Orbit ephemeris monitors for local area differential GPS

Pervan, Boris; Gratton, L.

doi:10.1109/taes.2005.1468740

Cited by 27 publications

(15 citation statements)

References 1 publication

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“…The comparison algorithm has a similar tendency with baseline length; however, it has a limit on baseline length because of the basic assumption that LOS vectors of two reference station about the target satellite are quasi-parallel. [8] This means that the proposed algorithm does not have to consider the baseline length limitation and is applicable to various GNSS augmentation systems: not only the local area system (GBAS) but also widearea systems (e.g., GRAS, SBAS). The various long baseline vectors, which can be implemented with the local azimuth and local elevation angle, are required to improve detection performance of the proposed algorithm.…”

Section: Sensitivity Evaluation Resultsmentioning

confidence: 99%

“…One method of detecting Type A failure is to monitor the range measurement correction (pseudorange correction, PRC) derived from the broadcast ephemeris and the location of the ground station antenna [7]. Other methods estimate satellite position error with range measurements [8] [9] or estimate the differential range of ground stations with short baseline vectors and range measurements [10][13]. However, these algorithms have some weaknesses.…”

Section: Introductionmentioning

confidence: 99%

“…The P-value of the comparison algorithm, which is used to compute the EPL, is shown in equation (24) [12]. to an integrated multipath limiting antenna (IMLA) used for RS [8]. The value of b represents the baseline length between multiple RS antennas and is similar to the RS of Gimpo International Airport.…”

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confidence: 99%

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Orbit Ephemeris Failure Detection in a GNSS Regional Application

Ahn¹,

Lee²,

Won³

et al. 2015

International Journal of Aeronautical and Space Sciences

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To satisfy civil aviation requirements using the Global Navigation Satellite System (GNSS), it is important to guarantee system integrity. In this work, we propose a fault detection algorithm for GNSS ephemeris anomalies. The basic principle concerns baseline length estimation with GNSS measurements (pseudorange, broadcasted ephemerides). The estimated baseline length is subtracted from the true baseline length, computed using the exact surveyed ground antenna positions. If this subtracted value differs by more than a given threshold, this indicates that an ephemeris anomaly has been detected. This algorithm is suitable for detecting Type A ephemeris failure, and more advantageous for use with multiple stations with various long baseline vectors. The principles of the algorithm, sensitivity analysis, minimum detectable error (MDE), and protection level derivation are described and we verify the sensitivity analysis and algorithm availability based on real GPS data in Korea. Consequently, this algorithm is appropriate for GNSS regional implementation.

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Section: Sensitivity Evaluation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Orbit Ephemeris Failure Detection in a GNSS Regional Application

Ahn¹,

Lee²,

Won³

et al. 2015

International Journal of Aeronautical and Space Sciences

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“…To mitigate Type B threats, the LGF stores validated ephemerides from previous days and uses them to project forward an independent predictive estimate of the current ephemeris for comparison. The LGF monitor that performs this function is called the Ephemeris Type B Monitor, and it has been described in detail in [1,2]. In Type A faults, ephemeris data is erroneous following a satellite maneuver.…”

Section: Ephemeris Threat Modelsmentioning

confidence: 99%

“…If the maneuver is in view of a particular LGF site, a 'do-not-use' waiting period for that satellite is initiated after the satellite flag is set back to healthy to collect the necessary data for the Type B monitor to function. The waiting period is nominally two days [1]. The following analysis of the A1 fault will therefore focus on situations in which maneuvers occur out of view of an LGF.…”

Section: Figure 1: Laas Ephemeris Failure Categoriesmentioning

confidence: 99%

Ephemeris type a fault analysis and mitigation for LAAS

Tang

Pullen

Enge

et al. 2010

IEEE/ION Position, Location and Navigation Symposium

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The Local Area Augmentation System (LAAS) has been developed by the FAA to enable precision approach and landing operations using the Global Positioning System (GPS). Each LAAS installation provides services through a LAAS Ground Facility (LGF) which is located at the airport it serves. By monitoring the GPS signals, measurements, and navigation messages, the LGF is able to exclude unhealthy satellites and broadcast real-time range-correction messages for healthy satellites to users via a VHF data link. Airborne users apply these corrections to remove errors that are common between the LGF and the aircraft.The LGF is also responsible for warning the aircraft of any potential integrity threats that cannot easily be resolved by excluding unhealthy satellites. One source of potential errors is the satellite broadcast ephemeris message, which users decode and use to compute GPS satellite positions. In LAAS, potential GPS ephemeris faults are categorized into two types, A and B, based upon whether or not the fault is associated with a satellite maneuver. This work focuses on aviation navigation threats caused by Type A faults. To detect and mitigate these threats, we investigate two LGF monitors based on comparing expected ranges and range rates (based on broadcast ephemeris) with those measured by the LGF. The effectiveness of these monitors is analyzed and verified in this paper.

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Ground‐Based Augmentation System

Pervan

2020

Position, Navigation, and Timing Technologies in the 21st Century

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Orbit ephemeris monitors for local area differential GPS

Cited by 27 publications

References 1 publication

Orbit Ephemeris Failure Detection in a GNSS Regional Application

Orbit Ephemeris Failure Detection in a GNSS Regional Application

Ephemeris type a fault analysis and mitigation for LAAS

Ground‐Based Augmentation System

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