Satellite communications using the telemetry tracking and control system

Claim 1

In a command, ranging, and telemetry arrangement including: a pair of command, ranging, and telemetry ground stations, each including: a ranging tone generator, means for modulating said ranging tone on a ranging tone subcarrier, means for combining said modulated ranging tone subcarrier with a command signal, means for transmitting said combined modulated ranging tone subcarrier and said command signal on an up-link carrier, means for receiving a down-link carrier, and means for recovering from said down-link carrier said modulated ranging tone subcarrier and for detecting said ranging tone; and a satellite including means for receiving said up-link carrier and for recovering said modulated ranging tone subcarrier and said command signal therefrom, and further including a source of said down-link carrier and means for transmitting said recovered modulated ranging tone subcarrier on said down-link carrier; whereby said satellite receives said modulated ranging tone subcarrier and retransmits it at the down-link frequency, and said retransmitted ranging tone subcarrier is received by the ground station from which it was transmitted and by the other ground station; an improvement for providing audio communications between said command, ranging, and telemetry ground stations comprising: at least a first of said ground stations further including means for providing a band limited audio signal, and means for modulating said band limited audio signal on said ranging tone subcarrier in place of said ranging tone; and at least said other of said command, ranging, and telemetry ground stations further including means for detecting said audio signals from said modulated ranging tone subcarrier and means coupled to said detecting means for applying said audio signal to a utilization device.