsidence and earth fissure monitoring requires understanding and quantification of historic subsidence, estimation of potential future subsidence, delineation of the risk for earth fissures that could impact infrastructure, and motivation and resources to continue monitoring through time. A successful monitoring system provides the means to measure ground deformation, grade changes, displacement, and anticipate and assess the potential for earth fissuring. Employing multiple methods, a monitoring strategy utilizes an integrated approach, including both regional and local measurements. Various methods implemented include conventional practices and proven, instrumented in-ground sensing systems. The conventional techniques include repeat optical levelling and global positioning system (GPS) surveys, ground reconnaissance, photo-geological analysis, groundwater monitoring, and tape-extensometers. Advanced techniques include the processing and interpretation of differential interferograms of repeat-pass, satellite-based synthetic aperture radar data (InSAR), borehole tiltmeters, microseismic arrays, excavation of monitoring trenches, and time-domain reflectometry (TDR).

Activity-specific ecological niche models for planning reintroductions of California condors (Gymnogyps californianus)

Ecological niche models can be a useful tool to identify candidate reintroduction sites for endangered species but have been infrequently used for this purpose. In this paper, we (1) develop activity-specific ecological niche models (nesting, roosting, and feeding) for the critically endangered California condor (Gymnogyps californianus) to aid in reintroduction planning in California, Oregon, and Washington, USA, (2) test the accuracy of these models using empirical data withheld from model development, and (3) integrate model results with information on condor movement ecology and biology to produce predictive maps of reintroduction site suitability. Our approach, which disentangles niche models into activity-specific components, has applications for other species where it is routinely assumed (often incorrectly) that individuals fulfill all requirements for life within a single environmental space. Ecological niche models conformed to our understanding of California condor ecology, had good predictive performance when tested with data withheld from model development, and aided in the identification of several candidate reintroduction areas outside of the current distribution of the species. Our results suggest there are large unoccupied regions of the California condor’s historical range that have retained ecological features similar to currently occupied habitats, and thus could be considered for future reintroduction efforts. Combining our activity-specific ENMs with ground reconnaissance and information on other threat factors that could not be directly incorporated into empirical ENMs will ultimately improve our ability to select successful reintroduction sites for the California condor.

User-Centered Design of an Attitude Aware Controller for Ground Reconnaissance Robots

Warfighter safety can be significantly increased by offloading critical reconnaissance and surveillance missions to robotic assets. The subtleties of these tasks require significant operator involvement--usually carried out locally to the robot's deployment. Human soldiers use gestures to communicate movements and commands when engaged in this type of task. While considerable work has been done with robots visually observing humans to interpret their gestures, we propose a simpler, more field-appropriate system that allows robot operators to use their natural movements and gestures (via inertial measurement units [IMUs]) to teleoperate a robot while reducing the physical, as well as the cognitive, load on the soldier.This paper describes an operator control interface implemented on a smartphone, in contrast to the proprietary robot controllers typically used. The controller utilizes the device's IMUs, or attitude sensors, to bypass the touchscreen while accepting user input via gestures; this addresses a primary concern for gloved users in dirty environments where touchscreens lack reliability. We also propose that it provides a less visually-intense alternative for control, freeing up the soldier's cognitive load toward other functions.We present details of the attitude-based control software, as well as the design heuristics resulting from its iterative build-test-rebuild development. Additionally, results from a set of user studies are presented, showing that as a controller, this technique performs as well, or better than, other screen-based control systems, even when ignoring its advantages to gloved users. Twenty-five users were recruited to assess usability of these attitude-aware controls, testing their suitability for both driving and camera manipulation tasks. Participants drove a small tracked robot on an indoor course using the attitude-aware controller and a virtual [touchscreen] joystick, while metrics regarding performance, mental workload, and user satisfaction were collected. Results indicate that the tilt controller is preferred by 64% of users and performs equally as well, if not better to the alternative, on most performance metrics. These results support the development of a smartphone-based control option for military robotics, with a focus on more physical, attitude-based input methods that overcome deficiencies of current touch-based systems, namely lack of physical feedback, high attention demands, and unreliability in field environments.

Fipa Furnaces and Slag: Distinguishing Criteria Based on Physical Analysis

Excavations and ground reconnaissance in December 2009 at Sumbawanga district, in southwestern Tanzania, revealed complete remains of natural draft iron smelting furnaces locally called ilungu (sing.) or malungu (pl.) standing up to 2.8 - 3.1 m tall. The aim of the study was to identify remains of indigenous African iron smelting furnaces on the landscape of Fipaland, examine the slag from the identified furnaces as very little amount of attention has been paid to furnace structures and analysis of the resultant residues. It has been usually studied in isolation of one of the order, while more attention was paid to furnace types; less has been done on slag analysis; in order to make for more reliable identification and develop a criteria for distinguishing this fast disappearing cultural heritage.

Preliminary Results of the Archaeological Reconnaissance carried out in Atsibi -Wemberta, Eastern Tigray, Ethiopia

Archaeological reconnaissance sponsored by the Authority for Research and Conservation of Cultural Heritage (ARCCH) was conducted under the direction of the author in February 2004 in Atsibi-Wemberta district (Wereda) in eastern Tigray Administrative Zone. The objective of the archaeological ground reconnaissance was to assess the archaeological and tourism potential of the same place and to prepare the ground for future research. The preliminary assessment survey resulted with the discoveries of several settlements, cemeteries and religious sites ascribable to the pre-Aksumite and Aksumite cultures dating to about the middle of the first millennium BC and the first seven centuries AD, respectively. Key words : cemetery, settlement, stelae, Tumulus.

Method for Detecting Regions of Interest and Active Surveillance Assistance in the Mobile Ground Reconnaissance System

Method for Detecting Regions of Interest and Active Surveillance Assistance in the Mobile Ground Reconnaissance System