Abstract: A radio occultation instrumentation system includes a first satellite arranged with a transmitter for transmitting a signal with a carrier frequency and a second satellite arranged with a receiver for receiving the signal. The receiver receives information I(x,v) regarding the position and velocity of the first and second satellite and provides a prediction of the Doppler shift displacement of the carrier frequency of the signal for use in tracking the signal. The predicted Doppler shift displacement is also used to determine atmospheric conditions.

Abstract: Apparatus for performing open loop tracking of a signal in a radio occultation instrumentation system including a first satellite arranged with a transmitting means arranged for transmitting a signal with well defined carrier frequency and a second satellite arranged with signal receiving means receiving said signal, wherein said transmitted signal has a ray path from said first satellite to said second satellite which descends into and ascends from the atmosphere, said apparatus including means for providing a control signal to a frequency control unit for signal acquisition included in said receiving means, means for receiving information I(x,v) regarding the position and velocity of the first and second satellite; arrangement for providing a prediction of Doppler shift displacement of a transmitted signal in such a radio occultation system; and method for determining atmospheric conditions from information of Doppler shift displacement in a radio occultation instrumentation system.

Abstract: A method and a system for maintaining a desired prescribed link quality from a communications terminal to a central node in a communications link system are described. A communication signal is transmitted from the communications terminal at a normal data rate on any given communication channel to the central node. The central node receiver then will order the communications terminal to step down its data rate if the central node receives poor signal quality. Then the central node will adopt its receiver channel bandwidth to the new lower data rate to obtain a desired power density per Hertz bandwidth, and simultaneously the central node will reallocate bandwidth no longer used for the particular communication terminal at the lower data rate to make this portion of its total bandwidth available for another channel in the communications link system. The method and system thereby provide an effective utilization of the available bandwidth at the system node.

Abstract: An inexpensive high gain antenna for use on terminals communicating with low earth orbit (LEO) satellites which include an elevation table mounted for arcuate movement about a transverse axis on an azimuth turntable mounted for rotational movement about a central axis. A plurality of antenna elements forming a phased array antenna are mounted on the top of the elevation table and have a scan plane which is parallel to and extends through the transverse axis of the elevation table. The antenna may be both mechanically and electrically scanned and is used to perform handoffs from one LEO satellite to another by positioning the elevation table of the antenna with its boresight in a direction intermediate the two satellites and with the scan plane of the antenna passing through both satellites. At the moment of of handoff, the antenna beam is electronically scanned from one satellite to another without any loss in data communication during the process.