Abstract: A method and apparatus for performing satellite signal acquisition are described. In one embodiment, a method for using a satellite antenna comprises estimating antenna orientation when the antenna is in motion, including estimating yaw using one or more sensors; and performing signal acquisition to search for a satellite signal with the satellite antenna by interleaving a plurality of signal searches performed by the satellite antenna, the plurality of signal searches being based on an estimated yaw.

Abstract: At a controller of an optical module including optical transmitters and optical receivers coupled to the controller and coupled to first and second optical fibers: responsive to a first command, first configuring the optical module to operate in a normal mode in which the optical module operates at a maximum communication capacity by transmitting and receiving a maximum number of wavelengths, that the optical module is capable of transmitting and receiving, on each of the first optical fiber and the second optical fiber; and responsive to a second command, second configuring the optical module to operate in a backward compatible legacy mode in which the optical module operates at a reduced communication capacity compatible with a legacy optical module by transmitting and receiving a reduced number of wavelengths, that is less than the maximum number of wavelengths, on each of the first optical fiber and the second optical fiber.

Abstract: A human-machine interface involves plural spatially-coherent visual presentation surfaces at least some of which are movable by a person. Plural windows or portholes into a virtual space, at least some of which are handheld and movable, are provided by using handheld and other display devices. Aspects of multi-dimensional spatiality of the moveable window (e.g., relative to another window) are determined and used to generate images. As one example, the moveable window can present a first person perspective “porthole” view into the virtual space, this porthole view changing based on aspects of the moveable window's spatiality in multi-dimensional space relative to a stationary window. A display can present an image of a virtual space, and an additional, moveable display can present an additional image of the same virtual space.

Abstract: Disclosed is a method and apparatus for correcting a satellite image acquisition time. The method may include receiving, from a ground-based orbit propagator, an initially predicted imaging time, a correction command execution time, and a desired satellite position for imaging, and calculating a waiting time for imaging, a predicted satellite position, a correction time, and a corrected imaging time to correct a satellite image acquisition time.

Abstract: Methods and systems for calibrating the return and forward links of a satellite communication system are provided according to embodiments of the invention. The phase and/or amplitude variations caused by the return and forward links are calculated and/or estimated to aid in beamforming, such as ground-based beamforming. Calibration earth stations, distributed within one or more beam patterns, may be used to transmit calibration codes to the gateway to calibrate the return link. Return links variations may be estimated using a weighted minimum mean square algorithm at the gateway. Forward links may be calibrated with calibration codes transmitted from the gateway through a hybrid matrix to at least one calibration station. Forward calibration links may also calibrate for temperature-dependent signal variations such as diplexer variations at the satellite.

Abstract: Various arrangements for compensating for Doppler shift on a non-terrestrial orthogonal frequency division multiplex (OFDM) network are presented. An absolute location of the UE instance may be determined. A relative velocity of the UE instance with respect to a satellite of the non-terrestrial OFDM network may be determined. A frequency delta due to Doppler shift may be determined. A transmission frequency at which an uplink OFDM symbol is to be transmitted to the satellite of the non-terrestrial OFDM network may be determined using the frequency delta.

Abstract: A device for interfacing with an interactive program, including: a housing, including, an IR projector for projecting an IR pattern into an interactive environment; a camera for capturing images of the projected IR pattern; an image processor configured to process the captured images for identification of the projected IR pattern; a transceiver configured to communicate with a computing device that executes the interactive program, the transceiver configured to transmit data generated by the image processor to the computing device, such that a position of the device in the interactive environment is determined based on the captured images of the IR pattern, the determined position of the device being utilized to update a state of the executing interactive program at the computing device.

Abstract: Systems and associated methods for reducing Doppler shifts in the broadband signals between Unmanned Aerial Vehicles (UAVs) and ground stations are disclosed herein. In one embodiment, a method for reducing the Doppler shift of wireless signals includes estimating a velocity of the UAV based on a Global Positioning System (GPS) or an Inertial Measurement Unit (IMU) of the UAV and calculating the Doppler shift of an upload (UL) wireless signal based on the velocity of the UAV. The method further includes predistorting a frequency of the UL wireless signal at the ground station to reduce the Doppler shift at a UAV receiver (RX) and transmitting the UL wireless signal from a ground station transmitter (TX) to the UAV RX. In some embodiments, calculating the Doppler shift of the UL wireless signal is performed at the ground station.

Abstract: The present application relates to the mobile communications field, and in particular, to a technology for determining a carrier center frequency in a wireless communications system. In a method for determining a carrier center frequency, a carrier center frequency used by a base station and UE to communicate is determined according to a frequency band starting frequency, an absolute radio frequency channel number, a frequency band offset, and a relative radio frequency channel number. According to a solution provided in this application, a time for searching for a cell by a terminal can be reduced, power consumption of the terminal can be reduced, and a battery life can be extended.

Abstract: Certain aspects and embodiments are directed to a Doppler shift correction sub-system that can be disposed in a mobile repeater. The Doppler shift correction sub-system can include a processor and a frequency-shifting module. The processor can be configured to determine a corrective frequency shift based on a velocity of the repeater relative to a source and a representative transmission frequency. The processor can provide the corrective frequency shift to a frequency-shifting module. The frequency-shifting module can be configured to shift the signal using the corrective frequency shift prior to transmitting the signal to a destination, such as a mobile device.

Abstract: Aspects of the disclosure provide a method of determining frame timing of one or more signals from one or more respective transmitters. The method determining first observation windows that correspond to first candidate segments of the one or more signals; calculating a first set of accumulated signal patterns, each accumulated signal pattern of the first set of accumulated signal patterns being calculated based on signal patterns in a respective subset of the first candidate segments of the one or more signals; determining whether a first set of accumulated synchronization words derived from the first set of accumulated signal patterns is consistent with a first set of corresponding benchmark synchronization words; and determining the frame timing of the one or more signals based on timing of the first observation windows when the first set of accumulated synchronization words is consistent with the first set of corresponding benchmark synchronization words.

Abstract: The transmitting and receiving information and power in a wireless communication system are provided. A transmitting apparatus includes a transceiver, and at least one processor coupled with the transceiver. The at least one processor is configured to generate a symbol including a first set of signals for transferring power and a first information value or a second set of signals for transferring power and a second information value, and transmit the symbol. The first information and the second information may be indicated by a result value determined based on a predefined rule on the basis of a first value acquired by forwardly rectifying the symbol and a second value acquired by reversely rectifying the symbol. Each of the first value and the second value may be determined based on at least one of frequencies, magnitudes, or phases of the signals included in the symbol.

Abstract: A correction data creation unit receives a value of an error used in satellite positioning at a first time interval, and receives a correction value of the error at a second time interval that is a time interval 1/n (n is an integer of two or larger) time interval of the first time interval. The correction data creation unit also corrects the value of the error at the second time interval by using the correction value.

Abstract: A vehicle, a satellite control system, and a method for controlling the same are provided. The satellite control system, for example, may include, but is not limited to, a control moment gyroscope having a gimbal, at least one gimbal angle sensor configured to determine an angle of the gimbal, each gimbal angle sensor having an output circuit configured to output the determined angle, a signal conditioner circuit having substantially identical circuit topology as the output circuit, and a common mode error compensation circuit electrically coupled to the signal conditioner, the common mode error compensation circuit configured to determine common mode error in the gimbal angle sensor based upon a voltage output from the signal conditioner circuit and to output a signal to compensate for the common mode error.

Abstract: Where a mobile computer device having a position sensor, such as a GPS sensor, and an accelerometer is configured to estimate a geographic position of the mobile computer device using the position sensor, the accuracy of such positions may be enhanced by correlating accelerations of the mobile computer device, as determined by the accelerometer, against the positions of known surface features within a vicinity of the estimated positions. If the observed accelerations are consistent with one of the known surface features, the location of the mobile computer device may be correlated with the location of the one of the known surface features.

Abstract: An apparatus includes an antenna array including at least a first antenna element and a second antenna element separated by a first distance. The apparatus receives a wireless advertising message, having a known bit pattern, via the first and second antenna elements. The apparatus samples a first portion of the known bit pattern from the wireless advertising message received via the first antenna element, and samples a second portion of the known bit pattern from the wireless advertising message received via the second antenna element, and determines a phase difference between the received wireless advertising message at each of the first and second antenna elements by correlating the first sampled portion and the second sampled portion to the known bit pattern. The apparatus then determines an angle of arrival (AoA) of the wireless advertising message based at least in part on the phase difference and the first difference.

Abstract: A method and system are disclosed for providing an estimate of a location of a user receiver device. The method involves emitting, from at least one vehicle, at least one spot beam on Earth; and receiving, with the user receiver device, at least one spot beam. The method further involves calculating, with the user receiver device, the estimate of the location of the user receiver device according to the user receiver device's location within at least one spot beam. Each spot beam contains at least one acquisition signal, which may comprise at least one ring channel. Each ring channel comprises a frame count; a space vehicle identification (SVID); a spot beam identification (ID); and/or X, Y, Z coordinates of the vehicle emitting the spot beam relative to an Earth coordinate system. In one or more embodiments, at least one vehicle may be a satellite and/or a pseudolite.

Abstract: A method for real-time calibration of a gyroscope, configured for supplying a value of angular velocity that is function of a first angle of rotation about a first angular-sensing axis that includes defining a time interval, acquiring from an accelerometer an equivalent value of angular velocity that can be associated to the first angle of rotation; calculating a deviation between the value of angular velocity and the equivalent value of angular velocity; iteratively repeating the previous steps through the time interval, incrementing or decrementing an offset variable by a first predefined value on the basis of the values assumed by the deviations during the iterations, and updating the value of angular velocity as a function of the offset variable.

Abstract: A method for capturing ionospheric data is disclosed. In accordance with one embodiment, a plurality of phase-coherent signals transmitted by at least one Global Navigation Satellite System (GNSS) satellite is received via a mobile multi-frequency GNSS receiver. Respective code phase data and carrier phase data for each of said plurality of phase-coherent signals are derived using a software defined GNSS receiver operating on a processor of a first communication device of the multi-frequency GNSS receiver. Respective code phase data and carrier phase data for each of the plurality of phase-coherent signals is stored in a data storage device. The respective code phase data and carrier phase data is appended with a respective time-stamp and position fix. An ionospheric sample based upon respective code phase data and carrier phase data of said plurality of phase-coherent signals is wirelessly transmitted to a second location.

Abstract: A method for self-interference cancellation in a wireless communication device. The wireless communication device has an estimator, a transmitter and a cancellation device. The estimator is configured to estimate a known signal received from a second wireless communication device when the second wireless communication device is utilized less than a predetermined threshold. The transmitter is configured to transmit within a coherence time of the estimated known signal, a predetermined signal. The cancellation device is configured to cancel the estimated known signal from a received signal.

Abstract: An apparatus for receiving reverse link signals from a plurality of subscriber units in a multi-path environment is described. The apparatus includes a receiver in a base station that receives a first plurality of reverse link signals and a second plurality of reverse link signals in a time interval. Each reverse link signal of the first plurality of reverse link signals is derived from at least a common pseudo noise (PN) sequence and unique orthogonal sequence and each reverse link signal of the second plurality of reverse link signals is derived from a unique pseudo noise (PN) sequence. The apparatus also includes a a processor that determines a timing offset associated with at least one reverse link signal to align a timing of the at least one reverse link signal with reverse link signals from other subscriber units.

Abstract: Various embodiments of the present invention provide methods, systems, apparatus, and computer program products for providing integrated attitude determination and attitude control for slewing of a satellite. In one embodiment a method is provided. The method comprises after receiving a repointing request, selecting a guide star sample comprising one or more guide stars from a guide star catalog; determining current attitude information; selecting and retrieving at least one point spread function (PSF) image from a PSF library; estimating an expected position for at least one guide star, the at least one guide star being one of the guide stars of the guide star sample; acquiring at least one star tracker image; calculating a cross-correlation function (CCF) to determine shifts in position of the at least one guide star compared to the expected position; and determining updated current attitude information based at least in part on the determined shifts in position.

Abstract: An optical multiplexing includes: a monitor configured to detect power of an optical component including a frequency component of a cross point between spectra of a first sub-carrier signal and a second sub-carrier signal; and a controller configured to control a modulation timing of a data symbol of the second sub-carrier signal according to the power detected by the monitor, wherein the second sub-carrier signal is multiplexed to a carrier to be adjacent to the first sub-carrier signal multiplexed to the carrier so as to generate an optical Orthogonal Frequency Divisional Multiplexing (OFDM) signal in which an interference between the first and second sub-carrier signals is suppressed.

Abstract: Methods and apparatus for processing of GNSS signals are presented. These include GNSS processing with predicted precise clocks, GNSS processing with mixed-quality data, GNSS processing with time-sequence maintenance, GNSS processing with reduction of position jumps in low-latency solutions, GNSS processing with position blending to bridge reference station changes, and GNSS processing with delta-phase correction for incorrect starting position.

Abstract: A high-speed platform telemetry system (“HSPTS”) within a high-speed platform (“HSP”), for compensating for high Doppler in a telemetry stream is disclosed. The HSP is in signal communication with a first station, the telemetry stream is transmitted between the HSP and the first station, and the high Doppler is created by the HSP as the HSP moves along a travel path that passed near the first station. The HSPTS may include a platform transmitter, an on-board storage device having a real-time Doppler map database and navigation information corresponding to the travel path of the HSP, a position location device, a processor in signal communication with the position location device and on-board storage device, and a frequency offset circuit in signal communication with the platform transmitter and processor.

Abstract: The subject matter disclosed herein relates to a system and method for acquiring signal received from satellite vehicles (SVs) in a satellite navigation system. In one example, although claimed subject matter is not so limited, information processed in acquiring a signal from a first SV may be used in acquiring a signal from a second SV.

Abstract: A cellular telephone handset stores audio files previously recorded by the user as well as voice mail messages from other users and selectively transmitted selected ones of these files to the remote listener, or to the voice mail system of a remote user. Voice mail messages are composed, stored, transmitted, forwarded and reviewed using a voice mail system without ringing the remote party's telephone, much as email is composed, stored, transmitted and reviewed using an email server.

Abstract: Methods and apparatuses for determining a position of a mobile satellite positioning system (SPS) receiver which is coupled to a communication receiver or transceiver. In one exemplary method, a change in a communication signal received by the communication receiver is determined. A parameter, based on the change, is determined, and SPS signals from SPS satellites are processed according to the parameter. According to further details of this method, the change involves the fluctuation of the level of the communication signal and the parameter is a motion information which specifies a frequency range for searching for SPS signals in the process of acquiring the SPS signals from SPS satellites. In an alternative embodiment the change in the communication signal is a change in the transmitted signal in response to power control commands. Apparatuses, such as a mobile communication system which includes an SPS receiver and a communication receiver, are also described.

Abstract: An adaptive method by which Differential GNSS corrections may be compressed. Each measurement datum to be transmitted to a rover for satellite navigation purposes is decomposed into two parts, namely, an anchor value and a delta value, and in some instances an added third part termed a nonce value is used. Encoding parameters such as the number of bits assigned to each part of the measurement datum, the order of the models used to convey positional data, and scaling constants in the models, are adjusted adaptively based on changing data and/or transmission medium characteristics. Adaptive compression also allows for anomalous conditions such as out-of-range data values to be handled gracefully.

Abstract: A method of determining the reliability of long-term predicted orbit data, includes: determining the reliability of long-term predicted orbit data, which is acquired by predicting a satellite orbit in a target period of at least one day, using predicted position data including predicted positions of a positioning satellite in time series and actual position data including actual positions of the positioning satellite corresponding to the predicted positions.

Abstract: In order to perform calibration of respective systems of an array antenna with high accuracy for adapting to a change in environmental condition, provided is a calibration device (20A) for calibrating an array antenna mounted on a satellite or the like, the calibration device including: a calibration coefficient calculating unit (21) to calculate a correlation of a plurality of input signals Xi(t,P), which are obtained by performing predetermined signal processing for signals received by an array antenna (11), to calculate weighting coefficients (?W) for calibrating systems of the array antenna; and a calibration executing unit (27) to calibrat the systems of the array antenna based on the weighting coefficients (?W).

Abstract: A navigation system determines its usage mode. In some embodiments, a method comprises determining a usage mode of a navigation system based on at least one of an acceleration indicator, a speed indicator, and a magnet sensor. The usage mode is at least one of a pedestrian mode, a vehicular mode, an aerial mode, a train mode, and a marine mode. The method further comprises configuring a navigation subsystem based on the usage mode.

Abstract: A method for communication includes modulating data to produce a series of symbols defined in a signal space. The symbols are pulse-shaped using a given pulse shape. A signal, which includes a sequence of the pulse-shaped symbols (104A . . . 104C) transmitted at a symbol rate that is higher than a Nyquist rate defined for the given pulse shape, is transmitted to a receiver (40). Prior to pulse-shaping the symbols, Inter-Symbol Interference (ISI) in the signal is pre-compensated for by applying a lattice precoding operation to the symbols. The lattice precoding operation confines the symbols to a predefined volume (110) in the signal space and is computed independently of any feedback from the receiver.

Abstract: A wireless communications device comprises a communication receiver and a positioning system receiver in the wireless mobile communication device. An absolute time signal is received at the positioning system. A network time signal is received at the communication receiver of the wireless mobile communication device. A controller is in signal communication with the position system receiver and the communication receiver. The controller is configured to determine an offset of the absolute time signal from the network time signal and generates a timing mark. The timing mark is tagged by the positioning system receiver with an internal clock value wherein the timing mark has a known relationship with the absolute time signal. A memory stores the offset of the absolute time signal from the network time signal. A transmitter in the wireless mobile communication device transmits the offset for receipt by another wireless mobile communication device.

Abstract: In one implementation, a first measurement of gain of a first calibration signal retransmitted from a first satellite element and a second measurement of gain of a second calibration signal retransmitted from a second satellite element may be obtained. A first expected gain for the first element and a second expected gain for the second element may be accessed. A weight indicative of a confidence in the first measurement may be computed using a gradient of a geodetic radiation pattern of the first element. A weight indicative of a confidence in the second measurement also may be computed using a gradient of a radiation pattern of the second element. A cost function may be generated and values for one or more unknown variables may be computed by reducing the cost function with respect to the one or more unknown variables. The computed values for the unknown variables may be stored.

Abstract: Gain measurements of one or more calibration signals communicated by one or more calibration stations and retransmitted by one or more satellite elements may be obtained. One or more weights indicating confidence in the gain measurements for the one or more satellite elements may be computed. A geodetic radiation gain pattern of a satellite element that is a function of a roll, a pitch, and a yaw of a satellite may be accessed. Partial derivatives of the geodetic radiation pattern may be computed with respect to roll, pitch and yaw at one or more points in the first geodetic radiation pattern corresponding to one or more geographic locations. A cost function may be generated and one or more unknown variables may be computed by reducing the cost function. A satellite pointing error may be determined using the computed variable values and the pointing error may be stored.

Abstract: Methods and apparatuses for determining a position of a mobile satellite positioning system (SPS) receiver which is coupled to a communication receiver or transceiver. In one exemplary method, a change in a communication signal received by the communication receiver is determined. A parameter, based on the change, is determined, and SPS signals from SPS satellites are processed according to the parameter. According to further details of this method, the change involves the fluctuation of the level of the communication signal and the parameter is a motion information which specifies a frequency range for searching for SPS signals in the process of acquiring the SPS signals from SPS satellites. In an alternative embodiment the change in the communication signal is a change in the transmitted signal in response to power control commands. Apparatuses, such as a mobile communication system which includes an SPS receiver and a communication receiver, are also described.

Abstract: Present novel and non-trivial system, device, and method for generating altitude data and/or height data are disclosed. A processor receives navigation data from an external source such as a global positioning system (“GPS”); receives navigation data from multiple internal sources; receives object data representative of terrain or surface feature elevation; determines an instant measurement of aircraft altitude as a function of these inputs; and generates aircraft altitude data responsive to such determination. In an additional embodiment, the processor receives reference point data representative of the elevation of the stationary reference point (e.g., a landing threshold point); determines an instant measurement of aircraft height as a function of this input and the instant measurement of aircraft altitude; and generates aircraft height data responsive to such determination.

Abstract: Provided is a device for tracking polarizations. A receiving polarization tracking device includes a feeder for finding vertical and horizontal vector components by receiving vertical and horizontal polarizations, a polarization estimator for estimating distortion of polarizations using the vertical and horizontal vector components outputted from the feeder, a polarization controller for controlling amplitudes and phases of vertical and horizontal polarizations based on information about the estimated distortion from the polarization estimator and an output signal from the receiving polarization tracking device, and a combiner for combining the vertical and horizontal polarizations controlled from the polarization controller.

Abstract: A satellite based positioning method and system including storing satellite sub-almanac data on a mobile station. Embodiments include using the sub-almanac data to take measurements and calculate a coarse position of the mobile station. Embodiments further include a location server calculating a correction to the coarse position, and the location server determining whether any sub-almanacs used to calculate the coarse position require replacement.

Abstract: The terminal apparatus has: base station and terminal error information generating means for generating base station and terminal error information indicating a rate of the base station and terminal frequency difference with respect to the official frequency; geostationary satellite and terminal difference information generating means for generating geostationary satellite and terminal difference information indicating a geostationary satellite and terminal frequency difference; geostationary satellite and terminal error information generating means for generating geostationary satellite and terminal error information indicating a rate of the geostationary satellite and terminal frequency difference with respect to the geostationary satellite frequency; base station frequency error information generating means for generating base station frequency error information indicating a frequency error of a transmitting radio wave from the communication base station based on the base station and terminal error.

Abstract: Estimation of a desired antenna tracking profile is provided for a radio frequency autotracked (RFAT) antenna in the absence of a ground reference. A first RFAT antenna subsystem has a first antenna and a first antenna positioning mechanism (APM), each mounted on a vehicle, and a first ground-based RF beacon; a second RFAT antenna subsystem has a second antenna and a second APM, each mounted on the vehicle, and a second ground-based RF beacon. A controller stores an accumulated record of actuations of the second APM as a function of time under normal operation, calculates a desired antenna tracking profile for the second antenna, from a first ground-based RF beacon and from the accumulated record, excluding any real-time data from the second ground-based RF beacon, and transmits actuation commands to the second APM so as to cause the second antenna to track the desired antenna tracking profile.

Abstract: A satellite based positioning method and system including storing satellite sub-almanac data on a mobile station. Embodiments include using the sub-almanac data to take measurements and calculate a coarse position of the mobile station. Embodiments further include a location server calculating a correction to the coarse position, and the location server determining whether any sub-almanacs used to calculate the coarse position require replacement.

Abstract: A navigation device is disclosed. In at least one embodiment, the navigation device includes a storage device to store map information; a processor to determine a route of travel based upon a current position of the navigation device and an input or selected destination position; and a display to display the current position on the map information corresponding to the determined route of travel, the display displaying zoomed-in display of the map information upon the processor determining that a decision point is within a threshold distance of the current position of the navigation device.

Abstract: The terminal apparatus has: base station and terminal error information generating means for generating base station and terminal error information indicating a rate of the base station and terminal frequency difference with respect to the official frequency; geostationary satellite and terminal difference information generating means for generating geostationary satellite and terminal difference information indicating a geostationary satellite and terminal frequency difference; geostationary satellite and terminal error information generating means for generating geostationary satellite and terminal error information indicating a rate of the geostationary satellite and terminal frequency difference with respect to the geostationary satellite frequency; base station frequency error information generating means for generating base station frequency error information indicating a frequency error of a transmitting radio wave from the communication base station based on the base station and terminal error.

Abstract: In a method and apparatus for processing a received navigation signal x?(t) of a satellite navigation system, the received navigation signal x?(t) contains at least four navigation codes. The navigation codes are modulated by a complex BOC signal and a defined subcarrier frequency such that the resulting signal has a constant amplitude. The resulting signal is then also modulated by means of a carrier signal. The navigation signal x?(t) is demodulated and then processed by a complex correlation with at least one reference signal.

Abstract: Disclosed herein are a system for automatically landing an aircraft using image signals and a method of controlling the system. The system includes an altimeter installed on the aircraft; a landing mark placed at a landing location on a landing runway; a camera installed on the aircraft, oriented toward the front of the aircraft, and configured to detect the shape of the landing mark in image information form; and a FCC configured to calculate the angle between the aircraft and the ground, the ground range and the slant range between the aircraft and the landing location using the altitude information measured by the altimeter, the image information of the landing mark captured by the camera, angle information composed of the pitch, roll and yaw angles of the aircraft, and the angle of entry into the landing runway, and configured to control the automatic landing of the aircraft.

Abstract: GPS gyro calibration methods and systems are described. In an embodiment, a ground station can receive antenna position data for a spot beam antenna from a global positioning system (GPS) platform where the antenna position data indicates a boresight direction of the spot beam antenna. GPS-enabled receiver(s) can receive scan signals transmitted via the spot beam antenna of the GPS platform, and the GPS-enabled receivers can determine signal power measurements for each of the scan signals. The ground station can receive the signal power measurements from the GPS-enabled receiver(s) and estimate a pointing error of the spot beam antenna based on the signal power measurements and the antenna position data received from the GPS platform. The ground station can then determine gyro calibration parameters from the estimated pointing error and communicate the gyro calibration parameters to the GPS platform to calibrate for gyro drift errors.

Abstract: A vertical integrity monitoring method and system are described. The vertical integrity monitoring method includes determining a noise sigma ratio parameter. The method also includes determining two vertical protection limit slopes and an associated covariance matrix. The method further includes determining a vertical integrity limit and set of weights based on the VPL slopes, covariance and the parameter; and applying the set of weights based on the parameter to calculate a vertical solution. An integrity monitoring system may have hardware and/or software embodying the one or more methods described.

Abstract: The apparatus of the present invention uses radar altimeter measurements and stored terrain altitude profiles to provide pre-filtered observations to a Kalman filter for estimating barometric offset at the airport runway, and barometric scale factor for offsets above the runway. These offsets are used with the smoothed baro-inertial output from an inertial reference system to provide 3 dimensional constant rate of descent approach procedures to replace non-precision approach procedures based on constant barometric altitude step approaches. The horizontal positions used as reference for the stored terrain altitude profiles are obtained from a prior art navigation apparatus. The integrity of all measurements is assured by using long term averages of the Kalman filter residuals to detect failures. In addition, the estimated baro offset at the runway is compared for consistency with the baro offset obtained by the pilot from the airport by radio.