Journal of the Institute of Navigation 2014 Fall

ljrlove2008

Journal of the Institute of Navigation. Volume 61, Number 3 (Fall 2014)

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A Survey of Spoofing and Counter-Measures（159 - 177）见2楼

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A Robust Technique for Unambiguous BOC Tracking（179 - 190）见3楼

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Differential Code Bias Estimation using Multi-GNSS Observations and Global Ionosphere Maps（191 - 201）见4楼

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Improved Troposphere Blind Models Based on Numerical Weather Data（203 - 211）见5楼

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Covariance Analysis of Spatial and Temporal Effects of Collaborative Navigation（213 - 225）见6楼

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Analytical Observability Analysis of INS with Vehicle Constraints（227 - 236）见7楼

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yaolongjiulu

Very good. Thanks very much. But do you have the articles for 2015 as well, also the proceedings?

ljrlove2008

Title:        Analytical Observability Analysis of INS with Vehicle Constraints
Author(s):        Yaacov Rothman, Itzik Klein and Sagi Filin
Abstract:        Vehicle constraints have been gaining increased popularity as a means to mitigate drift of Inertial Navigation Systems in GNSS deprived settings. While useful, such constraints cannot compensate for the drift of all state variables in the navigation solution. To study which variables are affected, empirical analyses under typical scenarios are commonly performed, however, no insight is provided into the inner effects amongst error states. Here we propose an analytical observability analysis which evaluates the contribution of vehicle constraint measurements to the solution and determines which error states or linear combination thereof are unobservable. Observability analysis has been mostly directed thus far at GPS/INS aiding. Here we fill this gap by deriving analytical terms for the unobservable subspace of the body velocity constraint, which is already utilized in urban driving scenarios. The resulting terms are verified via numerical degree of observability analyses.

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ljrlove2008

Title:        Covariance Analysis of Spatial and Temporal Effects of Collaborative Navigation
Author(s):        Chun Yang and Andrey Soloviev
Abstract:        Collaborative navigation allows a group of mobile networked users to improve their navigation performance. Each node in the network has a means of its own to navigate (e.g. INS/GPS). However, individual navigation performance is limited due to, for instance, inertial sensor drifts when GPS signal is lost. By exchanging navigation states and in particular obtaining relative measurements (range, range rate or angular) via radio communications, the distributed nodes collaborate and serve as anchors for one another. In this paper, we investigate spatial and temporal effects of collaborative navigation. The improvement in navigation performance is affected by the number of collaborating nodes and inter-node measurement quality in relation to the uncertainty of individual navigation states (spatial effect). Navigation errors after inter-node measurement exchanges become correlated, which limits further reduction in errors by subsequent measurements (temporal effect). Understanding of such fundamental effects provides practical guidelines for optimal design of communication protocols and estimation algorithms.

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ljrlove2008

Title:        Improved Troposphere Blind Models Based on Numerical Weather Data
Author(s):        Gregor Möller, Robert Weber, and Johannes Böhm
Abstract:        The troposphere blind model RTCA MOPS is the minimum operational performance standard for global positioning systems. With a standard deviation of 2.3% of the ZTD, it enables us to mitigate the main part of the tropospheric effect on GNSS signals. Nevertheless, the comparison of RTCA MOPS with modern troposphere models like the ESA model or GPT2 shows the limitation of RTCA MOPS and points out the potential of modern troposphere blind models based on climatological series derived from numerical weather data. The ESA model profits from a more advanced wet delay model and a higher spatial resolution. GPT2 shows the smallest mean bias on surface level in comparison to ray-tracing and IGS data and profits from additional mapping function coefficients – especially if the user is interested in tropospheric delay at low elevation angles. A revision of GPT2 - called GPT2w - combines the benefits of both aforementioned models.

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ljrlove2008

Title:        Differential Code Bias Estimation using Multi-GNSS Observations and Global Ionosphere Maps
Author(s):        O. Montenbruck, A. Hauschild and P. Steigenberger
Abstract:        Measurements of Global Navigation Satellite System (GNSS) receivers are affected by systematic offsets related to group and phase delays of the signal generation and processing chain. The resulting code and phase biases depend on the transmission frequency and the employed signal modulation.Within this study differential code biases (DCBs) of legacy and modernized GNSS signals are derived from pseudodrange observations of a global multi-GNSS receiver network. Global ionosphere maps (GIMs) are employed for the correction of ionospheric path delays. Based on six months of data collected within the Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS), DCBs for the publicly available signals of GPS, Galileo, and BeiDou have been determined. The quality of the resulting DCB estimates is assessed and compared against group delay parameters transmitted by the GNSS providers as part of the broadcast ephemeris data.

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ljrlove2008

Title: A Robust Technique for Unambiguous BOC Tracking
Author(s): J. Wendel, F. M. Schubert and S. Hager
Abstract:  The GPS M-Code, Galileo PRS Service, and Galileo Open Service on E1 use a Binary Offset Carrier modulation. The autocorrelation function of a BOC signal has multiple peaks. The main peak of the ACF is much narrower than the peak of the corresponding BPSK signal, which offers the potential for increased tracking accuracy and better multipath resistance. On the other hand, a tracking loop can lock to a side peak of the correlation function instead of the main peak, leading to systematic errors in the pseudorange measurements. In this paper, a new approach for tracking BOC signals is proposed: Ambiguous, accurate delay estimates and unambiguous, less accurate delay estimates are used to calculate a float position solution, and float sub-carrier ambiguities. Then, the LAMBDA method – typically used to fix the integer ambiguities of carrier phase measurements – is used to fix the sub-carrier ambiguities, which are then used to calculate the final position solution. First simulation results illustrate the potential of this technique.

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ljrlove2008

Title: A Survey of Spoofing and Counter-Measures
Author(s): Christoph Günther
Abstract: The growing economic importance of Global Navigation Satellite Systems (GNSS) makes it rewarding for malevolent people to aim at misleading receivers in their position and time estimation. This can be achieved by replacing or superposing signals to the authentic GNSS satellite signals and is called spoofing. Most current receivers are not designed to detect spoofing. The present article aims at a systematic exposition of threats. In many cases, they can be addressed by comparing the received signals, the estimated states, and their respective dynamics against models. A cryptographic signature of the navigation message would furthermore improve the detectability of fake synthetic signals, and should be implemented in the definition of new GNSS signals. In general, the analysis of spoofing should receive the same attention as the analysis of natural impairments. We hope that the present paper will contribute to achieve this.

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