scholarly journals Position finding using simple Doppler sensors

2007 ◽  
Vol 5 ◽  
pp. 153-156 ◽  
Author(s):  
S. Schelkshorn ◽  
J. Detlefsen
Keyword(s):  
Cellular Networks ◽  
Simultaneous Measurement ◽  
Navigation Systems ◽  
Position Information ◽  
Doppler Signals ◽  
Accurate Position ◽  
Gps System ◽  
Wireless Infrastructure ◽  
Position Estimate ◽  
Unknown Object

Abstract. An increasing number of modern applications and services is based on the knowledge of the users actual position. Depending on the application a rough position estimate is sufficient, e. g. services in cellular networks that use the information about the users actual cell. Other applications, e. g. navigation systems use the GPS-System for accurate position finding. Beyond these outdoor applications a growing number of indoor applications requires position information. The previously mentioned methods for position finding (mobile cell, GPS) are not usable for these indoor applications. Within this paper we will present a system that relies on the simultaneous measurement of doppler signals at four different positions to obtain position and velocity of an unknown object. It is therefore suiteable for indoor usage, extendig already existing wireless infrastructure.

Analysis of “Distance-Loss” Model Influence Factors in Vehicular Ad Hoc Networks

2012 ◽  
Vol 490-495 ◽  
pp. 1481-1485
Author(s):  
Jiang Feng Wang ◽  
Xue Dong Yan ◽  
Shuo Nie
Keyword(s):  
Measurement Error ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Influence Factors ◽  
Distance Measurement ◽  
Experimental Sample ◽  
Position Information ◽  
Loss Model ◽  
Accurate Position ◽  
Hoc Networks

In vehicular ad hoc network(VANETs), it is crucial for obtaining more accurate position information which variation rules between “distance-loss” model influence factors and distance measurement error is analyzed. Based on qualitative analysis of “distance-loss” model, field experimental scene and scheme are proposed. Using experimental sample data, the relation of environmental factor and shelter factor and distance measurement error is studied quantitatively. The experimental results show that distance measurement performance of optimized “distance-loss” model is significantly improved, and 6.7% is the largest reduction proportion of distance measurement error.

scholarly journals Obtaining World Coordinate Information of UAV in GNSS Denied Environments

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2241 ◽  
Author(s):  
Chengbin Chen ◽  
YaoYuan Tian ◽  
Liang Lin ◽  
SiFan Chen ◽  
HanWen Li ◽  
...  
Keyword(s):  
Visual Servoing ◽  
Field Tests ◽  
Visual Navigation ◽  
Sensor Data ◽  
Measurement Unit ◽  
Navigation Systems ◽  
Complex Environments ◽  
External Interference ◽  
Position Information ◽  
Self Powered

GNSS information is vulnerable to external interference and causes failure when unmanned aerial vehicles (UAVs) are in a fully autonomous flight in complex environments such as high-rise parks and dense forests. This paper presents a pan-tilt-based visual servoing (PBVS) method for obtaining world coordinate information. The system is equipped with an inertial measurement unit (IMU), an air pressure sensor, a magnetometer, and a pan-tilt-zoom (PTZ) camera. In this paper, we explain the physical model and the application method of the PBVS system, which can be briefly summarized as follows. We track the operation target with a UAV carrying a camera and output the information about the UAV’s position and the angle between the PTZ and the anchor point. In this way, we can obtain the current absolute position information of the UAV with its absolute altitude collected by the height sensing unit and absolute geographic coordinate information and altitude information of the tracked target. We set up an actual UAV experimental environment. To meet the calculation requirements, some sensor data will be sent to the cloud through the network. Through the field tests, it can be concluded that the systematic deviation of the overall solution is less than the error of GNSS sensor equipment, and it can provide navigation coordinate information for the UAV in complex environments. Compared with traditional visual navigation systems, our scheme has the advantage of obtaining absolute, continuous, accurate, and efficient navigation information at a short distance (within 15 m from the target). This system can be used in scenarios that require autonomous cruise, such as self-powered inspections of UAVs, patrols in parks, etc.

scholarly journals Multi-Instance Inertial Navigation System for Radar Terrain Imaging

2020 ◽  
Vol 12 (21) ◽  
pp. 3639
Author(s):  
Michal Labowski ◽  
Piotr Kaniewski
Keyword(s):  
Navigation System ◽  
Inertial Navigation System ◽  
Inertial Navigation ◽  
Navigation Systems ◽  
Time Duration ◽  
Navigation Data ◽  
Positioning Errors ◽  
Measurement Session ◽  
Single Aperture ◽  
Gps System

Navigation systems used for the motion correction (MOCO) of radar terrain images have several limitations, including the maximum duration of the measurement session, the time duration of the synthetic aperture, and only focusing on minimizing long-term positioning errors of the radar host. To overcome these limitations, a novel, multi-instance inertial navigation system (MINS) has been proposed by the authors. In this approach, the classic inertial navigation system (INS), which works from the beginning to the end of the measurement session, was replaced by short INS instances. The initialization of each INS instance is performed using an INS/GPS system and is triggered by exceeding the positioning error of the currently operating instance. According to this procedure, both INS instances operate simultaneously. The parallel work of the instances is performed until the image line can be calculated using navigation data originating only from the new instance. The described mechanism aims to perform instance switching in a manner that does not disturb the initial phases of echo signals processed in a single aperture. The obtained results indicate that the proposed method improves the imaging quality compared to the methods using the classic INS or the INS/GPS system.

An Overview of Positioning and Data Fusion Techniques Applied to Land Vehicle Navigation Systems

2010 ◽  
pp. 219-246 ◽  
Author(s):  
Denis Gingras
Keyword(s):  
Data Fusion ◽  
Mathematical Framework ◽  
Positioning System ◽  
Navigation Systems ◽  
Positioning Systems ◽  
Future Evolution ◽  
Land Vehicle Navigation ◽  
One Step ◽  
Definition Of ◽  
Position Estimate

In this chapter, the authors will review the problem of estimating in real-time the position of a vehicle for use in land navigation systems. After describing the application context and giving a definition of the problem, they will look at the mathematical framework and technologies involved to design positioning systems. The authors will compare the performance of some of the most popular data fusion approaches and provide some insights on their limitations and capabilities. They will then look at the case of robustness of the positioning system when one or some of the sensors are faulty and will describe how the positioning system can be made more robust and adaptive in order to take into account the occurrence of faulty or degraded sensors. Finally, they will go one step further and explore possible architectures for collaborative positioning systems, whereas many vehicles are interacting and exchanging data to improve their own position estimate. The chapter is concluded with some remarks on the future evolution of the field.

scholarly journals The Basic Architecture of the System with the A-GNSS Receiver

2019 ◽  
Vol 292 ◽  
pp. 04010
Author(s):  
Lucjan Setlak ◽  
Rafał Kowalik
Keyword(s):  
Mathematical Model ◽  
Research Literature ◽  
Navigation Systems ◽  
Practical Applications ◽  
Gnss Receiver ◽  
System A ◽  
System Solution ◽  
Specific Object ◽  
Mobile Receiver ◽  
Gps System

The paper presents the results of obtained research defining the accuracy of determining the position of a specific object (aircraft, UAV), equipped with a mobile receiver operating the navigation system A-GNSS. The Assisted GNSS technology is designed to improve the performance of the GNSS receiver by reducing the time needed for the receiver to calculate its location. It also increases the sensitivity of the received signal by the receiver, as a result, the accuracy of the determined position of a specific object can be improved. Thanks to its application, the radio-navigation receiver becomes compatible with the requirements of current standards, and what is associated with it this kind of technology has become an important part of the cellular industry. The aim of the article is to examine the solution of A-GPS system and to demonstrate its effectiveness in the process of determining the position of the UAV object. The paper presents aspects of the functionality of the A-GPS system solution work, mathematical model of object position determination using A-GNSS system and discusses the technology that is used for the integration of navigation systems with cellular network. In the final part of the work, based on the analysis of the research literature, the presented mathematical model and simulations, conclusions were formulated, which are reflected in practical applications.

A Self-Sensing Method for IPMC Actuator

2008 ◽  
Vol 56 ◽  
pp. 111-115 ◽  
Author(s):  
Byung Geun Ko ◽  
Hyok Chon Kwon ◽  
Song Jun Lee
Keyword(s):  
Electric Charge ◽  
Position Control ◽  
Conductive Polymer ◽  
Metal Composite ◽  
Position Information ◽  
The Status ◽  
Polymer Metal ◽  
Accurate Position ◽  
Novel Method ◽  
Electrically Charged

This paper describes a novel method of self-sensing Ion-conductive Polymer Metal Composite (IPMC) actuator. Unlike the previous self-sensing technique, the proposed principle is based on the electric charge of the IPMC itself, which is correlated with its curvature. At the normal state, IPMC is electrically charged, and the amount varies according to the status of IPMC. While it is operated as an actuator, it also gives position information in the form of the electric charge amount, which is utilized for fast and accurate position control. In order to get the bending status of the actuator, the instantaneous voltage of IPMC is measured during the open state for input signal. The uncomplicated system is constructed to verify if the developed method is effective for the selfsensing actuator and evaluated by the experimental basis. The way to actuate the IPMC with selfsensing is a supplying discrete signal as an input, and it is also evaluated experimentally. This research also represents relatively simple structure for both actuation and sensing, which is very important factor to be implemented as a controller circuit for various applications.

scholarly journals Assessments of the Challenges of Hydrography and Accuracy of the Chart Information Based on Requirements on Nautical Charts in Tanzania

2021 ◽  
pp. 85-95
Author(s):  
Joel Michael Ojode ◽  
Bian Hogwei
Keyword(s):  
Qualitative Data ◽  
Secondary Data ◽  
Analysis Data ◽  
Primary Data ◽  
Navigation Systems ◽  
Position Information ◽  
Face To Face ◽  
Safe Navigation ◽  
Electronic Chart ◽  
Collecting Techniques

Many of the electronic chart position deviations that observed today come from past graphic collecting techniques of Nautical Chart.This study introduces an assessment of the challenges of hydrography and accuracy of the chart information based on requirements on nautical charts in Tanzania. The assessment of the challenges of hydrography and accuracy of the chart information is particularly important to strengthen data accuracy and meet the requirement of nautical charts in Tanzania. Primary data were collected through face-to-face interviews with the respondents and questionnaires as a tool. Secondary data obtained through, journals, articles, and report both published and unpublished. Quantitative data were analyzed by using SPSS whereas qualitative data analyzed by using content analysis. Data provided in this article will improve nautical navigational charts practices in Tanzania and reduce variation greatly in accuracy to help mariners make informed decisions based on the data in their on-board navigation systems. The article is relevant to the new IHO guide on how to assess the accuracy and reliability of depth and position information in nautical navigation charts. The recommendations have been arranged that nautical charts, which offer much considerable information for the safe navigation of ships, are able to work more efficiently. Key words: Hydrography, Chart Information, Nautical charts, Tanzania

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