scholarly journals Comparative Analysis of Change between Ellipsoidal Height Differences and Equivalent Orthometric Height Difference

2020 ◽  
Vol 12 (1) ◽  
pp. 132-144
Author(s):  
Tata Herbert ◽  
Raufu Ibrahim Olatunji
Keyword(s):  
Comparative Analysis ◽  
Global Positioning System ◽  
Orthometric Height ◽  
Ellipsoidal Height ◽  
Height Difference ◽  
Significant Difference ◽  
Global Positioning ◽  
Analysis Of Change ◽  
Automatic Level

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.

scholarly journals Modeling the signature of a transponder in altimeter return data and determination of the reflection surface of the ice cap near the GRIP camp, Greenland

1998 ◽  
Vol 44 (148) ◽  
pp. 625-633
Author(s):  
G. Haardenog-Pedersen ◽  
K. Keller ◽  
C. C. Tscherning ◽  
N. Gundestrup
Keyword(s):  
Global Positioning System ◽  
Propagation Delay ◽  
Radar Altimeter ◽  
Reflection Point ◽  
Ice Cap ◽  
Global Positioning ◽  
Satellite Radar ◽  
The Difference ◽  
Satellite Radar Altimetry

AbstractUsing an active transponder with the ERS-I and ERS-2 radar altimeters, the distance to the satellite was measured at a location close to the GRIP site, Greenland, at an altitude of 3.2 km. The measurement was executed while the transponder was in the “ice-tracking mode”. It includes a bias due to the propagation delay. The location of the transponder was determined using the global positioning system.The transponder signal was modeled and the distance from the altimeter to the effective reflection point of the transponder was determined. Since the transponder was located within 1 km of the ground tracks, the measurement was corrected for this offset. A correction was also done for the surface slope, resulting in the distance (plus bias) to the closest sub-satellite point on the surface of the (compact) snow.The transponder signal was then removed from the radar altimeter waveform, enabling the determination of the distance (plus bias from the altimeter to the first reflective surface within the snow. The différence between this distance and that obtained using the transponder was < 2 m. This shows that the surface which gives rise to the first return of the reflection agrees with the surface of the (compact, dry) snow at this high-altitude location. This is an important result to be used when studying ice-cap topography using satellite radar altimetry.

scholarly journals Precise determination of Earth's center of mass using measurements from the global positioning system

1992 ◽  
Vol 19 (14) ◽  
pp. 1487-1490 ◽  
Author(s):  
Yvonne Vigue ◽  
Stephen M. Lichten ◽  
Geoffrey Blewitt ◽  
Michael B. Heflin ◽  
Rajendra P. Malla
Keyword(s):  
Global Positioning System ◽  
Center Of Mass ◽  
Precise Determination ◽  
Positioning System ◽  
Global Positioning

Determination of global positioning system (GPS) receiver clock errors: impact on positioning accuracy

2009 ◽  
Vol 20 (7) ◽  
pp. 075105 ◽  
Author(s):  
Ta-Kang Yeh ◽  
Cheinway Hwang ◽  
Guochang Xu ◽  
Chuan-Sheng Wang ◽  
Chien-Chih Lee
Keyword(s):  
Global Positioning System ◽  
Positioning System ◽  
Gps Receiver ◽  
Positioning Accuracy ◽  
Global Positioning ◽  
Receiver Clock

scholarly journals How Users of a Smartphone Weather Application Are Influenced by Animated Announcements Conveying Rainfall Intensity and Electronic Gifts Promoting Rain Evacuation

2019 ◽  
Vol 14 (9) ◽  
pp. 1236-1244
Author(s):  
Hiroko Nakajima ◽  
Kan Shimazaki ◽  
Yang Ishigaki ◽  
Akiko Miyajima ◽  
Akira Kuriyama ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Rainfall Intensity ◽  
Heavy Rain ◽  
Statistical Bias ◽  
Start Time ◽  
Location Data ◽  
Weather Information ◽  
Significant Difference ◽  
Global Positioning ◽  
The Relationship

In this study, we assumed that animated announcements that conveyed rainfall intensity of localized heavy rain and the distribution of electronic gifts to encourage rain evacuation would promote evacuation actions. If evacuation actions could be promoted through these methods, then the transmission of weather information could be improved. Therefore, we modified the features of a weather information application for smartphones, which was already widely used, and conducted a demonstrative experiment with application users who agreed to participate in order to check the validity. We analyzed users’ behaviors by transmitting information regarding the predicted start time of rain and recording the Global Positioning System coordinates of the users’ smartphones. In addition, a questionnaire survey was administered to the users after the experiment to collect data on their conception of rainfall intensity. The participants were also interviewed. The results of the experiment showed a significant difference in user conception of rainfall intensity depending on whether they had viewed the animation. However, a behavior analysis based on location data showed no statistical bias in the relationship between the animation and rain evacuation behavior.

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

2021 ◽  
Author(s):  
Anh The Hoang ◽  
Ziyu Shen ◽  
WenBin Shen ◽  
Chenghui Cai ◽  
Wei Xu ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Orthometric Height ◽  
Height Difference ◽  
Frequency Transfer

Relationship Between Life-Space Mobility and Health Characteristics in Older Adults Using Global Positioning System Watches

2021 ◽  
pp. 073346482110548
Author(s):  
Jane Chung ◽  
Joseph Boyle ◽  
David C. Wheeler
Keyword(s):  
Older Adults ◽  
Global Positioning System ◽  
Self Report ◽  
Functional Health ◽  
Movement Speed ◽  
Positioning System ◽  
Life Space ◽  
Total Distance ◽  
Significant Difference ◽  
Global Positioning

This study aimed to examine the feasibility of using global positioning system (GPS) watches to examine relationships between GPS-based life-space mobility (LSM) metrics and self-report LSM and health measures (physical, psychological, and cognitive function) among older adults. Thirty participants wore a Fitbit Surge for 3 days. Eight spatial and temporal LSM measures were derived from GPS data. About 90% of in-home movement speeds were zero, indicating the sedentary lifestyle, but they made some active out-of-home trips as the total distance traveled and size of movement area indicated. There was a significant difference in total distance traveled and 95th percentile of movement speed between mild cognitive and intact cognition groups. GPS-based higher proportion of out-of-home time was significantly associated with greater functional fitness. Greater GPS use hours were significantly associated with higher cognition. These findings suggest the potential of GPS watches to continuously monitor changes in functional health to inform prevention efforts.

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