Pointing losses in single‐axis and fixed‐mount earth‐station antennas due to satellite movement

Abstract

There are substantial cost advantages in the use of single‐axis or fixed‐mount earth‐station antennas, thus reducing or eliminating the need for autotracking in earth‐stations operating with quasi‐stationary satellites. Such cost advantages are more relevant in small antennas where the tracking system represents a larger percentage of the overall cost. In addition, small antennas are particularly suitable to be operated without autotracking, owing to their wider half‐power beamwidth. This paper describes a model for calculating the antenna pointing loss as a function of the antenna diameter, operating frequency band, satellite station‐keeping tolerances, and the relative geometry between the earth‐station and the satellite. The model has been extensively used in the development of INTELSAT's IBS and VISTA services as well as in domestic leases. Although the model has been developed based on orbital mechanics equations, its emphasis is towards earth‐station and systems engineering applications. Some example calculations and results obtained through an HP‐41 CV programmable calculator are also provided.

Performance Analysis of Space Information Networks with Backbone Satellite Relaying for Vehicular Networks

“…denotes the satellite elevation angle if the GEO satellite is not affected by the satellite perturbation. Considering the drift caused by satellite perturbation in the eastwest and northsouth directions, the elevation of satellite can be calculated by [46] = arctan [ sin Δ sin + cos Δ cos cos ( + Δ ) − 0.151…”