Abstract: An autopilot system includes a navigation application for computing angular position and angular turn rate of a pilot line and an autopilot steering application for calculating steering commands for a ship steering device. The pilot line provides directional guidance to a ship and is a vector having one end attached to a point on the ship and a second end pointing to a desired direction. The autopilot steering application receives the computed pilot line angular position and angular turn rate and calculates angular position steering commands for the steering device. The steering commands are calculated by taking into account the difference between the pilot line angular position and the ship's angular position and the difference between the pilot line angular turn rate and the ship's angular turn rate.

Abstract: An autopilot system includes a navigation application for computing angular position and angular turn rate of a pilot line and an autopilot steering application for calculating steering commands for a ship steering device. The pilot line provides directional guidance to a ship and is a vector having one end attached to a point on the ship and a second end pointing to a desired direction. The autopilot steering application receives the computed pilot line angular position and angular turn rate and calculates angular position steering commands for the steering device. The steering commands are calculated by taking into account the difference between the pilot line angular position and the ship's angular position and the difference between the pilot line angular turn rate and the ship's angular turn rate.

Abstract: A marine radar system having a multi-plane video memory for storing scan-to-scan integrated video data used to raster scan the CRT. A scan converter generates cartesian or x,y addresses for the video memory and synchronous with the generation of each, x,y address, generates a range address for reading corresponding video data from an r,.theta. or polar memory. The x,y addresses are generated along azimuth sweeps by incrementing one coordinate by a pixel unit and the other coordinate by a trigonometric function. The unit coordinate and the trigonometric function are determined by the 45.degree. octant in which the azimuth sweep is located. The pixel unit incremented coordinate is offset by one pixel unit from the origin of the azimuth sweep in alternate octants to address pixels along the octant boundaries and thereby avoid display artifacts.

Abstract: A pulse marine radar system having a threshold generator providing a range dependent threshold waveform which is a function of sea conditions, rain conditions, and radar parameters. Based on the radar settings and inputs from the operator regarding the sea and rain conditions, a processor uses a mathematical model to compute the mean of sea clutter, rain clutter, and receiver noise for each of a plurality of successive range intervals. In response to the mean values, a generator generates a range dependent piecewise linear analog waveform which is subtracted in range sychronism from the receiver video. Next, the video is filtered. For each range interval, the processor also calculates a threshold based on the probability of sea clutter, rain clutter, and receiver noise exceeding the threshold after subtracting the mean. In response to the threshold values, a generator generates a piecewise analog signal which is compared with the output of the filter to digitize the radar video.

Abstract: A radar system having a raster scan memory storing scan-to-scan integrated true motion stabilized data. A scan converter generates x,y addresses along azimuth sweeps from the x,y coordinates of own-ship relative to an arbitrary true reference origin. Accordingly, as own-ship moves, the initial x,y coordinates for the azimuth sweeps are continuously being updated. For each x,y coordinate generated, the scan converter also generates a range address for reading corresponding video data stored in polar coordinates relative to own-ship. The x,y coordinates are coupled to a PROM which rolls over the x,y coordinates that are outside of the x,y address field of the memory thereby enabling the addressing of the memory for storing data derived from corresponding polar coordinate video data. Data in the memory is used to raster scan a visual display. The memory is organized into a plurality of planes wherein the data for each pixel of the display is derived from a plurality of bits that are scan-to-scan integrated.

Abstract: A digital memory system is described wherein a plurality of digital storage sections are simultaneously fed by an analog signal. Each storage section is adapted to store a sample of such analog signal in response to a pulse. Trains of pulses are fed to the storage sections, the pulses in each train being displaced in time from a succeeding train an amount T/n where n is the number of storage sections and T is related to the bandwidth of the analog signal.

Abstract: A bright display radar system having anticollision capabilities in which received signals are digitized at a rate determined by a radar range setting and displayed at a constant relatively slow rate independent of the range setting. A computer based anticollision unit operates in response to the relatively slow digitized received signals so that targets may be tracked equally well at short and long ranges. Two sets of operator actuable switches are provided for controlling the anticollision unit. A first set of switches is provided which correspond directly to the most commonly used computer operating functions. The second includes an alphanumeric keyboard which may be used to actuate subroutines stored in a physically separate read-only memory which operates only in response to the alphanumeric keyboard.

Abstract: A system for digitally storing samples of an analog signal taken at a sampling rate, f, and for reconstructing said analog signal from such stored samples. The analog signal is separated into a plurality of, n, channels, each one of such channels having a digital storage section. Each one of the storage sections is adapted to store a sample of the analog signal in response to a sampling pulse. A pulse generator circuit is provided and supplies one of a plurality of trains of periodic sampling pulses to a corresponding one of the plurality of storage sections. The sampling pulses in each of the trains of sampling pulses have a pulse repetition frequency, f/n. Further, the sampling pulses in successive trains thereof are delayed in time 1/nth the period of the sampling pulses. Apparatus is provided for retrieving the samples stored in the plurality of storage sections in the same sequence as such samples were stored.

Abstract: A radar system in which the time duration of video pulses corresponding to echo returns is increased as a direct function of the range of the return. On a PPI visual indicator, the visibility of long range targets is thus enhanced by increased size without distorting the display of short range targets and clutter.

Abstract: A bright display radar system having anticollision capabilities in which received signals are digitized at a rate determined by a radar range setting and displayed at a constant relatively slow rate independent of the range setting. A computer based anticollision unit operates in response to the relatively slow digitized received signals so that targets may be tracked equally well at short and long ranges. Two sets of operator actuable switches are provided for controlling the anticollision unit. A first set of switches is provided which correspond directly to the most commonly used computer operating functions. The second includes an alphanumeric keyboard which may be used to actuate subroutines stored in a physically separate read-only memory which operates only in response to the alphanumeric keyboard.

Abstract: A variable range marker processing device for use with a PPI radar with digitized video displayed in non-real time. The position of the range marker is initially operator determined by rotation of a knob mechanically linked to an optically encoded disc. Optical sensors produce a digital output indicative of the disc rotation angle and range mark position as a distance from the center of the radar display screen. A counter is preset with the digital output at the start of each sweep and decremented once each range cell until a count of zero is reached at which time an unblanking pulse is produced. A numeric display of range is produced by dividing the number of range cells to the range mark by the range setting, scaling according to chosen units of measure, and displaying the result with a LED display, the computations being performed by a processor controlled by a permanently programmed memory. The range mark stays on target as the range scale is changed.

Abstract: A radar system with improved display brightness in high ambient lighting conditions and with simplified deflection and video amplifiers. The incoming radar return signals are digitized and stored in shift registers with the timing to write the data into the shift registers dependent upon the radar range setting. After the digitized radar return signals have been read into the shift registers, they are read out to the display in a constant time period independent of the range setting. The radar system may be used at closer ranges than was previously possible.

Abstract: A radar system with digitized video having a digital interference rejection circuit for eliminating spiral interference caused by nearby radar transmitters operating in the same frequency band. Video signals from each sweep are stored in a random access memory. A comparison is made between adjacent range cells in the present "live" video signal and the video signal from the previous sweep. The output video signal to the display device is inhibited should the comparison indicate the presence of interference.