Indoor multipath effect study on the Locata system

Bonenberg, Lukasz; Hancock, Craig M.; Roberts, Gethin Wyn

doi:10.1515/jag.2010.012

Cited by 7 publications

(8 citation statements)

References 6 publications

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“…A combined approach of Doppler and carrier-based hyperbolic positioning with a multi-channel GPS-pseudolite for indoor localization has also been proposed by Fujii et al [23], an state equation of three dimensional(3-D) receiver's position and orientation, and ambiguity is established, an observation equation for Doppler positioning is used to estimate the offset of three dimensional(3-D) position and orientation, a nonlinear observation equation for carrier phase difference between pseudolites is used to estimate ambiguity, therefore, it needs to overcome such problems as ambiguity resolution, non-linear observation equation, positioning stability and real-time, etc.. The most famous indoor pseudolites system is produced by Locata Corporation [2], [15], [16], which consists of a network (LocataNet) of time-synchronised transceivers (LocataLites), and it has the potential to allow point positioning with sub-cm precision (using carrier phase) for a mobile unit. To achieve synchronization among all the pseudolites' clock, TimeLoc technology can provide an autonomously synchronized network, which requires the additional ranging signals (code and carrier) and the visibility between pseudolites.…”

Section: Introductionmentioning

confidence: 99%

A New Array Pseudolites Technology for High Precision Indoor Positioning

Gan

Wang

et al. 2019

IEEE Access

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Global Satellite Navigation System (GNSS) can't provide normal location service in the indoor environment because the signal can be blocked by buildings. The pseudolites system can supplement GNSS, especially in the indoor environments. A new indoor array pseudolites system is introduced, its multi-channel transmitter has an identical clock source. The high-precision Doppler positioning method based on Z-fixed Known Point Initialization (Z-KPI) is developed without ambiguity resolution. Some static and dynamic tests are conducted to evaluate the positioning accuracy of this new method. In the static testing, the average Doppler measurement error is 1×10-5 m/s, which lays the foundation of the high precision velocity measurement, and the average positioning error is 0.02 m in X axis, 0.004 m in Y axis, and the average velocity error is 3.28×10 −5 m/s in X axis, 1.94×10 −5 m/s in Y axis. In the dynamic test, the maximum positioning error is 0.39 m in X axis, 0.34 m in Y axis. Finally, the reason for adopting the Z-fixed KPI algorithm is explained by the horizontal dilution of precision (HDOP), meanwhile, the influence of the known initialization point error on indoor positioning accuracy is analyzed, when a deviation from −1.5 m to 0.9 m is added to the Z-axis of the KPI, the maximum positioning error is 0.311 m in X axis, 0.08 m in Y axis; when the horizontal deviation tolerance of the KPI is set from-0.5 m to 0.5 m, the maximum horizontal positioning error is less than 0.5 m.

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Section: Introductionmentioning

confidence: 99%

A New Array Pseudolites Technology for High Precision Indoor Positioning

Gan

Wang

et al. 2019

IEEE Access

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“…However, in ground based positioning, the multipath effects sometimes are more severe than those in GNSS applications. There have been several solutions discussed [ 26 , 27 ].…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Since the multipath error varies at different positions, in this paper, it is considered as a kind of noise instead of a series of constant biases. The maximum multipath error is no larger than

, and there are ways to mitigate the multipath effects for ground based positioning via choke ring antenna, spatial, polarization or frequency design techniques [ 26 , 27 ].…”

Section: Problem Formulationmentioning

confidence: 99%

On-The-Fly Ambiguity Resolution Based on Double-Differential Square Observation

Wang

Yao

2018

Sensors

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Global navigation systems provide worldwide positioning, navigation and navigation services. However, in some challenging environments, especially when the satellite is blocked, the performance of GNSS is seriously degraded or even unavailable. Ground based positioning systems, including pseudolites and Locata, have shown their potentials in centimeter-level positioning accuracy using carrier phase measurements. Ambiguity resolution (AR) is a key issue for such high precision positioning. Current methods for the ground based systems need code measurements for initialization and/or approximating linearization. If the code measurements show relatively large errors, current methods might suffer from convergence difficulties in ground based positioning. In this paper, the concept of double-differential square observation (DDS) is proposed, and an on-the-fly ambiguity resolution (OTF-AR) method is developed for ground based navigation systems using two-way measurements. An important advantage of the proposed method is that only the carrier phase measurements are used, and code measurements are not necessary. The clock error is canceled out by two-way measurements between the rover and the base stations. The squared observations are then differenced between different rover positions and different base stations, and a linear model is then obtained. The floating integer values are easy to compute via this model, and there is no need to do approximate linearization. In this procedure, the rover’s approximate coordinates are also directly obtained from the carrier measurements, therefore code measurements are not necessary. As an OTF-AR method, the proposed method relies on geometric changes caused by the rover’s motion. As shown by the simulations, the geometric diversity of observations is the key factor for the AR success rate. Moreover, the fine floating solutions given by our method also have a fairly good accuracy, which is valuable when fixed solutions are not reliable. A real experiment is conducted to validate the proposed method. The results show that the fixed solution could achieve centimeter-level accuracy.

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“…Multipath is a serious error source due to the low elevation angles in a typical Locata scenario [21]. Bonenberg et al investigated the influence of issues, such as different power levels and shielding options (metal plate and a choke ring) [54]. Nowadays, using the VRay antenna is perhaps the best option for mitigating against multipath disturbance.…”

Section: Locata Development History and Mathematical Modelsmentioning

confidence: 99%

Background and Recent Advances in the Locata Terrestrial Positioning and Timing Technology

Rizos

Yang

2019

Sensors

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Global Navigation Satellite System (GNSS) is the most widely used Positioning, Navigation, and Timing (PNT) technology in the world today, but it suffers some major constraints. Locata is a terrestrial PNT technology that can be considered as a type of localised “constellation”, which is able to provide high-accuracy PNT coverage where GNSS cannot be used. This paper presents a comprehensive literature review of the Locata technology and its applications. It seeks to answer questions, such as: (1) What is Locata and how does it work? (2) What makes Locata unique compared with other terrestrial positioning systems? (3) How has Locata been used in different applications for accurate PNT? (4) What are the current challenging issues that may restrict its further adoption for custom-grade navigation in urban environments?

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Indoor multipath effect study on the Locata system

Cited by 7 publications

References 6 publications

A New Array Pseudolites Technology for High Precision Indoor Positioning

A New Array Pseudolites Technology for High Precision Indoor Positioning

On-The-Fly Ambiguity Resolution Based on Double-Differential Square Observation

Background and Recent Advances in the Locata Terrestrial Positioning and Timing Technology

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