6,645 research outputs found

    Multi-Level Sensory Interpretation and Adaptation in a Mobile Cube

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    Signals from sensors are often analyzed in a sequence of steps, starting with the raw sensor data and eventually ending up with a classification or abstraction of these data. This paper will give a practical example of how the same information can be trained and used to initiate multiple interpretations of the same data on different, application-oriented levels. Crucially, the focus is on expanding embedded analysis software, rather than adding more powerful, but possibly resource-hungry, sensors. Our illustration of this approach involves a tangible input device the shape of a cube that relies exclusively on lowcost accelerometers. The cube supports calibration with user supervision, it can tell which of its sides is on top, give an estimate of its orientation relative to the user, and recognize basic gestures

    Design enhancements of the smart sediment particle for riverbed transport monitoring

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    This paper discusses new enhancements that are being made to the existing ‘Smart Sediment Particle’. The smart sediment particle has been designed and implemented to track its own 3-dimensional trajectory when placed in a riverbed. This device serves as a tool to detect sedimentation in rivers. The device has been developed over the years, with its size diminishing significantly down to a sphere of 2cm radius. The readings obtained from the pebble are accurate and match well with other independent motion sensor readings. Currently a novel IPT (Inductive Power Transfer) based power supply is being integrated to this device, to charge it wirelessly, when it has been extracted from the water. A new low power, miniaturized microcontroller has been introduced to minimize the power consumption and the PCB real estate of the device. The paper discusses these new enhancements in detail and also other potential enhancements such as error compensation and wireless data transfer

    Survey of Inter-satellite Communication for Small Satellite Systems: Physical Layer to Network Layer View

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    Small satellite systems enable whole new class of missions for navigation, communications, remote sensing and scientific research for both civilian and military purposes. As individual spacecraft are limited by the size, mass and power constraints, mass-produced small satellites in large constellations or clusters could be useful in many science missions such as gravity mapping, tracking of forest fires, finding water resources, etc. Constellation of satellites provide improved spatial and temporal resolution of the target. Small satellite constellations contribute innovative applications by replacing a single asset with several very capable spacecraft which opens the door to new applications. With increasing levels of autonomy, there will be a need for remote communication networks to enable communication between spacecraft. These space based networks will need to configure and maintain dynamic routes, manage intermediate nodes, and reconfigure themselves to achieve mission objectives. Hence, inter-satellite communication is a key aspect when satellites fly in formation. In this paper, we present the various researches being conducted in the small satellite community for implementing inter-satellite communications based on the Open System Interconnection (OSI) model. This paper also reviews the various design parameters applicable to the first three layers of the OSI model, i.e., physical, data link and network layer. Based on the survey, we also present a comprehensive list of design parameters useful for achieving inter-satellite communications for multiple small satellite missions. Specific topics include proposed solutions for some of the challenges faced by small satellite systems, enabling operations using a network of small satellites, and some examples of small satellite missions involving formation flying aspects.Comment: 51 pages, 21 Figures, 11 Tables, accepted in IEEE Communications Surveys and Tutorial

    Integrating Multiple 3D Views through Frame-of-reference Interaction

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    Frame-of-reference interaction consists of a unified set of 3D interaction techniques for exploratory navigation of large virtual spaces in nonimmersive environments. It is based on a conceptual framework that considers navigation from a cognitive perspective, as a way of facilitating changes in user attention from one reference frame to another, rather than from the mechanical perspective of moving a camera between different points of interest. All of our techniques link multiple frames of reference in some meaningful way. Some techniques link multiple windows within a zooming environment while others allow seamless changes of user focus between static objects, moving objects, and groups of moving objects. We present our techniques as they are implemented in GeoZui3D, a geographic visualization system for ocean data

    Implementation of an Extended Kalman Filter Using Inertial Sensor Data for UAVs During GPS Denied Applications

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    Unmanned Aerial Vehicles (UAVs) are widely used across the industry and have a strong military application for defense. As UAVs become more accessible so does the increase of their applications, now being more limited by one’s imagination as opposed to the past where micro electric components were the limiting factor. Almost all of the applications require GPS or radio guidance. For more covert and longer range missions relying solely on GPS and radio is insufficient as the Unmanned Aerial System is vulnerable to malicious encounters like GPS Jamming and GPS Spoofing. For long range mission GPS denied environments are common where loss of signal is experienced. For autonomous flight GPS is a fundamental requirement. In this work an advanced inertial navigation system is proposed along with a programmable Pixhawk flight controller and Cube Black autopilot. A Raspberry Pi serves as a companion computer running autonomous flight missions and providing data acquisition. The advancement in inertial navigation comes from the implementation of a high end Analog Devices’ IMU providing input to an Extended Kalman Filter (EKF) to reduce error associated with measurement noise. The EKF is a efficient recursive computation applying the least-squares method. UAS flight controller simulations and calibrations were conducted to ensure the expected flight capabilities were achieved. The developed software and hardware was implemented in a Quadcopter build to perform flight test. Flight test data were used to analyze the performance post flight. Later, simulated feedback of the inertial navigation based state estimates (from flight test data) is performed to ensure reliable position data during GPS denied flight. The EKF applied to perform strapdown navigation was a limited success at estimating the vehicles’ inertial states but only when tuned for the specific flight trajectory. The predicted position was successfully converted to GPS data and passed to the autopilot in a LINUX based simulations ensuring autonomous mission capability is maintainable in GPS denied environments. The results from this research can be applied with ease to any vehicle operating with a Pixhawk controller and a companion computer of the appropriate processing capability

    Toward a Memory Model for Autonomous Topological Mapping and Navigation: the Case of Binary Sensors and Discrete Actions

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    We propose a self-organizing database for per- ceptual experience capable of supporting autonomous goal- directed planning. The main contributions are: (i) a formal demonstration that the database is complex enough in principle to represent the homotopy type of the sensed environment; (ii) some initial steps toward a formal demonstration that the database offers a computationally effective, contractible approximation suitable for motion planning that can be ac- cumulated purely from autonomous sensory experience. The provable properties of an effectively trained data-base exploit certain notions of convexity that have been recently generalized for application to a symbolic (discrete) representation of subset nesting relations. We conclude by introducing a learning scheme that we conjecture (but cannot yet prove) will be capable of achieving the required training, assuming a rich enough exposure to the environment. For more information: Kod*La
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