Doppler rate measurements in standard and high sensitivity GPS receivers: Theoretical analysis and comparison

2010 ◽  
Author(s):  
Nadez Sokolova ◽  
Daniele Borio ◽  
Borje Forssell ◽  
Gerard Lachapelle
Keyword(s):  
Theoretical Analysis ◽  
High Sensitivity ◽  
Gps Receivers

Theoretical Analysis and Basic Experiments for the 3D Displacement Measurement Using Ring-Shaped Laser Beam

2005 ◽  
Vol 295-296 ◽  
pp. 295-300
Author(s):  
S. Usuki ◽  
Kazuyuki Enami ◽  
M. Hiraki ◽  
S. Takahashi ◽  
Kiyoshi Takamasu
Keyword(s):  
Theoretical Analysis ◽  
Laser Beam ◽  
Optical System ◽  
High Sensitivity ◽  
Displacement Measurement ◽  
Contact Method ◽  
New Ideas ◽  
3D Positioning ◽  
The One ◽  
Basic Experiments

For flexible 3D positioning of a complex 3D mechanism, it is needed to measure 3D displacement of the end-effecter of the mechanism in high precision and by non-contact method. It was common to use plural sensors or scales together to measure the 3D displacement. However, it is difficult to calibrate the sensitivities of the plural sensors or scales. A novel 3D displacement measurement is proposed using an optical system in which lens focuses are collected at the center of the sphere, which has been used for the radius measurement of the sphere. Instead of facing in the XY direction that has high sensitivity, new ideas are necessary for the measurement in the Z direction of the optics where focuses are collected at the center of the sphere. The displacement in the XY direction and the one in the Z direction can be measured at the same time by using a ring-shaped laser beam instead of a simple ray.

scholarly journals Theoretical Analysis of a Microring Resonator Array with High Sensitivity and Large Dynamic Range Based on a Multi-Scale Technique

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 1987
Author(s):  
Wenqin Mo ◽  
Huiyun Liu ◽  
Fang Jin ◽  
Junlei Song ◽  
Kaifeng Dong
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Microring Resonator ◽  
Large Dynamic Range ◽  
Multi Scale

RISK AWARENESS TO EPIDEMIC INFORMATION AND SELF-RESTRICTED TRAVEL BEHAVIOR ON CONTAGION

2021 ◽  
pp. 2150001
Author(s):  
WEN-JUAN XU ◽  
CHEN-YANG ZHONG ◽  
HUI-FEN YE ◽  
RONG-DA CHEN ◽  
TIAN QIU ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Risk Aversion ◽  
Travel Behavior ◽  
Functional Relation ◽  
High Sensitivity ◽  
Risk Awareness ◽  
Rapid Progress ◽  
Sis Model ◽  
Encounter Probability ◽  
Global Movement

By incorporating delayed epidemic information and self-restricted travel behavior into the SIS model, we have investigated the coupled effects of timely and accurate epidemic information and people’s sensitivity to the epidemic information on contagion. In the population with only local random movement, whether the epidemic information is delayed or not has no effect on the spread of the epidemic. People’s high sensitivity to the epidemic information leads to their risk aversion behavior and the spread of the epidemic is suppressed. In the population with only global person-to-person movement, timely and accurate epidemic information helps an individual cut off the connections with the infected in time and the epidemic is brought under control in no time. A delay in the epidemic information leads to an individual’s misjudgment of who has been infected and who has not, which in turn leads to rapid progress and a higher peak of the epidemic. In the population with coexistence of local and global movement, timely and accurate epidemic information and people’s high sensitivity to the epidemic information play an important role in curbing the epidemic. A theoretical analysis indicates that people’s misjudgment caused by the delayed epidemic information leads to a higher encounter probability between the susceptible and the infected and people’s self-restricted travel behavior helps reduce such an encounter probability. A functional relation between the ratio of infected individuals and the susceptible-infected encounter probability has been found.

Positional Accuracy of Assisted GPS Data from High-Sensitivity GPS-enabled Mobile Phones

2011 ◽  
Vol 64 (3) ◽  
pp. 381-399 ◽  
Author(s):  
Paul A. Zandbergen ◽  
Sean J. Barbeau
Keyword(s):  
Mobile Phone ◽  
Mobile Phones ◽  
High Sensitivity ◽  
Harsh Environments ◽  
Gps Data ◽  
Positional Accuracy ◽  
Gps Receivers ◽  
Location Data ◽  
Assisted Gps ◽  
The Difference

Utilizing both Assisted GPS (A-GPS) techniques and new high-sensitivity embedded GPS hardware, mobile phones are now able to achieve positioning in harsh environments such as urban canyons and indoor locations where older embedded GPS chips could not. This paper presents an empirical analysis of the positional accuracy of location data gathered using a high-sensitivity GPS-enabled mobile phone. The performance of the mobile phone is compared to that of regular recreational grade GPS receivers. Availability of valid GPS position fixes on the mobile phones tested was consistently close to 100% both outdoors and indoors. During static outdoor testing, positions provided by the mobile phones revealed a median horizontal error of between 5·0 and 8·5 m, substantially larger than those for regular autonomous GPS units by a factor of 2 to 3. Horizontal errors during static indoor testing were larger compared to outdoors, but the difference in accuracy between mobile phones and regular GPS receivers was reduced. Despite the modest performance of A-GPS on mobile phones, testing under various conditions revealed that very large errors are not very common. The maximum horizontal error during outdoor testing never exceeded 30 metres and during indoor testing never exceeded 100 metres. Combined with the relatively consistent availability of valid GPS position fixes under varying conditions, the current study has confirmed the reliability of A-GPS on mobiles phones as a source of location information for a range of different LBS applications.

scholarly journals PERFORMANCE ANALYSIS OF LOW-COST SINGLE-FREQUENCY GPS RECEIVERS IN HYDROGRAPHIC SURVEYING

2017 ◽  
Vol XLII-4/W5 ◽  
pp. 67-71 ◽  
Author(s):  
M. Elsobeiey
Keyword(s):  
Low Cost ◽  
High Sensitivity ◽  
Single Frequency ◽  
Environment Protection ◽  
Dual Frequency ◽  
Gps Receivers ◽  
Survey Techniques ◽  
Different Types ◽  
Minimum Requirements ◽  
Hydrographic Surveying

The International Hydrographic Organization (IHO) has issued standards that provide the minimum requirements for different types of hydrographic surveys execution to collect data to be used to compile navigational charts. Such standards are usually updated from time to time to reflect new survey techniques and practices and must be achieved to assure both surface navigation safety and marine environment protection. Hydrographic surveys can be classified to four orders namely, special order, order 1a, order 1b, and order 2. The order of hydrographic surveys to use should be determined in accordance with the importance to the safety of navigation in the surveyed area. Typically, geodetic-grade dual-frequency GPS receivers are utilized for position determination during data collection in hydrographic surveys. However, with the evolution of high-sensitivity low-cost single-frequency receivers, it is very important to evaluate the performance of such receivers. This paper investigates the performance of low-cost single-frequency GPS receivers in hydrographic surveying applications. The main objective is to examine whether low-cost single-frequency receivers fulfil the IHO standards for hydrographic surveys. It is shown that the low-cost single-frequency receivers meet the IHO horizontal accuracy for all hydrographic surveys orders at any depth. However, the single-frequency receivers meet only order 2 requirements for vertical accuracy at depth more than or equal 100 m.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Microdiffraction Patterns of Small Metallic Particles II; Theoretical Analysis

1982 ◽  
Vol 40 ◽  
pp. 668-669
Author(s):  
A. Gómez ◽  
P. Schabes-Retchkiman ◽  
M. José-Yacamán ◽  
T. Ocaña
Keyword(s):  
Experimental Data ◽  
Electron Diffraction ◽  
Theoretical Analysis ◽  
Size Range ◽  
Dynamical Theory ◽  
Metallic Particles ◽  
Splitting Effect

The splitting effect that is observed in microdiffraction pat-terns of small metallic particles in the size range 50-500 Å can be understood using the dynamical theory of electron diffraction for the case of a crystal containing a finite wedge. For the experimental data we refer to part I of this work in these proceedings.

Sign in / Sign up

Export Citation Format

Share Document