Abstract: A mounting device for removably attaching a hand-held electronic instrument to a support surface includes a base adapted to be attached to the support surface. The base has a front surface for engaging the hand-held instrument. A pair of locking arms are attached to the base at laterally spaced locations. Each arm extends generally outwardly from the front surface and has a detent and a finger-engaging area associated therewith. The detents are capable of engaging the hand-held instrument to attach the instrument to the base. The arms have a first position wherein the detents engage the instrument. The arms also have a second position wherein the detents are disengaged from the instrument by an operator actuating the finger-engaging areas.

Abstract: A tapered slot quadrifilar antenna for GPS receivers. The antenna has a cylindrical dielectric body covered with a conductive coating. Four helical slots are formed in the antenna and extend around one half of its circumference to provide a right hand circular polarization for receiving GPS signals. A microstrip feed system is provided and is arranged to create balanced currents along both sides of each slot so that the impedance transformation is not adversely affected. Each slot has a narrow upper end and a wide lower end and a progressively greater width from the narrow end to the wide end.

Abstract: A method and navigation device for abbreviating names of cartographic markers. A navigation device has a processor, a display, an input, and a memory having cartographic data stored therein. The cartographic data includes names of geographical locations. Using the input, an operator of the navigation device enters a waypoint by selecting a desired geographical location. The processor retrieves from memory the geographic name associated with the selected location, and when the geographic name exceeds a desired number of characters, processes the name to abbreviate it to fit within the desired number of spaces. The abbreviation process involves eliminating spaces, vowels, one consonant of a pair of double consonants, one vowel of a pair of double vowels, and/or one or more special characters (e.g., colons, commas, apostrophes, slashes, symbols, or other punctuation marks) as necessary, to reduce the geographic name to the desired number of characters.

Abstract: A system for buffering data has a processor connected to a memory for storing mass data, connected to a single buffer having a plurality of buffer storage locations in a chain, and connected to a plurality of counters, wherein each counter corresponds to one of the buffer storage locations. The processor selects a sector of memory containing desired data associated with an open file, scans the buffer storage locations to determine whether the data is in the buffer and, when the data is not within the buffer, reads the data from the selected sector of memory into a selected buffer storage location that is unallocated to an open file. The processor then points to that allocated buffer storage location, so that the data can be retrieved from the buffer for processing. As additional data is desired that is not found in the buffer, the buffer storage location allocated to the open file is de-allocated and, if not allocated to any other open files, moved to the beginning of the chain of buffers.

Abstract: The storage space required for representing geographic features is reduced by determining an optimum number of bits that can be used to store coordinate data along each separate axis. Any coordinate change that cannot directly fit within the optimum bit size is subjected to an escape sequence made up of one or more special values and a normal value that fits in the optimum bit size. The special values are obtained by a predetermined calculation for each bit size. If all changes for one axis are in the same direction and special values are not needed, a global sign can be used to further enhance use of the available space on the storage medium.

Abstract: An AM radio transmitter utilizes a push-pull MOSFET based design that rejects even-ordered harmonics, and therefore produces minimal electromagnetic radiation. The transmitter contains a low level modulating circuit and a feedback modulation arrangement which linearizes the modulation of the transmitter, and also senses reverse power in the transmitter antenna line, so that the power and modulation can be reduced if the transmitter has a less than optimal load condition existing on an antenna port. A unique modulation amplifier utilizes a Darlington RF pair having an input stage including the collector of the first transistor of the pair, and a pin diode connected to the base of the first transistor of the pair. A radio signal is modulated by varying a voltage on the collector of the input stage, and simultaneously maintaining a constant voltage at an output stage of the Darlington RF transistor pair.

Abstract: A microstrip-fed cylindrical slot antenna is provided for allowing better communication between an object and a satellite. The microstrip-fed cylindrical slot antenna comprises a cylindrical base member; a first conductive coating disposed on the cylindrical base member; at least one slot disposed in the conductive coating, the slot having a helical configuration about the cylindrical base member; and a feed line corresponding to each of the slots, the feed line crossing each respective slot and extending beyond the slot by a distance D.

Abstract: An ergonomic and weatherproof hand-held electronic device 10. The device 10 includes a housing 12 which surrounds internal electronics. An input 28 and a display screen 32 are mounted on the housing 12. The housing 12 is has a narrow width such that, when held in a hand, the thumb of that same hand may extend fully across the input 28 for full access. The display screen 32 is mounted vertically below the input 28 such that the device may be more stable and more easily grasped. The device includes two cylindrical cavities 48 to receive batteries 42. The cavities 48 are located at the rear vertical edges of the housing such that the rear of the housing 12 is relatively rounded and thus easier to grasp. The battery cavities open to the exterior of the housing. A battery cover 54 is mounted to the housing and seals the cavities 48. A contact for each cavity 48 is located on the cover, and a bus bar extends between the contacts to complete the circuit between the batteries 42.

Abstract: An electronic navigation device and method, for displaying a visual representation of navigational information in a selected perspective view, includes a processor, a display, a key pad input, a memory, and an antenna. Navigational information, such as way-points in an active route, hazards and landmarks, and the position, direction, and speed of movement of the navigational device, are entered into the processor. The processor determines a trapezoidally-shaped visible region based upon user inputs, clips the navigational information to the visible region, and transforms the navigational information within the visible region to a selected perspective viewing plane. Polygons, representative of highway lanes, are displayed on the display, in the desired perspective view, for each route leg of a route within the visible region.

Abstract: A sonar depth sounder device, and a method for processing echo signals reflected from objects within a body of water, utilize a processor, a memory, a display, and a keypad connected to the processor. A transmitter excites a transducer which emits sonar pulses into a body of water, and a receiver receives reflected sonar echo signals. Particularly, signals that have reflected from an object suspended in the water have an intensity, a history time duration, and a depth spreading characteristic. The processor compares one or more of the intensity, history time duration, and depth spreading characteristic of the reflected signals with corresponding sets of parameters stored in memory, which sets of parameters are representative of one or more selected objects, cross-talk noise, and unidentifiable noise.

Abstract: A portable electronic device is provided which includes a housing having a front face, a base, and a back wall joined in a polyhedron configuration. The front face includes an input area having keys for data entry and a display area having a screen to illustrate information to the user. The front face, back wall, and base are joined in the polyhedron configuration, such that the front face is presented to the user at an angle to horizontal when the base is mounted upon a horizontal or vertical surface. The front face, back wall, and base are joined at rounded edges to afford a smooth contour which is easily and comfortably grasped within the hand of the user. The portable electronic device further includes a sensor to determine whether the housing is aligned upon a horizontal or vertical axis. This sensor delivers its output to a display control which realigns information displayed upon the view screen to shift the displayed information between vertical and horizontal configurations.

Abstract: A GPS frequency converter is provided, according to the present invention, to down-convert the frequency of an incoming GPS signal. The converter includes first and second mixers, the former of which receives the incoming RF signal and a signal from a local oscillator. The local oscillator signal is increased by a factor of 98 and then subtracted from the incoming RF signal to produce a first intermediate frequency signal (IF). The first IF signal is then passed to the second mixer which subtracts the frequency of the local oscillator therefrom to produce a second intermediate frequency signal (IF). The second IF signal is passed through a limiter and output as the frequency converted signal.

Abstract: An electro-optical display device having an improved connector arrangement. The display device includes a plurality of pixels arranged in commons and segments, with a lead trace associated with each commons and with each segment. These lead traces extend outward from an endmost commons to an edge of the device for subsequent connection to driving apparatus. The set of leads associated with the set of commons extends normally from such set of commons to the proximate edge of the device. The remaining set of leads, associated with the segments, is provided with lead traces which are redirected to also extend towards this same side of the device. As such, all leads for the device are accessible on a single side of the device. This may be accomplished by dividing the remaining set of commons in half, with each of these half-sets of leads being directed to a location on an associated side of the initial leads for the first set of commons.

Abstract: An ergonomic and weatherproof hand-held electronic device 10. The device 10 includes a housing 12 which surrounds internal electronics. An input 28 and a display screen 32 are mounted on the housing 12. The housing 12 is has a narrow width such that, when held in a hand, the thumb of that same hand may extend fully across the input 28 for full access. The display screen 32 is mounted vertically below the input 28 such that the device may be more stable and more easily grasped. The device includes two cylindrical cavities 48 to receive batteries 42. The cavities 48 are located at the rear vertical edges of the housing such that the rear of the housing 12 is relatively rounded and thus easier to grasp. The battery cavities open to the exterior of the housing. A battery cover 54 is mounted to the housing and seals the cavities 48. A contact for each cavity 48 is located on the cover, and a bus bar extends between the contacts to complete the circuit between the batteries 42.

Abstract: A device and method for compensating a crystal oscillator that is not electrically compensated over its operable temperature range. A GPS receiver device stores in memory data indicative of the actual offset frequency of oscillation of the crystal over its operable temperature range. The first time the device is activated, the temperature at the crystal is sensed and data, stored in memory, indicative of the specified frequency offset of the crystal at the sensed temperature is retrieved, and used to control the receiver.backslash.decoder. When the receiver locks onto a sufficient number of satellites to calculate its two-dimensional location, the actual frequency offset of the crystal is calculated and stored in memory. Repeated use of the receiver device permits a database of actual frequency offset data of the crystal, over its operable temperature range to be stored. Subsequent uses of the device permit retrieval of this data for use in locking the receiver onto satellite signals.