External Ground Monitoring v. Receiver Monitoring

1991 ◽  
Vol 44 (1) ◽  
pp. 11-24 ◽  
Author(s):  
R. Johannessen
Keyword(s):  
Data Stream ◽  
Civil Aviation ◽  
Integrity Monitoring ◽  
Warning Messages ◽  
Control Centre ◽  
Receiver Autonomous Integrity Monitoring ◽  
Failure Conditions ◽  
Ground Monitoring ◽  
Very High ◽  
Two Alternatives

The transmissions from GPS and GLONASS navigation satellites include information about the state of those transmissions as perceived by the control centre. In the case of GPS, for example, this information is contained in the data stream in Subframe 1 Word 3. However, with some of the failure conditions that can arise there is a delay of the order of half an hour before this message is altered to signal that a failure exists. A situation can therefore arise when the satellite signals that all is well, whereas in fact it is not. The very high levels of integrity which civil aviation require before satellite navigation can be used with confidence therefore means that the warning messages from the satellite must be augmented by some other form of monitoring. Two alternatives exist: (1) to have a monitor at some fixed and surveyed ground location which broadcasts a warning to the navigating aircraft when there is a malfunction (ground monitoring), or (2) to arrange for the navigating receiver to perform its own internal monitoring, known as receiver autonomous integrity monitoring (RAIM). Each alternative is beneficial in its own way.

scholarly journals ARAIM Integrity Support Message Parameter Validation by Online Ground Monitoring

2014 ◽  
Vol 68 (2) ◽  
pp. 327-337 ◽  
Author(s):  
Samer Khanafseh ◽  
Mathieu Joerger ◽  
Fang-Cheng Chan ◽  
Boris Pervan
Keyword(s):  
Service Provider ◽  
Integrity Monitoring ◽  
Provider Performance ◽  
Prior Probabilities ◽  
Receiver Autonomous Integrity Monitoring ◽  
Ground Monitoring ◽  
The Relationship ◽  
Monitoring Architecture ◽  
Advanced Receiver

In this paper we introduce a ground monitoring architecture to validate the Integrity Support Message (ISM) parameters to be used by aircraft for Advanced Receiver Autonomous Integrity Monitoring (ARAIM). This work focuses on two critical ISM parameters: Psat, which designates the prior probabilities of satellite faults, and bmax, which is a range domain bound on small faults that may occur at probabilities higher than Psat. We show that the choices of bmax and Psat are not independent. The paper first establishes the relationship between bmax, Psat, Time to Integrity Alert (TIA) and constellation service provider performance commitments. We then provide an example ground monitor design that detects inter-frequency bias faults and code-carrier divergence faults. We show that the performance of the monitor can be used to validate specific bmax and Psat values for ARAIM.

scholarly journals Analysis of BDS GEO satellite multipath effect for GNSS integrity monitoring in civil aviation

2021 ◽  
Author(s):  
Jin Chang ◽  
Xingqun Zhan ◽  
Yawei Zhai ◽  
Shizhuang Wang ◽  
Kui Lin
Keyword(s):  
Civil Aviation ◽  
Integrity Monitoring ◽  
Multipath Effect ◽  
Geo Satellite

scholarly journals Improvement of Anomalous Behavior Detection of GNSS Signal Based on TDNN for Augmentation Systems

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3800 ◽  
Author(s):  
Daehee Kim ◽  
Jeongho Cho
Keyword(s):  
Intelligent Transportation Systems ◽  
Satellite System ◽  
Anomalous Behavior ◽  
Transportation Systems ◽  
Civil Aviation ◽  
Integrity Monitoring ◽  
Delayed Neural Networks ◽  
Stringent Performance ◽  
Integrity Assurance ◽  
Global Navigation Satellite

The reliability of a navigation system is crucial for navigation purposes, especially in areas where stringent performance is required, such as civil aviation or intelligent transportation systems (ITSs). Therefore, integrity monitoring is an inseparable part of safety-critical navigation applications. The receiver autonomous integrity monitor (RAIM) has been used with the global navigation satellite system (GNSS) to provide integrity monitoring within avionics itself, such as in civil aviation for lateral navigation (LNAV) or the non-precision approach (NPA). However, standard RAIM may not meet the stricter aviation availability and integrity requirements for certain operations, e.g., precision approach flight phases, and also is not sufficient for on-ground vehicle integrity monitoring of several specific ITS applications. One possible way to more clearly distinguish anomalies in observed GNSS signals is to take advantage of time-delayed neural networks (TDNNs) to estimate useful information about the faulty characteristics, rather than simply using RAIM alone. Based on the performance evaluation, it was determined that this method can reliably detect flaws in navigation satellites significantly faster than RAIM alone, and it was confirmed that TDNN-based integrity monitoring using RAIM is an encouraging alternative to improve the integrity assurance level of RAIM in terms of GNSS anomaly detection.

Toxic surveillance using poison control centre data-stream

2010 ◽  
Vol 196 ◽  
pp. S2 ◽  
Author(s):  
S. Ballesteros ◽  
M. Martínez-Arrieta ◽  
M. Ramón
Keyword(s):  
Data Stream ◽  
Poison Control ◽  
Control Centre ◽  
Poison Control Centre

scholarly journals Positioning and integrity monitoring using the new DFMC SBAS service in the road transport

2020 ◽  
Author(s):  
Kan Wang ◽  
Ahmed El-Mowafy
Keyword(s):  
Urban Areas ◽  
Road Transport ◽  
Distribution Functions ◽  
Cumulative Distribution ◽  
Performance Standard ◽  
Civil Aviation ◽  
Dual Frequency ◽  
Test Bed ◽  
Integrity Monitoring ◽  
Positioning Errors

<p>Australia and New Zealand has initiated a two-year test-bed in 2017 for the new generation of Satellite-Based Augmentation System (SBAS). In addition to the legacy L1 service, the test-bed broadcasts SBAS messages through L5 to support the dual-frequency multi-constellation (DFMC) service for GPS and Galileo. Furthermore, PPP corrections were also sent via L1 and L5 to support the PPP service for dual-frequency GPS users and GPS/Galileo users, respectively.</p><p>The positioning and integrity monitoring process are currently defined for the aeronautical DFMC SBAS service in [1]. For land applications in road transport, users may encounter problems in complicated measurement environments like urban areas, e.g., more complicated multipath effects and frequent filter initializations of the carrier-smoothed code observations. In this study, a new weighting model related to the elevation angles, the signal-to-noise ratios (SNRs) and the filter smoothing time is developed. The weighting coefficients adjusting the impacts of these factors are studied for the open-sky, the suburban and the urban scenarios. Applying the corresponding weighting models, the overbounding cumulative distribution functions (CDFs) of the weighted noise/biases are searched and proposed for these scenarios.</p><p>Using real data collected under different measurement scenarios mentioned above, the DFMC SBAS positioning errors and protection levels are computed in the horizontal direction based on the proposed weighting models and the proposed overbounding CDFs. The results are compared with the case applying only the traditional elevation-dependent weighting model. While the positioning accuracy and protection levels did not change much for the open-sky scenario, the RMS of the positioning errors and the average protection levels are found to be reduced in both the suburban and urban scenarios. </p><p>[1] EUROCAE (2019) Minimum operational performance standard for Galileo/global positioning system/satellite-based augmentation system airborne equipment. The European Organisation for civil aviation equipment, ED-259, February 2019</p>

Localizability Analysis for GPS/Galileo Receiver Autonomous Integrity Monitoring

2004 ◽  
Vol 57 (2) ◽  
pp. 245-259 ◽  
Author(s):  
Steve Hewitson ◽  
Hung Kyu Lee ◽  
Jinling Wang
Keyword(s):  
Quality Measures ◽  
Integrity Monitoring ◽  
Satellite Navigation System ◽  
Detection And Identification ◽  
External Reference ◽  
Galileo System ◽  
Receiver Autonomous Integrity Monitoring ◽  
Navigation Signals ◽  
Gps System ◽  
Fundamental Equations

With the European Commission (EC) and European Space Agency's (ESA) plans to develop a new satellite navigation system, Galileo and the modernisation of GPS well underway the integrity of such systems is as much, if not more, of a concern as ever. Receiver Autonomous Integrity Monitoring (RAIM) refers to the integrity monitoring of the GPS/Galileo navigation signals autonomously performed by the receiver independent of any external reference systems, apart from the navigation signals themselves. Quality measures need to be used to evaluate the RAIM performance at different locations and under various navigation modes, such as GPS only and GPS/Galileo integration, etc. The quality measures should include both the reliability and localizability measures. Reliability is used to assess the capability of GPS/Galileo receivers to detect the outliers while localizability is used to determine the capability of GPS/Galileo receivers to correctly identify the detected outlier from the measurements processed.Within this paper, the fundamental equations required for effective outlier detection and identification algorithms are described together with the measures of reliability and localizability. Detailed simulations and analyses have been performed to assess the performances of GPS only and integrated GPS/Galileo navigation solutions with respect to reliability and localizability. Simulation results show that, in comparison with the GPS-only solution, the localizability of the integrated GPS/Galileo solution can be improved by up to 270%. The results also indicate an expectation of a considerable increase in the sensitivity to outliers and accuracy of their estimation with the augmentation of the Galileo system with the existing GPS system.

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