摘要:
A laser crosslink apparatus includes an optical device (212, FIG. 5), a beam splitter (512), an acquisition channel and a tracking and communication channel. The acquisition channel includes a high density optical fiber bundle and an acquisition channel device (510). The optical device (212) receives laser light from a wide field of view, and the beam splitter (512) splits the light into the two channels. The high density optical fiber bundle (204) has one end (206) in a focal plane of the optical device, and another end (208) coupled to the acquisition channel device (510). The acquisition channel device (510) includes an optical receiver array (400, FIG. 4). The location of spot footprints on the optical receiver array determines the direction from which the laser light is received within the wide field of view. The optical fiber bundle allows the optical receiver array to be located away from the optical device, near the receiving/tracking system, where it can be more easily shielded from the harmful effects of space.
摘要:
An optical interconnect system (100) includes an array of optical sources (102), a high-density fiber bundle (110), and an array of optical receivers (150). The density of the fiber bundle is such that each optical source (104) couples light to multiple fibers within the bundle. The fiber bundle has a consistent cross section along its length so that the footprint of fibers (306, FIG. 3) illuminated by a spot (304) from an optical source illuminates a similar footprint (404, FIG. 4) over the optical receivers (406). The optical receiver array has a density of optical receivers such that the footprint of fibers corresponding to a single optical source illuminates at least one optical receiver. A method (600, FIG. 6) for creating optical source/receiver pairs excites each optical source in turn and detects energy at the optical receiver array.
摘要:
A method and apparatus predicts a ground-to-satellite terminal's (16) percentage of successful communication linkage time to at least one satellite of a communication system in response to a terminal blockage profile (410), as created from the location of an antenna of the terminal, and a satellite blockage profile (412). The prediction may also be based upon a weather model data base (358) corresponding to the area where the terminal is located.
摘要:
An optical wireless communications system (1) comprises a server or transceiver hub (6) transmitting and/or receiving optical communications with geographically dispersed subscriber units (8) via optical beams. The transceiver hub (6) transmits a beam pattern that has an efficient, rectangular, flat-topped far field optical profile, thus permitting less complex and less expensive transceiver equipment to be employed in the transceiver hub (6) and in the subscriber units (8). In one embodiment, the transceiver hub (6) comprises an optical source (52, FIG. 3), an asymmetrical lens such as a cylindrical lens (60, FIG. 3), and a diffraction element such as a diffractive phase plate (65, FIG. 3). Various methods of shaping an optical transmission profile are also described.
摘要:
With a constellation of low-earth orbiting satellites, instantaneous photographs of all large cities can be made available in real-time or near real-time. Those photographs can be downloaded to ground stations, and there photographically interpreted to determine traffic conditions. The use of high and low photographic resolution permit making distinctions between different causes of traffic conditions. A color-coded map may be generated showing all major roads and their current status, showing such conditions as light traffic, medium traffic, heavy traffic and traffic accidents or jams, for example. These color-coded maps or color-coded alphabetized lists of streets may be broadcast to subscribers (broadcast stations, companies or individuals). From the color-coded traffic report, the subscribers are updated about which routes to avoid and what the best detours are around the more congested areas.
摘要:
The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.
摘要:
The present invention utilizes a dual polarization reception system (200) that utilizes the energy available in orthogonal polarizations to effectively increase link margin, thereby allowing for adequate signal quality reception in difficult environments. A co-polarized and a cross-polarized signal are separately downconverted and demultiplexed. The signals from each demultiplexed output are then sampled and weighted. The weighted samples for each polarity are combined in soft decision combining/decoding circuitry (255, 360), and this circuitry determines the most likely state of a received symbol's transmitted value.
摘要:
Communications path impairments are mitigated within a wireless communications system (10) comprising fixed, mobile, and portable subscriber units (SUs 1-N), server nodes (S1-SN), and a network operations center (NOC 2). Each SU can be served by at least two different server nodes, each communicating over a different channel. The SUs and/or the server nodes periodically evaluate the quality of the SU communications links and determine the link having optimum quality. The SU or the server node informs the NOC of the determination. Subsequent communications with the SU during the period are conducted using the optimum communications link. In the event of a temporary path impairment, an alternate communications link is promptly established to maintain uninterrupted communications with the SU. In another embodiment, the NOC performs the quality evaluation and/or determines the optimum communications link to the SU. The NOC communicates with the server nodes over separate communications links.
摘要:
A system (10) and method delivers simplex signals (26, 28) to a communication unit (24) located within an area (20) (e.g., a building) where an obstruction exists between the signal transmitter (12, 18) and the communication unit (24). The system (10) uses an infrastructure retransmission apparatus (14, 16, 22) to receive (204, 304, 402, 404) the signals (26, 28) and retransmit (208, 310, 410) them within the area (20). Geolocation signals (26) from navigation satellites (12) can be retransmitted (208, 310) using the infrastructure retransmission apparatus (14, 16, 22), thus enabling a communication unit (24) located within an obstructed area (20) to calculate its position.