Abstract: A global positioning system includes a base GNSS receiver that determines position and carrier phase measurements for GNSS satellites in view and a rover GNSS receiver, which is a single frequency receiver that captures GNSS satellite signals transmitted in the single frequency band during a capture window from a plurality of GNSS satellites, the plurality being large enough to provide a carrier phase data set from which a solution to associated integer carrier phase ambiguities is over determined. The system determining from the captured signals, a search space associated with the satellites in view, the code phase delays and associated position uncertainty. The system resolving the integer carrier cycle ambiguities using double difference carrier phase measurements associated with signal power values that are over a predetermined threshold value.

Abstract: A system and method is provided for improving the operating range for UWB communication systems by increasing the margin between true correlation peaks and false correlation peaks in a received UWB signal. A received signal is first correlated with a UWB kernel before being correlated with the PRN code. The UWB kernel is a very short UWB pulse having the same pulse shape as the UWB signal pulses. By pre-correlating the received signal with the UWB kernel at least once prior to correlating with the PRN code, the margin between true correlation peaks and false correlation peaks is substantially improved.

Abstract: A system for enhancing location estimates by movable rovers including one or more base stations that engage in two way time transfer (TWTT) with the rovers. Each TWTT operation between a given base station and a given rover provides range measurements and clock differences between the base station and rover. The range measurements are based on the travel time of return TWTT signals and the clock differences are based on a phase offset of a code in the return TWTT signal and/or timing information included in the return TWTT signals.

Abstract: The invention relates to a method for correcting a distortion in an aerial photograph caused by a flight movement in the forward direction. The aerial photograph is captured by a surface sensor, the sensor lines of which sensor are exposed at different, successive exposure times, so that each individual sensor line senses a strip of terrain of the terrain flow over at the different exposure times. A relative flight altitude above the strips of terrain captured by the respective sensor line is assigned to the individual sensor lines. Furthermore, a compensation factor is separately determined for each of the individual sensor lines, wherein the factor depends on an air speed of the flying object, a focal length of the aerial camera and the relative flight altitude assigned to the respective sensor line, and corrects the distortion in the aerial photograph for the lines based on the respective compensation factor.

Abstract: A system to determine position, frequency and clock offsets over a network utilizing signals of opportunity transmitted by one or more transmitters with known locations, the system includes a base receiver with a clock and a known position that determines ranges to the transmitters, takes a series of samples of the signals of opportunity and time tags the series with times of receipt, calculated times of transmission based on the calculated ranges, or both. The base receiver transmits the time tagged series and, as appropriate, computed ranges to the remote receivers. A given remote receiver saves and time tags samples of the signals of opportunity, correlates the time-tagged series with the saved samples, and calculates a time offset as a time difference of the times of receipt at the remote receiver and either the time of receipt at the base receiver or the time of transmission calculated at the base receiver.

Abstract: A system to distribute accurate time and/or frequency over a network utilizing signals of opportunity transmitted by one or more local transmitters with known locations, the system includes a base receiver with a clock synchronized to a reference time scale such as GNSS or UTC time that saves a series of samples of the signals of opportunity and time tags the series with a calculated time of broadcast. A remote receiver saves samples of the signals of opportunity and correlates the series with the saved samples. The remote receiver calculates a time of transmission of saved samples that correspond to the series, determines a time offset as a difference in the time of broadcast calculated at the remote receiver and the time of broadcast calculated at the base receiver, and determines the time offset with respect to the base receiver.

Abstract: A system for determining positions of fixed-position satellite signal receivers that have restricted views of the sky includes a data recording control center, and one or more base satellite signal receivers with associated antennas that together have substantially unrestricted views of the sky. The system batch processes range information provided by the fixed-position receivers over an extended period of time, determining the three dimensional position of a given fixed-position receiver using range data from at least three relatively short time intervals associated with different sky positions in which the receiver is tracking any two or more satellite signals simultaneously.

Abstract: The inventive shock damping system for vibration sensitive surface mounted devices consists of an elastomeric material having conductive fiber material disposed between a printed circuit board (PCB) and a surface mounted device. Once disposed between PCB and surface mounted device, the elastomeric material, the PCB and the surface mounted device are compressed together with a component restraining system, to provide a secure electrical connection between one or more interconnect pads conductively attached to surface mounted device and the PCB. The elastomeric material allows signals and current to flow between surface mounted device and PCB without the use of any attached wires or leads while at the same time providing a system for damping any shocks or vibrations that may be transferred to surface mounted device through the PCB or through the protective component restraining system that encloses the device and the elastomeric material.

Abstract: An AltBoc receiver accumulates power measurements over code chip ranges that are associated with time slots that span the code chips. The receiver combines a received signal with code and carrier phase offsets that correspond to the time slots to produce the power measurements, with the code phase offsets determined from compressed signals representing one or a combination of the codes in the AltBoc signal. The receiver recovers navigation data from the data channels of the received signal and combines the recovered data with the corresponding locally generated PRN codes to produce a locally generated 4 code signal that is then used track the full 8PSK AltBoc received signal. The receiver rotates and shifts the phase of the received signal in order to line up the subcarrier splitting code zero crossings. The pulse shape of this rotated and shifted signal is measured. The resulting sharp edges of the recovered subcarrier are used to control the code phase of the receiver.

Abstract: A pre-correlation filter determines the timing of a second pseudorandom number (“PRN”) code, using an image of the average chip shape formed for a first PRN code. The filter collects measurements corresponding to samples of a received signal over multiple code chips of the first PRN code at sample times that are asynchronous to code rate. A code phase decoder directs the measurements to accumulation registers that are associated with code chip ranges that are fractions of a code chip of the first PRN code based on the code phase angles of the samples in the first PRN code, to accumulate measurements relating to chip transitions in the first PRN code and measurements relating to chip transitions in the second PRN code. The chip edges of the second PRN code are detected from the image of average chip shape for the first PRN code formed from the accumulated measurements.

Abstract: A receiver utilizes an array of complex accumulation registers to form an image of the average chip shape or, as appropriate, chip edge shape, of the received signal over a specified period of time as a time series of complex power measurements. The receiver divides the length of the chip into a plurality of ranges, or bins, and, as appropriate, extends the bins to cover additional chips or portions thereof. When a sample is taken, the receiver enables the respective registers that are associated with the corresponding bin or bins, and the respective registers then accumulates the associated power measurement. The receiver uses the accumulated measurements from selected registers and/or selected groups of registers, to produce the correlation values that are needed to perform one or more correlation techniques and/or one or more multipath mitigation techniques.

Abstract: A receiver includes a pre-correlation filter that forms an image of the average chip shape of a received signal over a specified period of time. The filter includes an array of complex accumulation registers that accumulate measurements that are associated with signal samples from specific ranges of locations, or code chip phase angles, along a spread-spectrum chip. Using the accumulated measurements, the receiver estimates the location of the chip transitions in a direct path signal component. The receiver may thereafter change the starting point, size and number of ranges, such that the accumulation registers accumulate more detail from the chip edges. The receiver in addition may compare the accumulated measurements with a reference pulse shape to determine if any interference is present in the received transmission that will distort ranging information calculated from the received signal.

Abstract: The present disclosure provides a system for converting differential-GPS signals to a format suitable for input to a conventional GPS receiver and combining the converted signal with GPS ranging signals. The combined signals are provided to a conventional GPS receiver via a cable. Circuitry for converting the augmentation signal and combining it with a GPS signal are co-located in a housing which supports both a standard GPS antenna and a differential GPS augmenting signal antenna.

Abstract: A receiver for position-determining ranging signals transmitted by earth-orbiting satellites uses a set of accumulators, each of which accumulates signal samples corresponding with a position along the rising edges of incoming PRN pulses. An MMT processor calculates the rising edges of the direct path component of the received signal, selects the accumulator whose content correspond to a reference value related to the pulse height of the direct path component and compares the timing of the samples in that accumulator with the timing of the reference value on a reference pulse.

Abstract: A system for determining positions of fixed-position GPS receives that have restricted views of the sky includes a data recording and control center, and one or more base GPS receivers with associated antennas with a substantially unrestricted views of the sky. The system batch processes range information provided by the fixed-position GPS receivers over an extended period of time; determining which of the range data from the fixed-position receivers are valid, and using the valid range data to determine position. In this way, the precise positions of the respective fixed-position slave GPS receivers can be calculated, even if the fixed-position GPS receivers are able to observe and collect data from sets of two or more satellites for only three or four relatively short time intervals at various sky positions during the extended period.

Abstract: A system, for enhancing location estimates by movable rovers that use receivers for processing ranging signals from orbiting satellites, including a fixed base station that serves as a ranging signal source for the rovers' receivers. The base station may also determine and transmit the azimuthal angles of the respective rovers. The rovers use this information, along with a calculated or transmitted ranges to the base station to calculate the ranging system times at the locations of the rovers. Further, the rovers may use the information along with signals from satellites in view to determine position.

Abstract: A system consisting of a base GPS receiver with a clear view of the sky, one or more remote GPS receivers with restricted views of the sky and a processing center that batch processes range information provided by the GPS receivers determines the positions of the remote GPS receivers to within tight tolerances. The base GPS receiver and the remote GPS receivers produce range information based on the satellite signals that the respective receivers can track at a given time, and provide the range information to the processing center. The range information includes both code and carrier measurements for each of the signals that are being tracked by the respective GPS receivers. The center collects the range information over an extended period of time, for example, hours, days or weeks, and then batch processes the collected information in multiple passes through the data, to calculate the precise latitude, longitude and height of the receiver.

Abstract: A deformation monitoring system includes a data recording and control center, one or more base receivers with associated antennas that have a substantially unrestricted view of the sky and acquire and track satellite signals used for global positioning and slave receivers at various locations over the site being monitored, the slave receivers also acquiring and tracking the satellite signals. The system processes range information provided by the slave receivers over an extended period of time to determine the positions of the respective slave receivers. In this way, the precise positions of the respective slave receivers can be calculated, even if the slave receivers are able to observe and collect data from one or more satellites for only three or four relatively short time intervals at various sky positions during the extended period.

Abstract: A system for ascertaining the range from an interrogator to one or more transponders comprises an interrogator that transmits an RF carrier that is received by each transponder, the energy in the received carrier being used to charge up a storage capacitor in each senses the termination of the received carrier and initiates a known delay interval different from those of the other transponders. At the end of the delay interval, the transponder transmits an RF signal which is received by the interrogator. The interrogator then calculates the range to the transponder by subtracting the known delay interval from the round trip time registered in the timer.

Abstract: A system for analyzing three-dimensional seismic data includes a plurality of digitizer units, each with a configuration of geophones, a data recording and control center, a base GPS receiver with an associated antenna with a substantially unrestricted view of the sky and at the respective digitizer units low-power slave GPS receivers that acquire and track GPS satellite signals using tracking assistance information provided by the base GPS receiver. The slave GPS receivers use the tracking assistance information to acquire and track GPS satellite signals that may be relatively weak at the receivers, due to conditions at the site, such as foliage canopies and so forth. The system processes range information provided by the slave GPS receivers over an extended period of time.