Abstract: A modular system facilitates alignment of a simulation laser with the sights of a weapon. The modular assembly can be attached to the barrel of a weapon. A user can first align a target relative to the sights of the weapon. The laser can then be aligned with the target.

Abstract: A downward compatible laser transmitter of radiant energy at a 990 nm wavelength. The transmitter is usable with receivers of 905 nm radiant energy. The transmitted beam is less susceptible to humidity or temperature variations than a beam of radiant energy transmitted at 905 nm.

Abstract: A head tracking system combines a plurality of sources of radiant energy, a plurality of sensors and at least one reflective element. As the reflective element moves, various radiant energy beams become incident thereon. The incident beams are reflected to respective sensors thereby providing head position signals.

Abstract: A method of adapting a communication link in a network of radio communication nodes is disclosed. The method includes sending by a first node a first radio communication. The method also includes receiving by a second node the first radio communication. Further, the method includes estimating by the second node the dynamics of the communications channel. Further still, the method includes categorizing the dynamics of the communications channel into one of at least two groups, based on the estimate. Yet further still the method includes selecting, based on the chosen group, the use of either closed loop link adaption or open loop adaption of communication link parameters.