scholarly journals Detection of RINEX-2 Files With Mixed GPS L2P(Y)/L2C Carrier Phase Observations

Sensors ◽  
2018 ◽  
Vol 18 (12) ◽  
pp. 4507
Author(s):  
Lambert Wanninger
Keyword(s):  
Global Positioning System ◽  
Carrier Phase ◽  
Space Vehicles ◽  
Data Format ◽  
Precise Positioning ◽  
Gps Satellites ◽  
Global Positioning ◽  
Short Baselines ◽  
L2c Signal ◽  
Long Baselines

Presently, the global positioning system (GPS) satellite constellation consists of 40% older Block IIA and IIR space vehicles and 60% newer IIR-M and IIF satellites. Only newer GPS satellites are capable of transmitting the L2C signal which is in quadrature to the legacy L2P(Y) signal being broadcast by all satellites. The data format RINEX-2 is not prepared to contain carrier phase observations of both L2 signals, but should contain either one or the other. If a mix of unaligned L2P(Y) and L2C carrier phase observations are stored in a RINEX-2 file, the quarter cycle bias causes the file to be defective and not usable for precise positioning purposes. Algorithms that detect such files are presented in this study. They are mainly based on the analysis of widelane fractional ambiguities and were applied to RINEX-2 files of 2624 reference stations. Seventy-two station files (2.7%) were found to be defective since they contained mixed and unaligned L2P(Y) and L2C carrier phase observations. If such files are used for precise positioning with ambiguities being fixed to integer values, resulting coordinate errors in long baselines can reach centimeter levels. Unaligned L2 observations often prevent ambiguity fixing, especially in short baselines.

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

A Model for Combined GPS and BDS Real-Time Kinematic Positioning using one Common Reference Ambiguity

2018 ◽  
Vol 71 (4) ◽  
pp. 1011-1024 ◽  
Author(s):  
Rui Tu ◽  
Jinhai Liu ◽  
Rui Zhang ◽  
Pengfei Zhang ◽  
Xiaochun Lu
Keyword(s):  
Real Time ◽  
Global Positioning System ◽  
Carrier Phase ◽  
Satellite System ◽  
Phase System ◽  
Combined Model ◽  
Common Reference ◽  
Beidou Navigation Satellite System ◽  
Real Time Kinematic ◽  
Global Positioning

This paper proposes a model for combined Global Positioning System (GPS) and BeiDou Navigation Satellite System (BDS) Real-Time Kinematic (RTK) positioning. The approach uses only one common reference ambiguity, for example, that of GPS L1, and estimates the pseudo-range and carrier phase system and frequency biases. The validations show that these biases are stable during a continuous reference ambiguity period and can be easily estimated, and the other estimated double-differenced ambiguities, such as those of GPS L2, BDS L1, and BDS L2, are not affected. Therefore, our approach solves the problems of a frequently changing reference satellite. In addition, because all the carrier phase observations use the same reference ambiguity, a relationship is established between the different systems and frequencies, and the strength of the combined model is thus increased.

scholarly journals Covariance Analysis of Real-Time Precise GPS Orbit Estimated from Double-Differenced Carrier Phase Observations

2019 ◽  
Vol 11 (19) ◽  
pp. 2271 ◽  
Author(s):  
Sunkyoung Yu ◽  
Donguk Kim ◽  
Junesol Song ◽  
Changdon Kee
Keyword(s):  
Fault Detection ◽  
Real Time ◽  
Global Positioning System ◽  
Carrier Phase ◽  
Satellite System ◽  
Additional Parameter ◽  
Global Positioning ◽  
Correlation Information ◽  
Global Navigation Satellite ◽  
Orbit Errors

The covariance of real-time global positioning system (GPS) orbits has been drawing attention in various fields such as user integrity, navigation performance improvement, and fault detection. The international global navigation satellite system (GNSS) service (IGS) provides real-time orbit standard deviations without correlations between the axes. However, without correlation information, the provided covariance cannot assure the performance of the orbit product, which would, in turn, causes significant problems in fault detection and user integrity. Therefore, we studied real-time GPS orbit covariance characteristics along various coordinates to effectively provide conservative covariance. To this end, the covariance and precise orbits are estimated by means of an extended Kalman filter using double-differenced carrier phase observations of 61 IGS reference stations. Furthermore, we propose a new method for providing covariance to minimize loss of correlation. The method adopted by the IGS, which neglects correlation, requires 4.5 times the size of the covariance to bind orbit errors. By comparison, our proposed method reduces this size from 4.5 to 1.3 using only one additional parameter. In conclusion, the proposed method effectively provides covariance to users.

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.

Trail Blazer into Space

2000 ◽  
Vol 122 (10) ◽  
pp. 71-74
Author(s):  
Frank Wick
Keyword(s):  
Cold War ◽  
Global Positioning System ◽  
Space Vehicles ◽  
Positioning System ◽  
Information Revolution ◽  
United States Military ◽  
Post Cold War ◽  
Global Positioning ◽  
The Cold War ◽  
And Control

This article reviews that from the Cold War to Voyager, the work of Robert Goddard has received much recognition. Independently, Goddard started conceiving and designing a variety of air and space vehicles, and analyzing methods for propulsion and control. In 1903, Wilbur and Orville Wright had achieved powered flight with the three-axis control they had invented, but the flying machine was extremely difficult to manage. In 1907, while he was still an undergraduate, Goddard studied the dynamics of the Wright Flyer, and designed a gyroscope-based stabilizer for automatic control. His attempts to procure government funding were rejected by a United States military that did not recognize any value of rockets beyond the possibility of assistance at takeoff for aircraft. Rockets increasingly are supporting the marvels of our post-Cold War information revolution. The satellite-based Global Positioning System has brought the most sophisticated navigation system into the personal automobile. Within the century, Robert Goddard’s vision and life’s work begat far more than he could have imagined.

Sign in / Sign up

Export Citation Format

Share Document