Real-time precise point positioning with a low-cost dual-frequency GNSS device

Nie, Zhixi; Liu, Fei; Gao, Yang

doi:10.1007/s10291-019-0922-3

Cited by 107 publications

(58 citation statements)

References 37 publications

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“…The ionosphere-free combination formed by the carrier phase measurement at two frequencies can be expressed as [ 30 , 31 ]:

where

;

stands for the ionosphere-free ambiguity in meters;

denotes measurement noise of the ionosphere-free phase combination. Once the epoch-differencing is employed to high-rate smartphone GNSS ionosphere-free observations, the tropospheric delay would be nearly eliminated.…”

Section: Methodsmentioning

confidence: 99%

A Modified TurboEdit Cycle-Slip Detection and Correction Method for Dual-Frequency Smartphone GNSS Observation

Nie

Wang

et al. 2020

Sensors

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Recently, some smartphone manufacturers have subsequently released dual-frequency GNSS smartphones. With dual-frequency observations, the positioning performance is expected to be significantly improved. Cycle-slip detection and correction play an important role in high-precision GNSS positioning, such as precise point positioning (PPP) and real-time kinematic (RTK) positioning. The TurboEdit method utilizes Melbourne–Wübbena (MW) and phase ionospheric residual (PIR) combinations to detect cycle-slips, and it is widely used in the data processing applications for geodetic GNSS receivers. The smartphone pseudorange observations are proved to be much noisier than those collected with geodetic GNSS receivers. Due to the poor pseudorange observation, the MW combination would be difficult to detect small cycle-slips. In addition, some specific cycle-slip combinations, where the ratio of cycle-slip values at different carrier frequencies is close to the frequency ratio, are also difficult to be detected by PIR combination. As a consequence, the traditional TurboEdit method may fail to detect specific small cycle-slip combinations. In this contribution, we develop a modified TurboEdit cycle-slip detection and correction method for dual-frequency smartphone GNSS observations. At first, MW and PIR combinations are adopted to detect cycle-slips by comparing these two combinations with moving-window average values. Then, the epoch-differenced wide-lane combinations are used to estimate the changes of smartphone position and clock bias, and the cycle-slip is identified by checking the largest normalized residual whether it exceeds a predefined threshold value. The process of estimation and cycle-slip identification is implemented in an iterative way until there is no over-limit residual or there is no redundant measurement. At last, the cycle-slip values at each frequency are estimated with the epoch-differenced wide-lane and ionosphere-free combinations, and the least-square ambiguity decorrelation adjustment (LAMBDA) method is adopted to further obtain an integer solution. The proposed method has been verified with 1 Hz dual-frequency smartphone GNSS data. The results show that the modified TurboEdit method can effectively detect and correct even for specific small cycle-slip combinations, e.g., (4, 3), which is difficult to be detected with the traditional TurboEdit method.

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“…The ionosphere-free combination formed by the carrier phase measurement at two frequencies can be expressed as [ 30 , 31 ]:

where

;

stands for the ionosphere-free ambiguity in meters;

Section: Methodsmentioning

confidence: 99%

A Modified TurboEdit Cycle-Slip Detection and Correction Method for Dual-Frequency Smartphone GNSS Observation

Nie

Wang

et al. 2020

Sensors

Self Cite

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“…Yöntem ilk olarak Anderle (1976) tarafından uygulanmış olmakla birlikte, günümüzdeki anlamda ilk kez Zumberge ve arkadaşları tarafından 1997 yılında gerçekleştirilen çalışmalarıyla birlikte yaygın kullanıma başlanmıştır (Zumberge et al, 1997 (Zumberge et al, 1997;Héroux and Kouba, 2001;Rizos et al, 2012;Choy et al, 2017;Bahadur and Nohutcu, 2019;Dawidowicz, 2020;Facio and Berber, 2020;Kiliszek and Kroszczyński, 2020;Liu et al, 2020 (Wang, 2014). Ayrıca bu çözüm yöntemi float tamsayı belirsizliği çözümüne göre çok daha yüksek doğruluk ve güvenirlikte çözüm sağlamaktadır (Bisnath and Collins, 2012).…”

Section: Hassas Nokta Konumlama Tekni̇ği̇ (Ppp)unclassified

Farklı GNSS Uydu Sistemlerinin Hassas Nokta Konumlama (PPP) Tekniğinin Performansına Etkisinin İncelenmesi

et al. 2021

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Uydu jeodezisi ile veri işleme ve analizindeki gelişmeler sonucunda herhangi bir referans istasyonunda toplanan verileri kullanmaya gerek duymadan, tek bir GNSS alıcısı ile santimetre doğruluğunda konum belirlemeyi mümkün kılan Hassas Nokta Konumlama (PPP) tekniği geliştirilmiştir. Bu yöntemde, tek bir alıcı ile toplanan veriler, farklı kuruluşlarca üretilen hassas uydu yörünge ve saat bilgileri ile birlikte değerlendirilerek, statik veya kinematik olarak yüksek doğrulukta konum belirlenebilmektedir. PPP tekniği ile koordinatların belirlenebilmesi için pek çok yaklaşım olmakla birlikte, son zamanlarda web-tabanlı online veri değerlendirme servisleri tüm dünyada başarıyla yaygın olarak kullanılmaya başlanmıştır. Öte yandan GPS ile başlayan uydu-bazlı konum belirleme çalışmaları, izleyen zamanda GLONASS, Galileo ve BeiDou uydularının da eklenmesiyle birlikte Global Navigation Satellite System (GNSS) olarak adlandırılan tümleşik bir konum belirleme sisteminin meydana gelmesini sağlamıştır. Bu çalışmada İTÜ Ayazağa Kampüsünde, farklı uydu gözlem özelliklerine sahip noktalar tesis edilmiş ve çoklu-GNSS’in statik PPP nokta konum doğruluğuna etkisi incelenmiştir. Çalışmadan elde edilen sonuçlar PPP tekniği ile elde edilen doğrulukların ölçme yapılan noktadaki fiziki koşullara, uydu sayısına ve uyduların geometrisine bağlı olarak anlamlı şekilde değiştiğini, birden fazla uydu sistemi ile yapılan ölçmelerin de özellikle zorlu koşullara sahip noktalarda yapılan ölçmelerin sonuçları üzerinde anlamlı düzeyde iyileştirici bir rol oynadığını ortaya koymuştur.

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“…Recently, the investigation of multi-GNSS PPP data processing is not only about the dual-frequency models (Cai et al 2015), but also focusing on the multi-frequency observations (Li et al 2019b(Li et al , 2020a. Briefly, the multi-frequency and multi-GNSS based PPP is becoming increasingly fashionable for precise positioning services (Alkan and Öcalan 2013; Guo et al 2018), particularly in some new applications such as self-driving cars and unmanned aerial vehicles (Nie et al 2019;Geng and Guo 2020).…”

Section: Introductionmentioning

confidence: 99%

Semi-tightly coupled integration of multi-GNSS PPP and S-VINS for precise positioning in GNSS-challenged environments

et al. 2021

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Because of its high-precision, low-cost and easy-operation, Precise Point Positioning (PPP) becomes a potential and attractive positioning technique that can be applied to self-driving cars and drones. However, the reliability and availability of PPP will be significantly degraded in the extremely difficult conditions where Global Navigation Satellite System (GNSS) signals are blocked frequently. Inertial Navigation System (INS) has been integrated with GNSS to ameliorate such situations in the last decades. Recently, the Visual-Inertial Navigation Systems (VINS) with favorable complementary characteristics is demonstrated to realize a more stable and accurate local position estimation than the INS-only. Nevertheless, the system still must rely on the global positions to eliminate the accumulated errors. In this contribution, we present a semi-tight coupling framework of multi-GNSS PPP and Stereo VINS (S-VINS), which achieves the bidirectional location transfer and sharing in two separate navigation systems. In our approach, the local positions, produced by S-VINS are integrated with multi-GNSS PPP through a graph-optimization based method. Furthermore, the accurate forecast positions with S-VINS are fed back to assist PPP in GNSS-challenged environments. The statistical analysis of a GNSS outage simulation test shows that the S-VINS mode can effectively suppress the degradation of positioning accuracy compared with the INS-only mode. We also carried out a vehicle-borne experiment collecting multi-sensor data in a GNSS-challenged environment. For the complex driving environment, the PPP positioning capability is significantly improved with the aiding of S-VINS. The 3D positioning accuracy is improved by 49.0% for Global Positioning System (GPS), 40.3% for GPS + GLOANSS (Global Navigation Satellite System), 45.6% for GPS + BDS (BeiDou navigation satellite System), and 51.2% for GPS + GLONASS + BDS. On this basis, the solution with the semi-tight coupling scheme of multi-GNSS PPP/S-VINS achieves the improvements of 41.8–60.6% in 3D positioning accuracy compared with the multi-GNSS PPP/INS solutions.

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Real-time precise point positioning with a low-cost dual-frequency GNSS device

Cited by 107 publications

References 37 publications

A Modified TurboEdit Cycle-Slip Detection and Correction Method for Dual-Frequency Smartphone GNSS Observation

A Modified TurboEdit Cycle-Slip Detection and Correction Method for Dual-Frequency Smartphone GNSS Observation

Farklı GNSS Uydu Sistemlerinin Hassas Nokta Konumlama (PPP) Tekniğinin Performansına Etkisinin İncelenmesi

Semi-tightly coupled integration of multi-GNSS PPP and S-VINS for precise positioning in GNSS-challenged environments

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