2006 International Conference on Microwaves, Radar & Wireless Communications, 2006
The polarisation property of electromagnetic waves for applications in mobile communication syste... more The polarisation property of electromagnetic waves for applications in mobile communication systems has not been examined into detail yet. Due to multi-path effects and changes in the underlying coordinate systems of the involved antennas, the polarisation state of an electromagnetic wave at the receiving antenna of a mobile station is very likely to change. The presented project involves a data
... PEDESTRIAN RECOGNITION After the image was segmented the question must be answered how to cla... more ... PEDESTRIAN RECOGNITION After the image was segmented the question must be answered how to classify the particles that were found in the ... to the application of the camera mentioned in section II it is necessary to use a different approach because fast detection is required. ...
Physics and Chemistry of the Earth, Parts A/B/C, 2004
The tropospheric estimates, discussed in this paper, have been obtained from different GPS soluti... more The tropospheric estimates, discussed in this paper, have been obtained from different GPS solutions routinely generated at the Geodetic Observatory Pecný. Although each of the GPS solutions differs in primary motivation, implementation and in basic processing features, they were all finally enhanced by a special part devoted to the estimates of the tropospheric delays. This paper presents the comparisons between
Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, 2001
ABSTRACT We present here our hourly orbit product and we compare it to other near real-time (NRT)... more ABSTRACT We present here our hourly orbit product and we compare it to other near real-time (NRT) reliable orbits. The comparisons are based on satellite position differences with respect to the final IGS orbits. Experience shows that the use of predicted precise orbits in the NRT processing mode is usually problematic due to poorly determined arcs of only a few satellites. Thus, evaluation of satellite orbits is necessary. Nevertheless, we can find a decreased quality of some arcs also in ultra-rapid products, but the magnitude is significantly lower here. Reducing the predictions to 1–2 hours only, our hourly orbits improve especially the along-track satellite positions.
Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, 2001
ABSTRACT Since February 2000, the IGS combined ultra-rapid orbits have been available, requested ... more ABSTRACT Since February 2000, the IGS combined ultra-rapid orbits have been available, requested especially for the support of GPS near real-time (NRT) atmospheric monitoring. We have prepared and tested an hourly GPS orbit determination procedure at the Geodetic Observatory Pecny analysis center (GOP AC). The hourly orbits would preferably be used in our NRT tropospheric monitoring, which has been routinely performed since the beginning of 1999, thus far based on 2-day predicted orbits. The advantage of using the sub-daily orbits can be summarized in three contributions: the higher accuracy of the results (about 10-20 %), the stability of the evaluation (fewer weak periods, excluded results, etc.) and the significant simplicity of the procedure(e.g, orbit selection, orbit fixing).
Journal of the Meteorological Society of Japan, 2004
The GPS meteorology has been the driving force behind the near real-time (NRT) GPS analyses durin... more The GPS meteorology has been the driving force behind the near real-time (NRT) GPS analyses during the past few years. High availability of precise near real-time GPS orbits is essential for obtaining reliable solutions in almost all applications. This is especially true when estimating the troposphere parameters. Besides the demand on high accuracy, the orbit products should stand out for
The impact of precise GPS ephemeris errors on estimated zenith tropospheric delays (ZTD) is studi... more The impact of precise GPS ephemeris errors on estimated zenith tropospheric delays (ZTD) is studied for applications in meteorology. First, the status of IGS ultrarapid orbit prediction is presented and specific problems are outlined. Second, a simplified analytical solution of the impact of ephemeris errors on estimated ZTDs is presented. Two widely used methods are studied-the precise point positioning technique (PPP) and the double-difference network approach. A simulation experiment is additionally conducted for the network approach to assess the capability of ephemeris error compensation by the ambiguities. An example of marginal requirements for ephemeris accuracy is presented, assuming the compensation by ZTD only and admitting the error of 1 cm in ZTD. The requirement for the maximum orbit error 1 cm for radial and 8 cm for tangential position components using PPP approach, versus 217 cm (radial) and 19 cm (tangential) using network solution. Furthermore, an assessment of possible compensations of ephemeris errors by other estimated parameters was considered. In radial orbit position, an error of a few meters can be still absorbed by satellite clocks (96%) and phase ambiguities (96%) even for the PPP technique. A tangential orbit position error up to 16 cm for PPP and 38 cm for network solutions should not bias ZTD by more than 1 cm, but any bigger error could, in general. The error impact on ZTD in such cases depends on the compensation ability of ambiguities and clocks (PPP).
This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre fo... more This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre for the Earth Dynamics Research (CEDR, 2005(CEDR, -2009 project in the field of precise near real-time GNSS analyses. The GOP data centre supporting our own near real-time activities as well as those of various other institutes has been enhanced by including GLONASS data, real-time GNSS data and some other supporting products. The ultra-rapid GNSS orbits are routinely determined and predicted at GOP by analysing a global network of 60 stations. Significant improvements, which resulted in the fitted and predicted satellite position rms of 4 and 10 cm, respectively, were achieved within the CEDR project. The GOP orbit product is updated every 6 hours and it routinely contributes to the International GNSS Service (IGS). Based on these predicted precise orbits, the GOP near real-time regional GNSS network solution is routinely provided for monitoring water vapour in the atmosphere. Resulting zenith troposphere delays achieved a standard deviation of 3-5 cm compared to precise EUREF post-processing results or a standard deviation of 1-2 mm when converted to precipitable water vapour and compared to a nearby radiosonde. The troposphere delays estimated in GOP are operationally used in the Numerical Weather Prediction.
The Geodetic Observatory Pecný (GOP) routinely estimates near real-time zenith total delays (ZTD)... more The Geodetic Observatory Pecný (GOP) routinely estimates near real-time zenith total delays (ZTD) from GPS permanent stations for assimilation in numerical weather prediction (NWP) models more than 12 years. Besides European regional, global and GPS and GLONASS solutions, we have recently developed real-time estimates aimed at supporting NWP nowcasting or severe weather event monitoring. While all previous solutions are based on data batch processing in a network mode, the real-time solution exploits real-time global orbits and clocks from the International GNSS Service (IGS) and Precise Point Positioning (PPP) processing strategy. New application G-Nut/Tefnut has been developed and real-time ZTDs have been continuously processed in the nine-month demonstration campaign (February-October, 2013) for selected 36 European and global stations. Resulting ZTDs can be characterized by mean standard deviations of 6-10 mm, but still remaining large biases up to 20 mm due to missing precise models in the software. These results fulfilled threshold requirements for the operational NWP nowcasting (i.e. 30 mm in ZTD). Since remaining ZTD biases can be effectively eliminated using the bias-reduction procedure prior to the assimilation, results are approaching the target requirements in terms of relative accuracy (i.e. 6 mm in ZTD). Real-time strategy and software are under the development and we foresee further improvements in reducing biases and in optimizing the accuracy within required timeliness. The real-time products from the International GNSS Service were found accurate and stable for supporting PPP-based tropospheric estimates for the NWP nowcasting.
Geodetic Observatory Pecný (GOP) has been routinely estimating near real-time zenith total delay ... more Geodetic Observatory Pecný (GOP) has been routinely estimating near real-time zenith total delay (ZTD) parameters from GPS permanent stations since 2001. Currently, the GOP ZTDs are assimilated in several meteorological institutions. During last years new other tropospheric products were developed at GOP: 1) global hourly ZTD product, 2) multi-GNSS (GPS+GLONASS) regional ZTD product and 3) real-time ZTD product. All operationally running hourly updated ZTD solutions (stand-alone GPS, multi-GNSS and global) are based on the processing of batch data in a differential mode and using Bernese GNSS software and IGS ultra-rapid orbits. New real-time ZTD solution is implemented with completely different strategy - the Precise Point Positioning (PPP) and filtering technique - using real-time data streams and products and applying new developed software in GOP. Firstly, the presentation gives a brief introduction into the in-house software library (G-Nut) development and into the specific end...
The contribution will present new G-Nut software library aimed for the development of targeted en... more The contribution will present new G-Nut software library aimed for the development of targeted end-user GNSS applications in various geoscientific fields - geodesy, seismology, meteorology, climatology end others in future. The G-Nut core library has been developed since 2011 in Geodetic Observatory Pecný. Its status and more detais can be found at www.pecny.cz. The library is written in C++ applying the object oriented approach aiming for a flexible source code implementation, easy maintenance and future extension. Currently, the library supports the Precise Point Positioning GNSS processing technique as a core highly efficient and autonomous method suitable for most accurate post-processing tasks as well as real-time applications. Specific end-user applications are being developed - the tool for GNSS data converting, concatenating, editing and quality checking, the application for tropospheric parameter estimation in (near) real-time and post-processing and the application for the...
Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation and timing... more Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation and timing, becoming a common part of our everyday life. Aside from the more standard applications, GNSS has proved to be an accurate sensor of atmospheric water vapour, the most abundant greenhouse gas, accounting for 60-70% of warming, and of obvious importance in weather forecasting. Atmospheric humidity is one of the most important parameters for forecasting extreme weather events and monitoring climate change, but is under-sampled in current operational meteorological and climate observing systems. A new EU COST Action (ES1206): Advanced GNSS Tropospheric Products for Monitoring Extreme Weather Events and Climate (GNSS4SWEC) will address new and improved capabilities from concurrent developments in both GNSS and meteorological communities to improve (short-range) weather forecasting and climate projections. Multi-GNSS will be utilised to develop new, more advanced products, stimulating the fu...
2006 International Conference on Microwaves, Radar & Wireless Communications, 2006
The polarisation property of electromagnetic waves for applications in mobile communication syste... more The polarisation property of electromagnetic waves for applications in mobile communication systems has not been examined into detail yet. Due to multi-path effects and changes in the underlying coordinate systems of the involved antennas, the polarisation state of an electromagnetic wave at the receiving antenna of a mobile station is very likely to change. The presented project involves a data
... PEDESTRIAN RECOGNITION After the image was segmented the question must be answered how to cla... more ... PEDESTRIAN RECOGNITION After the image was segmented the question must be answered how to classify the particles that were found in the ... to the application of the camera mentioned in section II it is necessary to use a different approach because fast detection is required. ...
Physics and Chemistry of the Earth, Parts A/B/C, 2004
The tropospheric estimates, discussed in this paper, have been obtained from different GPS soluti... more The tropospheric estimates, discussed in this paper, have been obtained from different GPS solutions routinely generated at the Geodetic Observatory Pecný. Although each of the GPS solutions differs in primary motivation, implementation and in basic processing features, they were all finally enhanced by a special part devoted to the estimates of the tropospheric delays. This paper presents the comparisons between
Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, 2001
ABSTRACT We present here our hourly orbit product and we compare it to other near real-time (NRT)... more ABSTRACT We present here our hourly orbit product and we compare it to other near real-time (NRT) reliable orbits. The comparisons are based on satellite position differences with respect to the final IGS orbits. Experience shows that the use of predicted precise orbits in the NRT processing mode is usually problematic due to poorly determined arcs of only a few satellites. Thus, evaluation of satellite orbits is necessary. Nevertheless, we can find a decreased quality of some arcs also in ultra-rapid products, but the magnitude is significantly lower here. Reducing the predictions to 1–2 hours only, our hourly orbits improve especially the along-track satellite positions.
Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, 2001
ABSTRACT Since February 2000, the IGS combined ultra-rapid orbits have been available, requested ... more ABSTRACT Since February 2000, the IGS combined ultra-rapid orbits have been available, requested especially for the support of GPS near real-time (NRT) atmospheric monitoring. We have prepared and tested an hourly GPS orbit determination procedure at the Geodetic Observatory Pecny analysis center (GOP AC). The hourly orbits would preferably be used in our NRT tropospheric monitoring, which has been routinely performed since the beginning of 1999, thus far based on 2-day predicted orbits. The advantage of using the sub-daily orbits can be summarized in three contributions: the higher accuracy of the results (about 10-20 %), the stability of the evaluation (fewer weak periods, excluded results, etc.) and the significant simplicity of the procedure(e.g, orbit selection, orbit fixing).
Journal of the Meteorological Society of Japan, 2004
The GPS meteorology has been the driving force behind the near real-time (NRT) GPS analyses durin... more The GPS meteorology has been the driving force behind the near real-time (NRT) GPS analyses during the past few years. High availability of precise near real-time GPS orbits is essential for obtaining reliable solutions in almost all applications. This is especially true when estimating the troposphere parameters. Besides the demand on high accuracy, the orbit products should stand out for
The impact of precise GPS ephemeris errors on estimated zenith tropospheric delays (ZTD) is studi... more The impact of precise GPS ephemeris errors on estimated zenith tropospheric delays (ZTD) is studied for applications in meteorology. First, the status of IGS ultrarapid orbit prediction is presented and specific problems are outlined. Second, a simplified analytical solution of the impact of ephemeris errors on estimated ZTDs is presented. Two widely used methods are studied-the precise point positioning technique (PPP) and the double-difference network approach. A simulation experiment is additionally conducted for the network approach to assess the capability of ephemeris error compensation by the ambiguities. An example of marginal requirements for ephemeris accuracy is presented, assuming the compensation by ZTD only and admitting the error of 1 cm in ZTD. The requirement for the maximum orbit error 1 cm for radial and 8 cm for tangential position components using PPP approach, versus 217 cm (radial) and 19 cm (tangential) using network solution. Furthermore, an assessment of possible compensations of ephemeris errors by other estimated parameters was considered. In radial orbit position, an error of a few meters can be still absorbed by satellite clocks (96%) and phase ambiguities (96%) even for the PPP technique. A tangential orbit position error up to 16 cm for PPP and 38 cm for network solutions should not bias ZTD by more than 1 cm, but any bigger error could, in general. The error impact on ZTD in such cases depends on the compensation ability of ambiguities and clocks (PPP).
This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre fo... more This paper provides a summary of the Geodetic Observatory Pecný achievements within the Centre for the Earth Dynamics Research (CEDR, 2005(CEDR, -2009 project in the field of precise near real-time GNSS analyses. The GOP data centre supporting our own near real-time activities as well as those of various other institutes has been enhanced by including GLONASS data, real-time GNSS data and some other supporting products. The ultra-rapid GNSS orbits are routinely determined and predicted at GOP by analysing a global network of 60 stations. Significant improvements, which resulted in the fitted and predicted satellite position rms of 4 and 10 cm, respectively, were achieved within the CEDR project. The GOP orbit product is updated every 6 hours and it routinely contributes to the International GNSS Service (IGS). Based on these predicted precise orbits, the GOP near real-time regional GNSS network solution is routinely provided for monitoring water vapour in the atmosphere. Resulting zenith troposphere delays achieved a standard deviation of 3-5 cm compared to precise EUREF post-processing results or a standard deviation of 1-2 mm when converted to precipitable water vapour and compared to a nearby radiosonde. The troposphere delays estimated in GOP are operationally used in the Numerical Weather Prediction.
The Geodetic Observatory Pecný (GOP) routinely estimates near real-time zenith total delays (ZTD)... more The Geodetic Observatory Pecný (GOP) routinely estimates near real-time zenith total delays (ZTD) from GPS permanent stations for assimilation in numerical weather prediction (NWP) models more than 12 years. Besides European regional, global and GPS and GLONASS solutions, we have recently developed real-time estimates aimed at supporting NWP nowcasting or severe weather event monitoring. While all previous solutions are based on data batch processing in a network mode, the real-time solution exploits real-time global orbits and clocks from the International GNSS Service (IGS) and Precise Point Positioning (PPP) processing strategy. New application G-Nut/Tefnut has been developed and real-time ZTDs have been continuously processed in the nine-month demonstration campaign (February-October, 2013) for selected 36 European and global stations. Resulting ZTDs can be characterized by mean standard deviations of 6-10 mm, but still remaining large biases up to 20 mm due to missing precise models in the software. These results fulfilled threshold requirements for the operational NWP nowcasting (i.e. 30 mm in ZTD). Since remaining ZTD biases can be effectively eliminated using the bias-reduction procedure prior to the assimilation, results are approaching the target requirements in terms of relative accuracy (i.e. 6 mm in ZTD). Real-time strategy and software are under the development and we foresee further improvements in reducing biases and in optimizing the accuracy within required timeliness. The real-time products from the International GNSS Service were found accurate and stable for supporting PPP-based tropospheric estimates for the NWP nowcasting.
Geodetic Observatory Pecný (GOP) has been routinely estimating near real-time zenith total delay ... more Geodetic Observatory Pecný (GOP) has been routinely estimating near real-time zenith total delay (ZTD) parameters from GPS permanent stations since 2001. Currently, the GOP ZTDs are assimilated in several meteorological institutions. During last years new other tropospheric products were developed at GOP: 1) global hourly ZTD product, 2) multi-GNSS (GPS+GLONASS) regional ZTD product and 3) real-time ZTD product. All operationally running hourly updated ZTD solutions (stand-alone GPS, multi-GNSS and global) are based on the processing of batch data in a differential mode and using Bernese GNSS software and IGS ultra-rapid orbits. New real-time ZTD solution is implemented with completely different strategy - the Precise Point Positioning (PPP) and filtering technique - using real-time data streams and products and applying new developed software in GOP. Firstly, the presentation gives a brief introduction into the in-house software library (G-Nut) development and into the specific end...
The contribution will present new G-Nut software library aimed for the development of targeted en... more The contribution will present new G-Nut software library aimed for the development of targeted end-user GNSS applications in various geoscientific fields - geodesy, seismology, meteorology, climatology end others in future. The G-Nut core library has been developed since 2011 in Geodetic Observatory Pecný. Its status and more detais can be found at www.pecny.cz. The library is written in C++ applying the object oriented approach aiming for a flexible source code implementation, easy maintenance and future extension. Currently, the library supports the Precise Point Positioning GNSS processing technique as a core highly efficient and autonomous method suitable for most accurate post-processing tasks as well as real-time applications. Specific end-user applications are being developed - the tool for GNSS data converting, concatenating, editing and quality checking, the application for tropospheric parameter estimation in (near) real-time and post-processing and the application for the...
Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation and timing... more Global Navigation Satellite Systems (GNSS) have revolutionised positioning, navigation and timing, becoming a common part of our everyday life. Aside from the more standard applications, GNSS has proved to be an accurate sensor of atmospheric water vapour, the most abundant greenhouse gas, accounting for 60-70% of warming, and of obvious importance in weather forecasting. Atmospheric humidity is one of the most important parameters for forecasting extreme weather events and monitoring climate change, but is under-sampled in current operational meteorological and climate observing systems. A new EU COST Action (ES1206): Advanced GNSS Tropospheric Products for Monitoring Extreme Weather Events and Climate (GNSS4SWEC) will address new and improved capabilities from concurrent developments in both GNSS and meteorological communities to improve (short-range) weather forecasting and climate projections. Multi-GNSS will be utilised to develop new, more advanced products, stimulating the fu...
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