Abstract: Optionally, a plurality of spacers 228 is arranged between the planar surface 120 of the interfacing arrangement 114 (or the top horizontal arm) and the seat arrangement 102, for permanently raising the seat arrangement 102 with respect to the interfacing arrangement 114. The spacers 228 can be implemented as rectangular or cylindrical solid blocks that can be fabricated from plastics materials, metals, metal alloys, polymers, ceramics, wood, composites and so forth. The spacers 228 can be fixed between the seat arrangement 102 and the top planar surface 120 of the top horizontal arm of the interfacing arrangement 114 such that height of the seat arrangement 102 relative to the footrest arrangement 116 is raised. For example, a plurality of metallic spacers is fixed between the seat arrangement 102 and the interface arrangement by a technician such as by welding the metallic spacers between the seat arrangement 102 and the interface arrangement.

Abstract: A method for generating a global positioning signal from a space based craft including the steps of generating a plurality of binary modulating signals using a waveform generator; separately modulating an in-phase component of a desired carrier of the global positioning signal to be generated with at least a first binary, modulating signal selected from the plurality to generate at least one corresponding in-phase modulated signal component; separately modulating a quadrature component of the carrier with at least a second binary modulating signal selected from the plurality to generate at least one corresponding quadrature modulated signal component; and, combining the at least one in-phase modulated signal component and the at least one quadrature modulated signal component to generate the global positioning signal; wherein the global positioning signal has a constant envelope.

Abstract: An adaptive acquisition technique is disclosed for enabling the initial acquisition of a received coded signal in a direct sequence spread spectrum system using multiple access codes for code division multiplexing. In order to obtain code synchronization by initial acquisition, correlation of a received code with a reference code is performed by an adaptive serial search over the code phase uncertainty which compares the measured signal correlation levels with two thresholds fixed to have a constant difference. During code signal acquisition, the thresholds are increased each time the measured correlation level exceeds the upper threshold, by an amount which equals the difference between the correlation level and the current upper threshold. Initial code signal acquisition is indicated when the detected correlation level raises the threshold levels to a point after which no further correlation measurements exceed the lower threshold.