Satellite operators utilize a two-stations turn around ranging (TAR) system to reduce the ground station measurement system's complexity and cost while having the same or better orbit determination accuracy for communication satellites orbit determination recently. This study investigates two stations' performance, four-way ranging on communication satellite orbit determination, operational conformance, and cost. The observation data sets are collected using traditional single station tracking (SST) and the new method TAR. The computed results using the Monte Carlo method encourage the satellite operators to use a four-way ranging system to observe and measure required data sets. TAR performance is evaluated, taking SST as a reference. The six classical orbital elements (a, e, i, RAAN, AoP, and TA) are compared for large numbers of observation data. The SST and TAR results are very close to each other. The worst-case calculated Euclidian distance between SST and TAR is 1.893 km at the epoch below the 6 km success criteria. The TAR observation method is appropriate to collect data sets for precise orbit determination. This work result indicates that satellite operators should consider deploying TAR stations to collect two-station range data sets and compute the orbit for nominal north-south station-keeping maneuvers (NSSK) and east-west station-keeping (EWSK) maneuver operations. The TAR method is superior to SST in terms of accuracy, operational conformance, and costs.

Coğrafi Bilgi Sistemleri (CBS) ve Uzaktan Algılama (UA) yöntemleri çok uzun süredir tarım, haritacılık, hidroloji, jeoloji, madencilik, ormancılık, çevre, şehircilik, afet yönetimi ve arkeoloji gibi çok farklı faaliyet alanlarında, disiplinler arası iş birliğine dayalı olarak farklı yöntemlerle birlikte kullanılmaktadır. UA tarafında farklı mekânsal, spektral, radyometrik ve zamansal çözünürlüğe sahip algılayıcılardan elde edilen fotoğraflar kullanılarak çok çeşitli analizler yapılmakta, bunun sonucunda da planlama süreçleri yürütülmektedir. CBS alanında ise özel yazılım, donanım ve veri tabanı sistemleri kullanılarak coğrafi analizler yapılması noktasında her türlü bilginin birbiri ile ilişkilendirilmesi, işlenmesi, depolanması, analiz edilmesi ve değişiminin izlenmesi sağlanabilmektedir. Ancak haberleşme alanında UA ve CBS kullanımı incelendiğinde, dünya çapında yapılan örnekler bulunmakla birlikte Türkiye’de henüz yeni gelişmekte olan bir alan olduğu dikkat çekmektedir. Bu kapsamda düşünüldüğünde bu çalışmada literatürde Dünya ve Türkiye örneklerinin incelenmesi, UA ve CBS’nin haberleşme altyapı sistemlerinin tasarımı, planlanması, gerekli analizlerinin yapılması ve karar destek süreçlerine katkısının irdelenmesi amaçlanmaktadır. Bu sayede alanında yapılacak olan çalışmalara altlık teşkil edecek örnek bir çalışma ortaya koyulacaktır.

Geostationary Satellites (GEO) are being used commonly in communication market. The service providers uplink or downlink the signal by using their dedicated antennas (whether with or without tracking capability) to the GEO satellite. The satellite down-converts and amplifies the signal before sending back to the end users on Earth. Normally, the user set and adjust the uplink antenna to follow the GEO satellite movement as much as possible. As soon as there is no reduction in the link budget, this pointing assumed to be successful. On the other hand, the input power of the satellite, together with satellite longitude vs latitude, can give reasonable ideas about the accuracy of the ground antenna pointing. In the study, ground station pointing performance is shown with two different cases. One with tracking and one without tracking capability.

No abstract

The increase in forest fires worldwide as a result of global warming has recently been felt clearly in our country as well. This increase necessitated the activities to detect, monitor and control such incidents in the earliest way, to be carried out quickly, organized and correctly. There are different methods for detecting and monitoring forest fires at an early stage. Using satellite remote sensing data is one of these methods and valuable data can be obtained for fire detection through payloads placed on different satellites in low or geosynchronous orbit. In this study, in order to monitor forest fires and determine the area damaged by the fire, the forest fire that resulted in the burning of a huge area in Manavgat district of Antalya province in 2021 was examined using Sentinel-2A and Sentinel-3A data. As a result of the study, it has been seen that satellites provide valuable information in the monitoring of forest fires and it has been pointed out that the design of our next-generation satellites in geosynchronous orbit, in a way that will provide data for fire detection and monitoring will facilitate the follow-up of forest fires that will occur in our country.