| Author | Nalinrat Asokbunyarat |
| Call Number | AIT Thesis no.RS-16-24 |
| Subject(s) | Geographic information system
|
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Remote Sensing and Geographic Information Systems |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. RS-16-24 |
| Abstract | Accuracies of relative positioning techniques namely D - GPS were investigated to determine gradient and true north direction (azimuth) as accurate as possible using two GPS receivers with condition of difference of baseline length (2, 5 and 10 m) and difference of observed time (1, 5, 15 and 30 min). The data was processed using RTKLIB software with D - GPS analysis mode to obtain coordinate of each condition , and values of gradient and azimuth were calculated from that coordinate . In addition, gradient and true north direction (azimuth) using total station and automatic level w ere conducted to be a reference value due to high accuracy and general acceptability. Moreover, gradient and azimuth using two GPS receivers and using original total station and automatic level were compared to obtain percent error of two GPS receivers with condition of difference of baseline length and observed time . In this research , result s of the study presented that in effect of options in RTKLIB software on position accuracy, DGPS mode was better than single mode due to offset error such as clock error and ephemeris error. Higher elevation mask more than 25° affect to position accuracy du e to decrease of reading pattern (number of satellite less than 4). Data interval of 1 sec was better than data interval of 5 sec due to higher amount of data. In gradient and azimuth, error of azimuth and gradient decrease when baseline length and observe d time increase. In accuracy of gradient and azimuth, percent error of azimuth at all baseline lengths were very low due to fixed boundary. Percent error of gradient were high due to free boundary. Percent error of gradient decrease when baseline length in crease. In application of two GPS receivers, two GPS receivers can apply with vehicle such as car and bus. Only azimuth could apply with vehicle due to high accuracy of E, N coordinates, while gradient did not recommend to apply with vehicle due to low accuracy of U coordinate. In setting baseline length on vehicle for determining azimuth, long baseline length of 5 and 10 m should be recommended due to low percent error of azimuth. In setting observed time for determining azimuth, less observed time of 1 an d 5 min could be recommended due to low percent error of azimuth. |
| Year | 2016 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. RS-16-24 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Remote Sensing (RS) |
| Chairperson(s) | Nakamura, Shinichi, |
| Examination Committee(s) | Nagai, Masahiko;Sarawut Ninsawat |
| Scholarship Donor(s) | Asian Institute of Technology Fellowship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2016 |