A single receiving aperture used, for example, in an airborne seeker system collects energy for three discrete energy sensors/receivers including a laser spot tracker, an RF (millimeter wave) transmitter/receiver, and an infrared detector. The RF transmitter/receiver is located at the focus of a primary reflector located on a gimbal assembly. A selectively coated dichroic element is located in the path of the millimeter wave energy which reflects infrared energy from the primary reflector to an optical system which re-images the infrared energy on the infrared detector. The outer edge or rim of the primary reflector is deformed so that the incoming laser energy focuses to a location beyond the RF transmitter/receiver. The laser sensor is positioned adjacent the RF transmitter/receiver at this location in a back-to-back orientation. The laser energy is then detected using a secondary reflector and an optical system which directs the laser energy from the secondary reflector to a laser detector.

Tri-mode seeker

A dual-mode target seeking apparatus having a seeker dome defining an aperture and transmissive to microwave frequency energy of a first frequency and to light wave energy at a second frequency and at a third frequency. An optics system within the seeker dome is transmissive to the microwave frequency energy reflective to the light wave energy received via the aperture. A first detector receives the microwave frequency energy via the aperture, and a second detector images a target by the light wave energy of the second and third frequencies via the optics system.

Dual mode target sensing apparatus

An active protection system comprising an ultra wideband (UWB) radar for threat detection, an optical tracker for precision threat position measurement, and a high powered laser for threat kill or mitigation. The UWB radar may use a sparse array antenna and may also utilize Doppler radar information. The high powered laser may be of the optically pumped solid state type and in one embodiment may share optics with the optical tracker. In one embodiment, the UWB radar is used to focus the high power laser. Alternative interceptor type kill mechanisms are disclosed. In a further embodiment, the kill mechanism may be directed to the source of the threat. In a further embodiment, an antenna array is steered by using subarray groups having fixed timing within the group and variable timing from group to group.

System and method for ultra wideband subarray beam steering

A multiple band, polarization diversified antenna system that accommodates a plurality of independent and separate antenna subsystems that share a common aperture and boresight. The antenna system includes a first low-band antenna subsystem for one polarization mode in a low frequency band, a second low-band antenna subsystem for another polarization mode in the low frequency band and a high-band, dual-polarization, dual-reflector antenna subsystem for two high-frequency antenna subsystems having orthogonal polarization modes. The dual-reflector antenna subsystem includes a main reflector, a sub-reflector and a support cone. The two low-band antenna subsystems and the high-band, dual-polarization feed subsystems are all positioned behind the main reflector of the high-band dual-reflector antenna subsystem. The signals transmitted by the high-band antenna are directed towards the sub-reflector and are reflected therefrom to be directed towards the main reflector. The signals are reflected from the main reflector to be emitted toward free space from the antenna system through the support cone. The low-frequency signals pass through the main reflector, the sub-reflector and the support cone. The main reflector, the sub-reflector and the support cone are suitable frequency selective surfaces so that the main reflector and the sub-reflector are reflective to the high-frequency signals and are transparent to the low-frequency signals, and the support cone is transparent to both the high-frequency and low-frequency signals.

Multi-band and polarization-diversified antenna system

A tri-mode co-boresighted seeker including a primary collecting mirror assembly having a parabolic surface and a forwardly located dielectric secondary mirror assembly including a dielectric mirror coating which reflects infrared (IR) energy to an IR detector assembly located on a central longitudinal axis on one side of the secondary mirror while providing substantially unobstructed propagation of millimeter wave RF energy and laser energy in a joint or common signal path therethrough to means located on the other side of the secondary mirror for extracting and diverting laser energy away from the common RF-optical signal path to a laser sensor assembly while causing little or no disturbance to the RF signal as it propagates to a co-located bifurcated waveguide assembly which couples the RF energy to an RF sensor means located behind the primary mirror.

Tri-mode co-boresighted seeker

A multi-spectral seeker system for detecting radiation in the infrared (IR) band and a plurality of radio frequency (RF) bands suitable for use in a guided missile is disclosed. The IR and RF seekers are coaxially integrated on a single gimbaled platform and share a common aperture without significant performance degradation. In the preferred embodiment, the IR seeker uses a Cassegrainian reflector assembly with surfaces reflective to IR but transparent to RF signals. The first RF seeker uses a resonant dichroic reflector antenna which is transparent to RF signals at frequencies no closer than 0.5 octaves from the dichroic reflector system operating frequency. The second RF seeker may use any suitable RF antenna system although a planar-array of multi-mode spiral antennas or a standard flat plate slotted array are preferred. The second RF seeker may operate in an active, semi-active, or passive mode. The IR seeker means and both RF seeker means together provide coaxial seeking in a single aperture covering three frequency bands without significant loss of performance in the RF antenna and IR sensor. The material on which the parabolic reflector is formed is tapered in thickness as a function of radius to eliminate phase delays introduced by the curvature as seen by the second RF seeker.

Richard M. Pietrasz

Papers

Multi-spectral seeker antenna