Short Note: On the Relativistic Doppler Effect for Precise Velocity Determination using GPS

Zhang, Jason; Zhang, Kefei; Grenfell, R.; Deakin, R.

doi:10.1007/s00190-006-0038-8

Cited by 48 publications

(14 citation statements)

References 7 publications

(4 reference statements)

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“…However, experiments with our datasets have shown otherwise. Despite the speeds in most of the GPS devices being measured accurately with the Doppler effect (Zhang et al, 2006), because of insufficient sampling periods (equal or above five seconds) and because of the variation of speeds between the samples, the acceleration was not accurate enough to be used as indicators*. Furthermore, in our experience, when considering a larger number of transportation modes the acceleration is no longer an indicator that helps the segmentation process.…”

Section: Selection Of the Indicatorsmentioning

confidence: 82%

Transportation mode-based segmentation and classification of movement trajectories

Biljecki

Ledoux

Oosterom

2013

International Journal of Geographical Information Science

139

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The knowledge of the transportation mode used by humans (e.g. bicycle, on foot, car, and train) is critical for travel behaviour research, transport planning and traffic management. Nowadays, new technologies such as the GPS have replaced traditional survey methods (paper diaries, telephone) since they are more accurate and problems such as underreporting are avoided. However, although the movement data collected (timestamped positions in digital form) have generally high accuracy, they do not contain the transportation mode. We present in this paper a new method for segmenting movement data into single-mode segments and to classify them according to the transportation mode used. Our fully automatic method differs from previous attempts for five reasons: (1) it relies on fuzzy concepts found in expert systems, i.e. membership functions and certainty factors; (2) it uses OpenStreetMap data to help the segmentation and classification process; (3) we can distinguish between 10 transportation modes (incl. between tram, bus, and car) and we propose a hierarchy; (4) it handles data with signal shortages and noise, and other real-life situations; (5) in our implementation, there is a separation between the reasoning and the knowledge, so that users can easily modify the parameters used and add new transportation modes. We have implemented the method and tested it with a 17-million point dataset collected in the Netherlands and elsewhere in Europe. The accuracy of the classification with the developed prototype, determined with the comparison of the classified results with the reference data derived from manual classification, is 91.6 percent.

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Section: Selection Of the Indicatorsmentioning

confidence: 82%

Transportation mode-based segmentation and classification of movement trajectories

Biljecki

Ledoux

Oosterom

2013

International Journal of Geographical Information Science

139

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“…We summarize the basic observation equations and comment on the treatment of the various terms below. Further details of the velocity estimation procedure are provided in Zhang et al (2006b) and Zhang (2007).…”

Section: Gps Data and Velocity Determination Methodsmentioning

confidence: 99%

“…As the zenith tropospheric delay is usually modeled as a slowly varying quantity in GPS positioning, the change in satellite elevation angle is the main contribution to the derivative of the tropospheric delay over the timescales considered in this method. We also consider the second-order Doppler effect, which can be greater than 2 cm/s in rangerate (Zhang et al, 2006b). The relativistic effect can be well modeled and corrected (Zhang, 2007).…”

Section: Gps Data and Velocity Determination Methodsmentioning

confidence: 99%

Rapid earthquake focal mechanism inversion using high-rate GPS velometers in sparse network

Guo

Chen

et al. 2015

Sci. China Earth Sci.

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In this study, we demonstrate an approach for inverting earthquake source parameters based on high-rate global positioning system (GPS) velocity seismograms. The velocity records obtained from single-station GPS velocity solutions with broadcast ephemeris are used directly for earthquake source parameter inversion using the Cut and Paste method, without requiring conversion of the velocity records into displacement records. Taking the El Mayor-Cucapah earthquake as an example, GPS velocity records from 10 stations with reasonable azimuthal coverage provide earthquake source parameters very close to those from the Global centroid moment tensor (Global CMT) solution. In sparse network tests, robust source parameters with acceptable bias can be achieved with as few as three stations. When the number of stations is reduced to two, the bias in rake angle becomes appreciable, but the magnitude and strike estimations are still robust. The results of this study demonstrate that rapid and reliable estimation of earthquake source parameters can be obtained from GPS velocity data. These parameters could be used for early earthquake warning and shake map construction, because such GPS velocity records can be obtained in real time. high-rate GPS velometer, GPS velocity determination, CAP method, earthquake source parameters, sparse networkThe global positioning system (GPS) was designed to be a positioning, navigation, and timing (PNT) system. Currently, however, the system is used for applications far beyond its original intended design (Misra and Enge, 2006; HofmannWellenhof et al., 2008). In earthquake research, dynamic GPS displacement records with a 1 Hz or higher sampling rate, known as high-rate GPS, are now widely used to capture earthquake dynamic waveforms and to invert earthquake source parameters and rupture processes independently or together with seismological data (Larson et al.-rate GPS is not as sensitive as traditional instruments, e.g., velocity-type broadband seismometers and accelerometer-type strong motion instruments, high-rate GPS has become more popular in the last two decades. Compared with the traditional seismological instruments, this method avoids the problems of record clipping, tilting, and long-period drift that result from integrating acceleration or velocity into displacements. High-rate GPS can directly obtain arbitrarily large dynamic displacements (waveforms) and static offsets of earthquakes (co-seismic deformation) with millimeter-to centimeter-scale accuracy in the post-processing mode; in contrast, real-time and near real-time processing approaches have lower accuracy (Bock et al., 2004;Larson et al., 2007;

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“…If cycle-slips exist or the accuracy of phase-smoothed code is lower than that of Doppler measurements, Doppler-aided technique can be used further to smooth code and thus improve its accuracy (Cheng 1999). As an instantaneous measurement that directly relates to the relative movement between the receiver and satellite, Doppler shift has been widely used in velocity determination (Bruton et al 1999;Zhang et al 2006). Moreover, the position and velocity were trivially determined simultaneously by combining pseudorange and Doppler shifts (Mao et al 2002).…”

Section: Introductionmentioning

confidence: 99%

A windowing-recursive approach for GPS real-time kinematic positioning

Zhou

Shen

2010

GPS Solut

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All conventional Kalman filtering methods depend to a great extent on dynamic models for describing the motion state of vehicle. However, low-cost GPS navigation systems do not provide velocity and acceleration measurements to construct dynamic models. Therefore, it is rather difficult to establish reasonable dynamic models. A windowing-recursive approach (WRA) which employs previous positions to predict the current position is proposed, and the transition matrix is modeled for transforming the previous positions to the current one. Two typical transition matrices are constructed by numerical polynomial fitting and extrapolation. A real vehicular GPS experiment is carried out to demonstrate the WRA performances in two relative positioning scenarios. The data are processed by the least squares approach and by WRA using the two developed transition matrices. The results show that the WRA performed excellently in a high sampling rate data. In case of a lower sampling rate, higherorder polynomial fitting and extrapolation models work better than lower-order models for a given window. In addition, the extrapolation models can alleviate the computation burdens significantly relative to the polynomial fitting models.

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Short Note: On the Relativistic Doppler Effect for Precise Velocity Determination using GPS

Cited by 48 publications

References 7 publications

Transportation mode-based segmentation and classification of movement trajectories

Transportation mode-based segmentation and classification of movement trajectories

Rapid earthquake focal mechanism inversion using high-rate GPS velometers in sparse network

A windowing-recursive approach for GPS real-time kinematic positioning

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