Predictions of GPS X-Set Performance during the Places Experiment

Preexperimental predictions of GPS X-set receiver performance during the PLACES barium release experiment are presented for carrier frequencies from 150 to 250 MHz. Detailed examples of the X-set phase, frequency and code tracking performance are shown. For mean carrier power-to-noise density ratios of 35 db-Hz and less, erroneous Doppler aiding from the AFCCostas loop can cause degradations to the otherwise adequate code tracking loop. All receiver performance results presented are obtained using numerical multiple phase screen calculations of frequency-selective signal propagation through simulated barium clouds. These calculations are based upon a statistical model of a striated barium cloud developed from Fourier analysis of back propagation data taken during the STRESS barium release series. This model includes representation of the important barium striation parameters derived from measured power spectral density PSD properties including phase standard deviation, spectral index, and outer scale.