The accuracy of GPS (Global Positioning System) derived relative positions of stations depends on... more The accuracy of GPS (Global Positioning System) derived relative positions of stations depends on several factors such as the baseline length, duration of observation session, the methodology, the software for processing GPS data and employed single frequency GPS receivers used influence the results. The aim of this study is to obtain the usage of the single-frequency GPS receivers, which have much lower costs comparing with the dual-frequency GPS receivers and to analyze the usability of them, especially in the geodetic applications. Additionally, this study indicates the performance of the single-frequency GPS receivers comparing with the dual-frequency GPS receivers. Our study investigates how the accuracy depends on baseline length (denoted L), on the duration of the observing session (denoted T) using the single-frequency GPS receivers. For the analysis, we selected seven days in 2009 from the GPS observations which provided by the 'National Geodetic Survey' archives. The data with 4h, 6h, 12 h and 24 h observing session duration in 2009 were analyzed with Bernese 5.2 GNSS software. The baseline length varies between 11 km and 110 km. This study indicated that single-frequency GPS receiver can provide the root-means-square (RMS) that criterion for the accuracy of about 5 mm horizontally and 14 mm vertically for the average of all observation session and baseline length while dual-frequency GPS receiver can provide RMS values of about 1 to 3 mm horizontally and 4.5 mm vertically. It is evident that single-frequency GPS receiver would become an attractive alternative to the conventional dual frequency receiver in the geodetic applications.
The sensitivity analysis of geodetic monitoring networks is realized mainly to determine the mini... more The sensitivity analysis of geodetic monitoring networks is realized mainly to determine the minimum detectable displacements or to derive, if the corresponding network is capable of detecting the expected displacements with preassumed error probabilities. In this study, minimum detectable displacements for geodetic monitoring networks are examined as well as how point-based sensitivity is impressed by datum constraints which are supplemented to the adjustment model. A horizontal control network is used to study this effect. Our experiments on this network indicate that the furthest point to the reference points, which contribute to the datum definition, yields the largest magnitude of minimum detectable displacement. That is to say the closest point to the reference points owns the lowest minimum detectable displacement. Furthermore, the displacement magnitude reduces when the number of reference points are increased in geodetic monitoring networks.
Jeodezik izleme ağlarında duyarlılık analizi genellikle, ilgili ağda beklenen yerdeğiştirmeleri ö... more Jeodezik izleme ağlarında duyarlılık analizi genellikle, ilgili ağda beklenen yerdeğiştirmeleri öngörülmüş hata olasılıklarıyla saptamaya uygunsa, belirlenebilecek en küçük yerdeğiştirmelerin belirlenmesi veya ortaya çıkarılmasını sağlar. Bu çalışma ile jeodezik ağlarda datum sayısına bağlı belirlenebilecek en küçük deformasyon büyüklüklerinin belirlenmesi için duyarlılık analizi yapılmıştır. Bu amaç doğrultusunda, 13 noktalı bir jeodezik ağda gerçekleştirilen doğrultu ve kenar ölçüleri kullanılmıştır. Datum tanımına katkı sağlayan noktalara en uzak olan noktada yakalanabilecek en küçük deformasyon en büyük olarak berlirlenmiş ve datum noktalarının sayıları arttıkça yakalanabilecek en küçük deformasyon büyüklüğünün de azaldığı görülmüştür. Başka bir ifadeyle, referans noktalarına en uzak nokta en küçük yerdeğiştirmeye sahiptir. Ayrıca, yerdeğiştirme büyüklükleri ağdaki referans noktaları arttıkça azalmaktadır.
The accuracy of GPS (Global Positioning System) derived relative positions of stations depends on... more The accuracy of GPS (Global Positioning System) derived relative positions of stations depends on several factors such as the baseline length, duration of observation session, the methodology, the software for processing GPS data and employed single frequency GPS receivers used influence the results. The aim of this study is to obtain the usage of the single-frequency GPS receivers, which have much lower costs comparing with the dual-frequency GPS receivers and to analyze the usability of them, especially in the geodetic applications. Additionally, this study indicates the performance of the single-frequency GPS receivers comparing with the dual-frequency GPS receivers. Our study investigates how the accuracy depends on baseline length (denoted L), on the duration of the observing session (denoted T) using the single-frequency GPS receivers. For the analysis, we selected seven days in 2009 from the GPS observations which provided by the 'National Geodetic Survey' archives. The data with 4h, 6h, 12 h and 24 h observing session duration in 2009 were analyzed with Bernese 5.2 GNSS software. The baseline length varies between 11 km and 110 km. This study indicated that single-frequency GPS receiver can provide the root-means-square (RMS) that criterion for the accuracy of about 5 mm horizontally and 14 mm vertically for the average of all observation session and baseline length while dual-frequency GPS receiver can provide RMS values of about 1 to 3 mm horizontally and 4.5 mm vertically. It is evident that single-frequency GPS receiver would become an attractive alternative to the conventional dual frequency receiver in the geodetic applications.
The sensitivity analysis of geodetic monitoring networks is realized mainly to determine the mini... more The sensitivity analysis of geodetic monitoring networks is realized mainly to determine the minimum detectable displacements or to derive, if the corresponding network is capable of detecting the expected displacements with preassumed error probabilities. In this study, minimum detectable displacements for geodetic monitoring networks are examined as well as how point-based sensitivity is impressed by datum constraints which are supplemented to the adjustment model. A horizontal control network is used to study this effect. Our experiments on this network indicate that the furthest point to the reference points, which contribute to the datum definition, yields the largest magnitude of minimum detectable displacement. That is to say the closest point to the reference points owns the lowest minimum detectable displacement. Furthermore, the displacement magnitude reduces when the number of reference points are increased in geodetic monitoring networks.
Jeodezik izleme ağlarında duyarlılık analizi genellikle, ilgili ağda beklenen yerdeğiştirmeleri ö... more Jeodezik izleme ağlarında duyarlılık analizi genellikle, ilgili ağda beklenen yerdeğiştirmeleri öngörülmüş hata olasılıklarıyla saptamaya uygunsa, belirlenebilecek en küçük yerdeğiştirmelerin belirlenmesi veya ortaya çıkarılmasını sağlar. Bu çalışma ile jeodezik ağlarda datum sayısına bağlı belirlenebilecek en küçük deformasyon büyüklüklerinin belirlenmesi için duyarlılık analizi yapılmıştır. Bu amaç doğrultusunda, 13 noktalı bir jeodezik ağda gerçekleştirilen doğrultu ve kenar ölçüleri kullanılmıştır. Datum tanımına katkı sağlayan noktalara en uzak olan noktada yakalanabilecek en küçük deformasyon en büyük olarak berlirlenmiş ve datum noktalarının sayıları arttıkça yakalanabilecek en küçük deformasyon büyüklüğünün de azaldığı görülmüştür. Başka bir ifadeyle, referans noktalarına en uzak nokta en küçük yerdeğiştirmeye sahiptir. Ayrıca, yerdeğiştirme büyüklükleri ağdaki referans noktaları arttıkça azalmaktadır.
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