An Experimental Identification of Multipath Effect in GPS Positioning Error

Rumora, Ivan; Sikirica, Nenad; Filjar, Renato

doi:10.12716/1001.12.01.02

Cited by 7 publications

(3 citation statements)

References 1 publication

(1 reference statement)

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“…Multipath is a source of tracking error in GPS receivers, which leads to positioning errors [3,[14][15][16][17]. Multipath error envelopes have been used to analyze tracking error caused by multipath [5][6][7][8][9].…”

Section: Discussionmentioning

confidence: 99%

The Effect of Carrier Phase on GPS Multipath Tracking Error

Mubarak

2020

Eng. Technol. Appl. Sci. Res.

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Multipath is one of the main sources of tracking error in GPS receivers. This tracking error has previously been analyzed against the relative delay of the Line Of Sight (LOS) and reflected signals. However, only carrier phase differences of 0 and π were used, since they give tracking error with maximum magnitude. This paper shows that tracking error does not change linearly with changing carrier phase difference. Tracking error plots against relative carrier phase difference of the LOS and reflected signals have been used to analyze the relationship between the two in various scenarios. While maximum positive and negative errors are found at carrier phase difference of 0 and π, a sharp increase in tracking error is found around the phase difference of π. There is a zero crossing in all plots but that point is dependent on relative amplitude, delay, and carrier phase difference of the two signals. The analysis has also been extended to narrow correlators receiver. Tracking error is significantly reduced in this case, however, similar characteristics have been observed when the tracking error is analyzed against the relative carrier phase difference. Moreover, the tracking error was found to be less dependent on the relative delay between the two signals when correlators spacing is reduced.

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Section: Discussionmentioning

confidence: 99%

The Effect of Carrier Phase on GPS Multipath Tracking Error

Mubarak

2020

Eng. Technol. Appl. Sci. Res.

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“…Marine pilots in the Port of Koper have observed sudden jumps of the vessel or tug in certain areas, on their monitoring equipment. The effect may well be related to the presence at least of two types of reflective objects in the surroundings: port cranes and the surface of the sea [26]. In order to apply the variance model, a strong correlation must exist between the satellite elevation angle and the GNSS signal quality.…”

Section: Ppu: Limitation Of the Gnss And Ship's Gyromentioning

confidence: 99%

Laser-Based Aid Systems for Berthing and Docking

Perkovič

Gucma

Bilewski

et al. 2020

JMSE

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The berthing of an ultra large ship is always a difficult issue and becomes yet more complex when vessels must be handled in restricted manoeuvring areas of limited depth, exposed to a forceful crosswind, or manoeuvring in a strong current, or all three. The final approaching manoeuvre and precise positioning is particularly demanding at container terminals where many STS cranes are located along the quay, seriously limiting margin for error in the process of mooring a ship, especially when the cranes are located nearby a bridge wing or at the very edge of the pier. In order to avoid collisions, the final manoeuvre (side-push) must be fully controlled; the ship’s orientation must be parallel with the quay while maintaining the minimum lateral approaching velocity without significantly shifting the vessel longitudinally. The mooring of a Ro-Ro vessel is occasionally even more challenging: a precise docking manoeuvre is normally executed without any towing assistance. In this paper low cost laser-based berthing and docking systems developed for the ports of Koper and Swinousce are presented and several berthing manoeuvres are analysed and compared with the most commonly used GNSS-based navigational aid system portable pilot units (PPU).

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“…baseband stage, particularly in the signal processing chain of receivers (acquisition/tracking module), the multipath effect has been diminished. In code tracking stage, the mitigation methods such as correlation-based maximum likelihood (ML), nonlinear transforms, deconvolution, super-resolution/eigenvalue decomposition techniques, etc have also been implemented in GPS receivers [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] that works well to combat the multipath effect. In the navigation module of the receiver, few works associated with obstacle mapping [23], optimal combinations of function for carrier to noise ratio (C/N 0 ) measurements [24], and the correction in pseudorange observable has been performed using wavelet transform technique implemented in the navigation processing and positioning module for kinematic applications [1].…”

Section: Introductionmentioning

confidence: 99%

A new multipath channel estimation and mitigation using annihilation filter combined tracking loop implementation in software GPS receivers

Elango

Landry

2022

Meas. Sci. Technol.

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The multipath effect causes severe degradation in the positioning of commercial GPS receivers. Due to multipath error, the positioning accuracy could reach a few 10 meters. If the cumulative Multipath delay is less than 0.1-0.35 chips, then it is difficult to mitigate in GPS receivers. This causes severe degradation in GPS signals and can cause a measurement bias. To alleviate this problem, the estimation of multipath parameters using annihilating filter and its mitigation in the GPS tracking loop is proposed in this work. The estimation of randomly generated multipath signals can be performed in the receiver with a lower sampling rate when compared to the larger bandwidth of the GPS baseband signal. Here, the frequency components of the Multipath signal in superimposed complex exponentials have been transformed from the time delay and the amplitude of the path observables. The Rayleigh fading model in the urban scenario has been simulated in which the amplitude and the phase of the number of paths (i.e., the frequency component of superimposed complex exponentials) are set and this fading signal is convolved with GPS signal that forms the multipath faded signal. In the GPS receiver post-processing stage, with the help of the annihilation filter, the multipath components are estimated, then an inverse/adaptive filter and compensation technique are further applied to mitigate the multipath component. The mean square error with the different number of paths with noisy environments is analyzed utilizing the cadzaw denoising algorithm. The simulation results of the proposed technique employed in the tracking module of the software GPS receiver under severe multipath conditions indicate a substantial enhancement in the performance of the GPS receiver with minimal code and carrier phase error when compared to the least squares and adaptive blind equalization channel techniques. Moreover, the positioning accuracy is also calculated with the inclusion of multipath components in two satellites out of six satellites used in the simulation, the results showed that the annihilation filter improved the mean position accuracy up to 9.3023 meters.

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An Experimental Identification of Multipath Effect in GPS Positioning Error

Cited by 7 publications

References 1 publication

The Effect of Carrier Phase on GPS Multipath Tracking Error

The Effect of Carrier Phase on GPS Multipath Tracking Error

Laser-Based Aid Systems for Berthing and Docking

A new multipath channel estimation and mitigation using annihilation filter combined tracking loop implementation in software GPS receivers

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