Analisis Akurasi Geolokasi Smartphone di Ruang Terbuka dan Tertutup

Keakuratan geolokasi pada smartphone kini menjadi faktor krusial dalam pengalaman pengguna, terutama dalam penggunaan aplikasi berbasis lokasi seperti navigasi. Penelitian ini bertujuan untuk menganalisis akurasi geolokasi di ruang terbuka dan tertutup pada dua smartphone yang memiliki frekuensi sinyal yang berbeda. Metode yang digunakan adalah metode komparatif yang membandingkan hasil dari empat skenario yang berbeda. Pengukuran akurasi geolokasi dilakukan menggunakan aplikasi GPS Test. Hasil penelitian menunjukkan bahwa keakuratan geolokasi di ruang terbuka lebih tinggi ketika lokasi smartphone diam, sementara di ruang tertutup, keakuratan lebih baik saat lokasi smartphone bergerak. Dari keempat skenario yang diuji, perbandingan akurasi antara perangkat pertama dan kedua hanya signifikan pada skenario ketiga yaitu lokasi smartphone diam di ruang tertutup. Perangkat pertama menunjukkan tingkat keakuratan 58.65% lebih tinggi daripada perangkat kedua.Geolocation accuracy on smartphones is now a crucial factor in user experience, especially in location-based applications such as navigation and other location-based services. This research aims to analyze geolocation accuracy indoor and outdoor on two smartphones that have different signal frequencies. The method used is a comparative method that compares the results of four different scenarios. Geolocation accuracy measurements were carried out using the GPS Test application. The research results show that geolocation accuracy outdoors is higher when the smartphone location is still, while indoor, geolocation accuracy is better when the smartphone location is moving. Of the four scenarios tested, comparing accuracy between the first and second devices was only significant in the scenario where the smartphone was in a closed room. The first device shows an accuracy rate of 58.65% higher than the second device

Precise Point Positioning Augmentation for Various Grades of Global Navigation Satellite System Hardware

The next generation of low-cost, dual-frequency, multi-constellation GNSS receivers, boards, chips and antennas are now quickly entering the market, offering to disrupt portions of the precise GNSS positioning industry with much lower cost hardware and promising to provide precise positioning to a wide range of consumers. The presented work provides a timely, novel and thorough investigation into the positioning performance promise. A systematic and rigorous set of experiments has been carried-out, collecting measurements from a wide array of low-cost, dual-frequency, multi-constellation GNSS boards, chips and antennas introduced in late 2018 and early 2019. These sensors range from dual-frequency, multi-constellation chips in smartphones to stand-alone chips and boards. In order to be comprehensive and realistic, these experiments were conducted in a number of static and kinematic benign, typical, suburban and urban environments. In terms of processing raw measurements from these sensors, the Precise Point Positioning (PPP) GNSS measurement processing mode was used. PPP has become the defacto GNSS positioning and navigation technique for scientific and engineering applications that require dm- to cm-level positioning in remote areas with few obstructions and provides for very efficient worldwide, wide-array augmentation corrections. To enhance solution accuracy, novel contributions were made through atmospheric constraints and the use of dual- and triple-frequency measurements to significantly reduce PPP convergence period. Applying PPP correction augmentations to smartphones and recently released low-cost equipment, novel analyses were made with significantly improved solution accuracy. Significant customization to the York-PPP GNSS measurement processing engine was necessary, especially in the quality control and residual analysis functions, in order to successfully process these datasets. Results for new smartphone sensors show positioning performance is typically at the few dm-level with a convergence period of approximately 40 minutes, which is 1 to 2 orders of magnitude better than standard point positioning. The GNSS chips and boards combined with higher-quality antennas produce positioning performance approaching geodetic quality. Under ideal conditions, carrier-phase ambiguities are resolvable. The results presented show a novel perspective and are very promising for the use of PPP (as well as RTK) in next-generation GNSS sensors for various application in smartphones, autonomous vehicles, Internet of things (IoT), etc

Precise Orbit Determination of CubeSats

CubeSats are faced with some limitations, mainly due to the limited onboard power and the quality of the onboard sensors. These limitations significantly reduce CubeSats' applicability in space missions requiring high orbital accuracy. This thesis first investigates the limitations in the precise orbit determination of CubeSats and next develops algorithms and remedies to reach high orbital and clock accuracies. The outputs would help in increasing CubeSats' applicability in future space missions

Performance Evaluation of QZSS Augmenting GPS and BDS Single-Frequency Single-Epoch Positioning with Actual Data in Asia-Pacific Region

The Quasi-Zenith Satellite System (QZSS) service area covers the Asia-Pacific region and there are four quasi-zenith satellites (QZS) in orbit with three QZS in operation until March 2018. The QZSS is not required to work in a stand-alone mode, but the system can be used to enhance the Global Positioning System (GPS) or Beidou Satellite Navigation System (BDS). The availability, position dilution of precision (PDOP), ambiguity dilution of precision (ADOP), and success rate of GPS/QZSS and BDS/QZSS under different cut-off elevation angles were compared based on a simulation. Two sets of actual QZSS data were processed and analyzed for single-frequency single-epoch (SFSE) positioning together with GPS/BDS data in this paper. Different combination forms were executed to evaluate the positioning performance of GPS/QZSS and BDS/QZSS for two baseline cases. The results indicate that QZSS is able to increase the SFSE PDOP, ADOP, and success rate of the baseline resolution and decrease the position error for GPS or BDS, especially for longer GPS baseline data. The more QZS are used, the better the enhancement effect