Publications

In multispectral imaging, automated cross-spectral (band-to-band) image registration is difficult to achieve with a reliability approaching 100%. This is particularly true when registering infrared to visible imagery, where contrast reversals are common and similarity is often lacking. Algorithms that use mutual information as a similarity measure have been shown to work well in the presence of contrast reversal. However, weak similarity between the long-wave infrared (LWIR) bands and shorter wavelengths remains a problem. A method is presented in this paper for registering multiple images simultaneously rather than one pair at a time using a multivariate extension of the mutual information measure. This approach improves the success rate of automated registration by making use of the information available in multiple images rather than a single pair. This approach is further enhanced by including a cyclic consistency check, for example registering band A to B, B to C, and C to A. The cyclic consistency check provides an automated measure of success allowing a different combination of bands to be used in the event of a failure. Experiments were conducted using imagery from the Department of Energy's Multispectral Thermal Imager satellite. The results show a significantly improved success rate.

Abstract not provided.

The concept of building extremely small satellites which, either independently or as a collective, can perform missions which are comparable to their much larger cousins, has fascinated scientists and engineers for several years now. In addition to the now commonplace microelectronic integrated circuits, the more recent advent of technologies such as photonic integrated circuits (PIC's) and micro-electromechanical systems (MEMS) have placed such a goal within their grasp. Key to the acceptance of this technology will be the ability to manufacture these very small satellites in quantity without sacrificing their performance or versatility. In support of its nuclear treaty verification, proliferation monitoring and other remote sensing missions, Sandia National laboratories has had a 35-year history of providing highly capable systems, densely packaged for unintrusive piggyback missions on government satellites. As monitoring requirements have become more challenging and remote sensing technologies become more sophisticated, packaging greater capability into these systems has become a requirement. Likewise, dwindling budgets are pushing satellite programs toward smaller and smaller platforms, reinforcing the need for smaller, cheaper satellite systems. In the next step of its miniaturization plan, Sandia has begun development of technologies for a highly integrated miniature satellite. The focus of this development is to achieve nanosat or smaller dimensions while maintaining significant capability utilizing semiconductor wafer-level integration and, at the same time promoting affordability through modular generic construction.

The Global Verification and Location System (GVLS) is a satellite based communication package proposed for the Global Positioning System (GPS) Block IIR satellites. This system provides the capability to relay bursts of information from small, low power mobile transmitters to command and control facilities. Communication paths through multiple GPS satellites within the field of view allow location of the transmitter using time difference of arrival (TDOA) techniques. Alternately, the transmitter can transmit its own location if known by various other means. Intended applications include determination of the status and location of high-valued assets such as shipments of proliferation-sensitive nuclear materials and treaty-limited items or downed air crews and special operations forces in need of extraction from hostile territory. GVLS provides an enabling technology which can be applied to weapon impact location. The remote transmitter is small and light enough to be integrated into a weapon delivery vehicle, such as a cruise missile, and requires power only during the last second of flight. The antenna is a conformal patch design, therefore minimizing aerodynamic considerations. Precise impact locations are determined by the GVLS system and can be communicated to responsible commands in near real time allowing rapid bomb damage assessment and retargeting without the typical delays of overhead reconnaissance. Since burst data communication is used, weapon status immediately prior to impact can be transmitted providing knowledge of proper arming sequence and other pertinent information. If desired, periodic bursts can be transmitted while in flight, enabling in-course tracking of the weapon. If fully deployed, the GVLS system would consist of communication relays on 24 GPS satellites, five ground stations deployed worldwide, and portable base stations for authorized users to receive and display locations and contents of their transmissions.