Analysis of high-frequency multipath in 1-Hz GPS kinematic solutions

Ogaja, Clement; Satirapod, Chalermchon

doi:10.1007/s10291-007-0058-8

Cited by 37 publications

(22 citation statements)

References 12 publications

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“…We use short-session (2 h) high-rate (1-Hz) data from the GPS base station in Ballarat (BALL), whose (carrier-phase) kinematic analysis is reported in the article by Ogaja and Satirapod (2007). The GPS antenna at this station is located on a pole on a building rooftop.…”

Section: Test Examplementioning

confidence: 99%

“…Figure 5 is the FFT spectra of the L1 pseudorange multipath in the time span 01:10:01-01:26:41. This time span was selected based on the previous analysis of the high frequency multipath in the site position time series (Ogaja and Satirapod 2007). The two black circles indicate the dominant peaks in the low and high frequencies of the band 0-0.2 Hz.…”

Section: Test Examplementioning

confidence: 99%

“…In some scenarios, such as where GPS antennas are installed on building rooftops or on slender poles (see e.g. Ogaja and Satirapod 2007), high-frequency multipath needs to be detected so that it is not mistaken for building or antenna pole movements due to wind, local vibrations, or even sharp temperature changes.…”

Section: Introductionmentioning

confidence: 99%

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TEQC multipath metrics in MATLAB

Ogaja

Hedfors

2007

GPS Solut

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Knowledge of the local direction of multipath at a particular site is important for a number of reasons. For example, such information can be used to study site selections or during monument design for GPS installations. We present a MATLAB program for creating colorized polar maps of high-frequency multipath using TEQC report files of single-epoch data. The maps, although not necessarily indicating the actual local direction of multipath on the ground, give the orientation with respect to the geometry of the satellites in the sky. This information can aid the interpretation of ground multipath geometry at the site. We give an example of short-span data with 0.05 Hz multipath (i.e. repeat period % 20 s) although the program can be modified for long-term measurements as well.

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Section: Test Examplementioning

confidence: 99%

Section: Test Examplementioning

confidence: 99%

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TEQC multipath metrics in MATLAB

Ogaja

Hedfors

2007

GPS Solut

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“…The other type of multipath is a high frequency multipath with a period of sub-minute to 2 -3 minutes. This is caused by mobile or dynamic reflecting surfaces in the antenna environment, resulting in randomization of the multipath effects (Ogaja and Satirapod, 2007).…”

Section: Vertical Componentmentioning

confidence: 99%

GPS monitoring of a steel box girder viaduct

Ogundipe¹,

Roberts²,

Brown³

2012

Structure and Infrastructure Engineering

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Structural performance monitoring of bridges has increased as major infrastructure ages and is required to sustain loads that are significantly greater than those predicted during design. Structural stiffness and/or mass distribution can change over the lifespan of a bridge structure. Resulting changes in profile or resonant frequency provide key indicators of change, and may identify structural defects. Field tests using GPS for monitoring relatively small deformations were carried out on a steel box girder viaduct bridge in the UK. The configuration consisted of five GPS receivers located at key locations on the viaduct and two reference GPS receivers. GPS data was collected at either 10Hz or 20 Hz and post processed using proprietary software, along with appropriate filtering and spectral analysis. Three main frequencies were clearly detected by the GPS in the vertical component. A previously reported frequency of approximately 0.56 Hz was identified along with two other frequencies. The peak vertical deflections lie in the range of ±50mm, while lateral and longitudinal deflections of much smaller magnitude -in the order of a few mm -are also measured. The use of GPS leads to readily obtained and useful engineering data for continued monitoring of structures.

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“…It is hardly to identify structural dynamics from the original time series without removing this multipath signature. It was found that the dominant signals of low frequency nature between 0.001 Hz to 0.2 Hz are multipath and icker noise e ects [15]. Their e ects could be removed with a Chebyshev type 3-order digital lter designed to extract long-period component and then the dynamic de ections were extracted from the frequencies from 0.2 Hz above ( Figure 10).…”

Section: Multipath Isolation Based On a Chebyshev Ltermentioning

confidence: 99%

Optimal GPS/accelerometer integration algorithm for monitoring the vertical structural dynamics

Meng

Wang

Han

2014

Journal of Applied Geodesy

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Abstract:The vertical structural dynamics is a crucial factor for structural health monitoring (SHM) of civil structures such as high-rise buildings, suspension bridges and towers. This paper presents an optimal GPS/accelerometer integration algorithm for an automated multi-sensor monitoring system. The closed loop feedback algorithm for integrating the vertical GPS and accelerometer measurements is proposed based on a 5 state extended KALMAN lter (EKF) and then the narrow moving window Fast Fourier Transform (FFT) analysis is applied to extract structural dynamics. A civil structural vibration is simulated and the analysed result shows the proposed algorithm can e ectively integrate the online vertical measurements produced by GPS and accelerometer. Furthermore, the accelerometer bias and scale factor can also be estimated which is impossible with traditional integration algorithms. Further analysis shows the vibration frequencies detected in GPS or accelerometer are all included in the integrated vertical de ection time series and the accelerometer can e ectively compensate the short-term GPS outages with high quality. Finally, the data set collected with a time synchronised and integrated GPS/accelerometer monitoring system installed on the Nottingham Wilford Bridge when excited by 15 people jumping together at its mid-span are utilised to verify the e ectiveness of this proposed algorithm. Its implementations are satisfactory and the detected vibration frequencies are 1.720 Hz, 1.870 Hz, 2.104 Hz, 2.905 Hz and also 10.050 Hz, which is not found in GPS or accelerometer only measurements.

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Analysis of high-frequency multipath in 1-Hz GPS kinematic solutions

Cited by 37 publications

References 12 publications

TEQC multipath metrics in MATLAB

TEQC multipath metrics in MATLAB

GPS monitoring of a steel box girder viaduct

Optimal GPS/accelerometer integration algorithm for monitoring the vertical structural dynamics

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