1. Impacts of Carrier Wavelength and Physical Environment on Coverage of ORBCOMM LMSS with Different Antenna Radiation Patterns Steven J. Ma,Dr. Dave Michelson Department of Electrical and Computer Engineering University of British Columbia I - OBJECTIVES More ORBCOMM service users require adequate coverage in urban areas. While it is difficult to assess the coverage in urban area due to complex propagation environment. This research intends to give a quantitative analysis on the influences of following four factors on the coverage of ORBCOMM LEO narrowband messaging system in urban areas: 1.Physical environment, i.e., building height distribution etc. 2.Radio wave frequency - VHF band. 3.Antenna radiation pattern. 4.Urban noise. IV - ANTICIPATED OUTCOMES 1.Empirical Results Probability density function of mean signal power Vs. mean building height, latitude of receiver and carrier wavelength. Signal-to-noise ratio estimation based on noise information. 2.Space Domain Satellite Channel Modeling First and second order statistics of satellite signal terms of space factors. 3.An Evaluation Tool for Antenna Design Space domain statistic description of user application environment. Space domain statistics of Noise. Radio Science Lab III - METHODOLOGY 1.Deterministic Prediction with Numeric Electromagnetic Code – Basic Scattering Code Calculating path loss information with different antenna radiation pattern in the presence of scatters. UTD capability allows complex structures and their dielectric properties be included in the analysis. 2.Satellite Orbit Calculation with SATTRACK Calculating satellite movement. Deriving statistical properties of satellites’ movement, i.e., azimuth, elevation angle distribution. 3.Field Measurement For Comparison Collecting field measurement with ORBCOMM satellite receiver. 4.Field Measurement and Statistics for Noise II - BACKGROUND & MOTIVATION 1.Little Previous Research and Empirical Results in Literature for VHF LMSS OORBCOMM LEO system is working at VHF band (UL148-150.05 MHz, DL 137.0-138.0 MHz ). However, most of the studies in literature on propagation of LMSS were at L (1-2GHz) and Ku (12-18GHz) bands. 2.Frequency & Environmental Dimensions Are Significant Factors VHF radio wave has different interactions with its surrounding environment comparing with higher frequencies, which affect NLOS propagation hence overall link availability. 3.Receiver Antenna Radiation Pattern Vs. Environment Factor. Angles of incoming radio waves change with environment. Different types of antennas suit for different kind of applications. Tool for assessing antenna performance under different circumstance, or assisting design is very useful. 4.New Noise Property at VHF Band VHF band noise in urban areas has changed recently years due to new electronics equipments and new technologies in traditional products New space domain and a time domain statistical distribution of VHF noise will influence assessment of system performance and the design of antenna and receiver.