PENENTUAN ZENITH TROPOSPHERIC DELAY DAN PRECIPITABLE WATER VAPOR MENGGUNAKAN PERANGKAT LUNAK GAMIT

Abstract

Abstrak

Sinyal - sinyal dari setiap satelit Global Positioning System (GPS) yang mengorbit diatas permukaan bumi akan diterima oleh alat penerima dengan sebelumnya melalui lapisan atmosfer. Sinyal yang berupa gelombang elektromagnetik akan mengalami hambatan terbesar di lapisan ionosfer dan troposfer. Besarnya penyimpangan jarak akibat perlambatan waktu tempuh sinyal saat melewati lapisan troposfer umumnya disebut delay troposfer. Besaran ini juga dapat diekstraksi menjadikandungan uap air menggunakan data meteorologi permukaan.Dalam penelitian tugas akhir ini,dilakukan penentuan delay troposfer dan kandungan uap air menggunakan perangkat lunak ilmiah GAMIT dimulai pada doy 090 sampai 096 pada tahun 2014. Dengan memanfaatkan 10 titik pengamatan GPS CORS Badan Informasi Geospasial di Bantul, Cilacap, Kebumen, Magelang, Purbalingga, Pekalongan, Purwodadi, Semarang, Solo, dan Tegal. Serta diikatkan di 4 titik ikat IGS, diantaranya: Stasiun ALIC, COCO, NTUS, dan PIMO. Penelitian tugas akhir ini menghasilkan nilai variasi temporal delay troposfer di titik pengamatan berkisar antara 2446.2 - 2754.5 mm dan nilai variasi temporal kandungan uap air berkisar antara 38.81 - 64.46 mm. Adapun hasil validasi antara data ZPD di Stasiun IGS dengan ZTD hasil pengolahan diperoleh rerata RMS error 5.599 mm dengan korelasi 97.73% untuk project spza, 5.425 mm dengan korelasi 97.86% untuk project spzb, dan 10.462 mm dengan korelasi 92,99% untuk project spzc.

Kata Kunci: Delay Troposfer; GAMIT; GPS; Kandungan Uap Air

Abstract

The signals from each Global Positioning System (GPS) satellites that  orbiting above the earth's surface will be received by a receiver through the layers of atmosphere. The signal that in electromagnetic waves form will experience the biggest obstacle in ionosphere and troposphere. The amount of deviation due to a slowdown in signal’s travel time as it passes through the troposphere called tropospheric delay. This measurement can also be extracted into precipitable water vapour by using the surface meteorological data. This study was conducted to determine the zenith tropospheric delay and precipitable water vapour using scientific software GAMIT starts from doy 090 to 096 in 2014. By utilizing 10 GPS CORS observation points owned by Badan Informasi Geospasial in Bantul, Cilacap, Kebumen, Magelang, Purbalingga, Pekalongan, Purwodadi, Semarang, Solo, and Tegal. It also connected to 4 area points of IGS, that are: ALIC, COCO, NTUS, and PIMO Station. This research produces the value of temporal variation in zenith tropospheric delay observation point ranges between 2446.2 - 2754.5 mm and the value of temporal variation of precipitable water vapor ranges between 38.81 - 64.46 mm. The validation results between the ZPD data in IGS Station and the ZTD that was processed by GAMIT is 5.599 mm of RMS error average with a 97.73% of correlation for the spza project, 5.425 mm with a 97.86% of correlation for the spzb project, and 10.462 mm with a 92.99% of correlation for the spzc project.

Keywords:GAMIT; GPS; Precipitable Water Vapor; Zenith Tropospheric Delay

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