Welcome to the homepage of Micro-Laboratory of Atmospheric
Research and Geomatics Engineering (Micro-LARGE)
Recently updated (This page was
last updated on 9 April 2024)
[9 April 2024] Prof.
George Zhizhao Liu wrote a Chinese article to celebrate the 70th
birthday of Prof. Hui Lin, his remarkable achievements in his career, and significant
contributions to a wide community. The article can be found here.
[9 April 2024] Prof.
Hui Lin and Prof. George Zhizhao Liu initiated the “Siben Forum(思本論壇)” and the first
Siben Forum was successfully organized at Jiangxi Normal University, Nanchang, Jiangxi,
January 5-7, 2024. The Chinese news can be found here.
[9 April 2024] Prof.
George Zhizhao Liu is invited by the 台灣地球觀測學會(Taiwan Group of
Earth Observation, TGEO) to attend the International Conference on Earth
Observations and Societal Impacts (ICEO&SI) / Symposium of the
International Association of Geo-informatics, IAG'i) (https://2024-iceo-si.weebly.com/),
to be held at Taiwan Central University (台灣中央大學) June 28 to July
2, 2024. The title of his talk at the ICEO&SI/IAG’i will be determined
later.
[9 April 2024] Prof. George Zhizhao Liu will convene the Atmospheric Sciences (AS) Session AS18 “Assimilation of
Space- and Ground-based Water Vapor Observations for Weather Forecasting and
GNSS Applications” from 2:00 PM - 3:30 PM on 25 June 2024 at the Meeting Room:
InterContinental at the 2024 AOGS Annual Meeting, to be held 23 to 28 June 2024
at the Alpensia and Yong Pyong Ski Resorts, In Pyeongchang, Gangwondo (Home to
2018 Winter Olympics), South Korea. The title of his talk at AOGS is: “Assimilating
FY-4A PWV Retrievals to Improve the WRF Forecasting Performance of Typhoon
Haikui”. Please note that K-ETA is temporarily waived for visitors from many regions/countries.
The Co-Conveners of the AS18 Session include: Dr Jonathan Jones (Met
Office, United Kingdom), Prof Jens Wickert (GFZ German Research Centre for
Geosciences and Technical University of Berlin, Germany), Prof Shu-Chih Yang
(National Central University, Taiwan), and Prof Kefei Zhang (China University
of Mining and Technology, China).
[9 April 2024] Prof. George Zhizhao Liu has been appointed as a Visiting Professor by
the Department of Earth, Ocean and Atmospheric Sciences (https://www.eoas.ubc.ca/),
The University of British Columbia (https://www.ubc.ca/), Vancouver,
BC Canada. He will visit UBC during 15
June 2024 to 14 August 2024.
[9
April 2024] Prof. George Zhizhao Liu was invited to give a talk at the 2024 年導航衛星氣象觀測技術研討會 at Guangzhou 10-12 April 2024 organized by 中國氣象局氣象探測中心、廣東省氣象局、廣西壯族自治區氣象局。The title of his talk is: Assimilating Microwave
Satellite's PWV data to improve the rainfall forecasting performance for the
2023 Typhoon Haikui-induced heavy rainfall.
[9
April 2024] Prof. George Zhizhao Liu was invited to give a talk at
the 2024（第四屆）民航空中交通管理科學技術交流會 at Beijing 10-12 April 2024 organized by 中國航空學會航空電子與空中交通管理分會、空地一體新航行系統技術全國重點實驗室。The title of his talk is: 空間天氣對飛行運行的影響以及對空中交通管理的決策建議。
[9
April 2024] Prof. George Zhizhao Liu was invited to give a talk at the 大飛機氣象前沿技術及應用研討會 at Shanghai 27-29 March 2024 organized by 中國氣象服務協會、中國民用航空局空中交通管理局航空氣象中心、《氣象科技進展》編輯部、and 中國商飛民用飛機試飛中心。The title of his talk is: 基於同化微波衛星PWV 數據提高2023 年颱風“海葵”強降水預報性能。
[17 Aug
2023] Prof. George Zhizhao Liu’s list of journal papers is published here. Prof. Liu’s Lab has
published 111 journal papers so far.
[08 Aug 2023] Prof. George Zhizhao Liu is invited to give an oral presentation
at the 5th National Symposium of the Mesoscale Meteorology held in
Yinchuan, Ningxia, China, 9-12 August 2023. Prof. Liu’s presentation title is:
Assimilating OLCI and MODIS NIR calibrated Precipitable Water Vapor (PWV) to
improve weather forecasting performance. This is Prof. Liu’s 2nd
time to attend “atmospheric science/meteorology” related session in a national
conference. This is also the 4th time for Prof. Liu’s to attend
“atmospheric science/meteorology” related session in national/international
conferences.
[08 Aug
2023] Prof.
George Zhizhao Liu’s Lab did two presentations at the 20th
Annual Meeting of the Asia Oceania Geosciences Society (AOGS) held in Singapore
30 July to 04 August 2023. PhD students Yangzhao Gong and Jiafei Xu did their
oral presentations in the Atmospheric Science session (AS06): Assimilation of
Space- and Ground-based Water Vapor Observations for Weather Forecasting and
GNSS Applications. This is Prof. Liu’s 2nd time to attend
“atmospheric science/meteorology” related session in an international
conference.
[08 Aug 2023] Prof. George Zhizhao Liu did two oral
presentations at the 28th IUGG Assembly held in Berlin, Germany,
11-20 July 2023. Prof. Liu’s both presentations are on Atmospheric Science.
This is Prof. Liu’s 1st time to attend “atmospheric
science/meteorology” related session in an international conference.
（photo credit: Dr. Jungang Wang, GFZ）
[08 Aug 2023] Prof. George Zhizhao Liu did one
invited oral presentation at the “2023
CPGPS Summit” held in Wuhan, China, 28-29 June 2023.
[08 Aug 2023] Prof. George Zhizhao Liu did one oral
presentation at the 5th Congress of China Geodesy and
Geophysics (CCGG) held in Wuhan, China, 21-23 April 2023. Prof. Liu’s
presentation is on Atmospheric Science with a title “Assimilating Sentinel-3
All-sky PWV Retrievals to Improve the WRF Forecasting Performance over the
South China”. This is Prof. Liu’s 1st time to attend “atmospheric
science/meteorology” related session in a national conference.
[02 Feb 2023] Croucher
Summer Course 2023 GPS/Beidou/GNSS Satellite Positioning and Navigation and Earth
Observation
Hong Kong Polytechnic UniversityHong Kong, P. R. China
28 May (Sunday) to 3 June (Saturday),
2023
Click here to registration online on the Google form before it is full.
[30 January 2023] Dr. Shiwei Liu
successfully completed his PhD oral exam in November 2022 and was recently
awarded PhD degree by the Graduate School of Hong Kong PolyU.
[30 January 2023] Dr. Jie He successfully
completed her PhD oral exam in 2021 and was awarded the “Faculty Award for
Outstanding PhD Thesis” by Faculty of Construction and Environment (FCE), Hong
Kong PolyU in 2022.
[30 January 2023] Dr. Liu’s General
Research Fund (GRF) project was successfully funded by the Hong Kong Research
Grants Council (RGC). The result was announced on June 30, 2022. This was the No. 9 GRF
project received by Dr. Liu since he joined PolyU in 2009.
[30 January 2023] Dr. Liu’s rank of successful
General Research Fund (GRF) applications funded by the Hong Kong Research
Grants Council (RGC). The GRF is the most widely research grant and every year
almost all the research active academic staff across 8 public universities in
Hong Kong apply for the GRF projects. As of today, Dr. Liu’s GRF success rank
among ALL the 5795 funded
academic staff (plus some unfunded academic staff) in Hong Kong during the
period 2006-2022 is given below (from unofficial sources):
Rank=231, # of Projects= 9,
total_dollars=$ 7053500, average=$ 783722.22. mean # of projects received by ALL the 5795 funded academic staff in Hong Kong during the period 2006-2022
= 3.01 per funded academic
staff. Dr. Liu’s # of funded GRF project is 5.99 higher than the mean value
3.01 across Hong Kong’s 8 public universities.
Rank of Dr. Liu, Zhizhao in Hong Kong is: 231/5795=3.99%
As of today, Dr. Liu’s GRF success rank
among ALL the 923 funded
academic staff (plus some unfunded academic staff) in Hong Kong Polytechnic
University (PolyU) during the period 2006-2022 is given below:
Rank=25, # of Projects= 9,
total_dollars=$ 7053500, average=$ 783722.22. mean # of projects received by ALL the 923 funded academic staff in PolyU during the period 2006-2022
= 2.85 per academic staff. Dr. Liu’s # of funded GRF project is 6.15 higher than the mean value
2.85 across Hong Kong PolyU.
Rank of Dr. Liu, Zhizhao in Hong Kong PolyU is: 25/923=2.71%
[31 March 2021] Here are the impact factors
of a list of journals where we often publish papers. Click here. We will regularly
update this file. Please visit the website regularly to check up the update.
[30 March 2021] The Micro-LARGE Lab is very
pleased to announce that the Gail (Jia)’s paper titled “Water Vapor Retrieval
from MERSI NIR Channels of Fengyun-3B Satellite Using Ground-based GPS Data” has recently been accepted by Remote Sensing of Environment, which has an Impact Factor of 9.085 as of March
2021. This is Micro-LARGE Lab’s first time to publish at Remote Sensing of
Environment. Also it is so far the paper of the highest Impact Factor at the
Micro-LARGE’s Lab. Congratulations to Gail!
[30 March 2021] The Micro-LARGE Lab is very
pleased to announce that the following papers have been published/accepted
recently. Congratulations to all the contributors: Shiwei and Jia!
|
Yu, Shiwei*, Zhizhao Liu (✉️) (2021), The Ionospheric Condition and GPS
Positioning Performance during the 2013 Tropical Cyclone Usagi Event in the
Hong Kong Region, Earth Planets Space, 73, 66.
https://doi.org/10.1186/s40623-021-01388-2. |
|
He, Jia*, Zhizhao Liu (✉️) (2020), Water Vapor Retrieval from MERSI NIR
Channels of Fengyun-3B Satellite Using Ground-based GPS Data, Remote Sensing of Environment,
accepted. |
|
Yu, Shiwei*, Zhizhao Liu (✉️) (2020), Tropical cyclone-induced periodical
positioning disturbances during the Hato (1713) in the Hong Kong region, GPS
Solutions, accepted. |
|
He, Jia*, Zhizhao Liu (✉️) (2020), Applying the North Hemisphere
Developed New Water Vapor Retrieval Algorithm to the South Hemisphere, IEEE Transactions on Geoscience and
Remote Sensing (TGRS), accepted. |
|
Yu, Shiwei*, Zhizhao Liu (✉️) (2020), Temporal and Spatial Impact of the
Precipitable Water Vapor on the GPS Relative Positioning during the Hato
(2017) in Hong Kong and Taiwan Regions, Earth and Space Science, IF: 2.31, accepted 31 Jan 2021. |
[24 August 2020] The Micro-LARGE Lab is
currently recruiting one PhD student to work on GNSS Precise Point Positioning
(PPP). Full scholarship is available. Please contact Dr. Liu @ lszzliu@polyu.edu.hk if you are
interest. This scholarship is supported by Dr. Liu’s recent Hong Kong RGC GRF
research projects fund.
[24 August 2020] 28 August 2020, Dr. Liu
will be invited by the Department to share his RGC GRF project application
experience with his colleagues, particularly the young colleagues.
[24 August 2020] New PhD student Mr. Jiafei
Xu has arrived at Hong Kong and he will register in September for his PhD
program at Micro-LARGE group.
[24 August 2020] We are very pleased to announce that
the following papers have been published or accepted recently.
1.
Gong, Yangzhao*, Zhizhao
Liu () (2020), Evaluating the Accuracy
of Jason-3 Water Vapor Product Using PWV Data from Global Radiosonde and GNSS
Stations, IEEE Transactions on Geoscience and Remote Sensing (TGRS),
accepted. IF: 5.630 (PolyU Faculty
and Department A-journal)
2.
He, Jia*, Zhizhao
Liu () (2020), Refining MODIS NIR Atmospheric
Water Vapor Retrieval Algorithm Using GPS-derived Water Vapor Data. IEEE Transactions on Geoscience and Remote
Sensing (TGRS), accepted August 2020, IF:
5.630 (PolyU Faculty and Department A-journal)
3.
Li, Guozhu, Baiqi Ning, Yuichi Otsuka, Mangalathayil
Ali Abdu, Prayitno Abadi, Zhizhao Liu, Luca Spogli, and Weixing
Wan (2020), Challenges to equatorial plasma bubble and ionospheric
scintillation short-term forecasting and future aspects in East and Southeast
Asia, Surveys in Geophysics, accepted. IF:
5.544 (PolyU Faculty and Department A-journal)
4.
Zhu, Mingchen*, Zhizhao
Liu (), Wusheng Hu (2020), Observing
Water Vapor Variability during Three Super Typhoon Events in Hong Kong Based on
GPS Water Vapor Tomographic Modeling Technique, Journal of Geophysical
Research: Atmospheres, IF: 3.63, accepted 19 June 2020.
5.
He, Jia*, Zhizhao
Liu () (2020), Water Vapor Retrieval
From MODIS NIR Channels Using Ground-Based GPS Data. IEEE Transactions on Geoscience and Remote Sensing (TGRS), 58 (5):
3726–37, 12 pages, https://doi.org/10.1109/TGRS.2019.2962057, IF: 5.630 (PolyU Faculty and Department A-journal)
[24 August 2020] Dr. Liu (Team Leader) and
colleagues are very proud to receiver the “Dean’s Award for Outstanding
Achievement in Services (Team award)”. This is the single winning team in the
Faculty of FCE in this category in 2020. As a matter of fact, the Faculty of
FCE doesn’t award this “Service Award” every year as the selection criteria of
“Service Award” is high.
[24 August 2020] Same as last year, Dr. Liu
successfully secured a research fund from the Hong Kong RGC (Research Grants
Council) General Research Fund (GRF) upon the announcement of the outcome on 30
June 2020. The success rate of Hong Kong’s RGC GRF research project
applications is about 35%, which is about 10% higher of the US NSF 25%. Basically all the academic staff at the Hong
Kong universities attach importance to the RGC GRF application, as the success
rate is widely regarded an indicator to measure the research excellence. Over
the past 11 years, Dr. Liu successfully secured 7 RGC GRF projects, with a
success rate of 63.6%.
[25 May 2020] One Year-3 student visited my
office in the afternoon of 25 May 2020 and discussed a topic for her BSc Final
Year Project.
[25 May 2020] The presentation of BSc Final
Year Project was completed in this morning. Congratulations to Patrick.
[25 May 2020] We are glad to announce that
Dr. George Liu’s last year application for promotion to full professor has been
approved by the Department, Faculty, and University. Thank you all those who
have contributed and supported to the Micro-LARGE group. We pledge to work
harder to promote research excellence in the future.
[Sept. 2, 2016] We are pleased to see that
two co-authored papers have been accepted by the Journal of Geophysical Research - Space Physics, on the same day
September 01, 2016. One paper’s lead author is Dr. Tao YU, a professor at the
China University of Geoscience (Wuhan) and a Research Associate at PolyU.
Another paper’s lead author is Dr. Sanjay Kumar, a Research Associate of PolyU.
Congratulations to Dr. YU and Dr. Kumar! Click the Research for more details.
[Sept. 2, 2016] We are pleased to announce
that Jenny Yang’s paper has been accepted the GPS Solutions, on 28 August 2016. Congratulations to Jenny! Click
the Research
for more details.
[Aug. 29, 2016] Dr. Liu’s Research Proposal
was successfully funded by the General Research Fund (GRF) Scheme of Research
Grants Council (RGC), the Hong Kong SAR Government. The RGC’s fund application
is very competitive every year and only the real top quality proposals are
selected to be funded. The funding size to Dr. Liu’s project is HK$844,559, which
represents the largest
project in terms of funding size in the Faculty of Construction and
Environment, PolyU in 2016. PhD students are to be recruited and applications
are welcome!
[Aug. 29, 2016] Eventually our website has
been updated by myself. In the past one to two years, a number of students
promised to update/redesign my website but it was never realized.
[Dec. 03, 2014] We are pleased to share
with you that the following papers have been accepted for publication at top
journals.
Xu, Rui, Zhizhao Liu, and Wu Chen. 2014.
“Improved FLL-Assisted PLL with in-Phase Pre-Filtering to Mitigate Amplitude
Scintillation Effects.” GPS Solutions, June, 1–14.
doi:10.1007/s10291-014-0385-5.
Wong, Man Sing, Xiaomeng Jin, Zhizhao Liu,
Janet Nichol, and P. W. Chan. 2014. “Multi-Sensors Study of Precipitable Water
Vapour over Mainland China.” International Journal of Climatology, November,
n/a – n/a. doi:10.1002/joc.4199.
Weng, Duojie, Shengyue Ji, Wu Chen, and
Zhizhao Liu. 2014. “Assessment and Mitigation of Ionospheric Disturbance
Effects on GPS Accuracy and Integrity.” The Journal of Navigation 67 (03):
371–84. doi:10.1017/S0373463314000046.
Luo, Weihua, Zhizhao Liu, and Min Li. 2014.
“A Preliminary Evaluation of the Performance of Multiple Ionospheric Models in
Low- and Mid-Latitude Regions of China in 2010–2011.” GPS Solutions 18 (2):
297–308. doi:10.1007/s10291-013-0330-z.
Liu, Zhizhao, Biyan Chen, Sai T. Chan,
Yunchang Cao, Yang Gao, Kefei Zhang, and Janet Nichol. 2014. “Analysis and
Modelling of Water Vapour and Temperature Changes in Hong Kong Using a 40-Year
Radiosonde Record: 1973-2012.” International Journal of Climatology, April, n/a
– n/a. doi:10.1002/joc.4001.
Li, Zhongbin, Zhizhao Liu, and Wenzhong
Shi. 2014. “Semiautomatic Airport Runway Extraction Using a Line-Finder-Aided
Level Set Evolution.” IEEE Journal of Selected Topics in Applied Earth
Observations and Remote Sensing Early Access Online. doi:10.1109/JSTARS.2014.2298332.
[March 21, 2014] We are pleased to share
with you that the following papers have been accepted for publication at top
journals.
Biyan Chen and Zhizhao Liu (*) (2014),
Voxel-Optimized Regional Water Vapor Tomography and Comparison with Radiosonde
and Numerical Weather Model, Journal
of Geodesy, accepted (IF: 2.808)
Zhizhao Liu (*), Biyan Chen, Sai Tick Chan,
Yunchang Cao, Yang Gao, Kefei Zhang, and Janet Nichol (2014), Analysis and
modeling of water vapor and temperature changes in Hong Kong using a 40-year
radiosonde record: 1973-2012. International Journal of Climatology, accepted (IF: 2.479)
Cai, Changsheng, Xiaomin Luo, Zhizhao Liu
(*) and Qinqin Xiao (2014), Galileo Signal and Positioning Performance Analysis
Based on Four IOV Satellites. Journal of Navigation, accepted (IF: 0.618, Relative ranking within
Categories: Engineering, marine 5/14)
Zhongbin Li, Zhizhao Liu, and Wenzhong Shi
(*) (2014), Semiautomatic Airport Runway Extraction Using a Line-Finder-Aided
Level Set Evolution, IEEE Journal
of Selected Topics in Applied Earth Observations and Remote Sensing (IEEE
JSTARS), Accepted (2013 IF: 2.874)
[November
29, 2013] I am very pleased to
Dr. Liu’s application for the Croucher
Summer Course “GPS/Beidou/GNSS Satellite Positioning and Navigation
and Earth Observation” has
been successfully granted by The
Croucher Foundation Limited, Hong Kong, 5
years, 2014-2018. The generous support from The
Croucher Foundation Limited is HK$1,708,500, which will be
paid in three equal installments of HK$569,500. Thank you The
Croucher Foundation Limited!
[November
29, 2013] I am very pleased to
announce that TWO (2) Public
Policy Research (PPR) projects are funded. Dr. Liu is a Co-Investigator in these two
projects. Thank you Central Policy Unit, Government of Hong
Kong Special Administrative Region!
The project
information is:
2013, Co-Principal Investigator (Co-PI), “A
Remote Sensing Study of Solar Energy Supply in Cloud-prone Areas of Hong Kong”,
Public Policy Research Funding Scheme
(2013-2014), Central Policy Unit, Government of Hong Kong Special
Administrative Region (HKSAR), 12 months, HK$359,869.50. [PI: Dr. Charles Man Sing Wong, Assistant
Professor, Department of Land Surveying & Geo-Informatics, The Hong Kong
Polytechnic University]
2013,
Co-Principal Investigator (Co-PI),
“Study on the development potential and energy
incentives of rooftop solar photovoltaic applications in Hong Kong”, Public Policy Research Funding Scheme
(2013-2014), Central Policy Unit, Government of Hong Kong Special
Administrative Region (HKSAR), 12 months, HK$424,120. [PI: Dr. Vivien Lu, Associate Professor,
Department of Building Services Engineering, The Hong Kong Polytechnic
University]
[November 20, 2013] Dr. George Liu was
honored as a Guest Professor of the GNSS Research Center, Wuhan University.
[October 25, 2013] Dr. George Liu’s proposal
was funded by the University.
[October 08, 2013] Dr. George Liu joined
the HKIES society.
[September 22, 2013] We are very pleased to
announce that Dr. George Zhizhao Liu received the “Best Researcher of the Year
2013” from the Department of LSGI. This news was announced on 19 September 2013
by the Departmental Research Committee.
[August 18, 2013] We are very pleased to
announce that Dr. George Zhizhao Liu received the 2013 Dean’s Award. Dr. Liu
joined other 9 colleagues in the Faculty of Construction and Environment (FCE)
to receive this prestigious award. Also he is the only recipient from the
Department of LSGI. As the recipient of the Dean’s Award,
Dr. Liu will be honoured at the Faculty
Congregation and Prize Presentation Ceremony to be held November 2013 with a
cash prize of HK$15,000. In addition, he will be awarded a research grant of
HK$200,000 to support his future research!
More details can be found at the Faculty’s
eBulletin:
http://www.polyu.edu.hk/fce/eBulletin/public/issue33/#03
[July 08, 2013] We are very delighted to announce the
annual Hong Kong Research Grants Council (RGC)’s General Research Fund (GRF)
project application submitted by Dr. Liu last year is successfully funded!
This news was officially announced 28 June 2013. Dr.
Liu’s project titled “Investigating the Ionospheric Scintillation
Characteristics using Space- and Ground- Based GNSS Observations in Hong Kong
during Solar Maximum” is successfully selected to fund by the RGC for 36
months. This is one of PolyU’s 138 GRF projects funded by RGC this year. Dr.
Liu was successfully funded in the past 3 years in a row. One PhD student and
one Research Associate (or Research Assistant) will be recruited to work on
this project. Applicants must send email to contact Liu immediately.
[June 07, 2013] We are very delighted that the MicroLARGE Lab has
established the Hong Kong’s FIRST GNSS and Radiosonde collocation station at Hong Kong Observatory’s
facility at King’s Park, Kowloon, Hong Kong. This is the first time that the
GNSS station is established just nearby the Hong Kong’s only Radiosonde
station. Both GNSS receiver and Radiosonde are used to observe atmospheric
water vapor. The collocation of two observation techniques allows a direct
comparison of the water vapor measurements of these two methods. The Radiosonde
technique is traditionally believed a standard reference to which other water
vapor observation technique should be compared. The establishment of such a
facility will allow our researchers to gain more data to study the atmospheric
water vapor changes in Hong Kong and to have more insightful understanding of
the observation accuracy of each method.
[L to R: Dr. Weiwei Song (PolyU), Mr. Engineer (HKO), Dr. David Lam
(HKO), Mr. Wang-chun Woo (HKO), Dr. George Liu (PolyU)]
[L to R: Mr. Biyan Chen (PolyU), Dr. Weiwei Song (PolyU), Mr. Engineer
(HKO), Dr. David Lam (HKO), Mr. Wang-chun Woo (HKO)]
[May 26, 2013] Recently, Dr. Liu made a presentation of a paper titled
“A Comparison of GNSS-based Ionospheric Scintillation Observations in North and
South Hong Kong” at the recent 2013 Pacific PNT held at Honolulu, Hawaii, USA
during April 22-25, 2013. This paper was coauthored by Zhizhao Liu, Rui Xu, Yu
Morton, Jisheng Xu, Wouter Pelgrum, Steve Taylor, Wu Chen and Xiaoli Ding.
[May. 22, 2013] We are very pleased to announce that Dr. Liu is to
receive the Excellent Paper Award from the 2013 4th Chinese Satellite
Navigation Conference (CSNC 2013) in Wuhan, China.
In the recent 2013 China
Satellite Navigation Conference (CSNC) held May 15-17 in Wuhan, Dr. George
Zhizhao Liu from the Department of Land
Surveying & Geo-Informatics (LSGI) received the Excellent Paper Award for
his paper “The First PPP-based GPS Water Vapor Real-Time Monitoring System in
Pearl-River-Delta Region, China” co-authored with Research Associate Dr. Min
Li. This paper presents their research findings of developing the first
atmospheric water vapor real-time monitoring system for the Pearl-River-Delta
(PRD) region using the latest Global Positioning System (GPS) Precise Point
Positioning (PPP) technique. Based on their technique, now the amount of water
vapor in the atmosphere over the PRD region can be quickly and accurately
computed from GPS satellite signals. Since April 2012, the PolyU researchers
have been supplying their atmospheric water vapor data to the meteorological
agencies around the PRD region to support their daily services and research,
including Hong Kong Observatory, Macao Meteorological and Geophysical Bureau,
Guangdong Meteorological Bureau and Shenzhen Meteorological Bureau.
This
year is the first time for CSNC to have the Excellent Paper Award. Dr. Liu was
one of the nine award recipients out of 629 paper submissions. This research work was supported by the General
Research Fund (GRF) of Hong Kong Research Grants Council (RGC).
[May 11, 2013] We are very pleased to announce that
Dr. George Zhizhao Liu was given an honor of Individual Award of Shenzhen
Virtual University Park
for National Research Project, by the Shenzhen
Municipal Science and Technology Innovation Council December 2012.
[Jan. 04, 2013] Dr. Liu and his research team visited the Hong Kong
Observatory, Hong Kong Special Administrative Region (HKSAR). Dr. Liu was also
invited to give an open presentation titled “GNSS for Precise Water Vapor and
Ionosphere Space Weather Monitoring” for the HKO colleagues. Dr. Liu and his
team were guided by Mr. S. T. Chan, Senior Scientific Officer of HKO, to visit
the weather forecasting center.
[Dec. 12, 2012] The Inaugural Early Career Award Recipient (首届“杰出青年学者奖”), Hong Kong
Research Grants Council (RGC), Hong Kong Special Administrative Region (HKSAR).
Dr. Liu was one of the 19 recipients out of 334 applicants across all the
universities in Hong Kong in 2012 (success rate: 5.69%). He is also one of only
3 recipients in PolyU and one of 6 recipients in the Engineering Panel under
Hong Kong RGC.
Dr. Liu received the Early Career Award from the Chairman of the
Engineering Panel of Hong Kong Research Grants Council (Dec. 12, 2012)
The six recipients of Early Career Award of the Engineering Panel and
the Engineering Panel Chairman of Hong Kong Research Grants Council (Dec. 12,
2012)
[July 23, 2012] We are pleased to share with you that our research
project “Innovative Real-Time Cycle Slip Detection and
Rectification for High Precision GPS Positioning” led by Dr. George Zhizhao Liu is funded by the Early Career Scheme
(ECS), Hong Kong Research Grants Council (RGC), Hong Kong SAR Government. This
project, together with 19 other projects across all the universities in Hong
Kong, will be recognized with an
“Early Career Award” (ECA), which is the first time to give ECA in the history of
Hong Kong RGC.
For this project, one PhD student will be funded for three (3) years.
Interested applications are welcome to contact Dr. Liu.
[July 23, 2012] We are pleased to share with you that
our paper “Cycle slip detection and repair for
undifferenced GPS observations under high ionospheric activity” co-authored by Changsheng Cai • Zhizhao Liu •
Pengfei Xia • Wujiao Dai is published online @ GPS Solutions 4 July 2012. As of 23 July 2012 (20 days after the online
publication), this paper has been downloaded 174 times, ranked 2nd in the list of most downloaded
papers in the 30-days category. This paper can be downloaded @
http://www.springerlink.com/content/k214871257361300/
[May 29, 2012] The
Hong Kong GPS-based Real-time Water Vapor Monitoring System (GRWVMS) has been
successfully operating more than 40 days (since its first day 19 April 2012).
This is one of the countable GRWVMS in the world. To our knowledge, similar
systems are only available at a limited number of organizations, such as:
1. USA:
NOAA http://www.gpsmet.noaa.gov/
2. USA:
UCAR Suominet network: http://www.suominet.ucar.edu/
3. Netherlands:
KNMI (Royal Netherlands Meteorological Institute) http://www.knmi.nl/research/weather_observations/gps/real_time_IWV.html
[February 10, 2011] As of 10 Feb. 2011 our
paper (link
here) is ranked one of the 5 most downloaded papers in Journal of Geodesy
based on the downloads in the past 77 days since its first day of online
publication, one of the internationally well recognized journals in Geomatics.
This paper developed a fully
automated cycle slip detection and repair algorithm for dual-frequency GPS
carrier phase measurements. It can be safely said that the cycle slip problem
that have been hanging over the GPS community as long as the GPS history itself
(~30 years) is well resolved.
This algorithm is extremely effective
for high rate GPS data like 1Hz or higher. Virtually any size of cycle slips
can be detected and repaired.
For low rate GPS data (like 30 sec
data interval or larger) this algorithm can work for many cycle slip cases but
it might be a little difficulty for small cycle slips.
This method has been extensively
tested and examined in many scenarios such as:
o High dynamics (space-borne GPS
receiver payload on COSMIC satellite)
o Highly disturbed ionosphere (daily Kp
index =7.6 on 31 March 2001, the 4th highest daily Kp value in the
past 30 years)
We look forward to hearing your
feedback and your comments/suggestions are always welcome.
Geomatics,
an incredibly critical technology in this information era!
[April 21, 2010] I am very pleased that my students have
produced a beautiful Google Earth KML map based on their final year project. In
their final year project, the 3-girl group used the GPS RTK to survey one of
the most popular cycling paths in Hong Kong (from Tai Po to Sha Tin). It is
quite safe to say this Google Earth map for this HK cycling path is the most
comprehensive, the most accurate (only a few centimeters of error) information
that is accessible for free by the general public.
You
can download this Google Earth KML map to your computer from here (right click mouse and
save link as …). If you don’t have the Google Earth yet, you can download it
for free from earth.google.com
[Jan.10, 2010](This is an excerpt of my speech given
May 05, 2007 at my Toastmaster club). In this world, scientists, engineers,
researchers, and actually many people are working hard every day to try to
answer the following 6 most fundamental questions more correctly and more
precisely:
1) When 2) Where
3) Who 4)What 5)Why
6)How
At present, we can easily answer “When” in a
completely numerical way because our time has been digitalized, for instance:
the UTC time at this point of writing is: 2010-01-19 15:22:20. The numerical
expression of time is an important progress in human being history and it is
essential in this information era. So how about the other 4W1H questions? Can
you also use numbers to answer the remaining 4W1H questions? Answer is yes or
no. If you use Geomatics technology, you can answer the Where numerically
too. Without geomatics, you can’t. Why? The answer is simple. For example, Hong
Kong’s latitude and longitude is: 22°20 North, 114°11 East. So
you can see the location of Hong Kong can be easily described in numeric
numbers. How to get these numbers? It is a part of geomatics technology – using
Global Positioning System (GPS). With GPS, you may locate anywhere in the world
numerically and display it on your computer screen. This is the power and
beauty of geomatics technology – answering one of the world’s most fundamental
questions “WHERE” in a numerical way, a way people have never thought of and a
way that is so critical in today’s information era.
With GPS technology, now any objects in our
4-dimensional space-time domain can be completely digitalized and numerically
stamped. This is the contribution our geomaticians are making to the society.
[Dec03, 2009] Immediate Research
Associate Post Open: (!new!)
There is currently one Research Associate Post open.
The interested ones can find more
1. information here (English Version) or (Chinese Version). Thank you!
[Dec03, 2009] On December 3rd, 2009, this
website is drastically modified and improved to the current version. If you have
an interest to join this group or have any comments, please don’t hesitate to
contact us.
[Dec01, 2009] On December 1st, 2009, I am
very pleased to welcome Rui Xu to the Micro-LARGE. She is the first student and
first PhD student joining this Lab. She is from Nanjing University of
Aeronautics and Astronautics (NUAA) and will complete her PhD studies under the
joint
supervision of Prof. Wu Chen and myself. Welcome Rui!
[May 26, 2013] Recently, a paper was coauthored by Zhizhao Liu, Rui Xu,
Yu Morton, Jisheng Xu, Wouter Pelgrum, Steve Taylor, Wu Chen and Xiaoli Ding.
[May. 22, 2013] We are very pleased to announce that Dr. Liu is to
receive the Excellent Paper Award from the 2013 4th Chinese Satellite
Navigation Conference (CSNC 2013) in Wuhan, China.
In the recent 2013 China
Satellite Navigation Conference (CSNC) held May 15-17 in Wuhan, Dr. George
Zhizhao Liu from the Department of Land
Surveying & Geo-Informatics (LSGI) received the Excellent Paper Award for
his paper “The First PPP-based GPS Water Vapor Real-Time Monitoring System in
Pearl-River-Delta Region, China” co-authored with Research Associate Dr. Min Li.
This paper presents their research findings of developing the first atmospheric
water vapor real-time monitoring system for the Pearl-River-Delta (PRD) region
using the latest Global Positioning System (GPS) Precise Point Positioning
(PPP) technique. Based on their technique, now the amount of water vapor in the
atmosphere over the PRD region can be quickly and accurately computed from GPS satellite
signals. Since April 2012, the PolyU researchers have been supplying their
atmospheric water vapor data to the meteorological agencies around the PRD
region to support their daily services and research, including Hong Kong
Observatory, Macao Meteorological and Geophysical Bureau, Guangdong
Meteorological Bureau and Shenzhen Meteorological Bureau.
This
year is the first time for CSNC to have the Excellent Paper Award. Dr. Liu was
one of the nine award recipients out of 629 paper submissions (success rate:
1.43%).
This research work was supported by the General
Research Fund (GRF) of Hong Kong Research Grants Council (RGC).
[May. 11, 2013] We are very pleased to announce that Dr. George
Zhizhao Liu was given an
honor of Individual Award of
Shenzhen Virtual University Park for National Research Project, by the Shenzhen
Municipal Science and
Technology Innovation Council December 2012.
[Dec. 12, 2012] The Inaugural Early Career Award Recipient (首届“杰出青年学者奖”), Hong Kong
Research Grants Council (RGC), Hong Kong Special Administrative Region (HKSAR).
Dr. Liu was one of the 19 recipients out of 334 applicants across all the universities
in Hong Kong in 2012 (success rate: 5.69%). He is also one of only 3 recipients
in PolyU and one of 6 recipients in the Engineering Panel under Hong Kong RGC.
[July 23, 2012] We are pleased to share with you that our research
project “Innovative Real-Time Cycle Slip Detection and
Rectification for High Precision GPS Positioning” led by Dr. George Zhizhao Liu is funded by the Early Career Scheme
(ECS), Hong Kong Research Grants Council (RGC), Hong Kong SAR Government. This
project, together with 19 other projects across all the universities in Hong
Kong, will be recognized with an “Early Career Award” (ECA), which is the first time to give ECA in the history of
Hong Kong RGC. For this project, one PhD
student will be funded for three (3) years. Interested applications are welcome
to contact Dr. Liu.
[July 23, 2012] We are pleased to share with you that
our paper “Cycle slip detection and repair for
undifferenced GPS observations under high ionospheric activity” co-authored by Changsheng Cai • Zhizhao Liu •
Pengfei Xia • Wujiao Dai is published online @ GPS Solutions 4 July 2012. As of 23 July 2012 (20 days after the online
publication), this paper has been downloaded 174 times, ranked 2nd in the list of most downloaded
papers in the 30-days category. This paper can be downloaded @
http://www.springerlink.com/content/k214871257361300/
[14-15May 2012, Hong Kong]We are very pleased to announce theGNSSSchool(click for
announcement) will be held attheDepartment ofLSGI,Hong Kong
PolytechnicUniversity,
14-15 May 2012. Five distinguishedresearchers will give lectures for the GNSS
School. The registration fee isonly HK$200 (approx. US$25).
Dr. Jade
Morton: How
GNSS Signal ProcessingAlters Signal Parameters: A Cautionary Tale in Using GNSS
for Remote SensingApplications
Dr. PeterTeunissen: Carrier-Phase GNSS
Attitude Determination
Dr. Maorong Ge: PPP AlgorithmsDr. Peng Fang:Global and Regional Reference Frame: Establishment, Maintenance, and Application
Dr. Danan Dong:Dig out signals from deep interior of the Earth using GPS measurements
[14 May 2012,
HongKong]Dr. Jens Wickert,
Acting headof section 1.1 “GPS/Galileo Earth Observation”
German Research Center for Geosciences
GFZ, Potsdam,Germany is invited to give a talkon“GPS/Galileo Earth Observation at GFZ: Recent activities and results” attheHong Kong
PolytechnicUniversity.
[22
March 2012, Hong Kong] Dr.George Liu was invited to give a talk at theCivilEngineering and Development Department, Hong
Kong Special Administrative Region(HK SAR) Governmenton “Monitoring Equatorial andLow-latitude Ionospheric
Scintillation and Assessing Scintillation Impact onSatRef Network and GPS
Applications in Hong Kong”.
[13
March 2012, Hong Kong] Weare very glad that our paper “A
multi-sensor study of watervapour from radiosonde, MODIS and AERONET: a case
study of Hong Kong” was
published atINTERNATIONAL JOURNAL OF CLIMATOLOGY in December 2011. This paper
wascoauthored by
Zhizhao
Liu, Man Sing Wong,Janet Nichol and P. W. Chan. The citation is:Zhizhao Liu, Man Sing Wong,Janet Nichol
and P. W. Chan (2011),Amulti-sensor study of water vapour from
radiosonde, MODIS and AERONET: a case studyof Hong Kong,Int. J. Climatol.DOI:
10.1002/joc.3412.
[09
March 2012, Hong Kong] Dr.George Liu was invited to give a talk at theBeijingUniversity of Aeronautics and Astronautics
(BUAA)on “An innovative approach for successful cycle
slip detection and fix even with arbitrarily large pseudorange errors”.
[08
March 2012, Hong Kong] Dr.George Liu was invited to present the Compass
(Beidou) receiver evaluationresults at the Unicore Communications Inc. Beijing
with a title “Preliminary
Quality Analysis of the Pseudorange and Carrier PhaseData from Unicore
Compass+GPS Receiver”.
[17
February 2012, Hong Kong]Dr. George Liu was invited to give a talk at the
Chinese University of HongKong on “Water Vapor Observation in HongKong by
Radiosonde, AERONET and MODIS”.
[17 January 2012, Hong Kong]Dr. George
Liu is glad to receive fund support for the research “Improving the GPS SurveyingProductivity in
Construction by Modeling the Localized Errors in the GPSNetwork—Case Study with
Hong Kong’s SatRef Network” from
Construction Industry Institute Hong Kong /PolyU Innovation Fund Governing
Council. Thank youConstruction Industry InstituteHong Kong /
PolyUInnovation Fund Governing Council!
[05
January 2012, Hong Kong]Dr. Jade Morton, Professor atthe Department of Electricaland Computer
Engineering,Miami
U, USA,was invited to give a talk atthe
Department ofLSGI,Hong Kong PolytechnicUniversity on the
topic “Ionosphere Effects and other GNSS and RF
Navigation Research atMiami”.
[03
January 2012, Hong Kong]Dr. George Liu was invited to give a talk at the Hong
Kong Observatory (HKO) on“Preliminary
Investigation of Real Time PWV Monitoring in Hong Kong”.
[20
November 2011, Hong Kong]Dr. George Liu was invited to give a talk at the Wuhan
University, China on “Evaluating Water Vapor Observed by
Radiosonde, AERONET and MODIS inHong Kong”.
[11
October 2011, Hong Kong]Dr. Naser El-Sheimy, Professor at
theDepartment of Geomatics Engineering, U of Calgary, Canada,was invited to give a talk atthe
Department ofLSGI,Hong
Kong PolytechnicUniversity on the topic “EmergingMEMS Sensors
and Its Impact on Mapping and Navigation Applications”.
----------------------------------------------------------------------------------------------------------------------
Last updated
[24September 2011, Hong Kong] We are
very pleased to announce thatmultiple MSc level projects are available
for thenew MSc students.
The interested students are welcome tocontact Dr. George Liu by a visit HJ728
or an emaillszzliu@polyu.edu.hkor a call 27665961.
[24September 2011, Hong Kong]
[24September 2011, Hong Kong] We are very
pleased to announce that ourGeneral Research
Fund(GRF) application tothe Hong Kong ResearchGrants
Council (RGC)was successfully fundedafter a fierce competition.Thetitle of this project is “3D Water Vapor
TomographicModeling by Assimilating Multiple Sensors to Support Extreme
WeatherForecasting in Hong Kong and Mainland China”.
[24September 2011, Hong Kong] Our
publication was reported in“Science Letter”on 7 June2011.
[24September 2011, Hong Kong]As of
23Feb. 2011our paper(link here)wasranked 3rdin the most downloaded
papersin Journal of Geodesy
based on the downloads in the past 90 days since itsfirst day of online
publication, one of the internationally well recognizedjournals in Geomatics.
As
of 10 Feb. 2011ourpaper(linkhere)is ranked one of the 5 most downloaded papers
in Journal of Geodesybased on the downloads in the past 77 days since its first
day of onlinepublication, one of the internationally well recognized journals
in Geomatics.
This paper developed afully automated
cycle slip detection and repair algorithm for dual-frequencyGPS carrier phase
measurements. It can be safely said that the cycle slipproblem that have been
hanging over the GPS community as long as the GPShistory itself (~30 years) is
well resolved.
This algorithm is extremelyeffective
for high rate GPS data like 1Hz or higher. Virtually any size ofcycle slips can
be detected and repaired.
For low rate GPS data (like30 sec
data interval or larger) this algorithm can work for many cycle slipcases but
it might be a little difficulty for small cycle slips.
This method has beenextensively
tested and examined sin many scenarios such as:
o High dynamics (space-borne GPS
receiver payload on COSMICsatellite)
o Highly disturbed ionosphere (daily Kp
index =7.6 on 31 March2001, the 4thhighest daily Kp value in the
past 30 years)
We look forward to hearingyour
feedback and your comments/suggestions are always welcome.