Exploiting Antenna Motion for Faster Initialization of Centimeter-Accurate GNSS Positioning With Low-Cost Antennas

Pesyna, Kenneth M.; Humphreys, Todd E.; Heath, Robert W.; Novlan, Thomas; Zhang, Jianzhong Charlie

doi:10.1109/taes.2017.2665221

Cited by 33 publications

(34 citation statements)

References 29 publications

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“…As a result, what used in this study were not the complete tweets generated by Twitter users but their random samples. Furthermore, positioning accuracy of smartphones is reported to be 2-3 m under good multipath conditions and can degrade to 10 m or worse under adverse multipath conditions [57]. Such quality however is good enough for us since this study is mostly related to patterns of tweeting activities.…”

Section: Twitter Datamentioning

confidence: 92%

Discover Patterns and Mobility of Twitter Users—A Study of Four US College Cities

Shan

2017

IJGI

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Geo-tagged tweets provide useful implications for studies in human geography, urban science, location-based services, targeted advertising, and social network. This research aims to discover the patterns and mobility of Twitter users by analyzing the spatial and temporal dynamics in their tweets. Geo-tagged tweets are collected over a period of six months for four US Midwestern college cities: (1) West Lafayette, IN; (2) Bloomington, IN; (3) Ann Arbor, MI; (4) Columbus, OH. Various analytical and statistical methods are used to reveal the spatial and temporal patterns of tweets, and the tweeting behaviors of Twitter users. It is discovered that Twitter users are most active between 9:00 p.m. and 11:00 .pm. In smaller cities, tweets aggregate at campuses and apartment complexes, while tweets in residential areas of bigger cities make up the majority of tweets. We also found that most Twitter users have two to four places of frequent visits. The mean mobility range of frequent Twitter users is linearly correlated to the size of the city, specifically, about 40% of the city radius. The research therefore confirms the feasibility and promising future for using geo-tagged microblogging services such as Twitter to understand human behavior patterns and carry out other geo-social related studies.

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Section: Twitter Datamentioning

confidence: 92%

Discover Patterns and Mobility of Twitter Users—A Study of Four US College Cities

Shan

2017

IJGI

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“…where 2 represents the total noise level, 2 Δ∇ ,Φ 1 A represents the ionospheric delay error of B1, and 2 Δ∇ represents tropospheric delay error. For the short baseline, both ionospheric delay error and tropospheric delay errors are negligible due to strong temporal and spatial correlation.…”

Section: Reduce the Total Noise Level Of Nl Observationsmentioning

confidence: 99%

“…However, GNSS signals are obstructed and reflected by obstacles such as high-rise buildings and tunnels in complex environments, causing serious multipath effects and poor satellite geometry, which have become the great challenge to correctly resolve the integer ambiguity. Severe multipath effects reduce the quality of the observations, and poor satellite geometry increases the correlation between the observations, making it more difficult to search for integer ambiguities, all of which degrade the performance of Ambiguity Resolution (AR) and positioning [2]. Teunissen adopted the "Z" transform to degrade the correlation between the float ambiguities to speed up the fixation of ambiguities, which is known as the Least squares AMBiguity Decorrelation Adjustment (LAMBDA) method [3]; Teunissen and Odolinski also proposed that Multiple GNSS combinations increase the number of available satellites to improve satellite geometry and improve GNSS positioning performance in harsh environments [4,5].…”

Section: Introductionmentioning

confidence: 99%

A MEMS-IMU Assisted BDS Triple-Frequency Ambiguity Resolution Method in Complex Environments

Cheng

Zhao

2018

Mathematical Problems in Engineering

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Emerging technologies such as smart cities and unmanned vehicles all need Global Navigation Satellite Systems (GNSS) to provide high-precision positioning and navigation services. Fast and reliable carrier phase ambiguity resolution (AR) is a prerequisite for high-precision positioning. The poor satellite geometry and severe multipath effect caused by Beidou Navigation Satellite System (BDS) signal occlusion and reflection in complex environments will degrade the AR performance. In this contribution, a fast triplefrequency AR method combining Microelectromechanical System-Inertial Measurement Unit (MEMS-IMU) and BDS is proposed. First, the Extra-Wide Lane (EWL) ambiguity is fixed with the positioning parameters of MEMS-IMU instead of the pseudorange. Then, the phase noise variance of Narrow Lane (NL) observation is obtained from ambiguity-fixed EWL observation to reduce the total noise level of NL observation, and the NL ambiguity can be reliably fixed, and the BDS positioning result is obtained. Finally, the BDS positioning result is used as the posterior measurement of the extended Kalman filter to update the MEMS-IMU positioning parameters to form the coupling loop of MEMS-IMU and BDS. The data of urban road vehicle experiments were collected to verify the feasibility and effectiveness of the proposed algorithm. Results show that MEMS-IMU can speed up AR, and reduction of total noise level can significantly improve the reliability of AR.

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“…This is true for two reasons. First, for stationary users with low-cost equipment, multipath errors dominate in the carrier-phase measurement and are strongly correlated over 100 seconds or more [3]. Thus, if single-epoch AR fails then a static user may have to wait an unacceptably long time for multipath errors to decorrelate enough to permit AR.…”

Section: Ambiguity Resolution Performance As a Function Of Ionospmentioning

confidence: 99%

“…The model is highly accurate for single-epoch AR, but only approximate for multiple epochs, with accuracy degrading as the data interval lengthens. The model's inaccuracy results from its assumption that overhead satellites remain static from epoch to epoch, which yields pessimistic results for even fairly short data capture intervals (e.g., 30 seconds) [3]. Fully accounting for satellite motion in an analytical model for ADOP is an open problem (presently intractable), which is why ADOP studies that wish to account for satellite motion resort to simulation [3].…”

Section: Ambiguity Resolution Performance As a Function Of Ionospmentioning

confidence: 99%

A dense reference network for mass-market centimeter-accurate positioning

Murrian

Gonzalez

Humphreys

et al. 2016

2016 IEEE/ION Position, Location and Navigation Symposium (PLANS)

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Abstract-The quality of atmospheric corrections provided by a dense reference network for centimeter-accurate carrierphase differential GNSS (CDGNSS) positioning is investigated. A dense reference network (less than 20 km inter-station distance) offers significant benefits for mass-market users, enabling lowcost (including single-frequency) CDGNSS positioning with rapid integer ambiguity resolution. Precise positioning on a massmarket platform would significantly influence the world economy, ushering in a host of consumer-focused applications such as globally-registered augmented and virtual reality and improved all-weather safety and efficiency for intelligent transportation systems, applications which have so far been hampered by the several-meter-level errors in standard GNSS positioning. This contribution examines CDGNSS integer ambiguity resolution performance in terms of network correction uncertainty, and network correction uncertainty, in turn, in terms of network density. It considers the total error in network corrections: a sum of ionospheric, tropospheric, and reference station multipath components. The paper's primary goal is to identify the network density beyond which mass-market users would see no further significant improvement in ambiguity resolution performance. It finishes by describing development and deployment of a low-cost dense reference network in Austin, Texas.

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Exploiting Antenna Motion for Faster Initialization of Centimeter-Accurate GNSS Positioning With Low-Cost Antennas

Cited by 33 publications

References 29 publications

Discover Patterns and Mobility of Twitter Users—A Study of Four US College Cities

Discover Patterns and Mobility of Twitter Users—A Study of Four US College Cities

A MEMS-IMU Assisted BDS Triple-Frequency Ambiguity Resolution Method in Complex Environments

A dense reference network for mass-market centimeter-accurate positioning

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