Directorate for Engineering

A new approach is proposed which will allow air-to-ground target identification of slow moving vehicles in clutter. A wideband space-time adaptive (STAP) filter for clutter suppression is developed which preserves the target amplitude integrity of returns from multiple range bins within the automatic target recognition (ATR) high range resolution (HRR) approach. The wideband STAP processor utilizes narrowband STAP principles to generate a series of adaptive sub-band filters. The performance of this new approach is demonstrated and quantified through the implementation of a one dimensional template-based minimum mean squared error classifier. Successful minimum velocity identification (ID) is defined in terms of probability of correct ID, probability of false ID of an unknown target, and probability of declaration. The performance of the wideband STAP/ATR algorithm is characterized for various degrees of freedom (DOF).

Missions to surfaces of planetary bodies and asteroids, whether manned or robotic, will encounter dust, soil, and rock fragments, possibly combined with ice, which will affect mechanical operations. Contact with these materials may be incidental or intentional in the case of digging or drilling operations. The complications encountered on the Apollo missions must be resolved before a long-term facility can be established on the lunar surface. In the quest for a manned mission to Mars there are many unanswered questions about the Martian surface and how it will impact the mechanical and life-support operation on the Martian surface. Robotic missions will also encounter the soils and rocks of Mars and interesting asteroids on sample return missions. This paper discusses potential problems associated with mechanical operations in contact with the regolith (soil and rocks). Typical operations that may take place are described as background information and a detailed description or the Martian regolith is presented for background purposes. A companion paper titled "The Impact of Incidental Contact with Regolith in Martian and Lunar Environments," describes the lunar regolith and discusses potential problems contact with the regolith may cause for surface operations Potential problems associated with intentional contact are discussed in this paper along with recommended areas for further research. The paper culminates with a list of recommended research areas, many of which require physical experiments for validation.