Abstract: A precise automated work system and method is provided. One or more self-navigating robots can perform automated work operations with precision given six degrees of freedom in a undulating, sloping or irregular terrain, such as, a commercial truck garden. A self-propelled robot moves through the garden and performs gardening tasks following a specified course by dead-reckoning and periodically determining its position and orientation by a navigation fix. At least seven navigation beacons are positioned around a perimeter of a garden work area. Each beacon emits electromagnetic radiation across the garden for detection by the self-propelled robot. A panoramic image collector gathers and focuses electromagnetic radiation from each navigation beacon on an electronic camera to form at least seven beam spots.

Abstract: An ice measurement instrument includes a waveguide operating in a transmission mode passing energy from an input port to an output port. The resonant frequency of the waveguide depends on the presence and/or thickness of ice at a measuring location. The energy applied to the input port is swept in frequency from a first frequency to a second frequency at or above an ice-free resonant frequency of said waveguide, and back to said first frequency. Energy received at the output port is peak detected to provide a detection signal with four recognizable transitions identifying a pair of peaks which correspond to the resonant frequency of the waveguide. The time delay between these peaks can be used, in comparison with the time delay corresponding to an ice-free condition, to determine ice thickness.

Abstract: A system for indicating ice thickness and rate of ice thickness growth on surfaces is disclosed. The region to be monitored for ice accretion is provided with a resonant surface waveguide which is mounted flush, below the surface being monitored. A controlled oscillator provides microwave energy via a feed point at a controllable frequency. A detector is coupled to the surface waveguide and is responsive to electrical energy. A measuring device indicates the frequency deviation of the controlled oscillator from a quiescent frequency. A control means is provided to control the frequency of oscillation of the controlled oscillator. In a first, open-loop embodiment, the control means is a shaft operated by an operator. In a second, closed-loop embodiment, the control means is a processor which effects automatic control.