Positioning System GPS Research Articles

Research on Embedded Sun-Tracking Control System Based on GPS

To improve the efficiency of the power generation，the scheme of the solar tracking system is designed by analyzing the technical characteristics of the GPS positioning system. The microcontroller is chosen as the core which has realized the initiative sun-tracking to improve the efficiency of the power generation. The solar elevation angle and azimuth are calculated by extracting the GPS real-time datas. The position of the solar panels can be obtained through the angle sensor. Finally, adjust the orientation of the panels by the driving stepping motor to track the sun.

Forensic Engineering Applications Of Gps Data

Digital Sources Of Data Have Become Increasingly Important In The Forensic Engineering Analysis Of Vehicular Collisions. One Such Type Of Data, From Global Positioning System (Gps) Devices, Has Increased In Prevalence Within The Last Decade. As With Other Digital Data Types, It Is Important For Forensic Engineers To Understand The Sources And Types Of Gps Data Before Applying Them Within Their Analysis Framework. Validation Of The Gps Concept And Individual Devices, And Examples Of Gps Accepted Use Within The Engineering Community, Make This Technology An Important And Appropriate Tool For Forensic Engineering Analysis. Gps Data Can Be Acquired From A Variety Of Electronic Data Recorder (Edr) Sources, Both On-Vehicle And Off-Vehicle. Many Gps Data Sources Have Limitations That Can Lead To Misapplications Or Incorrect Conclusions If Not Properly Studied. Appropriate Mathematical Calculations And Analytical Procedures Will Be Addressed, Including The Types Of Collision Events That Can Best Benefit From The Context Of Gps Data. Gps Data Applications In Real-World Forensic Engineering Cases, Including Insurance Claims And Litigation, Reflect The Power Of Robust Analysis And Well As The Potential For Erroneous Conclusions If The Data Are Misused By The Analyst.

The Error Caused by Relativity in GPS Positioning System

In GPS Positioning System, distance measurement between the receiver and the satellite is affected by all kinds of factors. So it has errors. Some of these errors, which are caused by relativity can’t be neglected when it is being accurate positioned. This essay analyses and estimates these errors. Key words: GPS; Positioning; Measurement; Error Special; Theory of Relativity; General; Theory of Relativity

From emission to inertial coordinates: a numerical approach

We numerically implement the coordinate transformation between emission and inertial coordinates recently derived –in Minkowski space-time- by Coll et al. [1]. In order to carry out this transformation, we must know both proper times from four satellites and the inertial coordinates of these satellites when they emitted. It allows us to determine the position and the time coordinate of the receiver. Since we need to know the satellite positions at any time, we have simulated satellite constellations similar to those of GPS and Galileo global positioning system. All the satellite positions are calculated, at any time, with respect to an inertial frame with the origin at the Earth center. The orientation criterion described by the same authors [2] has been also implemented. The code has been appropiately tested and, then it has been applied to perform a preliminary study about the structure of the emission coordinate region and the grid region. The errors due to uncertainties in satellite positions have been also estimated.

Description of a Remote Still Photography System for Collection of Benthic Photo-Quadrats

AbstractQuantitative sampling of benthic communities is central to a wide range of ecological research, from understanding spatial distribution and ecology to impact studies. With the need to sample deep as well as shallow regions, limited sampling capabilities of diver-based methods and the expanding footprint of human activity, there is a need for an effective system capable of classifying benthic assemblages and able to monitor potential anthropogenic impacts. Here we describe a remote system capable of collecting benthic photo-quadrats to depths of 100 m. A procedure for the classification of these images into 64 abiotic and biotic categories is also described. During a 64-day sampling program that included sampling at seven locations along 1,200 km of coastline that resulted in the collection of over 9,000 images, only one day of sampling was lost due to equipment malfunction, with 99.5% of points able to be classified to the taxonomic resolution required, demonstrating the reliability and accuracy of this system. Furthermore, the incorporation of differential GPS and ultra-short baseline positioning system allowed collected images to be geo-referenced to within 0.5 m. Such precision allows the system to be used in conjunction with hydroacoustic habitat mapping techniques and potentially for repeated monitoring of areas with a small spatial extent. Development of this system provides a cost-effective means of quantifying benthic assemblages over broad scales.

Effects of Forest Edges on the Distribution, Abundance, and Regional Persistence of Wood‐Rotting Fungi

Abstract: Designing reserves and management practices to contribute to the persistence of old‐forest specialized species in fragmented landscapes requires data on plant and animal species responses to edges. We studied 15 edges between Picea abies [L. Karsten] dominated old‐growth forests and young clearcuts (6–23 years), old clearcuts (25–39 years), and natural peatlands in eastern Finland. All fallen spruce logs (>10‐cm diameter; 10,679 logs) in old‐forest fragments (13–85 ha) were located by GPS positioning system. Environmental variables and occurrences of old‐forest indicator fungi (Phlebia centrifuga P. Karsten, Amylocystis lapponica [Romell] Singer, Fomitopsis rosea [Alb. & Schwin.: Fr] P. Kartsen, Phellinus ferrugineofuscus [P. Kartsen] Bourdot); a light‐adapted fungus (Gloeophyllum sepiarium [Wulfen: Fr] P. Karsten); and a pathogen and saprophyte fungus (Fomitopsis pinicola [SW.: Fr] P. Karsten) were investigated. The frequency of G. sepiarium was higher and the frequencies of old‐forest indicator fungi and F. pinicola were lower near (<25 m) young clearcut edges in comparison with interiors. Frequencies of some indicator fungi, however, were highest at intermediate distances (10–25 m) from old clearcut and peatland edges. Indicator fungi preferred thick logs of intermediate decay stages in moist biotopes, and their incidence patterns in old‐growth forest stands were aggregated. We applied a geographic information system (GIS)‐based edge model to calculate edge‐interior area relationships of 2,698 old‐forest fragments with three values for depth of edge effect: 25 m, 2*(height of old forest), and 2*(differences between the heights of old and adjacent forests). Interior area was reduced to 55–71% of the original with different depth‐of‐edge values. Total numbers of separate interior areas increased, although interior areas disappeared from the smallest fragments. The results showed that the edge effect is complex and also that it changes when the edge matures because of interactions among several factors. We suggest that sequential management of forests adjacent to reserves and the formation of larger reserves would increase the capacity of the reserves to maintain edge‐sensitive species.

On Ultrahigh-Precision GPS Positioning and Navigation

This paper introduces an ultrahigh-performance GPS positioning and navigation system for gantry crane auto-steering. The system differs from conventional systems in terms of the achievable positioning accuracy and precision. Aside from ambiguity resolution and reliability, many error sources (such as phase wrap-up, antenna phase-center variation, instrumental group delay bias, receiver clock jumps, and residual tropospheric delay.) must be handled precisely to attain ultrahigh-precision positioning solutions. The paper also introduces an optimal interfrequency carrier-phase linear combination of the L1 and L2 measurements that can reduce the effects of quasirandom errors (that is, errors including significant low-frequency components and showing to some extent random behavior over relatively short intervals of time), such as multipath, diffraction, and ionospheric scintillation. A practical approach to estimating realistic receiver system noise is also introduced.

Testing Climate Models: An Approach

Abstract The scientific merit of decadal climate projections can only be established by means of comparisons with observations. Testing of models that are used to predict climate change is of such importance that no single approach will provide the necessary basis to analyze systematic errors and to withstand critical analysis. Appropriate observing systems must be relevant, global, precise, and calibratable against absolute standards. This paper describes two systems that satisfy these criteria: spectrometers that can measure thermal brightness temperatures with an absolute accuracy of 0.1 K and a spectral resolution of 1 cm-1, and radio occultation measurements of refractivity using satellites of the GPS positioning system, which give data of similar accuracy. Comparison between observations and model predictions requires an array of carefully posed tests. There are at least two ways in which either of these data systems can be used to provide strict, objective tests of climate models. The first looks f...

Realistic Autofarming Closed-Loop Tractor Control over Irregular Paths Using Kinematic GPS

High-precision ‘autofarming’ makes possible farming techniques previously impractical using metre-level Differential GPS-based control systems: techniques such as tape irrigation, the elimination of guess rows, and precise contour farming. A Carrier-Phase Differential gps positioning and attitude system with centimetre-level and 0·1° accuracy was installed in a large farm tractor. Four types of trajectories (lines, arcs, spirals, and curves) were identified as basic building blocks necessary to generate a ‘global’ trajectory for a realistic autofarming path. Information about each trajectory type was translated into reference state specifications that a linear controller used to control the tractor over velocities between 0·7 and 2·8 m/s to within approximately 6 cm (1 σ) without implement and 10 cm (1 σ) with implement on sloped terrain using a previously developed tractor model. These results are a significant step towards a realistic autofarming system because they not only demonstrate accurate control over various realistic operating speeds but over different types of trajectories necessary for a commercial system.

Development of an autonomous navigation system for an outdoor vehicle

This paper describes the autonomous navigation system of a tracked off-road vehicle manufactured by Modulaire Ltd. Autonomous navigation is performed with the help of a real-time kinematic GPS positioning system and a fibre optical gyro. A mission planning and control unit allows remote mission monitoring and planning with graphical tools in a PC-Windows-environment.

Development of an Autonomous Navigation System for an Outdoor Vehicle

This paper describes the autonomous navigation system of tracked off-road vehicle manufactured by Modulaire Ltd. Autonomous navigation is performed with the help of a Real-Time Kinematic GPS positioning system and a fibre optical gyro. Mission planning and control unit allows remote mission monitoring and planning with graphical tools in PC-Windows-environment.

GPS-based timing and clock synchronisation for real time computers

A new approach for and hardware realisation of timers is described. The timers are designed for use in distributed real-time systems to realise precise timing and ease of time handling by using alarm jobs. No synchronisation is needed, because the exact UTC is received via satellite from the global navigation and positioning system GPS.

A GPS Attitude Determination System

In 1991 Trimble Navigation introduced a Global Positioning System (Gps)-based attitude determination receiver capable of 3-axis solutions with accuracy to several milliradians for airborne, sea and land platforms. This paper discusses the physical, architectural, and operational features of this receiver system. Analysis of system performance will also be reviewed for various configurations and user applications. The Trimble Navigation attitude determination receiver uses differential carrier phase techniques to determine azimuth, pitch and roll angles of a 3-antenna array. This product is designed to operate in a variety of user applications and to withstand rugged operating environments. Trimble Navigation has expanded its proven GPS sensor architecture to incorporate three independent RF sections and additional processing channels to measure and process the differential phase between antennas on two orthogonal baselines. Direct measurement of differential phase utilizing a common local oscillator provides highly accurate relative phase data. The navigation and attitude processor computes azimuth, pitch, and roll angles as well as position, velocity and time. The solution accuracy and stability statistics are sensitive to various parameters. Antenna baseline length, signal multipath, platform dynamics and filtering are investigated. Test data from static and various dynamic platforms are also presented.