A single null miniature direction finder which may be worn on the arm of the user and is fully automatic in operation. Signals from a single loop antenna and a sense antenna are summed; however, the amplitude of the sense signal is adjusted at first and second phase angles and the phase of the sense antenna is automatically switched from the first phase angle to the second phase angle prior to summing to produce either a single null or a no null pattern. These patterns are compared to each other as the user extends his arm horizontally and rotates his body. When the null occurs an indicator gives the relative direction to the transmitter.
A path finder/tracker system for assisting a person in finding the way back to a home base comprising a transmitter having a housing with electronic components therein, the electronic components including a emitter to emit a signal of a predetermined magnitude and frequency, the transmitter couplable to a power source with an on/off switch; and a receiver having a housing with electrical components including associated electrical components to receive the signal of the predetermined magnitude and frequency in the citizen band range tuned to that emitted by the transmitter, an antenna adapted to be retracted to a storage position within the receiver housing and extendable from the front edge thereof in a horizontal plane which is within the plane of the receiver, the receiver also including an array of lights across the front edge and adapted to sequentially light as a function of the strength of the signal received by the antenna whereby when the antenna is pointing directly at the transmitter, a predetermined light will be lit but when not pointed directly at the signal, another light will be lit, a panel to display the distance of the receiver from the transmitter.
A position and direction finding instrument including a single, direction-finding, multimode antenna having at least four (4) arms for receiving RF signals from one or more satellites, a feed circuit connected to the direction-finding antenna for receiving signals from the antenna and for generating mode one and mode two signals, and a global positioning system (GPS) receiver having stored satellite ephemeris data for determining the latitude and longitude (position) of the GPS receiver and comprising electronic processing means connected to the feed circuit for determining a ratio of the magnitudes of the mode one and mode two signals relative to each other to determine a phase difference between the mode one and mode two signals, the electronic processing means determining a forward direction of the instrument from the phase difference between the mode one and mode two signals, the stored satellite ephemeris data, and the latitude and longitude of the GPS receiver.
An apparatus and a system, as well as a method and an article, may include detecting an indication of an amplifier output signal amplitude and responsively adjusting the amplifier input signal phase to reduce a change in the phase of the output signal.
An aircraft mounted pulse radar unit transmits a low-energy, test output pulse and processes the resulting test return signal to determine the VSWR and whether the VSWR exceeds a predetermined threshold. If the VSWR exceeds the threshold, the unit prevents transmission of a nominal energy output pulse which might result in damage to the receiver due to an excessive energy level of the return signal. In one embodiment, the unit uses the VSWR to determine and enable output signals at reduced power levels such that energy levels of any return signals would be insufficient to damage the receiver.
A remote command and control center follows and finds a small object located within the geographic area of coverage of one or more cellular radiotelephone systems. A tagging device, radiotelephone, with a unique identification placed on or in any object will automatically activate when required and emit radio frequency signals, allowing it to be traced and located throughout the nation's cellular radiotelephone system. The radiotelephone accepts and implements commands from the remote command and control center and will ultimately be acquired with the use of a mobile direction finding radio/receiver and antenna set.
