Abstract:
An approach for timing synchronization in a satellite system involving synchronizing a master clock onboard an orbiting satellite with a time standard; synchronizing a plurality of terrestrial gateways with the master clock; and synchronizing a plurality of wireless transceivers with the master clock; whereby each of the plurality of gateways and each of the plurality of wireless transceivers are synchronized with the master clock onboard the orbiting satellite.
Abstract:
An approach for immediate channel assignment in a wireless communications system involves receiving a channel request message from a wireless transceiver, the channel request message including a dialed party number; forming an immediate assignment message including a channel assignment; transmitting the immediate assignment message to the wireless transceiver; and establishing a communications channel between the wireless transceiver and a called party by establishing a channel between the wireless transceiver and the called party.
Abstract:
In a dual-mode satellite/cellular phone system, a user has the option of placing or receiving calls to and from the satellite network with either the cellular/PCS phone or the fully self-contained, stand-alone satellite phone. If the user places or receives a satellite call with the cellular/PCS phone, the communication signals to and from the cellular/PCS phone will first be received from or transmitted to the sallelite phone over a short-range, low-power communication link. The satellite phone, in turn, communicates directly with the satellite network from a location that is within a short range of the cellular/PCS phone, and from a location that preferably has a direct line-of-sight with the one or more satellites that make up the satellite network.
Abstract:
The invention concerns a terminal-antenna device (1, 10) transmitting/receiving radio signals to and from satellites (2, 3) selected among a constellation of moving satellites, comprising means for determining the position of the satellites sighted by the terminal-antenna, means for focusing quasi-plane waves received from or sent to a selected sighted satellite towards a focal surface S, primary sources transmitting/receiving signals in the form of quasi-spherical waves, independently mobile on the sphere S controlled by the determined position of the moving satellites.
Abstract:
A proximity detector detects objects which may interfere with a wireless antenna beam. The proximity detector includes infrared sensors, sonar detectors, motion detectors and optical devices to determine a range and bearing of objects that may interfere with the antenna beam. When an object may be harmed or interfere with the antenna beam, an alarm may be activated to warn the user and/or the object of potential harm from the electro-magnetic energy transmitted by the directed antenna. Also, based on the proximity detector's outputs, an antenna beam pattern may be changed to reduce the power at the object or the transmitted power may be reduced to prevent harm to the object.
Abstract:
A Multi-Band, Concentric Helical Antenna (20) operating in a conical mode which produces a uniform radiated flux within a footprint is disclosed. This antenna offers substantial benefits for satellite communication systems, since the size and volume of the antenna are compact, and is well suited for use on a spacecraft.
Abstract:
An antenna apparatus (806) for receiving and transmitting signals having a frequency less than one gigahertz is disclosed. The antenna apparatus (806) includes a dish portion (1101) having at least one wire antenna (1102) mounted thereon or embedded therein. The dish portion (1101) receives signals having frequencies greater than one gigahertz, while the wire antenna (1102) is capable of transmitting and receiving signals having frequencies less than one gigahertz. The antenna apparatus (806) may optionally include plural wire antennas (1102, 1103) for communications in different frequency bands below one gigahertz. In a preferred embodiment, an extension (1104) made of a dielectric material is coupled to the periphery of the dish (1101) and the wire antenna or antennas (1102, 1103) are embedded in the extension (1104) by thermal copper spraying or by spraying conductive ink thereon to form the wire antenna or antennas (1102, 1103).
Abstract:
An installation system for a cellular terminal separation type satellite communication portable terminal; which comprises a ground cellular terminal (11) capable of stand-alone communication, and a satellite communication portable terminal (12) that houses a ground cellular terminal, is electrically connected with the ground cellular terminal via a specified connector, and can communicate with a satellite under the control of the ground cellular terminal; and which is provided with a fixing unit (25) that is fixed to a location least affected by radio wave transmission troubles and has a separated satellite communication portable terminal installed therein, and with connection units (14a, 14b, 24a, 24b, 28) for permitting communications via a satellite by extending the span of the specified connector to electrically connect the separated satellite communication portable terminal with the separated ground cellular terminal.
Abstract:
A mobile satellite communication terminal which provides dual mode communication and has a small volume even when it is carried because dual-mode antennas are contained/installed in a structure simpler than conventional. A method for using the same is also disclosed. A satellite antenna (6) has a hollow tubular shape, and a ground antenna (5) is disposed in the hollow part of the satellite antenna (6). The satellite antenna (6) is retractable into the case of the terminal and extendable from it, and comprises a helical antenna element section (61) having tubular surface wound spirally with four turns of a wire (611), and an antenna feeder section (62) provided at the lower part of the helical antenna element section (61) integrally therewith and having, on the tubular surface, circuits (621, 622, 623).
Abstract:
A switch between satellite communication and cellular communication modes occurs at a predetermined threshold. Therefore, there is a problem that the communication modes are switched depending only on the relation between the signal level and the threshold, regardless of terminal user's intention. To solve the problem, there are provided input means that presents a selection menu to a terminal user and accepts the input of the communication mode selected by the user; and means that alters the threshold for evaluating the communication quality of the received signal in response to the desired communication mode selection from the input means and changes the switching sensitivity of the communication mode for the communication quality of the received signal.