The Comparative Analysis and Research of the Correction Model on Troposphere Delay

2012 ◽  
Vol 166-169 ◽  
pp. 960-963
Author(s):  
Chun Lai Dong
Keyword(s):  
Atmospheric Pressure ◽  
Choice Model ◽  
Paper Briefly ◽  
Angle Variation ◽  
Correction Model ◽  
Correct Model ◽  
Correction Effect ◽  
Time Calculation ◽  
Reasonable Choice ◽  
Delay Correction

This paper briefly describes the troposphere delay correction model, It developed a software using the real-time calculation of the troposphere delay corrections modified value. Based on the concept of sensitivity, Respectively on temperature, atmospheric pressure and high Angle variation, drawing analyzes correction effect of three correct model (Hopfield, Saastamoinen and Black), making a reasonable choice model of beneficial conclusion.

scholarly journals Long-term Performance Evaluation for Ionospheric Delay Correction of BeiDou Navigation Satellite System

2019 ◽  
Vol 131 ◽  
pp. 01075
Author(s):  
Chen Liu ◽  
Yi Jiang ◽  
Ye Chen ◽  
Ao Xu ◽  
Junpeng Li ◽  
...  
Keyword(s):  
Satellite System ◽  
Ionospheric Delay ◽  
Navigation Satellite ◽  
Dual Frequency ◽  
Correction Model ◽  
Beidou Navigation Satellite System ◽  
Correction Rate ◽  
Klobuchar Model ◽  
Delay Correction ◽  
Ionospheric Grid

Ionospheric delay is one of the main errors in the satellite navigation and positioning system. At present, ionospheric delay correction model and grid ionospheric information are provided to correct the error in BeiDou Navigation Satellite System (BDS). The ionospheric delay correction model is the Klobuchar model with 8 parameters at the geographic latitude for basic navigation. Grid ionospheric information is the ionospheric grid map covering China region for enhanced services. The dual-frequency pseudo-range combination data and ionospheric data from 2013 to 2018 have been used to make comprehensive assessments of the correction performance of BDS Klobuchar model and ionospheric grid information. The average correction rate of ionospheric grid information is about 85%, and the average correction rate of BDS Klobuchar model is about 73%. The correction accuracy of BDS Klobuchar model varies little, and the ionospheric grid information has a single-peak structure. The correction accuracy in summer and autumn is slightly higher than that in winter and spring. Changes in solar activity have a greater impact on BDS Klobuchar model correction bias. Ionospheric grid information owns relatively strong anti-disturbance ability, and BDS Klobuchar model also has a definite anti-disturbance capability compared with the GPS Klobuchar model.

Research on the Application of IBE in IEC61850 Substation Automation System

2011 ◽  
Vol 130-134 ◽  
pp. 2805-2808
Author(s):  
Shao Ping Yin
Keyword(s):  
Public Key Infrastructure ◽  
Public Key ◽  
Communication Security ◽  
Automation System ◽  
Paper Briefly ◽  
Iec 61850 ◽  
Smart Grid Communications ◽  
Identity Based ◽  
Substation Automation ◽  
Reasonable Choice

In order to reap the benefits promised by the Smart Grid, communications between the IEDs in IEC 61850 Substation Automation System (SAS) will need to be made much more secure.Traditional security solutions based on Public Key Infrastructure (PKI) are calculation intensive and introduces latency that will be difficult to meet substation environmental and electrical requirements, so they are not well suited for IEC 61850 SAS. Identity based encryption (IBE) schemes, introduced by Shamir in 1984 [5] are based on the idea to use participant’s unique identities as public key and public key directories are unnecessary. Thus, utilizing IBE in IEC 61850 SAS is a reasonable choice. This paper briefly introduces the features of IEC 61850 SAS communication security and IBE and then propose an IBE-based Self Private Key Generated (SPKG) encryption scheme to establish encryption system in IEC 61850 SAS. Advantages of this SPKG Scheme are also discussed in the paper.

scholarly journals An empirical zenith wet delay correction model using piecewise height functions

2018 ◽  
Author(s):  
YiBin Yao ◽  
YuFeng Hu
Keyword(s):  
Tropospheric Delay ◽  
Test Results ◽  
Correction Model ◽  
Height Functions ◽  
Zenith Wet Delay ◽  
Space Geodetic Techniques ◽  
Vertical Variations ◽  
Gpt2w Model ◽  
Modelling Methods ◽  
Delay Correction

Abstract. Tropospheric delay is an important error source in space geodetic techniques. The temporal and spatial variations of the zenith wet delay (ZWD) are very large, and thus limit the accuracy of tropospheric delay modelling. Thus it is worthwhile undertaking research aimed at constructing a precise ZWD model. Traditional tropospheric modelling methods do not consider the effects of different heights on ZWD. Based on the analysis of vertical variations of ZWD, we divided the troposphere into three height intervals: below 2 km, 2 km to 5 km, and 5 km to 10 km, and determined the fitting functions for the ZWD within these height intervals. The global ZWD model HZWD, which considers the periodic variations of ZWD with a spatial resolution of 5° × 5°, is established using the ECMWF ZWD profiles from 2001 to 2010. Validated by the ECMWF ZWD data in 2015, the precisions of the ZWD estimation in the HZWD model over the three height intervals are improved by 1.4 mm, 0.9 mm, and 1.2 mm, respectively, compared to that of the currently best GPT2w model (23.8 mm, 13.1 mm, and 2.6 mm). The test results from ZWD data from 318 radiosonde stations show that the root mean square (RMS) error in the HZWD model over the three height intervals was reduced by 2 %, 5 %, and 33 %, respectively, compared to the GPT2w model (30.1 mm, 15.8 mm, and 3.5 mm) over the three height intervals. In addition, the spatial and temporal stabilities of the HZWD model are higher than those of GPT2w and UNB3m.

Establishment of a new tropospheric delay correction model over China area

2011 ◽  
Vol 54 (12) ◽  
pp. 2271-2283 ◽  
Author(s):  
ShuLi Song ◽  
WenYao Zhu ◽  
QinMing Chen ◽  
YueiAn Liou
Keyword(s):  
Tropospheric Delay ◽  
Correction Model ◽  
Delay Correction
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