scholarly journals Influence of Ephemeris Error on GPS Single Point Positioning Accuracy

2013 ◽  
Vol 48 (3) ◽  
pp. 125-139
Author(s):  
Ma Lihua ◽  
Meng Wang
Keyword(s):  
Global Positioning System ◽  
Simulation Analysis ◽  
Single Point ◽  
Line Of Sight ◽  
Positioning System ◽  
Gps Satellites ◽  
Time Period ◽  
Global Positioning ◽  
Orbital Position ◽  
The Relationship

Abstract The Global Positioning System (GPS) user makes use of the navigation message transmitted from GPS satellites to achieve its location. Because the receiver uses the satellite's location in position calculations, an ephemeris error, a difference between the expected and actual orbital position of a GPS satellite, reduces user accuracy. The influence extent is decided by the precision of broadcast ephemeris from the control station upload. Simulation analysis with the Yuma almanac show that maximum positioning error exists in the case where the ephemeris error is along the line-of-sight (LOS) direction. Meanwhile, the error is dependent on the relationship between the observer and spatial constellation at some time period.

High Accuracy Pseudolite-based Navigation System: Compensating for Right-Hand Circularly Polarized Effect

2006 ◽  
Vol 59 (2) ◽  
pp. 307-320 ◽  
Author(s):  
Haeyoung Jun ◽  
Changdon Kee
Keyword(s):  
Global Positioning System ◽  
Navigation System ◽  
Line Of Sight ◽  
Positioning System ◽  
Phase Measurements ◽  
Circularly Polarized ◽  
Position Accuracy ◽  
Right Hand ◽  
Gps Satellites ◽  
Global Positioning

This paper presents further research on the SNUGL pseudolite-based navigation system presented in this journal in 2003. This system has centimetre-level accuracy, but has an error source arising from right-hand circularly polarized (RHCP) transmissions, unlike outdoor Global Positioning System (GPS). The GPS satellites and pseudolites use RHCP signals, and the polarization affects carrier-phase measurements according to the Line-of-Sight (LOS) vectors from transmitters to receivers. The RHCP error is eliminated by a double differencing process in outdoor GPS, but the error remains in the pseudolite-based system because the LOS vectors from transmitters to a reference and user receivers are different for the close transmitter constellations. This paper shows the RHCP effect on the pseudolite-based navigation system through simulations and experiments. It then shows the RHCP-compensation method improves the measurement and position accuracy by over 10%.

scholarly journals Optical Astrometry and the Global Positioning System

1991 ◽  
Vol 127 ◽  
pp. 284-287
Author(s):  
P.C. Kammeyer ◽  
H.F. Fliegel ◽  
R.S. Harrington
Keyword(s):  
Global Positioning System ◽  
Optical Sensors ◽  
Optical Observations ◽  
Line Of Sight ◽  
Positioning System ◽  
Charge Coupled Device ◽  
Gps Satellites ◽  
Global Positioning ◽  
Device Technology ◽  
Stellar Background

AbstractAstrometric accuracies of a few tens of milliarcseconds are expected to be attainable within five years by calibrating astrograph plates with optical observations of Global Positioning System (GPS) satellites against a stellar background. The line of sight from an observer on the Earth’s surface to a GPS satellite may be calculated with high accuracy. Motion on each day of the line of sight to the satellite and changes from day to day in the apparent path of the satellite are sufficiently slow to make it possible to reduce atmospheric errors by averaging. Advanced ground-based optical sensors, probably using charge coupled device technology, will be required for GPS optical astrometry.

Ultra-Wideband-Based Localization for Quadcopter Navigation

2016 ◽  
Vol 04 (01) ◽  
pp. 23-34 ◽  
Author(s):  
Kexin Guo ◽  
Zhirong Qiu ◽  
Cunxiao Miao ◽  
Abdul Hanif Zaini ◽  
Chun-Lin Chen ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Global Positioning System ◽  
Ultra Wideband ◽  
Line Of Sight ◽  
Positioning System ◽  
Localization Algorithm ◽  
Control Loop ◽  
Flight Tests ◽  
Localization System ◽  
Global Positioning

Micro unmanned aerial vehicles (UAVs) are promising to play more and more important roles in both civilian and military activities. Currently, the navigation of UAVs is critically dependent on the localization service provided by the Global Positioning System (GPS), which suffers from the multipath effect and blockage of line-of-sight, and fails to work in an indoor, forest or urban environment. In this paper, we establish a localization system for quadcopters based on ultra-wideband (UWB) range measurements. To achieve the localization, a UWB module is installed on the quadcopter to actively send ranging requests to some fixed UWB modules at known positions (anchors). Once a distance is obtained, it is calibrated first and then goes through outlier detection before being fed to a localization algorithm. The localization algorithm is initialized by trilateration and sustained by the extended Kalman filter (EKF). The position and velocity estimates produced by the algorithm will be further fed to the control loop to aid the navigation of the quadcopter. Various flight tests in different environments have been conducted to validate the performance of UWB ranging and localization algorithm.

scholarly journals LIDAR Self Driving Car

2021 ◽  
Vol 9 (10) ◽  
pp. 1334-1337
Author(s):  
Soham Phansekar
Keyword(s):  
Global Positioning System ◽  
Electromagnetic Waves ◽  
Traffic Accidents ◽  
Positioning System ◽  
Automated Driving ◽  
Sensing Technology ◽  
Gps Satellites ◽  
Global Positioning ◽  
Total Travel Time ◽  
Car Navigation System

Abstract: Increasing population is the major issue of transportation nowadays. People who live and work in the major cities of the world are faced with increasing levels of congestion, delays, total travel time, costs, frustration, accidents and loss of life. The objective of this project is to help prevent traffic accidents and save people’s time by fundamentally changing car use. The system would have sensors to detect the obstacles and to be able to react according to their position. In this project we have developed an automated driving system which drives the car automatically. We have developed a technology for cars that drives it automatically using LIDAR. This car is capable of sensing the surroundings, navigating and fulfilling the human transportation capabilities without any human input. It continuously tracks the surrounding and if any obstacle is detected vehicle senses and moves around and avoids the obstacle. An autonomous car navigation system based on Global Positioning System (GPS) is a new and promising technology, which uses real time geographical data received from several GPS satellites to calculate longitude, latitude, speed and course to help navigate a car. As we know the development of gps is more improved now the accuracy of gps we can see centimetre also so Like for our car to go at specific inputted location we use this gps technology.Lidar is used for sensing the surroundings. Like radar, lidar is an active remote sensing technology but instead of using radio or microwaves it uses electromagnetic waves. Keywords: Congestion, Traffic Accident, LIDAR sensor, Global Positioning System, Electromagnetic waves

scholarly journals Traffic Flow Pattern in Road Network Using Clustering

2020 ◽  
Vol 5 (8) ◽  
pp. 229-230
Author(s):  
Ganga Gudi ◽  
Dr. Hanumanthappa M
Keyword(s):  
Traffic Flow ◽  
Global Positioning System ◽  
Road Network ◽  
Location Based Services ◽  
Positioning System ◽  
Specific Time ◽  
Real World Problem ◽  
Time Period ◽  
Global Positioning ◽  
Enormous Amount

Wireless communication has become important in location-based services. The enormous amount of data is extracted for useful information to solve the real world problem. Global positioning system, is used to captures the position of an object at specific time period. The scheme is finding the congested route by considering the number of vehicles in a road segment. It consists of two methods, firstly it finds the group of points based on consistency of route points and second it arranges the groups in sequence of values for each route

Accuracy of a Global Positioning System (GPS) for Weed Mapping

1997 ◽  
Vol 11 (4) ◽  
pp. 782-786 ◽  
Author(s):  
Theodore M. Webster ◽  
John Cardina
Keyword(s):  
Measurement Error ◽  
Global Positioning System ◽  
Patch Size ◽  
Positioning System ◽  
Weed Mapping ◽  
Global Positioning ◽  
The Relationship

Experiments were conducted to test the accuracy of a global positioning system (GPS) in measuring the area of simulated weed patches of varying size and to determine the accuracy in navigating back to particular points in a field. Circular areas of 5, 50, and 500 m2 were established and measured using point and polygon features of a GPS. The GPS estimations of the area of those patches had errors ranging from 7 to 45%, 6 to 15%, and 3 to 6%, respectively, when compared to actual measurements. As patch size increased, errors decreased. A curve describing the relationship between GPS error and patch size had an excellent fit (r2 = 0.92). The error remained the same in all measurements across all patch sizes, but composed a smaller percentage of large patches. The GPS had submeter accuracy in navigation to the correct quadrat 73% of the time, located the correct quadrat 27% of the time, and invariably navigated to within 1.58 m of the correct quadrat. The relationship between patch size and measurement error was applied to natural infestations of hemp dogbane.

scholarly journals Analyzing Road Coverage of Public Vehicles According to Number and Time Period for Installation of Road Inspection Systems

2020 ◽  
Vol 9 (3) ◽  
pp. 161 ◽  
Author(s):  
Takehiro Kashiyama ◽  
Yoshihide Sekimoto ◽  
Toshikazu Seto ◽  
Ko Ko Lwin
Keyword(s):  
Global Positioning System ◽  
Local Governments ◽  
Inspection System ◽  
Positioning System ◽  
Efficient Operation ◽  
Time Period ◽  
Global Positioning ◽  
Inspection Systems ◽  
Road Inspection

Shortages of engineers and financial resources have made it difficult for municipalities to identify and address problems with aging road infrastructures. To resolve these problems, numerous studies have focused on automating road inspection, including a study in which we developed a smartphone-based road inspection system. For efficient operation of the system, it is necessary to understand the usage of vehicles in which the system will be installed. In this study, we analyzed the usage of public vehicles with long-term global positioning system (GPS) probe data collected from public vehicles operating in Kakogawa city and Fujisawa city in Japan. As a result, we discovered that local governments of the same size have similar tendencies in terms of road coverage. Moreover, we found that installing road inspection systems on only a few public vehicles can cover the entire road inspection area. We anticipate that these results will assist local governments in making informed decisions during the system introduction process and provide an indicator of the accuracy required for road inspection systems to future researchers.

scholarly journals Algorithms of Position and Velocity Estimation in GPS Receivers

2016 ◽  
Vol 23 (1) ◽  
pp. 53-68 ◽  
Author(s):  
Piotr Kaniewski ◽  
Rafał Gil ◽  
Stanisław Konatowski
Keyword(s):  
Global Positioning System ◽  
Velocity Estimation ◽  
Frame Of Reference ◽  
Positioning System ◽  
Gps Receivers ◽  
Extended Kalman Filters ◽  
Navigation Solution ◽  
Gps Satellites ◽  
Global Positioning ◽  
Simulation Results

Abstract Processing of signals in Global Positioning System (GPS) receivers includes numerous signal and data operations leading to calculation of coordinates and velocities of satellites in global Earth-Centered Earth-Fixed (ECEF) frame of reference as well as pseudoranges and delta-ranges between the user and all the tracked GPS satellites. Further processing of these data consists in estimation of the user’s position, velocity and time (PVT) and nowadays it is usually realized by means of an Extended Kalman Filters (EKF). The choice of measuring data processed by the Kalman filter significantly influences the accuracy of navigation solution. In simpler GPS receivers, the estimation of user’s position and velocity is based on pseudoranges only, whereas in more advanced ones delta-ranges are also applied. The paper describes both possible solutions and compares the accuracy of estimation of the user’s position and velocity in both cases. The comparison is based on simulation results, which are included in the paper.

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