System phase bias estimation of the Chung-Li VHF radar

2002 ◽  
pp. 259-264
Author(s):  
R.M. Kuong ◽  
Y.H. Chu ◽  
S.Y. Su ◽  
C.L. Su
Keyword(s):  
Bias Estimation ◽  
Vhf Radar ◽  
Phase Bias ◽  
System Phase

A novel phase bias estimation method for multichannel HRWS SAR system in azimuth based on RDS analysis

2020 ◽  
Vol 12 (1) ◽  
pp. 42-50
Author(s):  
Jianhui Zhao ◽  
Kuan Wang ◽  
Ling Wang ◽  
Zhengwei Guo ◽  
Ning Li
Keyword(s):  
Estimation Method ◽  
Bias Estimation ◽  
Phase Bias

scholarly journals Extended Application of a Novel Phase Calibration Approach of Multiple-Frequency Range Imaging to the Chung-Li and MU VHF Radars

2009 ◽  
Vol 26 (11) ◽  
pp. 2488-2500 ◽  
Author(s):  
Jenn-Shyong Chen ◽  
Ching-Lun Su ◽  
Yen-Hsyang Chu ◽  
Gernot Hassenpflug ◽  
Marius Zecha
Keyword(s):  
Time Delay ◽  
Double Layers ◽  
Small Scale ◽  
Multiple Frequency ◽  
Frequency Range ◽  
Range Imaging ◽  
Vhf Radar ◽  
Phase Calibration ◽  
Phase Bias ◽  
Calibration Approach

Abstract Multiple-frequency range imaging (RIM), designed to improve the range resolution of radar echo distribution, is now available for the recently upgraded Chung-Li VHF radar (24.9°N, 121.1°E). To complete the RIM technique of this radar, a novel phase calibration approach, proposed initially for the Ostsee Wind (OSWIN) VHF radar, was employed to examine the effects of phase bias and the range-weighting function on the received radar echoes. The estimated phase bias indicated a time delay of ∼1.83 μs for the signal in the radar system. In contrast, such a time delay is more difficult to determine from the phase distribution of two-frequency cross-correlation functions. The same calibration approach was also applied successfully to the middle and upper atmosphere (MU) radar (34.85°N, 136.11°E) and revealed a time delay of ∼0.33 μs for the radar parameters employed. These calibration results for various radars demonstrate the general usability of the proposed calibration approach. With the high-resolution performance of RIM, some small-scale Kelvin–Helmholtz (KH) billows, double-layer structures, and plumelike structures in the troposphere that cannot be seen in height–time intensity plots have been recognized in present observations. The billows and double layers were found to be closely related to strong vertical wind shear and small Richardson number, supporting the hypothesis of a dynamic process of KH instability. On the other hand, the plumelike structures were observed to grow out of a wavy layer and could be attributed to saturation and breaking of gravity waves. These fine structures have shown some remarkable features resolved by the RIM method applied to VHF radars in the lower atmosphere.

scholarly journals Multi-GNSS Relative Positioning with Fixed Inter-System Ambiguity

2019 ◽  
Vol 11 (4) ◽  
pp. 454 ◽  
Author(s):  
Hua Chen ◽  
Weiping Jiang ◽  
Jiancheng Li
Keyword(s):  
Double Difference ◽  
Relative Positioning ◽  
New Approach ◽  
Gnss Positioning ◽  
Ambiguity Fixing ◽  
Single Difference ◽  
Phase Bias ◽  
System Phase

In multi-GNSS cases, two types of Double Difference (DD) ambiguity could be formed including an intra-system ambiguity and an inter-system ambiguity, which are identified as the DD ambiguity between satellites from the same and from different GNSS systems, respectively. We studied the relative positioning methods using intra-system DD observations and using Un-Difference (UD) observations, and developed a frequency-free approach for fixing inter-system ambiguity based on UD observations for multi-GNSS positioning, where the inter-system phase bias is calculated with the help of a fixed Single-Difference (SD) ambiguity. The consistency between the receiver-end uncalibrated phase delays (RUPD) and the SD ambiguity were investigated and the positioning performance of this new approach was assessed. The results show that RUPD could be modeled as a constant if the receiver were tracking satellites continuously. Furthermore, compared to the method using DD observations with only an intra-system DD ambiguity fixed, the new ambiguity fixing approach has a better performance, especially in hard environments with a large cut-off angle or serve signal obstructions.

scholarly journals Accounting for Signal Distortion Biases for Wide-Lane and Narrow-Lane Phase Bias Estimation with Inhomogeneous Networks

2022 ◽  
Vol 14 (1) ◽  
pp. 191
Author(s):  
Chuang Shi ◽  
Yuan Tian ◽  
Fu Zheng ◽  
Yong Hu
Keyword(s):  
Large Data ◽  
Satellite System ◽  
Navigation Satellite ◽  
Signal Distortion ◽  
Bias Estimation ◽  
Data Set ◽  
Ambiguity Fixing ◽  
Wide Lane ◽  
Phase Bias ◽  
Global Navigation Satellite

Due to different designs of receiver correlators and front ends, receiver-related pseudorange biases, called signal distortion biases (SDBs), exist. Ignoring SDBs that can reach up to 0.66 cycles and 10 ns in Melbourne-Wübbena (MW) and ionosphere-free (IF) combinations can negatively affect phase bias estimation. In this contribution, we investigate the SDBs and evaluate the impacts on wide-lane (WL) and narrow-lane (NL) phase bias estimations, and further propose an approach to eliminating these SDBs to improve phase bias estimation. Based on a large data set of 302 multi-global navigation satellite system (GNSS) experiment (MGEX) stations, including 5 receiver brands, we analyze the characteristics of these SDBs The SDB characteristics of different receiver types for different GNSS systems differ from each other. Compared to the global positioning system (GPS) and BeiDou navigation satellite system (BDS), SDBs of Galileo are not significant; those of BDS-3 are significantly superior to BDS-2; Septentrio (SEPT) receivers show the most excellent consistency among all receiver types. Then, we apply the corresponding corrections to phase bias estimation for GPS, Galileo and BDS. The experimental results reveal that the calibration can greatly improve the performance of phase bias estimation. For WL phase biases estimation, the consistencies of WL phase biases among different networks for GPS, Galileo, BDS-2 and BDS-3 improve by 89%, 77%, 76% and 78%, respectively. There are scarcely any improvements of the fixing rates for Galileo due to its significantly small SDBs, while for GPS, BDS-2 and BDS-3, the WL ambiguity fixing rates can improve greatly by 13%, 27% and 14% after SDB calibrations with improvements of WL ambiguity fixing rates, the corresponding NL ambiguity fixing rates can further increase greatly, which can reach approximately 16%, 27% and 22%, respectively. Additionally, after the calibration, both WL and NL phase bias series become more stable. The standard deviations (STDs) of WL phase bias series for GPS and BDS can improve by more than 46%, while those of NL phase bias series can yield improvements of more than 13%. Ultimately, the calibration can make more WL and NL ambiguity residuals concentrated in ranges within ±0.02 cycles. All these results demonstrate that SDBs for phase bias estimation cannot be ignored and must be considered when inhomogeneous receivers are used.

Phase bias estimation for multi‐channel HRWS SAR based on Doppler spectrum optimisation

2016 ◽  
Vol 52 (21) ◽  
pp. 1805-1807 ◽  
Author(s):  
Zhibin Wang ◽  
Yanyang Liu ◽  
Zhenfang Li ◽  
Gang Xu ◽  
Junli Chen
Keyword(s):  
Doppler Spectrum ◽  
Bias Estimation ◽  
Phase Bias
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