SBIR-STTR Award

The acquisition of post boost phase vehicles and/or individual reentry vehicles by an infrared sensor on board a small g hardened projectile which subsequently homes on and impacts its target offers an attractive approach for reentry vehicle kinetic energy kill. The acquisition, tracking, discrimination and guidance functions required of such an IR sensor result in a number of critical issues. The sensor acquisition range is of primary importance and if extended significantly can provide dramatic performance improvement and over_ all system cost reduction. Acquisition range is limited primarily by hard earth background (both dc and clutter) and the detection algorithms used to identify targets. Sensor waveband optimization for reducing hard earth background as well as extended MTI (moving target indicator) algorithms are proposed for this investigation. Extending projectile acquisition range will increase total divert capability subsequently relaxing both handover error volume and launcher pointing accuracy requirements.

Long range acquisition of cold hardbody targets against the infrared earth background is a critical function required for an advanced kinetic energy weapon (kew) sensor. This acquisition process involves extraction of targets from backgrounds whose radiance means and standard deviations are many times that of the target. In the previous research phase, the potential of moving target indicator (mti) algorithms was developed and demonstrated as were simple spatial filters for extending acquisition range by a factor of 4 to 5. In addition, an infrared earth background model based on measured data in the 4.3 micrometer region was developed for testing acquisition algorithms and was integrated with the engagement generation software. In the current research phase, broad characterization and expansion of the mti algorithms is being extended to cover time of day, time of year, latitude/longitude, and spectral region variations. To fully validate the acquisition algorithms, a full parameterization of the set of acquisition algorithms is being performed in terms of probable false alarm versus probable detection curves over each of six spectral regions. Extending acquisition range of the projectile will increase total divert capability, thereby, relaxing handover error volume and launcher pointing accuracy requirements.