Abstract: The lightning ranging system for determining distance between a lightning discharge and an airborne object includes a receiver on the airborne object adapted to receive electromagnetic radiation signals generated by a lightning discharge along both a direct and a surface reflected path. Signal processing apparatus is interconnected with the receiver for determining the difference in the time of arrival of the direct and reflected signals. A computer is provided to calculate the range of the lightning discharge from the difference in the time of arrival of the direct and reflected signals. In a preferred embodiment, the signal processing apparatus is digital and includes at least a 10-bit analog-to-digital converter with at least a 36 megahertz sampling rate.

Abstract: A method and apparatus for radio position determination is provided including an unknown position transmitter for transmitting a radio wave having compensation for multipath, a plurality of base repeaters having a synchronized pulse for time reference, for receiving the radio wave emitted by the unknown position transmitter and for determining the relative times-of-arrival of the radio wave with respect to the synchronized pulse, and a central monitoring station coupled to the base repeaters for computing from the locations of the base repeaters and from the measured times-of-arrival, a coarse-position fix of the unknown-position transmitter. The system may include a mobile reference transceiver located within the coarse-position fix, for transmitting a reference signal, wherein the central monitoring station generates a differential position from the reference signal and the radio wave for guiding the mobile reference transceiver to the unknown position transmitter.

Abstract: The positions of a non-cooperative emitter (illuminator) and reflector (target) relative to a receiver of electromagnetic energy, which neither directly nor indirectly controls the illuminator, is determined utilizing emissions received directly from the illuminator as well as reflected emissions from the target. A range R.sub.I between the receiver and the non-cooperative illuminator is determined by measuring the time difference between receiving the reflected signals at a pair of interferometer antennas located at the wing tips of a receiver aircraft. Calculation of the location of the target is accomplished by utilizing range R.sub.I, as well as a time differential .DELTA.t between the receipt of the reflected signals at the interferometer antennas and the receipt of a corresponding direct signals at a radar antenna located at the aircraft. In the event there is clutter in the reflected signal which hinders the determination of the time differential .DELTA.

Abstract: A system for detecting the presence and depth of an object submerged in a medium having transmission characteristic substantially different than the atmosphere by means of receiving radiation from lighting incident to a reflected from the submerged object.

Abstract: A position finding and collision avoidance system derives, at an Own station within the service area of an identified SSr at a known location, differential azimuth (A), differential time of arrival (T), identity and altitude data regarding any transponder-equipped Other station or stations within a predeterminable region surrounding Own station, from standard ATCRBS interrogations and replies. These data are used to compute the positions of Other stations for display at Own station.

Abstract: This invention relates to a system for detecting submerged objects by receiving an incident indication of electromagnetic energy and also the reflection of said energy caused by the presence of a submerged object and to comapre the field strength of the incident radiation with the field strength of the reflected radiation to determine the relation therebetween, the relation being a measure of the object location.

Abstract: A method for passively locating in range and azimuth both active, such as radar, and passive objects. The present invention uses existing direction finding equipment located on a platform, such as an aircraft or ship. At the platform, the invention includes measuring the scan period of the radar, the time of intercept of the main beam of the radar, the angle of arrival of the radar main beam, the time of arrival of a bistatic signal echo from a passive object which has been illuminated by the radar, and the angle of arrival of the echo; calculating the difference between the angle of arrival of the echo and the angle of arrival of the radar main beam to obtain an angle .theta.; determining an angle .phi.