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Psychas, D.V. (author), Khodabandeh, A. (author), Teunissen, P.J.G. (author)PPP-RTK corrections, aiding GNSS users to achieve single-receiver integer ambiguity-resolved parameter solutions, are often estimated in a recursive manner by a provider. Such recursive, multi-epoch, estimation of the corrections relies on a set of S-basis parameters that are chosen by the provider so as to make the underlying measurement...journal article 2024
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Khodabandeh, A. (author), Teunissen, P.J.G. (author)Carrier phase signals are considered among the key observations in global navigation satellite systems (GNSSs) and several other high-precision interferometric measurement systems. However, these ultra-precise measurements are not fully exploited when the integerness of their inherent ambiguities is discarded during the estimation process....journal article 2023
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Sadegh Nojehdeh, Parvaneh (author), Khodabandeh, Amir (author), Khoshelham, Kourosh (author), Amiri Simkooei, A. (author)The provision of accurate ionospheric corrections in PPP-RTK enormously improves the performance of single-receiver user integer ambiguity resolution (IAR), thus enabling fast high precision positioning. While an external provider can disseminate such corrections to the user with a time delay, it is the task of the user to accurately time...journal article 2023
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Khodabandeh, A. (author), Teunissen, P.J.G. (author), Psychas, D. (author)To obtain single-receiver Global Navigation Satellite System (GNSS) parameter solutions, the PPP-RTK user-filter combines measurements with time-correlated corrections that are separately computed by the filter of an external provider. The consequence of exercising such double-filtering is that the Kalman filter’s standard assumption of...journal article 2023
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Teunissen, P.J.G. (author), Khodabandeh, A. (author)In this contribution, we generalize PPP–RTK theory by allowing the transmitters to transmit on different frequencies. The generalization is based on the integer-estimability theory of Teunissen (A new GLONASS FDMA model. GPS Solutions, 2019). As the theory and associated algorithms provided are generally applicable, they apply to satellite...journal article 2022
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Psychas, D.V. (author), Khodabandeh, Amir (author), Teunissen, P.J.G. (author)The corrections needed to realize integer ambiguity resolution-enabled precise point positioning (PPP-RTK) at a single-receiver user are often treated as if they are deterministic quantities. The present contribution aims to study and analyze the effect the neglected uncertainty of these corrections, which are subject to time delay, has on...journal article 2022
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Teunissen, P.J.G. (author), Khodabandeh, A. (author), Psychas, D.V. (author)In this contribution, we introduce a generalized Kalman filter with precision in recursive form when the stochastic model is misspecified. The filter allows for a relaxed dynamic model in which not all state vector elements are connected in time. The filter is equipped with a recursion of the actual error-variance matrices so as to provide an...journal article 2021
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Teunissen, P.J.G. (author), Khodabandeh, A. (author)Although ionosphere-weighted GNSS parameter estimation is a popular technique for strengthening estimator performance in the presence of ionospheric delays, no provable rules yet exist that specify the needed weighting in dependence on ionospheric circumstances. The goal of the present contribution is therefore to develop and present the...journal article 2021
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Zaminpardaz, Safoora (author), Teunissen, P.J.G. (author), Khodabandeh, Amir (author)An assessment of standalone GLONASS RTK performance is provided using its FDMA and CDMA signals. The new integer-estimable GLONASS FDMA model (Teunissen 2019), which guarantees the integer-estimability of its ambiguities, is employed. We introduce the combined integer-estimable GLONASS FDMA+CDMA model and compare its strength against the FDMA...journal article 2021
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Wang, K. (author), Khodabandeh, A. (author), Teunissen, P.J.G. (author)Various studies have been performed to investigate the accuracy of troposphere zenith wet delays (ZWDs) determined from GPS. Most of these studies use dual-frequency GPS data of large-scale networks with long baselines to determine the absolute ZWDs. For small-scale networks the estimability of the absolute ZWDs deteriorates due to high...journal article 2019
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Khodabandeh, A. (author), Teunissen, P.J.G. (author)In view of the recent proliferation of low-cost mass-market receivers, the number of network receivers and GNSS users will be growing rapidly, demanding an efficient way of data processing in terms of computational power and capacity. One way of improving the computational capacity is to decentralize the underlying data processing and distribute...journal article 2019
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Khodabandeh, A. (author), Teunissen, P.J.G. (author)Estimability and S-systems are important concepts when dealing with rank-defect models. In this contribution, we generalize the concept of estimability to integer estimability and determine the necessary and sufficient conditions that need to be satisfied for parameter functions to be integer estimable. This is then worked out and applied to the...journal article 2019
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Olivares-Pulido, G. (author), Terkildsen, M. (author), Arsov, K. (author), Teunissen, P.J.G. (author), Khodabandeh, A. (author), Janssen, V. (author)Successful implementation of integer ambiguity resolution enabled precise point positioning (aka PPP-RTK) algorithms is inextricably linked to the ability of a user to perform near real-time positioning by quickly and reliably resolving the integer carrier-phase ambiguities. In the PPP-RTK technique, a major barrier to successful ambiguity...journal article 2019
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Teunissen, P.J.G. (author), Khodabandeh, A. (author)A new integer-estimable GLONASS FDMA model is studied and analysed. The model is generally applicable, and it shows a close resemblance with the well-known CDMA models. The analyses provide insights into the performance characteristics of the model and concern a variety of different ambiguity-resolution critical applications. This will be done...journal article 2019
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Wang, Kan (author), Khodabandeh, Amir (author), Teunissen, P.J.G. (author)For long-baseline over several hundreds of kilometers, the ionospheric delays that cannot be fully removed by differencing observations between receivers hampers rapid ambiguity resolution. Compared with forming ionospheric-free linear combination using dual- or triple-frequency observations, estimating ionospheric delays using uncombined...journal article 2018
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Wang, Kan (author), Khodabandeh, Amir (author), Teunissen, P.J.G. (author), Nadarajah, Nandakumaran (author)The real-time kinematic precise point positioning (PPP-RTK) technique enables integer ambiguity resolution by providing singlereceiver users with information on the satellite phase biases next to the standard PPP corrections. Using undifferenced and uncombined observations, rank deficiencies existing in the design matrix need to be eliminated to...journal article 2018
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Nadarajah, Nandakumaran (author), Khodabandeh, Amir (author), Wang, Kan (author), Choudhury, Mazher (author), Teunissen, P.J.G. (author)Precise point positioning (PPP) and its integer ambiguity resolution-enabled variant, PPP-RTK (real-time kinematic), can benefit enormously from the integration of multiple global navigation satellite systems (GNSS). In such a multi-GNSS landscape, the positioning convergence time is expected to be reduced considerably as compared to the one...journal article 2018
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Wang, K. (author), Khodabandeh, A. (author), Teunissen, P.J.G. (author)In PPP-RTK network processing, the wet component of the zenith tropospheric delay (ZTD) cannot be precisely modelled and thus remains unknown in the observation equations. For small networks, the tropospheric mapping functions of different stations to a given satellite are almost equal to each other, thereby causing a near rank-deficiency...journal article 2018
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Khodabandeh, A. (author), Teunissen, P.J.G. (author)Integer ambiguity resolution (IAR) is the key to fast and precise GNSS positioning and navigation. Next to the positioning parameters, however, there are several other types of GNSS parameters that are of importance for a range of different applications like atmospheric sounding, instrumental calibrations or time transfer. As some of these...journal article 2018
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Teunissen, P.J.G. (author), Khodabandeh, A. (author), Zhang, B. (author)In this contribution, we present full-rank observation equations of the network and user receivers, of mixed types, through an application of S-system theory. We discuss the important roles played by the inter system biases (ISBs), and we show how the three-component structure of PPP-RTK is affected by the inclusion of the ISBs as extra...conference paper 2018
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