Abstract: A portable compass comprises a body (18) and a compass needle (22) mounted on the body for indicating North/South. A bearing signal representing a required bearing is received, for example from a GPS receiver, and a display (30) responsive to the bearing signal receiving means indicates a required position of the compass needle relative to the body. A fixed indicator (26) on the body points to the required bearing when the body is oriented so that the compass needle is in the required position relative to the body.

Abstract: The present invention relates to a device for determining a time and/or direction for prayer, comprising: receiving means for receiving signals indicative of a position on or above the earth; computing means for computing a time for prayer on the basis of the received signals; and display means for displaying a computed time for prayer, characterized in that the receiving means are adapted to receive GPS signals coming from satellites, that the computing means are adapted and connected to the receiving means such that the desired prayer direction on the basis of the position as well as the desired time for prayer are computed directly from the GPS signals, and both are displayed on a screen of the display means.

Abstract: A timepiece (7) including hands (4, 5), direction determining means (10, 11, 14, 12) including data input means (14) arranged for inputting the geographical coordinates of a “target” location in data processing means (12). This timepiece is characterized in that said direction determining means are formed of an antenna (10) and a GPS type receiver (11) for determining the geographical coordinates of the location in which said timepiece (7) is situated, and in that the 6 o'clock-12 o'clock axis of said timepiece (7) is used as a reference axis, and in that at least said first hand (4, 5) is arranged so as to be able to indicate the direction of the “target” location with respect to said reference axis. Such a structure is improved in that it does not need to refer to magnetic north to determine the direction of the “target” location.

Abstract: A collision alert system employs combined binaural acoustic effects combined with optical indicators to direct the attention of a person in a desired direction. The pilot utilizes normal delay and acoustic modification of high frequencies to determine roughly the direction to look for the target. A corresponding optical indicator is energized in a position corresponding to the target angle to confirm and refine the angle to the target.

Abstract: A personal direction finding apparatus for determining the direction to be followed in order to reach a predetermined spot which includes a headset provided with two earphones and a circuit for generating a track error signal. The circuit includes a compass supported on the headset for outputting a heading signal corresponding to the heading of the direction of travel, a receiver for a position location and navigation system outputting a signal for the heading to be followed via one output, and a track error computing circuit.

Abstract: A personal direction finding apparatus for sensing electromagnetic, infrared or ultrasound radiation from a source (S) to determine the direction of the source or generate a virtual sound environment. The apparatus is characterized in that it comprises a radiation sensing device (1) worn on the user's head (2) for generating a signal having a variable characteristic depending on the direction (R) of the source (S) relative to the sensing device (1), i.e. the position of the user's head, a receiver (4) optionally provided as a demodulator, a direction signal processing circuit (5) outputting a control signal (x) indicating the angular deviation (a) between the direction of the source (S) and the current position of the sensing device (1), i.e. the user's viewing axis, and two earphones (3d, 3g) placed over the user's ears and connected to the output of the processing circuit (5).

Abstract: A collision alert system employs binaural acoustic effects to direct the attention of a person in a desired direction. In one embodiment, the angular location of a possible collision risk is detected to energize one of a plurality of acoustic generators spaced angularly apart about the cockpit of an aircraft. The Pilot utilizes normal delay and acoustic modification of high frequencies to determine the direction to look for the target. In another embodiment, the pilot wears headphones which inhibit normal binaural direction location. The delay and acoustic modification are simulated before being fed to left and right headphones. In a wired system, the headphone signals are produced off the headphones. The head angular position of the pilot is compensated so that, as the pilot's head is turned toward the simulated target position, the delay and acoustic modification are adjusted to compensate for the actual head position.

Abstract: A hybrid motion tracker captures the motion of a person. Magnetic field sensors and optical sources are placed on a person, each located on different limbs. A fixed transmitter emits electromagnetic energy and infrared light is transmitted from the optical light sources to the fixed optical sensors. The magnetic field sensors sense the magnetic field and a computer calculates each sensor's position and orientation relative to the fixed transmitter. The optical system's Position Sensing Detectors measure the transmitted infrared light and the computer calculates the position and orientation of each optical light source. The position and orientation of each sensor is used to reconstruct the person's motion in real time, which is sent to a host computer. The computer utilizes the optical system which is more precise than the magnetic field system to compensate for the magnetic field system and thereby achieve higher accuracies. The system is a hybrid system using both magnetic fields and infrared light.

Abstract: A method and apparatus for campers, hikers, and hunters enjoying the out-of-doors and nature in the wilderness is disclosed. In the preferred embodiment of the invention the transmitter is adapted to be plugged into the cigarette lighter in a vehicle and is fitted with an antenna which can be magnetically adhered to the roof of the vehicle. The transmitter emits a distinctive warble tone. The receiver is configured with a telescoping antenna and an audio level meter to more accurately determine the direction of maximum signal strength. The apparatus is inexpensive, as well as being simple and convenient to use.

Abstract: An automatic apparatus and relevant method for discovering and designating air targets constituted by a transmitter assembly which can be associated with a radar and connected via radio with a portable receiver assembly. The portable receiver assembly is further constituted by a headset unit, an auxiliary terminal and a receiver unit with a satellite system and data processing electronics.The headset unit includes an earphone and a Magnetic North sensor and is connected with the receiver unit. The portable receiver assembly can orient an operator, by means of audio signals, towards the direction of provenance of a selected target and supply her/him with information relevant to the target by means of sound messages, e.g., digitalized voice.

Abstract: A system for the instantaneous determination of the frequencies and angles of arrival of a plurality of simultaneously incoming signals. The system includes beam network matrix for receiving the simultaneously incoming signals, the matrix providing one or more superimposed output signal which includes phase information associated with the angles of arrival of the signals. The system uses a Fourier receiver which includes a sampler means for periodically producing a sample of the superimposed output signals and a frequency differentiator for differentiating the sample by frequency into a train of discrete waveforms. Each of the train of discrete waveforms is associated with one of the incoming signals and includes phase information associated with one of the incoming signals. The Fourier receiver further includes a mechanism for determining frequency which determines from one of the train of discrete waveforms the frequency of one of the incoming signals.

Abstract: A position/navigation device (10) and method is disclosed wherein a waypoint apparatus (11-14, 18, 43) sequentially designates and stores a continuous ordered sequence of n waypoints corresponding to positions of the device (10). Route and route reversal apparatus, (11-14, 18, 44) selects the stored sequence of n waypoints as a group without designating individual waypoints and forms a reverse route by reversing the order of the stored waypoints. Navigation means (14, 15, 18, 45) provides navigation information to an operator of the device (10) for following the reverse route to each of the n waypoints.

Abstract: In a radio signal detecting system, an antenna is rotatably mounted on a wrist watch type case, and this antenna is manually rotated to receive a radio signal reflected from a target to be distance-measured every time the antenna is rotated by a preselected rotation angle. The reflected radio signal is digitally converted into field strength data, or distance data. These field strength data, or distance data are sequentially stored into a memory circuit in correspondence with the rotation angle of the antenna. Since the data stored into the memory circuit at every rotation angle for the antenna are displayed on a liquid crystal display unit, the radio signal detecting system can be made compact and operated under low power consumption.

Abstract: A passive emitter location system is capable of performing emitter location autonomously from a single airborne observation platform and includes a bearing measurement system, a system for measuring doppler induced frequency shifts, and means for estimating the emitter location based on non-simultaneous measurement of the bearing and frequency using extended Kalman filters preferably initialized by a single measurement delayed initialization procedure.

Abstract: A method and apparatus for determining the position and orientation of a remote object relative to a reference coordinate frame includes a source having a plurality of field-generating elements for generating electromagnetic fields, a drive for applying, to the generator element, signals that generate a plurality of electromagnetic fields that are distinguishable from one another, a remote sensor having a plurality of field-sensing elements for sensing the fields generated by the source, and a processor for processing the outputs of the sensing elements into remote object position and orientation relative to the source reference coordinate frame. The processor compensates the position and orientation values as a function of displacement of either the field-generating elements from a common center, or the field-sensing elements from a common center, or both.

Abstract: A very high frequency omni-range (VOR) receiver for use in aircraft radio-navigation, which provides an indication of course deviation that is substantially immune to effects such as reflections in transmitted VOR signals, transients occurring in an aircraft's electrical system and propeller and/or rotor modulations of an incoming VOR signal and the like which are all unrelated to actual course deviation, is disclosed. The receiver phase synchronizes a signal from a 1.08 MHz crystal oscillator to a 30 Hz reference signal and a 30 Hz variable signal; both the reference and variable signals are received from a VOR ground station. As a result of the phase synchronization, the receiver produces timing pulses which are accurately phase synchronized to a synchronized reference pulse stream derived from the 30 Hz reference signal. Additionally, the receiver produces a synchronized variable pulse stream that is derived from the 30 Hz variable signal.

Abstract: An electronic direction finder (10) includes a navigation receiver (28) and a compass (32) to generate a bearing signal that indicates that direction of a desired destination. The bearing signal is received by a display driver (34) which causes an electronic display (14) to generate a visible image of a rotatable pointer that points in the direction of the user's desired destination. Preferably, the display also shows an electronic compass card indicating the direction of north.

Abstract: A microwave signal detector system provides a visual indication of the relative bearing of a remote source of microwave energy. An antenna for receiving said microwave energy includes a plurality of microwave-sensitive elements arranged in a planar circular array for receiving pulses from all azimuth directions. Each microwave sensing element is adapted to monitor energy received in a predetermined angular sectors and includes a horn element and a microwave energy responsive diode disposed within said horn element. The diode is connected as part of a voltage divider to develop a noise signal corresponding to the microwave energy received at each sector resulting from vibrations in the diode which occur at an audio frequency. The resultant developed noise signal is digitized and compared to a predetermined threshold to provide an output control signal when the developed signal exceeds the value of the threshold. The output signal drives an LED indicator.

Abstract: The present invention concerns an apparatus and method for measuring the azimuth and elevation of an object. The apparatus includes a platform; a base plate arranged to the construction of the platform rotatably in a plane, which is essentially horizontal; a sensor frame attached to the base plate; at least three sensor elements attached to the sensor frame; and an electronics unit for the control of the sensor elements, capable of performing the processing of signals received by the sensors. The sensor frame is rigidly attached to the base plate and the directional pattern of the sensor elements is such as to cover the entire angle span of interest in the elevation plane, while the pattern covers an essentially narrower angle in the azimuth plane. The direction finder does not easily lose the tracked object performing movements particularly in the elevation plane.

Abstract: A receiver selects and amplitude demodulates an RF signal from one of a pality of directional antennas. The demodulated signal is then delayed to put it in time synchronism with the same signal information from an omnidirectional antenna. A signal is then generated of the peak pulses of the demodulated signal when the pulses are in time synchronism with pulses from the omnidirectional antenna. A control indicator receives the peak pulses along with periscope bearing signals and ship's heading signals and gives an r,.THETA. display of the amplitude of the RF signal selected from the directional antenna at the periscope true bearing angle.

Abstract: A signal processor for radar systems having phased array antenna structures. The processor determines the angle of arrival of the signal from a discrete energy source. The separate elements or output ports of the antenna structure are sampled to form a matrix of signal values. These values are converted into polynomial expressions consistent with one of the spectral estimating methods of maximum entropy, maximum likelihood, and thermal noise. The roots of the polynomial expressions are found and compared to the distance of the unit circle in a pole-zero diagram. Roots sufficiently close to the unit circle are selected as representative of the source signal peaks and the angular directions to such sources are determined by the corresponding angular location of the selected roots in the pole-zero diagram.

Abstract: In a direction finder operating according to the Watson-Watt principle and having two separate receivers (3, 4) of the same type and of simple construction for the signals of the two crossed directional antenna systems (A, B, C, D), the vectorial simulation signals VN in a transmission line for intermediate frequency antenna signals are compared to vectorial rectified signals VV in order to compensate the phase shift caused in both receivers by means of an adjustable phase shifter (21). The vectorial signals VV are selectively derived from the antenna signals as sum signals or difference signals. In one embodiment, a reconstructed phase signal is obtained by reverse pulse control in a direction finding ellipse generator (24, 25) having two outputs on the basis of the difference between the vectorial rectified signal VV and the rectified vectorial simulation signal VN.

Abstract: A radio direction finding system comprises a receiving portion for receiving a radio signal and a direction determining portion coupled to the receiving portion for developing a direction signal corresponding to the direction of arrival of a received radio signal. A memory is also provided for storing direction data corresponding to the direction of arrival of at least one received radio signal, and a control circuit is coupled intermediate the direction determining portion and the memory for producing direction data corresponding to the direction signal for storage by said memory. In accordance with a further aspect of the invention, an indicator is provided for actuation by the control circuit to produce an observable indication of the direction of arrival of a received radio signal, and the direction finding system further includes an EPIRB detector portion for producing an EPIRB reception signal in response to reception of an EPIRB signal.