Akıllı mobil telefonlardan elde edilen çift frekanslı ham GNSS gözlemleri ile PPP konum belirleme performansının araştırılması

Abstract

Akıllı mobil telefonların ham GNSS verilerinin erişilebilir hale gelmesi ve bu yönüyle işlenebilir olması, düşük maliyetli GNSS konum belirleme çalışmaları için inovasyon olmuştur. Mayıs 2018’de Xiaomi firması tarafından dünyanın ilk çift frekanslı GNSS çipine sahip Mi8 model telefonun piyasaya sürülmesi ise mühendislik uygulamaları için akıllı mobil telefonlarla konum belirlemedeki çalışmalara büyük bir ivme kazandırmıştır. Bu gelişim dinamiği dikkate alınarak gerçekleştirilen bu çalışmada iki gün tekrarlı ve iki saat süre ile toplanan Xiaomi Mi8 akıllı telefon statik GNSS gözlemleri, GipsyX ve RTKLIB yazılımları ile farklı uydu yükseklik açılarında epok epok kinematik olarak hassas mutlak nokta konum belirleme (Precise Point Positioning, PPP) yöntemi ile değerlendirilmiş, yatay konum doğrulukları hesaplanmıştır. Xiaomi Mi8’den elde edilen çift frekanslı GNSS gözlemlerinin PPP performansı, farklı uydu yükseklik açılarında incelenmiştir. Çözümler eş zamanlı gözlem yapan Topcon Hiper SR jeodezik alıcının bağıl konumlama çözümleri referans alınarak karşılaştırılmıştır. Elde edilen bulgular sonucunda RTKLIB çözümlerinin yatay konum doğruluğunun uydu yükseklik açısı ile ters orantılı olduğu, buna karşın GipsyX çözümlerinde bu bağlamda farklılıklar olduğu gözlemlenmiştir. Xiaomi Mi8 çift frekanslı GNSS gözlemlerinin PPP yöntemi ile değerlendirmesinde GipsyX çözümlerinin RTKLIB çözümlerinden daha yüksek doğrulukta sonuçlar ürettiği görülmüştür.

Keywords

• Akıllı mobil telefon
• GNSS
• PPP
• Xiaomi Mi8
• GipsyX
• RTKLIB

Investigation of PPP performance with dual frequency raw GNSS observations obtained from smartphones

Abstract

Being accessible and processible of the raw GNSS data of smartphones has been an innovation for low-cost GNSS positioning studies. With the release of world’s first smartphone with dual frequency GNSS chipset Mi8 by Xiaomi in May 2018, studies on smartphone-based positioning for engineering applications have gained great momentum. Considering these development dynamics, in this study, repeatedly collected Xiaomi Mi8 dual frequency static GNSS observations for two days in two-hour time span were processed using GipsyX and RTKLIB software with epoch by epoch kinematic Precise Point Positioning (PPP) method at different satellite elevation angles, and horizontal positioning accuracies were calculated. The PPP performance of dual frequency GNSS observations collected by Xiaomi Mi8 was investigated at different satellite elevation angles. The process outputs were compared with results analyzed by relative positioning method collected simultaneously with Topcon Hiper SR geodetic receiver by considering as a reference solution. According to the results, it was noted that the horizontal positioning accuracy of RTKLIB outputs has directly inverse relationship with increasing satellite elevation angles whereas GipsyX outputs have differences in this context. In the processing of Xiaomi Mi8 dual frequency observations with PPP method, it was concluded that GipsyX produced higher horizontal positioning accuracy than RTKLIB.

Keywords

• Smartphone
• GNSS
• PPP
• Xiaomi Mi8
• GipsyX
• RTKLIB

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