Abstract: An inexpensive, reliable apparatus and method for autonomously monitoring, measuring the incident level, recording, comparing, reporting, and optionally displaying an indication of intentional or unintentional low-power interfering signals or emissions, including naturally occurring emissions and reflections, as received at the input of an operating system. A particular application of this invention is to monitor, measure, record, compare, report and optionally display an indication of low level interference in the L1 and L2 bands of operation of the NAVSTAR Global Positioning System (GPS). The received signals in L1 and L2 bands are compared to a reference received signal in a third band. This comparison provides a sensitive means to detect the presence of an interfering emission or signal in the L1 band or the L2 band via canceling out the variation in the radiometric scene temperature. The reported data are used for dynamic decision making.

Abstract: An improved buoyancy compensator that reduces the scuba diver's attention and exertion required for buoyancy control and vertical propulsion. The buoyancy compensator, which includes an electronic sensor/valve assembly and a flexible air bladder, automates and controls the vertical motion of the scuba diver. An embedded computer acquires pressure, temperature, and air flow sensor measurement data to determine the diver's vertical motion and the amount of the air in the bladder. The computer controls electronic fill and release valves to change the bladder air volume. Algorithms are implemented, by the computer, to automate controlled vertical propulsion for ascending and descending, neutral buoyancy maintenance, and surface operation. Automated transitions are provided between modes of operation and for a timed safety stop during the ascent from the dive.

Abstract: The detection, by doppler frequencies in reflected wave energey, of an obt, such as an obstruction on a landing surface approached along a path at a shallow angle to the surface, using doppler frequencies returned from a fixed range. The frequencies returned by the surface and the obstruction are distinguished by their relation to a threshold frequency determined by the velocity along the path and the angle. Returns from the surface as the angle of incidence at the fixed range increases from the initial normal angle of incidence are minimized by selection of the carrier frequency, and clutter is rejected by ignoring a return at the fixed range that does not correspond to a subsequent return at a nearer range.