(Usability of Generating Long Term GNSS Time Series Using CSRS-PPP and Site Velocity Estimation)

Son yıllarda PPP (Precise Point Positioning) yöntemiyle konum belirleme doğruluğunun artması yönteme olan ilginin artmasına ve yöntemin daha yaygın kullanılır hale gelmesine neden olmuştur. CSRS-PPP (The Canadian Spatial Reference SystemPPP), APPS (Automatic Precise Positioning Service) v.b. gibi Web-Tabanlı PPP yazılımlarla tek nokta GNSS verileri herhangi bir ücret ödemeksizin statik ya da kinematik yöntemlerden biri ile kolaylıkla değerlendirilebilmektedir. prensibi gözlem verilerinin RINEX (The Receiver Independent Exchange Format) formatında Web ara yüzleri kullanılarak sunuculara gönderilmesi ve sunucu tarafından hesaplama sonuçlarının web den doğrudan ya da e-posta yolu ile gönderilen linkten indirilmesi işlemine dayanır. Bu çalışmada, CSRS-PPP yazılımının uzun dönemli zaman serilerinin üretilmesinde ve bu zaman serilerinden nokta hızlarının kestirilmesindeki performansı değerlendirilmiştir. Bu amaçla, IGS (International GNSS Service) ağından seçilen 3 noktanın uzun dönemli zaman serileri günlük PPP çözümleri ile elde edilmiştir. CSRS-PPP yazılımı kullanılarak elde edilen zaman serilerinden nokta hızları robust regresyon yöntemi ile kestirilmiş ve JPL (Jet Propulsion Laboratory) zaman serileri kullanılarak kestirilen nokta hızlarıyla karşılaştırılması yapılmıştır.Recently, the improvement in the accuracy of positioning with PPP (Precise Point Positioning) method has caused an increase in interest and to become more widely used. Using the web-based PPP softwares such as CSRS-PPP (The Canadian Spatial Reference System-PPP), APPS (Automatic Precise Positioning Service), etc., stand-alone GNSS data can be easily processed in both static and kinematic mode without any payment. The basic principle of these software is to send observation data in RINEX (The Receiver Independent Exchange Format) format from web interface and to download results via a link received by e-mail. In this study, performance of the CSRS-PPP software was evaluated in terms of generating longterm time series and estimating station velocity. For this purpose, time series of three stations from IGS (International GNSS Service) network is generated by daily PPP solutions. The velocities of these stations based on time series generated from CSRS-PPP were estimated by means of robust regression methods and they were compared with the velocities estimated from JPL (Jet Propulsion Laboratory) time series

Assessing the performance of BDS-3 for multi-GNSS static and kinematic PPP-AR

MakaleWOS:000921074500001As of 2021, a total of four different GNSS constellations - namely, GPS, GLONASS, Galileo, and BDS-3 - can be used with Full Operational Capability (FOC). In this work, the contribution of BDS-3 FOC to GPS + GLONASS + Galileo (GRE) PPP-AR is inves-tigated, considering the three different cut-off angles (7 degrees, 30 degrees, and 45 degrees) and different lengths of static observation sessions (24-, 12-, 6-, 3-, 1-, 0.5-, 0.25-hour). The data of 31 IGS-MGEX stations is processed with GRE PPP-AR and GREC3 (GPS + GLONASS (using float mode) + Galileo + BDS-3) PPP-AR modes. The results showed that BDS-3 degraded the horizontal (except for 24-h sessions) and ver-tical accuracy of static GRE PPP-AR solutions regardless of the elevation cutoff angle and observation time. The kinematic results showed that BDS-3 significantly contributed to the accuracy of GRE kinematic PPP-AR for 30 degrees and 45 degrees cutoff angles. The convergence time analysis showed that BDS-3 only contributes to GRE kinematic PPP-AR for the vertical component.(c) 2022 COSPAR. Published by Elsevier B.V. All rights reserved