scholarly journals Determination of the orthometric height difference based on optical fiber frequency transfer technique

Author(s):  
Anh The Hoang ◽  
Ziyu Shen ◽  
WenBin Shen ◽  
Chenghui Cai ◽  
Wei Xu ◽  
...  
2020 ◽  
Vol 12 (1) ◽  
pp. 132-144
Author(s):  
Tata Herbert ◽  
Raufu Ibrahim Olatunji

Height is an important component in the determination of the position of a point. The study aimed at performing a comparative analysis of change between ellipsoidal height differences and the equivalent orthometric height difference of points. A hi-target Differential Global Positioning System (DGPS) was used to acquire GPS data with an occupation period of thirty (30) minutes on each point, which were processed using Hi-target Geomatics Office (HGO) software to obtain the ellipsoidal heights. An automatic level instrument was used to acquire leveling data, which were processed using the height of collimation method to obtain the orthometric heights. A total of fifty (50) points were occupied as common points for both the GPS and levelling observations at 20-meter intervals. The accuracy of the height difference was determined using standard deviation with the ellipsoidal height difference as 53.59cm and the orthometric height as 53.07cm respectively. A Root Mean Square Error value of 0.0621m was obtained as the accuracy of the change between the two height differences. Statistical analysis using the independent-sample Z test was used to analyze the data at a 5% significant level. The result shows no significant difference in the performance of the two height systems. It is worthy to note that GPS and spirit levelling height differences can be used interchangeably for any heighting in short distances for surveying and engineering applications.


Author(s):  
B.A. Lapshinov ◽  
◽  
N.I. Timchenko ◽  

Spectral pyrometry was used to determine the surface temperature distribution of Si, Nb, Cu, and graphite samples when they were locally heated by continuous radiation of an Nd:YAG laser (λ = 1.064 μm). With prolonged exposure to radiation, a stationary temperature field was established in the samples. The thermal spectra were recorded with a small spectrometer in the visible range in the temperature range above 850 K. The optical fiber used to transmit the radiation spectrum to the spectrometer had an additional diaphragm with a diameter of 1 mm located at a certain distance from the fiber end, which ensured the locality of the recorded spectra. The optical fiber moved continuously along the sample, and the spectrometer recorded up to 100 spectra with a frequency of 5-10 Hz. The temperature profile of the samples was calculated based on the results of processing the spectra using the Spectral Pyrometry program.


Author(s):  
Albin Czubla ◽  
Roman Osmyk ◽  
Piotr Szterk ◽  
Waldemar Adamowicz ◽  
Michal Marszalec ◽  
...  

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 97487-97491 ◽  
Author(s):  
Chenxia Liu ◽  
Shujin Zhou ◽  
Jianming Shang ◽  
Zhuoze Zhao ◽  
Hao Gao ◽  
...  

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