Experimental Observations and Integrity Monitor Applications of LAAS IMLA Carrier Phase Measurements

This paper evaluates the integrity performance of carrier phase measurement based monitors for the Local Area Augmentation System Ground Facility. It shows the experimental verification for the type A1 ephemeris threat monitor (after-maneuver validation) and initial results for an ionospheric threat monitor for a static storm. It starts by describing in detail the carrier phase performance of the Integrated Multipath Limiting Antennas (IMLA’s), including an assessment of differential phase pattern variations with respect to azimuth and elevation. It also defines the mathematical model developed for differential phase variation, explains its use in precise antenna calibration, and demonstrates that the resulting IMLA double difference carrier phase errors have a standard deviation of less than 3 mm. Finally, the calibrated double difference carrier phase measurements are used toward the detection of the ephemeris and ionospheric front anomalies. The integrity performance of the LGF SIS monitor functions is quantified analytically and by simulation, and verified experimentally by deliberately injecting failures into the broadcast ephemeris or the raw LTP data.