Spread-spectrum code and carrier synchronization errors caused by multipath and interference

Nee, R.D.J. van

doi:10.1109/7.259541

Cited by 100 publications

(48 citation statements)

References 6 publications

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“…The complex baseband signal received by the antenna array is (1) where denotes the superimposed signal replicas (2) defines the steering vector of the antenna array and denotes a known signal waveform with unknown delay . We define the parameter vector , where is the sample interval and denotes the sampling frequency.…”

Section: A Structured Modelmentioning

confidence: 99%

The Extended Invariance Principle for Signal Parameter Estimation in an Unknown Spatial Field

Antreich

Nossek

Swindlehurst

2011

IEEE Trans. Signal Process.

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Abstract-This paper treats the problem of joint estimation of time-delay, Doppler frequency, and spatial (direction-of-arrival or DOA) parameters of several replicas of a known signal in an unknown spatially correlated noise field. Both spatially unstructured and structured data models have been proposed for this problem and corresponding maximum likelihood (ML) estimators have been derived. However, structured models require a high computational complexity and are sensitive to the antenna array response, while unstructured models are unable to achieve good performance in some scenarios. In this paper, it is shown how the extended invariance principle (EXIP) can be applied to obtain estimates with the quality of a spatially structured model, but with much lower complexity than directly utilizing a structured

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Section: A Structured Modelmentioning

confidence: 99%

The Extended Invariance Principle for Signal Parameter Estimation in an Unknown Spatial Field

Antreich

Nossek

Swindlehurst

2011

IEEE Trans. Signal Process.

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“…Estimating and from the signal is actually the process realized by any GNSS receiver since the beamformer output can be considered to be the signal received by a single equivalent antenna. Consequently, the estimators in (52) and (53) could be replaced by any of the single-sensor methods implemented in conventional receivers, such as the DLL and its variants [7], [9], [32] or the MEDLL [8]. In particular, the PAC or the Enhanced Strobe Correlator (ESC) [10] can be used at the output of the hybrid beamformer as they are complementary to the spatial filtering performed by the array.…”

Section: B Iterative Algorithm Based On the Hybrid Beamformermentioning

confidence: 99%

“…Errors in the pseudorange and carrier-phase measurements produced by the multipath propagation have been studied in [4]- [7], among others. Only reflections correlated with the direct signal, which are usually referred to as coherent multipath, cause these errors; this is the type of reflections considered in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…The most widespread multipath-mitigation techniques are those based on modifications of the conventional DLL, which are realtime signal processing methods. Some of these techniques are the Narrow Correlator DLL [7], the Multipath Estimating DLL (MEDLL) [8], the Pulse Aperture Correlator (PAC) (patented by NovAtel Inc.), and the Edge Correlator and (Enhanced) Strobe Correlator [9], [10] (patented by Ashtech Inc.). These singlesensor techniques are able to discriminate the LOSS from the reflections only in the temporal domain, and hence, their performance is still limited for many precise applications.…”

Section: Introductionmentioning

confidence: 99%

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ML estimator and hybrid beamformer for multipath and interference mitigation in GNSS receivers

Seco-Granados

Fernandez–Rubio

Fernández‐Prades

2005

IEEE Trans. Signal Process.

104

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Abstract-This paper addresses the estimation of the code-phase (pseudorange) and the carrier-phase of the direct signal received from a direct-sequence spread-spectrum satellite transmitter. The signal is received by an antenna array in a scenario with interference and multipath propagation. These two effects are generally the limiting error sources in most high-precision positioning applications. A new estimator of the code-and carrier-phases is derived by using a simplified signal model and the maximum likelihood (ML) principle. The simplified model consists essentially of gathering all signals, except for the direct one, in a component with unknown spatial correlation. The estimator exploits the knowledge of the direction-of-arrival of the direct signal and is much simpler than other estimators derived under more detailed signal models. Moreover, we present an iterative algorithm, that is adequate for a practical implementation and explores an interesting link between the ML estimator and a hybrid beamformer. The mean squared error and bias of the new estimator are computed for a number of scenarios and compared with those of other methods. The presented estimator and the hybrid beamforming outperform the existing techniques of comparable complexity and attains, in many situations, the Cramér-Rao lower bound of the problem at hand.

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“…Multipath signals are additional signal replicas generated by reflection in local environment. These duplicated signals may introduce a bias in delay lock loops (DLLs) of GNSS receivers, which finally leads to an increase in pseudorange error [2]. To mitigate the impact of multipath, theories and algorithms are proposed.…”

Section: Introductionmentioning

confidence: 99%

Assessment Method of Multipath Mitigation Performance for GNSS Antenna with Receiver Algorithms

Yuan

et al. 2017

International Journal of Antennas and Propagation

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Multipath is one of the most important sources of positioning error in GNSS. Well-designed antennas can mitigate multipath signals and enhance the performance of GNSS receivers. This paper concentrates on methods to assess multipath mitigation performance for GNSS antennas. We propose a model to describe multipath environment in GNSS ground stations. The model analyzes effects caused by inclined reflective surfaces and multipath mitigating algorithms in receivers. A method to assess multipath mitigation performance is put forward by analyzing pseudorange code phase errors caused by multipath signals after signal processing. Based on the model and method, principles in site selection for GNSS antenna are introduced to minimize effects caused by multipath.

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Spread-spectrum code and carrier synchronization errors caused by multipath and interference

Abstract: It is clear from (2), that the path r specified by (3), is a function only of the ratio a~/ a z .

Cited by 100 publications

References 6 publications

The Extended Invariance Principle for Signal Parameter Estimation in an Unknown Spatial Field

The Extended Invariance Principle for Signal Parameter Estimation in an Unknown Spatial Field

ML estimator and hybrid beamformer for multipath and interference mitigation in GNSS receivers

Assessment Method of Multipath Mitigation Performance for GNSS Antenna with Receiver Algorithms

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