Abstract: The trirectangular tetrahedron array provides nearly constant gain over a hemisphere, by adaptively combining signals from elements, having substantially cosine-squared power patterns, on orthogonal faces. By using a deterministic aperiodic lattice, the array can use higher gain elements rather than lower gain elements for traditional wide-scan phased arrays. Thus, the number of elements needed can be reduced by more than a factor of two. Importantly, element spacing is increased with this design, thus lowering mutual coupling and the associated potential for scan blindness. Higher gain elements require spacing exceeding ½ wavelength can have grating lobes. This is addressed with an aperiodic lattice designed to ensure that no grating lobe can form. By connecting two trirectangular tetrahedrons by their bases and mounting on an air/space-based platform, nearly spherical coverage with constant gain results.

Abstract: A system and method for operating a communications or radar system wherein the system is a closed-loop coherent transmit array consisting of a plurality of antenna elements that may be widely-spaced, many wavelengths apart, an array control system, and a remote receiver that can feedback a measure of the transmit performance, and is a cooperative receiver, a bent-pipe, or a reflector. The method involves generation of weights which are applied to the array transmit signals based on feed-back data from a remote receiver compensating for at least one: circuit, propagation, and polarization phase errors. The method correlates feedback performance changes with transmit weight perturbations, enabling maximization of transmitted power delivered to the remote receiver.

Abstract: A system for detection and orbit determination of Earth orbiting objects includes a first plurality of sensors including at least one first antenna. The at least one first antenna is configured to point in a stare mode to broadcast a first detection signal at an angular region centered on an equatorial plane to maximize detection of orbiting objects regardless of altitude, grade, or inclination. The first antenna may be configured to stare at a low inclination angle, and may be configured to stare at one of due east and due west along the equator.