A system may include a mobile ad-hoc network (MANET) including a plurality of nodes. Each of the plurality of nodes is configured to transmit communication data packets and transmit beacons. Each of the plurality of nodes has passive spatial awareness. A first node has information of own node velocity, own node orientation, and a destination. The first node may be configured to: calculate a direct line or an arc from the first node to the destination; utilize passive spatial awareness; assess possible relay routes beyond the communication range and within the beacon range of the first node; determine a next relay node that is on one of the possible relay routes wherein the one of the possible relay routes may be closest to the direct line or the arc without being determined to be part of a dead-end route; and transmit a communication data packet to the next relay node.

A system and method for frequency offset determination in a MANET via Doppler nulling techniques is disclosed. In embodiments, a receiving (Rx) node of the network monitors a transmitting (Tx) node of the network, which scans through a range or set of Doppler nulling angles adjusting its transmitting frequency to resolve Doppler frequency offset at each angle, the Doppler frequency shift resulting from the motion of the Tx node relative to the Rx node. The Rx node detects the net frequency shift at each nulling direction and can thereby determine frequency shift points (FSP) indicative of the relative velocity vector between the Tx and Rx nodes. If the set of Doppler nulling angles is known to it, the Rx node can determine frequency shift profiles based on the FSPs, and derive therefrom the relative velocity and angular direction of motion between the Tx and Rx nodes.

A system and method for frequency offset determination in a MANET via Doppler nulling techniques is disclosed. In embodiments, a receiving (Rx) node of the network monitors a transmitting (Tx) node of the network, which scans through a range or set of Doppler nulling angles adjusting its transmitting frequency to resolve Doppler frequency offset at each angle, the Doppler frequency shift resulting from the motion of the Tx node relative to the Rx node. The Rx node detects the net frequency shift at each nulling direction and can thereby determine frequency shift points (FSP) indicative of the relative velocity vector between the Tx and Rx nodes. If the set of Doppler nulling angles is known to it, the Rx node can determine frequency shift profiles based on the FSPs, and derive therefrom the relative velocity and angular direction of motion between the Tx and Rx nodes.

A system may include a transmitter node and a receiver node. Each node may include a communications interface including at least one antenna element and a controller operatively coupled to the communications interface, the controller including one or more processors. Each node may be time synchronized to apply Doppler corrections to said node's own motions relative to a stationary common inertial reference frame. The stationary common inertial reference frame may be known to the transmitter node and the receiver node prior to the transmitter node transmitting signals to the receiver node and prior to the receiver node receiving the signals from the transmitter node.

A radar system controls accesses to an environment where a machinery can be present. Radar devices are placed along an access path to the environment. The radar devices check the presence of targets in passage regions, arranged to be sequentially met along the access path. A control unit has stored predetermined ordered entry and exit sequences of events, given by changes of the passage regions between occupied and clear. If the registered sequence matches the entry sequence, that is the passage regions are occupied in the correct order, the environment is classified as occupied, and the machinery stops working. The machinery restarts when the environment is classified again as clear, based on the registered sequence matching the exit sequence, that is the passage regions being cleared in order.

Apparatus and methods for contact-minimized automated teller machine (“ATM”) use and transaction processing using Doppler-radar based gesture recognition and authentication. The apparatus and methods may include an ATM including a millimeter-wave radar transmitter and receiver. Movement of one or more objects, including fingers, within a radar field may be analyzed and translated into gestures and authentication passcode(s). By utilizing the radar field instead of physical buttons or a touchscreen, contact with the ATM may be minimized.

A movement-distance measuring apparatus is provided with: an antenna, a phase detection circuit, a phase-shift calculation circuit, and a movement-distance calculation circuit. The antenna transmits a radio wave toward a plurality of reflectors arranged at constant intervals along a moving path of a moving object, and receives a reflected wave from the reflectors. The phase detection circuit detects a phase of the reflected wave received by the antenna. The phase-shift calculation circuit calculates a phase shift based on the phase detected by the phase detection circuit. The movement-distance calculation circuit calculates a movement distance of the moving object, based on the phase shift calculated by the phase-shift calculation circuit, and based on the interval of the reflectors.

A movement-distance measuring apparatus is provided with: an antenna, a phase detection circuit, a phase-shift calculation circuit, and a movement-distance calculation circuit. The antenna transmits a radio wave toward a plurality of reflectors arranged at constant intervals along a moving path of a moving object, and receives a reflected wave from the reflectors. The phase detection circuit detects a phase of the reflected wave received by the antenna. The phase-shift calculation circuit calculates a phase shift based on the phase detected by the phase detection circuit. The movement-distance calculation circuit calculates a movement distance of the moving object, based on the phase shift calculated by the phase-shift calculation circuit, and based on the interval of the reflectors.

Techniques and apparatuses are described that implement a smart-device-based radar system capable of detecting user gestures in the presence of saturation. In particular, a radar system employs machine learning to compensate for distortions resulting from saturation. This enables gesture recognition to be performed while the radar system's receiver is saturated. As such, the radar system can forgo integrating an automatic gain control circuit to prevent the receiver from becoming saturated. Furthermore, the radar system can operate with higher gains to increasing sensitivity without adding additional antennas. By using machine learning, the radar system's dynamic range increases, which enables the radar system to detect a variety of different types of gestures having small or large radar cross sections, and performed at various distances from the radar system.

Techniques and apparatuses are described that implement a smart-device-based radar system capable of detecting user gestures in the presence of saturation. In particular, a radar system employs machine learning to compensate for distortions resulting from saturation. This enables gesture recognition to be performed while the radar system's receiver is saturated. As such, the radar system can forgo integrating an automatic gain control circuit to prevent the receiver from becoming saturated. Furthermore, the radar system can operate with higher gains to increasing sensitivity without adding additional antennas. By using machine learning, the radar system's dynamic range increases, which enables the radar system to detect a variety of different types of gestures having small or large radar cross sections, and performed at various distances from the radar system.