Abstract: This invention is concerned with an indicator apparatus for determination of the trajectory or the trajectory direction of a projectile travelling at supersonic speed. It comprises pressure sensitive transducers (T.sub.1 -T.sub.4), which have fixed positions relative to each other or move relative to each other in a defined way, and which are devised to measure the pressure wave generated by the projectile. Also, there are means to produce electrical signals from the transducers, which represent the pressure values sensed by the transducers. Using said signals from each pressure transducer the computing circuits determine a value for a time instance when the pressure wave pass the transducer. From these time values and the geometrical quantities, which specify the position of each transducer in relation to a spatial coordinate system, the computing circuits evaluate the direction of the projectile trajectory more or less accurately.

Abstract: A sonar depth sounder system is provided in which a plurality of elements are combined to form a sonar transducer capable of generating a plurality of narrow overlapping beams and receiving sonar echoes. The sonar return information is filtered, amplified through a log converter, digitized and then analyzed by a high-speed microprocessor. This analysis stage combines information obtained from each one of the plurality of sound beams generated by the transducers, determines correct target location and size, distinguishes fish from other targets such as thermoclines or structure based on heuristic algorithms and provides an output data set for display. Representations of three-dimensional submerged structures are presented in a variety of formats to the user, including utilizing a grid line display of the contour of the bottom surface and location lines from displayed fish above the surface to grid lines on the bottom surface display.

Abstract: An improved microprocessor-controlled sonar depth sounder, which is automatically operative to detect and lock to the bottom of a body of water, fill in the display below the detected bottom, change display scales in response to the detected bottom going off-scale, and reformat the entire display in response to a scale change. A memory is provided for storing target data up to the operable depth limits of the device, thereby allowing display reversing and display expansion or "zoom" of a predetermined portion of the display selected by a zoom cursor. The zoom or cursor is variably positionable at different depths. The device employs an improved variable sensitivity amplifier. Also disclosed is an improved water-resistant switch construction for marine electronic equipment.

Abstract: An improved microprocessor-controlled sonar depth sounder, which is automatically operative to detect and lock to the bottom of a body of water, fill in the display below the detected bottom, change display scales in response to the detected bottom going off-scale, and reformat the entire display in response to a scale change. A memory is provided for storing target data up to the operable depth limits of the device, thereby allowing display reversing and display expansion or "zoom" of a predetermined portion of the display selected by a zoom cursor. The zoom or cursor is variably positionable at different depths. The device employs an improved variable sensitivity amplifier. Also disclosed is an improved water-resistant switch construction for marine electronic equipment.

Abstract: A chart recorder useful in a marine depth sounder or in other applications. Chart paper for the recorder is loaded into a paper cartridge, which is insertable in the recorder. The paper cartridge supports a roll of chart paper, a takeup spindle for winding the paper, and a viewing surface across which the paper travels after data marks are recorded on the paper. An internally-driven roller within the recorder frictionally engages the takeup spindle when the cartridge is in place, so as to move the chart paper at a selected linear speed. The drive roll is operated by an electric motor and a multiple-stage compound reduction gear arrangement, all entirely contained within the drive roller.The paper marking stylus of the recorder makes full-time contact with a stylus engaging surface throughout each revolution of the stylus drive belt. An inductive sensing device is located between sides of the drive belt, and senses a magnet carried on the outside of the belt.