RPU Technology

SBIR Project Overviews

1996 Phase I SBIR (MDA): Spatial Modulation Sensor for Target Detection in Clutter

In 1996 RPU Technology received a Phase I SBIR from BMDO (now MDA) to investigate a new type of IR staring sensor (Spatial Modulation sensor) for small target detection in clutter using a much lower density (and physically much smaller IRFPA) than would otherwise be needed. In a computer simulation of the Spatial Modulation sensor an average gain of 50:1 in target-to-clutter was demonstrated over a set of 20 clutter images, relative to a conventional sensor covering the same WFOV with the same IRFPA.

In 1997 RPU Technology formed a relationship with Aerodyne Research Inc. Billerica, MA to jointly pursue applications of Spatial Modulation technology (with royalty rights for RPU Technology). In 1998 and 1999 they received Phase I and Phase II awards from the USAF (AFRL) to apply this technology for missile approach warning. A real time staring IR Spatial Modulation sensor (SIRSMS) was developed covering a 90-degree FOV at 1 mr optical resolution using only a 256x256 IRFPA (6 mr detector resolution). (Patent Pending)

The detection-in-clutter performance of the Spatial Modulation sensor (without any spatial filtering) is equivalent to that of a high-resolution conventional sensor (1 mr resolution) having a 1,536x1x1536 IRFPA, plus a processing intensive high pass spatial filter. Because the IRFPA is much smaller, much less cryogenic power is needed. SIRSMS was successfully demonstrated from the tower at Bldg 620 at WPAFB against small targets in urban clutter at 5 km. A flight test program was funded by the Missile Development Agency (MDA).


IRST WFOV high-resolution target detection, particularly in the LWIR band (for which large format IR detector arrays may not be affordable or available)
Missile Approach Warning Spatial Modulation makes high resolution IR Missile Approach Warning over a WFOV (e.g. 4π) affordable for protection of military and civilian aircraft because of the greatly reduced IRFPA density (e.g. 6x6 lower)
Foveated sensors In a foveated image sensor a multi mega pixel detector array senses the scene at high resolution. The selection of small ROIs is performed at low pixel density. The small ROIs are displayed (or relayed) at high resolution. Low pixel density Spatial Modulation is much more effective for the critical task of ROI detection than conventional low resolution