Abstract: A reconfigurable polar molecule includes a symmetric nonpolar molecule portion having an elongated shape defined by a longitudinal axis and lateral axis, the longitudinal axis being longer than the lateral axis; a positive ionically charged group at a first end and a negative ionically charged group at a second end of the longitudinal axis, the positive and negative ionically charged groups forming a permanent dipole; a first bridging group and a second bridging group on opposing ends of the lateral axis, the first and second bridging groups being linear nonpolar groups; and a first support portion bonded to the first bridging group, and a second support portion bonded to the second bridging group, the first bridging group and the second bridging group being nonpolar and having structures that enable free rotation of the symmetric nonpolar molecule portion through the first bridging group and the second bridging group.

Abstract: A support structure for a reconfigurable molecule includes a first support portion having a first mounting region; a second support portion having a second mounting region; and a rotatable molecule anchored between the first support portion and the second support portion on the first mounting region and the second mounting region, the rotatable molecule having an internal rotational axis extending from the first mounting region to the second mounting region; wherein the first support portion and the second support portion are mirror images of one another.

Abstract: The present disclosure is directed to a seeker system having an infrared (IR) sensor pedestal, an IR sensor disposed on the IR pedestal and a plurality of radio frequency (RF) antenna elements symmetrically disposed in a circumferential direction around the IR sensor pedestal. The seeker system further includes a plurality of RF waveguiding structures. In an embodiment, each of the RF waveguiding structures have first and second ends and are symmetrically disposed in a circumferential direction around the IR sensor pedestal such that in response to an RF signal incident on a first end of the waveguiding structure, the RF signal is provided to one of the plurality of RF antenna elements such that in response to an RF signal incident on the seeker system from any direction, each of the plurality of RF antenna elements receive the RF signal with a desired phase characteristic.

Abstract: A reconfigurable polar molecule includes a symmetric nonpolar molecule portion having an elongated shape defined by a longitudinal axis and lateral axis, the longitudinal axis being longer than the lateral axis; a positive ionically charged group at a first end and a negative ionically charged group at a second end of the longitudinal axis, the positive and negative ionically charged groups forming a permanent dipole; a first bridging group and a second bridging group on opposing ends of the lateral axis, the first and second bridging groups being linear nonpolar groups; and a first support portion bonded to the first bridging group, and a second support portion bonded to the second bridging group, the first bridging group and the second bridging group being nonpolar and having structures that enable free rotation of the symmetric nonpolar molecule portion through the first bridging group and the second bridging group.

Abstract: A support structure for a reconfigurable molecule includes a first support portion having a first mounting region; a second support portion having a second mounting region; and a rotatable molecule anchored between the first support portion and the second support portion on the first mounting region and the second mounting region, the rotatable molecule having an internal rotational axis extending from the first mounting region to the second mounting region; wherein the first support portion and the second support portion are mirror images of one another.

Abstract: A sensor system and method of reducing plasma-induced communication inhibition for a main antenna includes using auxiliary antennas for detecting a density of plasma that affects operation of the main antenna, and re-orienting an electromagnetic field around the main antenna in response to the density detected to reduce effect of the plasma on the main antenna. The auxiliary antennas are also operable for data link communication and switchable such if the density of the plasma inhibits receipt or sending of signals by one of the auxiliary antennas, another one of the auxiliary antennas may be used for data link communication.

Abstract: The present disclosure is directed to a seeker system having an infrared (IR) sensor pedestal, an IR sensor disposed on the IR pedestal and a plurality of radio frequency (RF) antenna elements symmetrically disposed in a circumferential direction around the IR sensor pedestal. The seeker system further includes a plurality of RF waveguiding structures. In an embodiment, each of the RF waveguiding structures have first and second ends and are symmetrically disposed in a circumferential direction around the IR sensor pedestal such that in response to an RF signal incident on a first end of the waveguiding structure, the RF signal is provided to one of the plurality of RF antenna elements such that in response to an RF signal incident on the seeker system from any direction, each of the plurality of RF antenna elements receive the RF signal with a desired phase characteristic.

Abstract: A sensor system and method of reducing plasma-induced communication inhibition for a main antenna includes using auxiliary antennas for detecting a density of plasma that affects operation of the main antenna, and re-orienting an electromagnetic field around the main antenna in response to the density detected to reduce effect of the plasma on the main antenna. The auxiliary antennas are also operable for data link communication and switchable such if the density of the plasma inhibits receipt or sending of signals by one of the auxiliary antennas, another one of the auxiliary antennas may be used for data link communication.

Abstract: A missile includes a radar system that has a radome through which a main antenna sends and receives signals. The radome includes a radome body and a radome tip include different transmissive materials, with for example the radome body primarily made of a lossy optically nontransparent material, and the radome tip primarily made of a lossless (permittivity with low imaginary part) glass material that may also be optically transparent. A laser may be used in conjunction with the radome to send and receive encoded signals. The laser may be located behind (aft of) the main antenna, and one or more optical fibers may extend into and/or along the radome to guide laser signals to the radome tip. The laser may be used to emit encoded signals so as to allow multiple radar systems operating in the same area at the same time to discriminate between different targets.

Abstract: Virtual Aperture Radar (VAR) imaging provides terminal phase radar imaging for an airborne weapon that can resolve multiple closely-spaced or highly correlated scatterers on a given target with a single pulse to provide an aimpoint update at a useful range to target without training data and without requiring a large aperture antenna. VAR imaging exploits the sparse, dominant-scatterer nature of man-made targets. The array manifold is constructed with a large number of basis functions that are parameterized by range or angle (or both) to target. The number of basis functions extends the capability to resolve scatterers beyond the Rayleigh resolution. However, this also makes the manifold underdetermined. A sparse reconstruction technique that places a sparsity constraint on the number of scatterers is used to solve the manifold to uniquely identify the ranges or angles to the scatterers on the target.

Abstract: A missile radar system includes a tapered radome covering a front face of a main antenna. A calibration antenna is the combination of a metal tip and an attached one or more radiating or excitation elements (monopole) on the tip. A narrow end (wedge) of the radome may aid in directing planar calibration waves toward the main antenna. The metal tip has a curved inner surface that acts, with the attached radiating element(s), as an aperture antenna. Signals are emitted from the calibration antenna back toward the front face of the main antenna. The signals pass from the tip/reflector to the front face of the main antenna through a substantially-metal-free and substantially-dielectric-free volume defined by the inner surface of the radome. The radar system allows for calibration of the antenna prior to launch and/or during flight of the missile.

Abstract: Virtual Aperture Radar (VAR) imaging provides terminal phase radar imaging for an airborne weapon that can resolve multiple closely-spaced or highly correlated scatterers on a given target with a single pulse to provide an aimpoint update at a useful range to target without training data and without requiring a large aperture antenna. VAR imaging exploits the sparse, dominant-scatterer nature of man-made targets. The array manifold is constructed with a large number of basis functions that are parameterized by range or angle (or both) to target. The number of basis functions extends the capability to resolve scatterers beyond the Rayleigh resolution. However, this also makes the manifold underdetermined. A sparse reconstruction technique that places a sparsity constraint on the number of scatterers is used to solve the manifold to uniquely identify the ranges or angles to the scatterers on the target.

Abstract: A missile radar system includes a tapered radome covering a front face of a main antenna. A calibration antenna is the combination of a metal tip and an attached one or more radiating or excitation elements (monopole) on the tip. A narrow end (wedge) of the radome may aid in directing planar calibration waves toward the main antenna. The metal tip has a curved inner surface that acts, with the attached radiating element(s), as an aperture antenna. Signals are emitted from the calibration antenna back toward the front face of the main antenna. The signals pass from the tip/reflector to the front face of the main antenna through a substantially-metal-free and substantially-dielectric-free volume defined by the inner surface of the radome. The radar system allows for calibration of the antenna prior to launch and/or during flight of the missile.

Abstract: A missile includes a radar system that has a radome through which a main antenna sends and receives signals. The radome includes a radome body and a radome tip include different transmissive materials, with for example the radome body primarily made of a lossy optically nontransparent material, and the radome tip primarily made of a lossless (permittivity with low imaginary part) glass material that may also be optically transparent. A laser may be used in conjunction with the radome to send and receive encoded signals. The laser may be located behind (aft of) the main antenna, and one or more optical fibers may extend into and/or along the radome to guide laser signals to the radome tip. The laser may be used to emit encoded signals so as to allow multiple radar systems operating in the same area at the same time to discriminate between different targets.

Abstract: Systems and methods of tracking a beam-aspect target are provided. In embodiments, a target is tracked with a Kalman filter while detections are received. After a detection is missed, the Kalman filter may be concurrently propagated with a blind-zone particle filter until a probability that the target is in a blind zone exceeds a threshold. When the probability exceeds the threshold, the Kalman filter may refrain from further propagating. After a gated detection is received, the blind-zone particle filter and an unrestricted-zone particle filter may be concurrently propagated while a probability that the target is in an unrestricted zone exceeds a threshold. The system may return to tracking with the Kalman filter when a covariance of the unrestricted-zone particle filter falls below a predetermined covariance.

Abstract: Systems and methods of tracking a beam-aspect target are provided. In embodiments, a target is tracked with a Kalman filter while detections are received. After a detection is missed, the Kalman filter may be concurrently propagated with a blind-zone particle filter until a probability that the target is in a blind zone exceeds a threshold. When the probability exceeds the threshold, the Kalman filter may refrain from further propagating. After a gated detection is received, the blind-zone particle filter and an unrestricted-zone particle filter may be concurrently propagated while a probability that the target is in an unrestricted zone exceeds a threshold. The system may return to tracking with the Kalman filter when a covariance of the unrestricted-zone particle filter falls below a predetermined covariance.

Abstract: A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component; extracting from the imaginary component information representative of the phase component of the return signal; and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal; performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels); and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly.

Abstract: A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component; extracting from the imaginary component information representative of the phase component of the return signal; and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal; performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels); and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly.

Abstract: A radar antenna for a guided missile is calibrated in flight using a point source of microwave radiation and a lens to emulate a far field source. The microwave source and lens fit behind a metal cap at the leading end of the radome and so do not adversely affect the radar. A variety of techniques to power the point source are disclosed, and a variety of lens arrangements are disclosed. The invention allows a radar antenna to be calibrated in flight, and so insures against mis-calibration due to aging components as well as the heat and mechanical forces associated with storage and/or launch of the missile.