Positions Of Beacons Research Articles

A BLE beacon global tracking strategy for small robot using an ESP32 beacon system and GPS

This study aims to estimate the position of a small robot in both outdoor and indoor environments using a combination of RSSI-to-distance calculation, trilateration, and MQTT protocol for communication between ESP32 stations and the server. RSSI is utilized to approximate the distance between the ESP32 and the beacon, while trilateration is employed to determine the precise position of the beacon. The ratio of the imaginary circles is calculated by various signal measurement techniques, and the MQTT protocol is used to set up communication between ESP32 stations and the server. Once the beacon device is visible to all three ESP32 modules, trilateration takes place, and the position of the BLE beacon is displayed as a web page. The server collects the largest RSSI values from the nearest three ESP32 stations, and trilateration is performed from the distances obtained, with the coordinates being sent to the dashboard for visual representation. This strategy is supported by a GPS in outdoor environments, and indoors when structures allow it. Furthermore, the study includes the implementation of an experimental procedure and findings that involve utilizing ESP32 modules as scanning stations to track a BLE beacon.

A Simultaneous Localization and Mapping Approach Based on Detection of Magnetic Beacons

In this letter, a novel-feature-based simultaneous localization and mapping (SLAM) approach based on detection of magnetic beacons is presented as a convenient and accurate navigation solution. The magnetic beacons can be accurately detected with unknown background magnetic field by modeling the background field with polynomials and performing joint estimation. By taking the beacons as landmarks, a particle-filter-based SLAM model is established with the dead-reckoning system as state prediction and the relative positions of magnetic beacons as measurement. The potential false detection results are excluded to improve the robustness of the system and reduce computation cost. Experiments based on real-world data are performed to validate the effectiveness and accuracy of the approach.

An Ultrasonic Heading Goniometer Intrinsically Robust to Magnetic Interference

An ultrasonic heading measurement method, working under magnetic interference prohibitive for magnetometers, was prototyped, validated, and metrologically characterized. Two capacitive ultrasonic transducers convert the mechanical rotation in two correspondingly time-delayed electrical sine waves. Then, the time delay is estimated using the standard tree parameter sine-fitting algorithm. The prototyped goniometer achieves the same repeatability level (<36 mrad) of a magnetometer-based heading in the range [−437 mrad, 437 mrad]. Simultaneously, a throughput of 505 Sa/s is proven on an STM32F303xC Arm Cortex −M4 32-bit microcontroller. An interference analysis revealed the experimental deterministic error well explained by the combined effect of beacon and receiver directivity, as well as by the relative position of beacon, receiver, and reflective surfaces. Noise robustness was assessed in case of SNR decayed to 9.1 dB from the initial value of 36.6 dB; the maximum deterministic error in the range [−437 mrad, 437 mrad] increased less than 10% (from 21 to 23 mrad in absolute value).

Metric Dimension of Generalized Möbius Ladder and its Application to WSN Localization

Localization is one of the key techniques in wireless sensor network. While the global positioning system (GPS) is one of the most popular positioning technologies, the weakness of high cost and energy consuming makes it difficult to install in every node. In order to reduce the cost and energy consumption only a few nodes, called beacon nodes, are equipped with GPS modules. The remaining nodes obtain their locations through localization. In order to find the minimum positions of beacons, a resolving set with minimal cardinality has been obtained in the network which is called metric basis. Simultaneous local metric basis of the network is also given in which each pair of adjacent vertices of the network is distinguished by some element of simultaneous local metric basis which makes the network design more reasonable. In this paper a new network, the generalized Möbius ladderMm,n, has been introduced and its metric dimension and simultaneous local metric dimension of its two subfamilies have been calculated.

A Low Cost Indoor Positioning System Using Bluetooth Low Energy

In this paper, we present a Bluetooth Low Energy (BLE) based indoor positioning system developed for monitoring the daily living pattern of old people (e.g. people living with dementia) or individuals with disabilities. The proposed sensing system is composed of multiple sensors that are installed in different locations in a home environment. The specific location of the user in the building has been pre-recorded into the proposed sensing system that captures the raw Received Signal Strength Indicator (RSSI) from the BLE beacon that is attached on the user. Two methods are proposed to determine the indoor location and the tracking of the users: a trilateration-based method and fingerprinting-based method. Experiments have been carried out in different home environments to verify the proposed system and methods. The results show that our system is able to accurately track the user location in home environments and can track the living patterns of the user which, in turn, may be used to infer the health status of the user. Our results also show that the positions of the BLE beacons on the user and different quality of BLE beacons do not affect the tracking accuracy.

CONSTRUCTING AN OPTICAL LUNAR NAVIGATION SYSTEM BASED ON SPACECRAFT MADE BY LAVOCHKIN ASSOCIATION

The paper discusses the problem of developing an optical system for global positioning on the Moon to within one meter designed to service a limited number of users. It was demonstrated that the optimal solution of the problem would be to continuously monitor the positions of laser light beacons on the lunar surface from on-board an artificial satellite of the Moon equipped with an onboard TV camera, as well as from onboard a spacecraft placed at the L1 and L2 Lagrange points of the Earth-Moon system. The paper demonstrates the feasibility of a global lunar optical navigation and communications system based on space systems projects that are being developed at NPO Lavochkin: Spektr-UV observatory, lunar spacecraft Luna-25 and Luna-26. The use of these space systems will make it possible to start working in realistic terms on the navigation/communications system as a part of the future engineering infrastructure for lunar exploration. Keywords: telescope, optical navigation system, lunar base, Lagrange point, Spektr-UV, Luna-25, Luna-26.

A Case Study on Three-Dimensional Single-Beacon Localization for Autonomous Underwater Vehicles

Circular trajectory is most frequently used when an autonomous underwater vehicle calibrates positions of underwater acoustic beacons or corrects its own navigation errors using beacons. However, the space-time effect on control and navigation data processing and the impact of the angle of attack on three-dimensional localization performance of AUVs have rarely been mentioned in previous studies. To improve the three dimensional localization performance of AUVs with a single-beacon aiding, methods for space-time trade-offs from a control perspective and determination of the optimal angle of attack are investigated in this study. Through theoretical deduction aided with numerical simulation, concerned quantitative values with their corresponding preconditions are given, and some general conclusions which can greatly improve the navigation capability of AUVs have been made.

Calibration of Beacons for Indoor Environments based on a Digital Map and Heuristic Information

This paper proposes an algorithm for calibrating the position of beacons which are placed on the ceiling of an indoor environment. In this context, the term calibration is used to estimate the position coordinates of a beacon related to a known reference system in a map. The positions of a set of beacons are used for indoor positioning purposes. The operation of the beacons can be based on different technologies such as radiofrequency (RF), infrared (IR) or ultrasound (US), among others. In this case we are interested in the positions of several beacons that compose an Ultrasonic Local Positioning System (ULPS) placed on different strategic points of the building. The calibration proposal uses several distances from a beacon to the neighbor walls measured by a laser meter. These measured distances, the map of the building in a vector format and other heuristic data (such as the region in which the beacon is located, the approximate orientation of the distance measurements to the walls and the equations in the map coordinate system of the line defining these walls) are the inputs of the proposed algorithm. The output is the best estimation of the position of the beacon. The process is repeated for all the beacons. To find the best estimation of the position of the beacons we have implemented a numerical minimization based on the use of a Genetic Algorithm (GA) and a Harmony Search (HS) methods. The proposal has been validated with simulations and real experiments, obtaining the positions of the beacons and an estimation of the error associated that depends on which walls (and the angle of incidence of the laser) are selected to make the distance measurements.

Measurement of Relative Position of Camera and Optical Beacon by Simultaneous Passive Method

The paper deals with a problem of a passive measurement of the relative position of an optical beacon and an optical camera by a simultaneous analytical method. The beacon is composed of nine light sources which are arranged in space in a defined way. The proposed beacon layout enables the measurement of the beacon range and one position angle of the camera. This paper presents the mathematical model of the measurement method and the results, which were gathered on the basis of two experimental measurements. The first experiment was only indicative. The extreme results of the second experiment were as follows: the minimum and maximum absolute percentage errors of the beacon range were zero and 1.72%, the minimum and maximum errors of the position angle were 0.1 deg and 1.64 deg. The standard commercial cameras and lenses with different focal lengths were used.

Beacon trust management system and fake data detection in vehicular ad‐hoc networks

A vehicular ad-hoc network is an emerged technology, where vehicles communicate with one another and Road Side Units. Vehicular ad-hoc networks are categorised as a sub-branch of mobile ad-hoc networks, and they help in enhancing traffic efficiency and safety. Vehicular ad-hoc networks facilitate communication by dissemination of messages relaying through vehicles. However, malicious nodes can propagate false safety alert in a network due to its malicious behaviour or selfishness. False messages in vehicular ad-hoc networks can change drivers behaviour and create a disastrous situation in the network. Therefore, it is more important to thwart these false messages. The article presents a beacon trust management system and fake data detection (BTMS-FDD) scheme. The trust management system uses speed and density information to establish a relationship with vicinity vehicles. The false safety event detection scheme uses relative safety and beacon messages to detect false safety event more accurately. For false safety events, a scheme uses position and speed information of beacon and safety-related messages. To analyse the performance of proposed detection scheme, it is compared with ELIDV and host IDS schemes. The simulation results demonstrate that proposed malicious data detection scheme is better in terms of true positive, false positive and overhead.

The establishment of the early scholarship of professional and technical surveying education in South Africa for the period 1657 to 1929

Historical Research deals with the meaning of events, and it tries to make sense of an ever-flowing stream of events and continuing changes in human life and its institutions. Surveying activities in South Africa, sometimes by people with no survey-specific education, started in 1657.Early in the 19th century, disputes arose regarding the positions of boundary beacons and the incorrect diagrams representing them. In 1834, the Cape Colony government decreed that land surveyors should only be allowed to practise after completing a qualifying examination set by the Surveyor- General. Early land surveyors were expected to be competent in cadastral, engineering, topographical and mine surveying, and cartography.This paper will focus on the time period before the existing familiar Professional Degrees and National Diplomas were offered by Universities in South Africa. It will highlight the remarkable achievements of the early surveyors, some of whom were self-taught, and their mentors. It will investigate the first formal learning that surveyors had to undergo to acquire the competencies needed to practise as surveyors.Keywords: Universities, technikons, colleges, surveying, profession

Development of a high-precision selenodetic coordinate system for the physical surface of the Moon based on LED beacons on its surface

The paper presents a mathematical algorithm for processing an array of angular measurements of light beacons on images of the lunar surface onboard a polar artificial lunar satellite (PALS) during the Luna–Glob mission and coordinate–time referencing of the PALS for the development of reference selenocentric coordinate systems. The algorithm makes it possible to obtain angular positions of point light beacons located on the surface of the Moon in selenocentric celestial coordinates. The operation of measurement systems that determine the position and orientation of the PALS during its active existence have been numerically simulated. Recommendations have been made for the optimal use of different types of measurements, including ground radio trajectory measurements, navigational star sensors based on the onboard star catalog, gyroscopic orientation systems, and space videos of the lunar surface.

An Efficient Geometric Localization Approach for Distributed Sensor Networks

Localization is a fundamental problem in wireless sensor networks. Many approaches, including range-based and range-free techniques, have been proposed to determine the optimal location for sensor nodes. This paper presents a simple range-free localization scheme that is based on received signal strength indicator (RSSI) geometric localization for wireless sensor networks. The node locations are computed by performing simple geometric calculations that rely on the specific approximate RSSI values with the position of a mobile beacon equipped with a global positioning system. The simulation results showed that the proposed scheme is efficient, and that the node positions can be determined accurately.

Beacon selection and calibration for the efficient localization of a mobile robot

SUMMARYThis paper proposes a localization scheme using ultrasonic beacons in an unstructured multi-block workspace. Indoor localization schemes using ultrasonic sensors have widely been studied due to their low costs and high accuracies. However, ultrasonic sensors are susceptible to environmental noise due to the propagation characteristics of ultrasonic waves. In addition, the decay of ultrasonic signals over long distances implies that ultrasonic sensors are unsuitable for use in large indoor environments. To overcome these shortcomings of ultrasonic sensors, while retaining their advantages, a multi-block approach was devised by dividing an indoor space into several blocks with multiple beacons in each block. However, it is difficult to divide an indoor space into several blocks when beacons cannot be installed in a regular manner or when some new beacons are installed. To resolve this difficulty, a dynamic algorithm is needed to divide an indoor space into multiple blocks and to select suitable beacons. Therefore, this paper proposes a real-time localization scheme to estimate the position of a mobile robot independent of beacon locations and to estimate the position of a new beacon installed at an unknown position. A beacon selection algorithm was developed to select optimal beacons according to robot position and to set up sets of beacons for mobile robot navigation. By using the new beacon searching and calibration algorithm, a mobile robot is able to navigate in an unknown space without requiring the additional setup time needed to install new beacons. The performance of the proposed localization system was verified using real experiments.

DESIGN AND IMPLEMENTATION OF AN INDOOR LOCALIZATION SYSTEM FOR THE OMNIBOT OMNI-DIRECTIONAL PLATFORM

The design and implementation of an indoor absolute localization system for a novel threedegree-of-freedom (DOF) omni-directional mobile platform is presented. This localization system is a modification of the Cricket indoor localization system developed at the Massachusetts Institute of Technology (MIT) and is similar to the Global Positioning System (GPS) used in outdoor applications. The designed system has an active mobile architecture with actively transmitting beacons mounted on the mobile platform, and receivers (listeners) fixed at known positions on the ceiling of the operating environment. Position estimates of the mobile beacons, relative to a global coordinate system, are obtained using trilateration; a technique that determines the position of a beacon using distance estimates between the beacon and the fixed listeners. The distance estimates between the beacons and listeners are calculated using the time-of-flight of radio frequency and ultrasonic signals. Testing of the localization system was performed and experimental results are presented. These preliminary results indicate that the modified Cricket system has improved accuracy in distance and position estimation compared to the original system, as well as a higher position update rate when performing tracking of the mobile platform.

Robust Range-Only Beacon Localization

In this paper, we present a system capable of simultaneously estimating the position of an autonomous underwater vehicle (AUV) and the positions of stationary range-only beacons. Notably, our system does not require beacon positions a priori, and our system performs well even when range measurements are severely degraded by noise and outliers. We present a powerful outlier rejection method that can identify groups of range measurements that are consistent with each other, and a method for initializing beacon positions in an extended Kalman filter (EKF). We have successfully applied our algorithms to real-world data and have demonstrated a simultaneous localization and mapping (SLAM) system whose navigation performance is comparable to that of systems that assume known beacon locations