A radio telescope array is provided for tracking radio sources that are essentially infinitely stable and resilient transmitters. The radio telescope array may be implemented with just a few antennas in different applications, such as an ionospheric density gradiometer or an imaging scintillometer. Data received at the radio telescope array may be utilized for various purposes, for example, to analyze ionospheric variations, study bursts of radio emission or monitor cosmic objects.

A radio telescope array is provided for tracking radio sources that are essentially infinitely stable and resilient transmitters. The radio telescope array may be implemented with just a few antennas in different applications, such as an ionospheric density gradiometer or an imaging scintillometer. Data received at the radio telescope array may be utilized for various purposes, for example, to analyze ionospheric variations, study bursts of radio emission or monitor cosmic objects.

Satellite communications systems, methods, and related devices are described. In one embodiment, a satellite communications system is configured to dynamically allocate bandwidth among different downlink beams. The satellite may receive and compile traffic measurements and terminal parameters. The satellite may be configured with different downlink beam coverage areas, and may dynamically allocate downlink bandwidth and particular frequency channels to different beam coverage areas based on the measurements and parameters. The satellite may also assign frequency channels and time slots based on such measurements and parameters.

Satellite communications systems, methods, and related devices are described. In one embodiment, a satellite communications system is configured to dynamically allocate bandwidth among different downlink beams. The satellite may receive and compile traffic measurements and terminal parameters. The satellite may be configured with different downlink beam coverage areas, and may dynamically allocate downlink bandwidth and particular frequency channels to different beam coverage areas based on the measurements and parameters. The satellite may also assign frequency channels and time slots based on such measurements and parameters.

A communication system uses multiple communications links, preferably links that use different communications media. The multiple communications links may include a high latency/high bandwidth link using a fiber-optic cable configured to carry large volumes of data but having a high latency. The communications links may also include a low latency/low bandwidth link implemented using skywave propagation of radio waves and configured to carry smaller volumes of data with a lower latency across a substantial portion of the earth's surface. The two communications links may be used together to coordinate various activities such as the buying and selling of financial instruments.

A communication system uses multiple communications links, preferably links that use different communications media. The multiple communications links may include a high latency/high bandwidth link using a fiber-optic cable configured to carry large volumes of data but having a high latency. The communications links may also include a low latency/low bandwidth link implemented using skywave propagation of radio waves and configured to carry smaller volumes of data with a lower latency across a substantial portion of the earth's surface. The two communications links may be used together to coordinate various activities such as the buying and selling of financial instruments.

A communication system uses multiple communications links, preferably links that use different communications media. The multiple communications links may include a high latency/high bandwidth link using a fiber-optic cable configured to carry large volumes of data but having a high latency. The communications links may also include a low latency/low bandwidth link implemented using skywave propagation of radio waves and configured to carry smaller volumes of triggering data with a lower latency across a substantial portion of the earth's surface. The triggering data may be sent in a data stream as data frames without headers, security information, or error checking codes. The two communications links may be used together to coordinate various activities such as the buying and selling of financial instruments.

A wireless communication system includes a first wireless communication node for transmitting a data signal that is sent to a second wireless communication node by skywave propagation over at least two different data transmission paths. The first data transmission path includes at least one reflection point where the data signal is reflected by the atmosphere and the second data transmission path includes more reflection points than the first data transmission path. The data signal that travelled along the first data transmission path is decoded before the data signal that travelled along the second data transmission path.

A wireless communication system includes a first wireless communication node for transmitting a data signal that is sent to a second wireless communication node by skywave propagation over at least two different data transmission paths. The first data transmission path includes at least one reflection point where the data signal is reflected by the atmosphere and the second data transmission path includes more reflection points than the first data transmission path. The data signal that travelled along the first data transmission path is decoded before the data signal that travelled along the second data transmission path.

A communication system allows for clock synchronization between a transmitter and a receiver when switching from transmission of an analog signal to transmission of a digital signal. The system uses clock synchronization during transmission of the digital signal, but the clock synchronization may be lost when switching to transmission of an analog signal. A digital clock synchronization is embedded in the analog signal so that the clock synchronization between the transmitter and the receiver may be reestablished upon switching to a digital signal without any delay in transmission of the digital signal.