LAAS Integrated Multipath-Limiting Antenna

Thornberg, D. Bryce; Thornberg, Dean S.; Dibenedetto, M.; Braasch, Michael S.; Graas, Frank van; Bartone, Chris

doi:10.1002/j.2161-4296.2003.tb00323.x

Cited by 30 publications

(18 citation statements)

References 6 publications

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“…This requirement stemmed from needing to support dual-port antennas such as the LAAS integrated multipath limiting antenna (IMLA) [7]. Hence, a dual-channel RF front end with near-identical performance on both channels needed to be developed.…”

Section: Dual Antenna Portsmentioning

confidence: 99%

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Remote-Controlled, Continuously Operating GPS Anomalous Event Monitor

et al. 2009

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The observation, capture, and analysis of GPS anomalies is vital for verifying its quality and integrity for safety-of-life applications. Clearly, it is difficult to obtain detailed insight into observed anomalies using only the handful of outputs such as range measurements and tracking status available from a regular GPS receiver. The GPS anomalous event monitor (GAEM) captures a raw sampled-signal data record centered on suspected anomalous GPS events. These files are accessed remotely via the Internet and analyzed in detail by clients using software radio processing methods. Three GAEM systems were installed in geographically diverse locations in the United States and have been in continuous operation for the last two years. This paper describes the development and architectural details of the system. In addition, processed results from significant observed events are also presented.

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Section: Dual Antenna Portsmentioning

confidence: 99%

“…Both GPS receivers share RF inputs with the GAEM data collection server. For the GAEM at Ohio, the LGF antenna is a dual port integrated multipath limiting antenna (IMLA) comprised of a high-zenith antenna (HZA) and a multi-element multipath limiting antenna (MLA) [7]. Each port is monitored by a separate receiver.…”

Section: Anomaly Detection Systemmentioning

confidence: 99%

Remote-Controlled, Continuously Operating GPS Anomalous Event Monitor

et al. 2009

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“…The sites FLD5 and FLD6 were used for GPS/APL reception, and site FLD8 was used for APL transmission. At each reception site, an integrated multipath limiting antenna configuration, using a combination of a high-zenith antenna (HZA) and a multipath limiting antenna (MLA), was employed in order to minimize ground multipath (low frequency) regardless of the elevation angle of the ranging source (Thornberg et al 2002). The HZA was used for the reception of GPS SVs at elevation angles between approximately 30 and 90°, and the MLA for the reception of SVs between 5 and 30°.…”

Section: Flight Test Demonstration Of Power-induced Error Mitigationmentioning

confidence: 99%

Verification and mitigation of the power-induced measurement errors for airport pseudolites in LAAS

Kiran

Bartone

2004

GPS Solutions

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Certain GPS receivers exhibit a powerinduced measurement error when the input signal power exceeds a certain threshold that is a function of the receiver architecture. The characterization of this error is important in the case of airport pseudolites (APLs) due to receiver saturation at ranges close to the transmission antenna. This paper details an effort using laboratory test to characterize the power-induced measurement error in NovAtel Millennium and Beeline receivers that are widely used for APL development. The results from the laboratory tests show that this effect can lead to errors as large as 3 m on pseudorange measurement for the dynamic range typical for APLs. The carrierphase error however is seen to be limited to 5 cm. On the verification and characterization of the error, a cost-effective mitigation technique for LAAS is proposed. A solution for the ground subsystem is sought by employing power-control measures to limit the amount of APL power that LGF GPS/APL receivers are exposed to. In order to keep the integration cost low, the solution for the airborne subsystem does not involve hardware modifications or additions, but rather relies on the transition to a differential carrier-phase positioning algorithm prior to the onset of the power-induced error along the approach path. The proposed architecture was flight-tested to verify successful mitigation of the power-induced error on both the ground and air, and the results from these tests are presented in the paper.

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“…Integrated Multipath Limiting Antennas (IMLA) are being used in Local Area Augmentation Systems (LAAS) to conform to the multipath rejection capabilities that is critical to meeting the integrity and accuracy of operation in fight control environments [2]. Such an antenna is a dual band antenna operating in the L1/L2 GPS bands [3].…”

Section: Introductionmentioning

confidence: 99%

“…It consists of two antennas, a High Zenith Antenna (HZA) covering from 90 o -30 o in elevation, and a Multipath Limiting Antenna (MLA) covering from 35 o -0 o . The Desired-to-Undesired (D/U) ratio which is a parameter that describes the ability of the antenna in rejecting ground multipath signals and has to be ≥ 30 dB [2], [3], [4].…”

Section: Introductionmentioning

confidence: 99%

WLC26-6: C/No Estimation in a GPS Software Receiver in the Presence of RF Interference Mitigation via Null Steering for the Multipath Limiting Antenna

Sharawi

Aloi

2006

IEEE Globecom 2006

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Estimation of the Carrier-to-Noise ratio C/N0 is an important aspect of the functionality of global positioning system (GPS) receivers. This estimate is used to weight the measurements obtained from each satellite in order to improve the accuracy of the position calculation. The Multipath Limiting Antenna (MLA) has shown promising results in combating ground multipath errors. Radio frequency interference (RFI) is a major error source for GPS receivers. Such interference can be reduced by using null steering at the antenna side. In this work, we present a novel null steering approach for the MLA, and demonstrate its effect on the estimation of the C/N 0 in a GPS software receiver. Two types of RFI sources are investigated; narrow band Continuous Wave (CW) and wide band Pulsed wave (PPS). Performance of two C/N0 estimation algorithms is compared under different RFI and directions of arrivals.

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LAAS Integrated Multipath-Limiting Antenna

Cited by 30 publications

References 6 publications

Remote-Controlled, Continuously Operating GPS Anomalous Event Monitor

Remote-Controlled, Continuously Operating GPS Anomalous Event Monitor

Verification and mitigation of the power-induced measurement errors for airport pseudolites in LAAS

WLC26-6: C/No Estimation in a GPS Software Receiver in the Presence of RF Interference Mitigation via Null Steering for the Multipath Limiting Antenna

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