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    81.
    发明专利
    未知

    公开(公告)号：NO922212L

    公开(公告)日：1992-06-04

    申请号：NO922212

    申请日：1992-06-04

    Applicant: QUALCOMM INC

    Inventor： AMES WILLIAM G ,  JACOBS IRWIN M ,  WEAVER LINDSAY A ,  GILHOUSEN KLEIN S

    IPC: G01S5/12 ,  G01S5/14 ,  G01S13/87 ,  G01S19/00 ,  G01S19/01 ,  G01S19/38 ,  G01S19/48 ,  H04B7/185 ,  H04B

    Abstract: A method and system for determining the position of an object using a fixed station and a plurality of earth orbit satellites whose positions are known. Separate periodic signals are transmitted from the fixed station via first and second satellites to the object whose postion is to be determined. The phase offset in periodic characteristics of the periodic signals as received from the first and second satellites is measured at the object. The phase offset corresponds to a relative time difference in propagation of the signals traveling two different paths to the object. The object transmits via the first satellite a return signal indicative of the measured relative time difference. This return signal is activated some time in the future according to the object local time, which is slaved to receipt of the periodic signal sent through the first satellite. This future time is the start of the particular time period as decided by the fixed station's schedule. At the fixed station, an instantaneous round trip delay, determined by the time offset of the current transmission clock time relative to the receive clock time of reception of the return signal, along with the measured relative time difference sent back on the return signal, is used to calculate the distances between the first and second satellites to the object. From these distances the position of the object is calculated.

    ALTERNATING SEQUENTIAL HALF DUPLEX COMMUNICATION SYSTEM
    82.
    发明专利
    ALTERNATING SEQUENTIAL HALF DUPLEX COMMUNICATION SYSTEM 未知

    公开(公告)号：AU3059789A

    公开(公告)日：1989-08-11

    申请号：AU3059789

    申请日：1989-12-21

    Applicant: QUALCOMM INC

    Inventor： GILHOUSEN KLEIN S ,  ANTONIO FRANKLIN P ,  JACOBS IRWIN M ,  WEAVER LINDSAY A JR

    IPC: G02B6/293 ,  G02B6/34 ,  G02B6/42 ,  H01S3/08 ,  H01S5/14 ,  H01S5/40 ,  H04B1/7136 ,  H04B7/212 ,  H04B10/155 ,  H04L5/16 ,  H04B7/26 ,  H04J3/26

    Abstract: A message communication system employing one or more centralized communication stations transferring messages through Earth orbit repeater satellites to or from mobile terminals with at least one central communication station having a first transceiver for transmitting a first communication signal to one or more mobile terminals and at least one mobile terminal having a second transceiver for receiving the first communication signal and demodulating it, and for transmitting at a predetermined duty cycle of the second transceiver, a second communication signal to at least one of the central communication stations. The preferred duty cycle over which the second communication signal is transmitted is about fifty percent of the second transceiver duty cycle. The communication system uses Time Division Multiplexed (TDM) communication signals using a number of channels as designated address channels with the remainder being used for data transfer. Information transmitted on the address channels is used by terminals to determine both the presence of a message and its corresponding data transmission or reception channel. In addition the terminals use the reception of the first communication signal to adjust return link transmission frequency to compensate for transmission path errors. The alternating duty cycle allows mobile terminals to use a single set of local oscillators for both transmission and reception modes of operation. To decrease interference with other systems the present system employs a power dispersal modulation function to achieve the footprint of a video signal for high transfer rate digital communication signals.

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