Abstract: An autonomous interrogatable information and position device combines the functionality of a satellite communications device capable of sending and receiving voice and digital data messages, a geo-location device capable of self-determining its positional location; an input/output port configured to allow attachment of the device to external local site sensors or equipment in order to obtain external local site sensor data or control the equipment, and a control processor capable of monitoring and responding to positional location information, input sensor data, and incoming voice and digital data messages.

Abstract: A method and system for reducing the sampling rate of a signal for use with high modulation index frequency modulated signals reduces the power consumption and processing requirements of the digital signal processing equipment which performs the demodulation. In a preferred embodiment, a high modulation index FM signal is divided into in-phase and quadrature phase components by a downconverter (FIG. 1, 10). These components are sampled by analog to digital converters (20, 21) and input to a delay element (40, 41). The resulting delayed and undelayed samples are conveyed to downsamplers (60-63) where the sampling rate is reduced. The undelayed in-phase and delayed quadrature phase components are multiplied together by a first multiplier (70) while the undelayed quadrature phase and delayed in-phase components are multiplied together by a second multiplier (71).

Abstract: An apparatus for wide bandwidth analog to digital and digital to analog signal conversion is disclosed. An input/output stage (40) is coupled to an external analog system and includes reference voltages for calibration of the analog to digital (A/D) conversion process. A conversion stage (46), comprising a plurality of A/D converters (ADC) (48, 50) and a digital to analog converter (52), is coupled to the input/output stage and to a digital signal conditioning stage (54) which is coupled to an external digital system. Offset and gain errors in the outputs of each ADC are corrected by the application of appropriate correction parameters in the digital signal conditioning stage. The sampling intervals for each ADC are phased to allow the digital outputs of the ADCs to be interleaved and form a resulting digital data stream with a sampling rate a multiple of that of any one ADC.

Abstract: A method and apparatus for efficiently tracking satellites includes a geosynchronous satellite (10) for transmitting the ephemeris of non-geosynchronous satellites (20, 30) to a ground terminal (50). The ephemeris is computed by the non-geosynchronous satellites (20, 30) or by other means such as a ground station (60). A ground terminal (50) can quickly acquire a non-geosynchronous satellite (20, 30) by receiving fresh ephemeris data from a geosynchronous satellite (10), determining a location of a non-geosynchronous satellite (20, 30), and orienting an antenna.

Abstract: A dual quadrature branchline in-phase power combiner and power splitter provides a low cost and symmetrical structure for combining power from two signal ports (20, 30, FIG. 1) to an output signal port (10). When used as a power splitter, the structure accepts power from a signal port and divides the power equally and in-phase between the output signal ports (20, 30). The structure can be fabricated using microstrip, stripline, or similar technology such as suspended stripline. The structure is well matched over a large bandwidth and provides high isolation between the splitter output signal ports (20, 30).

Abstract: A method and apparatus predicts a ground-to-satellite terminal's (16) percentage of successful communication linkage time to at least one satellite of a communication system in response to a terminal blockage profile (410), as created from the location of an antenna of the terminal, and a satellite blockage profile (412). The prediction may also be based upon a weather model data base (358) corresponding to the area where the terminal is located.

Abstract: A satellite-based air traffic control system utilizes global-coverage satellite communications network to provide voice and data communication between an air traffic control center and one or more aircraft worldwide. Each aircraft is provided with an airborne navigation location reporting system device which has the capability of determining positional information of the aircraft and to transmit and receive voice and data messages to and from the ATC center via the satellite communications network.

Abstract: A battery powered electronic system (50, FIG. 1) is controlled by a movement sensor (20) which senses the acceleration of the electronic system (50). The output of the movement sensor (20) is filtered by an event duration filter (FIG. 2, 120, 121) which determines if the output is of sufficient duration and acceleration to trigger a change in the operation of the electronic system (50). If the acceleration meets the triggering criteria, the electronic system (50) can be made to change an on/off state, an operating mode, or to effect an incremental change in the electronic system (50) such as adjusting the volume or channel setting. Additional movement sensors (20) oriented in different axes can be used to trigger a change in the operation of the electronic system (50) according to a plurality of different directions of acceleration.

Abstract: A linear optocoupler (71) having a light emitting diode (28) and a detector diode (29) formed on a common semiconductor substrate (33). Light emitted by the light emitting diode (28) is transmissive to semiconductor substrate (33). A layer of light reflective material (34) is formed on a side opposite from which the light emitting diode (28) and the detector diode (29) on the semiconductor substrate (33). A portion of light emitted by the light emitting diode (28) transmits through the semiconductor substrate (33) to be reflected by the layer of light reflective material (34). The reflected light transmits through the semiconductor substrate (33) to be received by the detector diode (29). A photo detector diode (61) and the semiconductor substrate (33) including the light emitting diode (28) and the detector diode (29) are mounted on a lead frame (51) co-planar to one another. A light flux coupling media (76) couples light from the light emitting diode (28) to the photo detector diode (29).

Abstract: A survival radio of the type useable in search and rescue operations and carried by the party to be rescued is described. The survival radio includes a GPS receiver, a transceiver and a microcontroller. The microcontroller responds to interrogation messages containing a predetermined identification code for the survival radio to cause a transceiver to transmit a geographic location of the survival radio as derived from GPS signals.

Abstract: An advanced signal processing technique accurately discriminates and estimates a small sinusoidal signal in close proximity from one or more large sinusoidal signals. The technique involves using digital processing techniques to accurately estimate the frequency (96), amplitude (94) and phase (98) of the one or more large sinusoids and then using this estimate to obtain an accurate estimate of the small sinusoidal signal by subtracting the large sinusoid from the data to obtain a residual and reprocessing the residual.

Abstract: In a GPS receiver, power is conserved by powering down P-code circuitry during and utilizing C/A code circuits during times when interfering signals, such as spoofing signals, are not detected. When spoofing is detected, the P-code circuitry is powered up so that the GPS receiver can continue to operate in the presence of spoofing.

Abstract: A secure, portable position locating radio has a geolocation receiver providing local position and timing information from geolocation means (e.g. GPS satellites) and a local transceiver for sending local position information to a communication system (e.g., an airborne or orbiting transceiver). A crypto unit is provided between the receiver and local transceiver for encrypting the local position information prior to transmission. A data processor coupled to the local transceiver, receiver and crypto unit controls operation of the device, including storing local position information and separating signals broadcast by the communication system into those intended or not intended for the device. An external interface and display and a real-time clock (e.g., slaved to the GPS receiver) are also coupled to the data processor. Encryption keys and message abbreviation codes are conveniently loaded into the device from a demountable accessory unit at the interface, and stored therein.

Abstract: A local traffic signal controller (3) is interfaced to a conventional pager (16) to provide for centralized control of the traffic signals controlled by the local controller. The central controller (7) may use the existing pager infrastructure (12) to provide for the transfer of program control information to local controllers. A two-way pager may be utilized to provide for the return of information from the local traffic signal controller. Such return information may include indications of lamp failures, traffic pattern information and other status or traffic related information.

Abstract: A method (60) for molding (67) a component (73) including a free floating insert (11). The method includes steps of providing an insert (11) including one or more weakened regions (23) coupled to a removable leader (20) and molding (67) a moldable compound (25) about the insert (11) and a portion of the removable leader (20). The method (60) further includes a step of pulling (69) on the removable leader (20) to fracture the weakened regions (23) and thereby detach the removable leader (20) from a molded component (73) including the insert (11) therein. The molding step (67) desirably includes a step of injection molding (67) a thermoplastic material (25) about the insert (11) and the portion of the removable leader (20).

Abstract: A secure, portable position locating radio has a geolocation receiver providing local position and timing information from geolocation means (e.g. GPS satellites) and a local transceiver for sending local position information to a communication system (e.g., an airborne or orbiting transceiver). A crypto unit is provided between the receiver and local transceiver for encrypting the local position information prior to transmission. A data processor coupled to the local transceiver, receiver and crypto unit controls operation of the device, including storing local position information and separating signals broadcast by the communication system into those intended or not intended for the device. An external interface and display and a real-time clock (e.g., slaved to the GPS receiver) are also coupled to the data processor. Encryption keys and message abbreviation codes are conveniently loaded into the device from a demountable accessory unit at the interface, and stored therein.

Abstract: A method and apparatus accurately synchronizes a communications equipment (101) to a precise 1 PPS signal (229) when the remote GPS equipment (112) and the communications equipment (101) are separated by a cable (110) of unknown length. Accordingly, integrity and precision of the 1 PPS timing signal is maintained when synchronizing the communications system.

Abstract: A communication network (10) includes any number of interconnected nodes (20), including a sending node (22), a sending gateway (24), a receiving gateway (26), and a destination node (28). A low capacity or expensive communication channel (30) resides between the sending and receiving gateways (24, 26). An original digitally signed message is sent from the sending node (22) toward the destination node (28). When the original message arrives at the sending gateway (24), the original signature is verified. If verified, the sending gateway (24) shrinks the original message into a reduced message and re-signs the message with a gateway digital signature before sending the message onward through the communication channel (30) toward the destination node (28). The destination node (28) verifies the gateway digital signature against the reduced message and is not required to de-compress the reduced message into a precise duplicate of the original message.