摘要:
A communication system includes a set of non-geostationary satellites setting up communication links between ground stations and terminals, the links from a station terminating at associated terminals in a limited geographical area including the station. A communication link between a particular station and the associated terminals is set up by a satellite of the set of satellites. The satellite is commanded to set up for this purpose a steerable transmit beam and a steerable receive beam pointing at the limited area including the particular station and supporting the communication link.
摘要:
A feed device for a radiating element operating in dual polarization, for use especially in the field of space transmission, comprises a first feed line penetrating into a first cavity located beneath said radiating element, and a second feed line disposed in a configuration orthogonal to the first line and penetrating into a second cavity located in line with the first, a conductive part forming a coupling slot between the two cavities.
摘要:
In a method of handing off traffic in a low orbit satellite communication system serving terminals, a terminal being connected to a terrestrial communication network by means of a connection station, handing off of the satellite-terminal and satellite-connection station links is possible only within a particular area. The decision to hand off the traffic is based on deterioration of the quality of service and of the radio environment for a group of terminals of said area. The system for implementing this method includes transmit/receive terminals and terrestrial connection stations.
摘要:
The invention concerns, in particular, a system of observation of geostationary satellites (10.sub.1 -10.sub.n). In accordance with the invention, this system comprises at least one observation satellite (15) in an observation orbit (16, 17) near the geostationary orbit (11), this observation satellite (15) having an apparatus for observation of the geostationary satellites (10.sub.1 -10.sub.n) and an apparatus for transmission of the information obtained from the observation apparatus (20, 21, 22) to a receiver. The invention applies, in particular, to the discrimination of communication, meteorological, early warning and electromagnetic monitoring satellites.
摘要:
A power distributor for microwave signals has n inputs and n outputs, n/2 coupler elements, four power distributor elements each having n/2 inputs and n/2 outputs. The inputs of the first and third distributor elements correspond to respective inputs of the distributor and the outputs of the second and fourth distributor elements correspond to respective outputs of the distributor. The outputs of the first distributor element are connected to respective first inputs of the couplers and the outputs of the third distributor element are connected to respective second inputs of the couplers. The inputs of the second distributor element are connected to respective first outputs of the couplers and the inputs of the fourth distributor element are connected to respective second outputs of the couplers.
摘要:
The invention proposes a memory relay system for observation spacecraft, for example observation satellites or interplanetary probes. The object of the invention is to alleviate the absence or possible failure of onboard memory of these craft. The system of the invention provides a substitute solution which returns full functionality to an observation system capable of acquiring and transmitting observation data but not of storing it. In accordance with the invention, an artificial satellite or craft comprising at least one transponder and at least one writable memory is disposed near an observation satellite or a probe. The transponder is capable of receiving signals transmitted by the observation satellite or probe and then transmitting the signals to the Earth or to another destination. The memory of this artificial satellite or craft stores the information received until it is retrieved and retransmitted to the receiving station, a station on the ground, for example.
摘要:
In a method of calculation by a GPS receiver of the position of a mobile in space and time relative to a predetermined frame of reference, the position is calculated from data supplied by at least four GPS satellites selected by the GPS receiver to form a calculation constellation. The method includes the step of estimating the error in the position calculation. This error is estimated by the GPS receiver for each calculated position. The estimated error therefore varies with the position of the mobile.
摘要:
The invention relates to a reconfigurable transmission antenna comprising a reflector (10) for energy focussing, and an array (11) of source elements situated in the focal region of the reflector, so that the electromagnetic field is synthesized in said region, wherein a spot (SPi) is the result of radiation from a number of sources that is fixed and identical for all the spots; any one source participating at any one time in radiating one spot at the most, and high-level switching being used to reconfigure the spots by selecting the sources that participate in a given spot. Application to the space telecommunications field in particular.
摘要:
Spacecraft payload architecture which includes an array (10) of radiating elements preceded by an amplification stage (17) and a focusing optical system (11), characterized in that the architecture is adapted to a telecommunication mission by taking into account the overall requirements of the system, namely the radiation performance required for the mission, efficient rating of the amplification stage and attractive overall balances.
摘要:
The invention relates to a structure for making microwave circuits and components, in which the mechanical and electrical functions are integrated overall but dissociated locally. The invention is particularly suitable for space applications.