Embodiments relate to a bidirectional free space optical (FSO) communications system. Specifically, data-encoded FSO beams are transmitted and received between two terminals. A transmit (Tx) direction of a beam transmitted from the first terminal is dithered by a beam steering unit (BSU). As the dithered beam is received by the second terminal, the power levels of the beam are measured. The power levels are then encoded in a data-encoded FSO beam transmitted to the first terminal. This allows the first terminal to decode the received FSO beam and determine the power levels. The power levels allow the first terminal to determine Tx direction misalignments and adjust the Tx direction for the Tx beam sent to the second terminal. This process may be repeated to reduce Tx misalignments and may be performed by both terminals such that each terminal sends power level information to the opposite terminal.

Techniques for determining an alternative communication mode for vehicle-to-vehicle communication at a host vehicle can include monitoring the primary mode of RF communication to ensure it is effectively communicating and, if not, intelligently selecting a backup communication mode comprising one or more other sensors and/or systems of the vehicle. The selection of the backup communication mode may take into account various factors that can affect the various modes of communication from which the backup communication mode is selected.

Embodiments relate to a free space optical (FSO) communications system with a feed-forward control path. A data-encoded FSO beam is transmitted from a local terminal to a remote terminal. The local terminal directs a propagation direction of the FSO beam by a beam steering unit. To reduce pointing errors between the terminals, the FSO communications system includes a feed-forward control path. The control path includes an inertial measurement unit (IMU) that outputs motion data indicative of motion of the local terminal, for example if the local terminal is mounted to a tower that sways. The control path also includes a controller that receives the motion data from the IMU and generates feed-forward control signals for the beam steering unit. The control signals compensate for an effect of the motion of the local terminal on the propagation direction of the FSO beam.

Embodiments relate to a bidirectional free space optical (FSO) communications system. Specifically, data-encoded FSO beams are transmitted and received between two terminals. A transmit (Tx) direction of a beam transmitted from the first terminal is dithered by a beam steering unit (BSU). As the dithered beam is received by the second terminal, the power levels of the beam are measured. The power levels are then encoded in a data-encoded FSO beam transmitted to the first terminal. This allows the first terminal to decode the received FSO beam and determine the power levels. The power levels allow the first terminal to determine Tx direction misalignments and adjust the Tx direction for the Tx beam sent to the second terminal. This process may be repeated to reduce Tx misalignments and may be performed by both terminals such that each terminal sends power level information to the opposite terminal.

Improvements in secure communication using drones. The communication uses aircraft to provide a secure communication link that prevents undesirable reception. The secure link can be between two people, groups or more specific people. Optical transmission can be from laser, infrared, ultraviolet, white light or a particular wavelength of light. One or multiple of aircraft to relay information between senders and receivers. The aircraft can be drones that operate within buildings or with overhead aircraft. The aircraft can intelligently follow or lead a person to maintain a line-of-sight. Each user can have their own tracking aircraft and the aircraft can communicate between each other using light and/or wireless communication to optimize line-of-sight between the aircraft over geographic medium. The geographic medium may include one or more of terrain, air, water, and space. The object may be a soldier, vehicle, drone, or ballistic.

A method, system, and apparatus are disclosed for a free-space communication optical terminal comprising an optical telescope (or telescopes) for bidirectional communication and navigation, a pointing and tracking system for transmission and reception of narrow optical beams, and a modem.

In order to reliably communicate with a communication object even when a relative positional relationship with the communication object cannot be accurately recognized, an inter-mobile-body communication system includes: a control device which performs control of switching between a first mode of transmitting wide-area signal light, and a second mode of transmitting selective signal light toward a communication object in response to response signal light responding to the wide-area signal light transmitted in the first mode, and performs control of selectively receiving the response signal light from the communication object; and a light transmitting/receiving device which transmits the wide-area signal light in the first mode, transmits the selective signal light toward the communication object in the second mode, and selectively receives the response signal light from the communication object, according to control by the control device.

An object of the present invention is to provide an optical/RF wireless hybrid communication system and a control method capable of solving the instability of link states of an RF wireless link and an optical wireless link. According to an optical/RF wireless hybrid communication system and a control method of the present invention, when data is transmitted, the link is not limited to one of an RF wireless link and an optical wireless link, a link state is determined based on signal quality received in channels of both the RF wireless link and the optical wireless link, and a distribution of data to be transmitted in each link is determined based on a result thereof. For this reason, the link can be switched according to circumstances of the transmission state due to an external disturbance and the like.

This application relates to the field of space communications technologies, and provides an acquisition, pointing, and tracking (APT) subsystem and a spacecraft communications system. The APT subsystem includes a first controller, a first terahertz transceiver, and a terahertz antenna array that are sequentially connected, where the first terahertz transceiver is configured to modulate and demodulate a terahertz wave; the terahertz antenna array is configured to send and receive the terahertz wave; and the first controller is configured to control the first terahertz transceiver to acquire, point, and track another APT subsystem by using the terahertz antenna array.

Embodiments of an optical data communication apparatus using micro-electro-mechanical system (MEMS) micro-mirror arrays is described herein. The apparatus may include a router configured to operate as a relay to exchange optical data signals between optical switches of the apparatus. The optical switches may be configured to switch between reflection directions to reflect the optical signals over different optical connections between the optical switches and different receiving ports of the router. The reflection directions may be switched in accordance with predetermined mappings between the receiving ports of the router and destinations of the optical signals. The router includes a MEMS micro-mirror array configured to reflect received optical signals to the destinations. A processing element of the optical data switching circuitry may generate a plurality of optical data signals and may send the optical data signals to an optical switch of the optical data switching circuitry.