Abstract: An enhanced precision forward observation system and method employs a satellite positioning system receiver, range finder, and a compass/inclinometer. The satellite positioning system receiver is used to calculate an observer's position and target position estimation software employs data from multiple measurements for improved target position estimation.

Abstract: A sigma-delta-sigma modulator for analog-to-digital and digital-to-analog converters is described. The sigma-delta-sigma modulator is amenable to fabrication of high speed LSI and VLSI digital components for fixed and programmable processes for minimizing and eliminating required analog circuitry in a digital radio. The sigma-delta-sigma modulator is utilized in a direct sampling receiver in which the received RF is converted by high resolution analog-to-digital processing and subsequently translated to baseband, filtered and demodulated completely in the digital domain. The modulator is also utilized in a direct digital transmitter in which the baseband modulation is formed, translated to RF, and converted to analog by high resolution digital-to-analog processing completely in the digital domain.

Abstract: Disclosed is an avionics display device adapted for insertion into an avionics panel of an aircraft. The avionics display device includes a liquid crystal display having a liquid crystal display element and a bezel surrounding the liquid crystal display element. The avionics display device also includes a low profile rotary switch mounted on the bezel of the liquid crystal display to save avionics panel space in the aircraft. The low profile rotary switch includes a printed circuit board positioned beneath the bezel and having a plurality of electrical pads formed thereon. The switch also includes a contact member positioned adjacent the printed circuit board and having a first contact formed thereon. Rotation of the contact member causes the first contact to be electrically coupled to one of the plurality of electrical pads formed on the printed circuit board. A knob is coupled to the contact member such that rotation of the knob causes rotation of the contact member.

Abstract: A method and apparatus for collecting and analyzing soil chemistry information from a tract of land is described. An information management system receives reference signals from a global positioning system from which soil sample collection coordinate location information may be calculated and utilized to generate a soil sampling plan for the tract of land. The information management system guides the collection of soil samples according to the soil sampling plan and records geo-referenced soil sample collection information which may be merged with the results of laboratory analysis performed on the soil samples to generate accurate geo-referenced soil chemistry information.

Abstract: A communications, navigation and identification (CNI) avionics system is disclosed. The CNI system includes a first integrated sensor performing a first CNI function and a second integrated sensor performing a second CNI function of a lower priority than the first CNI function. A first communication path is assigned to the first integrated sensor such that it carries signals between the first integrated sensor and a first system asset. A second communication path is assigned to the second integrated sensor such that it carries signals between the second integrated sensor and a second system asset. Each of the first and second communication paths includes a common first interconnect coupled to both of the first and second integrated sensors, a common second interconnect coupled to each of the first and second system assets, and a separate cryptographic processor.

Abstract: Disclosed are a backlight and avionics display using the same to provide light to a liquid crystal display (LCD) device. In the backlight, a day mode light source positioned on a first side of the LCD device and adapted to provide a first source of light for use by the LCD device during day mode operations. A night mode light source positioned on the first side of the LCD device is adapted to provide a second source of light for use by the LCD device during night mode operations. A sculptured transflector positioned between the day mode light source and the night mode light source has, at a first side adjacent the day mode light source, a transflective material and a plurality of arcuate or parabolic surfaces in order to maximize a percentage of light from the day mode light source which is reflected toward the LCD device.

Abstract: Disclosed is a GPS pseudolite transmitter, receiver and navigation system. The GPS pseudolite transmitter is adapted to transmit a first phase modulated L-band signal at a first signal pulse repetition rate having an associated first period time duration. The first phase modulated L-band signal is modulated with a short period code having a code epoch of at least about one millisecond. For each consecutive transmission pulse having the first period time duration, the pseudolite transmitter transmits the first phase modulated L-band signal during less than one half of the first period time duration, and for at least about 1 millisecond so that the first pseudolite transmitter transmits an epoch of the short period code during each transmission pulse.

Abstract: A switchable biasing device for an analog CMOS differential amplifier provides a supply bias current and a corresponding input bias voltage to achieve reliable performance with various power supply voltages. The bias device may include a control element having states corresponding to power supply voltages. The control element controls a supply bias circuit for supplying bias current to a differential amplifier at a level corresponding to the power supply voltage represented by a control signal from the control element. The bias current is made lower for a low power supply voltage to ensure that current source stage elements of the differential amplifier operate within their saturation region, and higher for a high power supply voltage to ensure sufficient current to maintain slew rates. The control element further controls an input bias circuit for providing a dc bias voltage at inputs of the differential amplifier at levels corresponding to the power supply voltage represented by the control signal.

Abstract: An open loop fiber optic gyroscope having improved linearity and scale factor accuracy in the rate signal output and improved modulation index control is disclosed. A digital phase tracker is utilized to derive the Sagnac phase shift from signals proportional to cosine and sine values of the Sagnac phase shift. The rate output is independent of the amplitude of the optical power in the gyroscope and is linear for very large input rates. A modulation servo utilizes the second and fourth harmonic signals from the output of the fiber optic gyroscope to control modulation.

Abstract: A method for calculating the phase reception pattern of an antenna system utilized in attitude determination is disclosed. The antenna system is disposed on a platform (or rate table) that rotates about a single, fixed axis at a constant rate as incoming signals from one or more satellites are received, thereby revolving the antennas about the axis. Information collected from the satellite signals is utilized to calculate a differential phase map (phase measurement error correction map) for the antenna system. The rate of rotation of the table is approximately known, and small variations in the rotation rate may be compensated. The baseline vector connecting two or more antennas is preferably approximately perpendicular to the axis of rotation of the platform. Phase measurement data is collected and may be processed off-line to compute a phase measurement correction map. Attitude calculations may be compensated with the determined differential phase measurement correction map.

Abstract: Disclosed is a secure data system power supply having an input coupleable to an input voltage line and an output coupleable to a secure data system and providing isolation between the input voltage line and the secure data system such that information communicated within the secure data system is undetectable from the input voltage line. The power supply does not utilize a linear current source for isolation, and thereby greatly reduces power loss. A constant power flyback converter is adapted to be coupled between the input voltage line and the secure data system. The constant power flyback converter takes as an input from the input voltage line a constant power input and provides at a converter output an output signal for use in powering the secure data system. A shunt voltage regulator is coupled to the converter output and maintains the output signal at a substantially constant voltage.

Abstract: An antenna for utilization in a fuse of an artillery shell is disclosed. The antenna comprises a radiator, a capacitance hat disposed at a first end of the radiator for capacitively loading the radiator and a ground plane disposed at a second end of the radiator such that the antenna is a monopole antenna. The antenna also includes a dielectric having a top surface, a bottom surface and a central longitudinal axis wherein the capacitance hat is disposed on the top surface of the dielectric and the ground plane is disposed on the bottom surface of the dielectric. A fuse utilized for detonating the explosive charge of an artillery shell is further disclosed. The fuse includes a fuse casing with the antenna of the present invention disposed within the interior cavity of the fuse casing.

Abstract: A mixer for use in a direct conversion receiver includes a compensating differential amplifier which injects equal amplitude opposite phase currents with respect to even order distortion currents. The compensating differential amplifier utilizes an ideal current source. The mixer is an active mixer which utilizes four switching transistors. The even order distortion is introduced by non-linear components which demonstrate strong off-channel signals.

Abstract: Disclosed are methods for minimizing the security boundary of PPS GPS receivers. The primary disclosure is a lump sum SA correction method. This method can be used to limit the security boundary to the portion of the GPS receiver that generates the lump sum SA correction, allowing all PPS measurement processing (within the receiver or across a PPS measurement interface) to reside outside the security boundary. In addition, two methods are disclosed (passive residual method and active residual method) by which the data content of the PPS measurement interface is entirely unclassified when keyed, thereby limiting the security boundary to the GPS receiver itself.

Abstract: Disclosed are dual frequency GPS receivers using single frequency sequencing and methods of using the same to track both first global positioning signals at a first frequency and second global positioning signals at a second frequency. Both of the first global positioning signals and the second global positioning signals are received with a multi-frequency antenna or multiple antennas of different frequencies. The first global positioning signals and the second global positioning signals are separated and converted into first and second translated global positioning signals, respectively, having an intermediate frequency or frequencies. Frequency sequencing is controlled to selectively alternately couple the first and second translated global positioning signals one at a time to the channels of the digital signal processor for use in navigation solution determination.

Abstract: Provided are a method of, and system for, generating agricultural field maps. Latitude and longitude of a GPS receiver carried by a vehicle are determined at predetermined time intervals or positions within the field and are recorded in first and second data channels. First and second characteristics of the field are sensed using first and second agricultural sensor types. The values of the first and second sensed characteristics at different field locations are recorded in third and fourth data channels. At least one of the third and fourth data channels are selected for use in field map generation and the field map is generated as a function of the information recorded in the first and second data channels and as a function of the information recorded in the selected ones of the third and fourth data channels.

Abstract: A method and apparatus is provided for calibrating and detecting faults in a receiver having a multi-element antenna. The method includes the steps of selecting an antenna element of the multi-element antenna and transmitting a signal through the selected element. The method further includes the steps of detecting the transmitted signal through at least one antenna element of a remaining set of elements of the multi-element antenna and calculating a phase shift for the at least one antenna element of the remaining set of elements.

Abstract: A method and apparatus for Doppler compensation in a satellite communications system such as Inmarsat's SATCOM network are disclosed. An aircraft terminal provides satellite communications services in one of several user-selectable modes including a circuit-mode services only mode and other modes providing some data packet services. The terminal includes multiple channel units coupled to a processing circuit. The channel units communicate radio signals via data or circuit channels between the aircraft and a satellite. Each channel unit can receive a channel input transmitted at a known frequency, and measure its frequency. Each channel unit can also transmit a channel output at an adjustable frequency. Each channel unit is operated as a circuit channel when circuit-mode services only is selected. Doppler shift is measured using the difference between the measured and known transmitted frequencies of at least one channel input.

Abstract: A method and apparatus are provided for modulating a frequency synthesizer with an adjusted frequency control word determined by adjusting a carrier frequency control word based upon a bit content of a unsigned modulation control word. The method includes the steps of inverting a most significant bit of the unsigned modulation control word to produce an adjusted modulation control word and replicating the inverted most significant bit and appending the replicated bits to a most significant bit side of the adjusted modulation control word to increase a width of the adjusted modulation control word to a width of the carrier frequency control word. The method further includes the step of adjusting the carrier frequency control word by adding the replicated bits and the adjusted modulation control word to corresponding bits of the carrier frequency control word.

Abstract: An improved flow sensor is disclosed for use with a crop harvesting device to determine flow volume of a crop yield product. The improved flow sensor is of the type which uses a strain gauge and includes an improved probe coupled to the strain gauge and adapted to cooperate with the strain gauge to produce a signal indicative of pressure being applied to the probe by the crop yield product. The improved probe includes first and second connection members adapted to couple the probe to the strain gauge. A probe middle portion is coupled to each of the first and second connection members and extends from a location between the first and second connection members into a middle portion of the flow path of the crop yield product. First and second probe legs are coupled to and extend from first and second sides of the probe middle portion into first and second sides of the flow of crop yield product.