Description of the FAA's Local Area Augmentation System (LAAS)*

Braff, Ronald

doi:10.1002/j.2161-4296.1997.tb02357.x

Cited by 22 publications

(10 citation statements)

References 1 publication

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“…errors derived in equation 6 for conventional single-frequency differential. The steady-state differential iono error due to a bias plus ramp iono delay characteristic, with B ( B , can be determined to 1 In contrast with conventional differential systems, the iono divergence does not cancel even when the airborne and ground smoothing filters match. This result shows that there is a slight penalty from using conventional DGPS processing in the remote in conjunction with the new dualfrequency architecture.…”

Section: Conventional Single-frequency Remotementioning

confidence: 99%

Enhanced Differential GPS Carrier-Smoothed Code Processing Using Dual-Frequency Measurements

1999

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This paper describes methods for using dual‐frequency GPS data to improve the accuracy of carrier‐smoothed code pseudorange measurements by eliminating the limitations imposed by ionospheric divergence. With these techniques, the steady‐state time constant used in the smoothing filter can be vastly extended as long as continuous carrier tracking is maintained. When used for Differential GPS (DGPS), the smoothing requirements for the reference and remote receivers can be decoupled since there will be no need to contend with ionospheric divergence. A new DGPS architecture that exploits these dual‐frequency smoothing techniques to improve the accuracy of code differential systems is presented. Applications of these techniques to stand‐alone GPS navigation are also discussed.

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Section: Conventional Single-frequency Remotementioning

confidence: 99%

Enhanced Differential GPS Carrier-Smoothed Code Processing Using Dual-Frequency Measurements

1999

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“…GPS range measurements are majorly affected by ionospheric and tropospheric errors, satellite clock, ephemeris errors, multipath and receiver noise etc. LAAS employs Single Frequency Carrier Smoothing (SFCS), at both user and LAAS Ground Facility (LGF), to attenuate multipath and thermal noise [2]. Temporal and spatial gradients of ionosphere occurring during anamolous condition of ionosphere, impose limitations to SFCS [3].…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation of single and dual frequency Carrier Smoothing techniques for LAAS

Reddy

Sriharsha

Sarma

et al. 2011

2011 IEEE Applied Electromagnetics Conference (AEMC)

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The state-of-art Local Area Augmentation System (LAAS) system for 21st century is being developed by USA, to provide aircraft precision approach and landing. In India, LAAS is still in conceptual stage. Prominent error sources namely ionosphere, troposphere, multipath and receiver noise affect LAAS performance. LAAS employs Single Frequency Carrier Smoothing (SFCS) to mitigate spatially uncorrelated errors like multipath and thermal noise. Temporal and spatial gradients of ionosphere affect the performance of SFCS. As India comes under low latitude regions, Indian ionosphere is characterized by large ionosphere gradients. To mitigate ionospheric effects, dual frequency GPS data for smoothing is employed. This paper presented the effect of temporal gradients on SFCS and assessed the performance of Dual Frequency Smoothing (DFS) techniques. The results due to the developed algorithms are encouraging and are agreeing with the results published elsewhere.

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“…Other countries like India are expected to implement such a system in the near future. This is being aimed at providing category II and III precision approach and landing of aircraft [1]. For such high precision requirement large numbers of satellites in space having wider angular separation between them is essential.…”

Section: Introductionmentioning

confidence: 99%

A Wide Band Antenna for Multi-Constellation GNSS and Augmentation Systems

Kumar¹,

Sarma²,

Mondal³

et al. 2010

PIER M

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Abstract-Local Area Augmentation System (LAAS) based on multiconstellation GNSS can provide improved accuracy, availability and integrity needed to support all weather category II and III precision approach landing of aircraft. In order to receive satellite signals of GNSS, an antenna working over wide frequency band and high phase center stability is preferred. Commonly used antennas like crossed dipoles, patch etc. are inherently narrow band. This paper describes the design and development of half-cardioid shaped dual arm, wide band printed circuit antenna. The antenna has low VSWR of < 3 : 1, a stable phase center and good right hand circularly polarized radiation patterns covering full L-band frequencies. The simulated and measured results compare well. This compact antenna can also be used on ground, ship and airborne platforms to receive signals from multiple GNSS satellites above the horizon.Corresponding author: K. Yedukondalu (kyedukondalu@gmail.com). 66Kumar et al.

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Description of the FAA's Local Area Augmentation System (LAAS)*

Cited by 22 publications

References 1 publication

Enhanced Differential GPS Carrier-Smoothed Code Processing Using Dual-Frequency Measurements

Enhanced Differential GPS Carrier-Smoothed Code Processing Using Dual-Frequency Measurements

Performance evaluation of single and dual frequency Carrier Smoothing techniques for LAAS

A Wide Band Antenna for Multi-Constellation GNSS and Augmentation Systems

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