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 method and apparatus for maintaining integrity of long-term-orbit information used by a Global-Navigation-Satellite-System or other positioning receiver is described. The method comprises obtaining a predicted pseudorange from a first set of long-term-orbit information possessed by a positioning receiver; obtaining, at the positioning receiver from at least one satellite, a measured pseudorange; determining validity of the predicted pseudorange as a function of the predicted pseudorange and the measured pseudorange; and excluding from the long-term-orbit information at least a portion thereof when the validity of the predicted pseudorange is deemed invalid. Optionally, the method may comprise updating or otherwise supplementing the long-term-orbit information with other orbit information if the validity of the predicted pseudorange is deemed invalid.

Abstract: Disclosed is a system and method for detecting false Global Navigation Satellite System (GNSS) satellite signals. False GNSS satellite signals can be used malevolently to take control of a body such as a vehicle or ship that is using GNSS satellite signals for navigation. In some embodiments a GNSS attitude system is used to detect the false GNSS satellite signals. The GNSS attitude system measures the code or carrier phase of the GNSS satellite signals at two or more antennas to detect the false GNSS satellite signals. In some embodiments the attitude system computes first measured and second estimated carrier phase differences in order to detect the false GNSS satellite signals. The attitude system may compute the attitude of a baseline vector between the two antennas. Once false GNSS satellite signals are detected, the method can include preventing the attitude determining system from outputting position or location data.

Abstract: A system and method for detecting global positioning system (GPS) spoofing attacks includes collecting GPS readings along with inertial navigational system (INS) readings as a ground truth, and sequentially testing the GPS readings and INS readings through the use of a sequential probability ratio testing (SPRT) process.

Abstract: The disclosed method for determining atmospheric time delays involves receiving at least two signals, where the signals each have a different carrier frequency. The method further involves amplifying each of the signals with a respective amplifier for each of the signals to produce amplified signals. Also, the method involves digitizing each of the amplified signals with a respective analog to digital converter (ADC) for each of the amplified signals to produce digital signals. In addition, the method involves correlating each of the digital signals with a code using a respective correlator for each of the digital signals to determine the time group delay differential between the signals. Further, the method involves calculating, with at least one processor, the time group delay coefficient of the signals by using the time group delay differential. The time group delay coefficient is used to correct for the atmospheric time delays in the signals.

Abstract: The present invention relates to a method and an apparatus for determining an integrity indicating parameter (e.g. an integrity risk IR or a protection level PL) indicating the integrity of positioning information determined from positioning information signals disseminated from a plurality of space vehicles SAT1, SAT2, SAT3 of a global positioning system. An input parameter (e.g. an alert limit AL or an integrity risk IR) is provided, a plurality of integrity information parameters (?SISA, ?SISMA or equivalent, ?X, kX) are received, and the integrity indicating parameter (IR; PL) is determined on the basis of the input parameter (AL; IR) and on the basis of a first relation between the integrity indicating parameter (IR; PL) and the input parameter (AL; IR) and the plurality of integrity information parameters (?SISA, ?SISMA or equivalent, ?X, kX).

Abstract: To detect an abnormal value in a satellite positioning system with high precision even when the observation environment changes or there is the time series correlation between data. An abnormal value index calculation unit 11 calculates an abnormal value index at each time of time-series data such as a pseudo distance between each artificial satellite and a receiver in the satellite positioning system or the like. A dynamic model forming unit 12 dynamically forms a model from the abnormal value index in a predetermined period and calculates a change point index from the time-series abnormal value index based on the dynamic model. The change point index is an index for determining whether the time-series is a one-shot outlier from a dynamic model or the dynamic model itself of input data changes when the time-series value which suddenly increases and decreases exists.

Abstract: A method for detecting anomalies on satellite navigation signals consists in extracting the code error values delivered at the output of the N code discriminators, and comparing the extracted code error values with a same first threshold value corresponding to an acceptable maximum code error value and assigning a confidence index to each navigation signal received on each reception channel i, the confidence index depending on the result of the comparison carried out on the code error values.

Abstract: A method of advanced receiver autonomous integrity monitoring of a navigation system is discussed and two modifications facilitating its implementation in a hybrid navigation system are disclosed. In the first approach, relations describing the effect of unmodeled biases in pseudo-measurement on the Kalman filter state estimate are analytically derived and their incorporation into the integrity monitoring algorithm is described. The method comprises receiving a plurality of signals transmitted from spaced-based satellites, determining a position full-solution and sub-solutions, specifying a pseudorange bias, computing a transformation matrix for the full-solution and all sub-solutions using a Kalman filter, computing a bias effect on an error of filtered state vectors of all sub-solutions, and adding the effect to computed vertical and horizontal protection levels.

Abstract: A satellite-based positioning system (SPS) signal processing technique re-samples a received series of PRN sequences from an SPS satellite to align them with a nominal sampling rate for a corresponding series of perfect reference PRN replica sequences.

Abstract: Disclosed herein is a system for detecting manipulation of a GNSS signal and mitigating against such manipulation. A GNSS receiver receives GNSS signals from a plurality of GNSS satellites, and calculates event times for each GNSS satellite. The GNSS receiver then compares a next event time for a particular GNSS satellite with an expected next event time for the particular GNSS satellite. If the difference between the expected next event time and the next event times exceeds a predetermined threshold, then the GNSS receiver indicates that signal integrity may be compromised.

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: Systems and methods are disclosed herein for verifying the quality of global navigation satellite system (GNSS) measurements. The system includes a GNSS receiver, a wireless communications device, and a fault detection processor. The GNSS receiver includes a GNSS antenna for receiving signals from a plurality of global navigation satellites and a processor for calculating a ranging measurement for each of the global navigation satellites from the GNSS receiver to the global navigation satellite. The wireless communications device receives ranging measurements from at least one other GNSS receiver. The fault detection processor performs a fault detection algorithm to determine if there is an anomaly affecting the ranging measurements of the GNSS receiver and the at least one other GNSS receiver.

Abstract: A method and apparatus for managing events in an electrical distribution system. A number of events in the electrical distribution system are identified for an operator based on a profile for the operator. A wireless mobile device is assigned to the operator and the profile includes a role of the operator. The number of events is sent to the wireless mobile device assigned to the operator.

Abstract: The present disclosure relates to a monitoring system which comprises at least one monitoring satellite placed in orbit at a lower altitude than that of the satellites of the satellite constellation so as to be capable of receiving the positioning signals emitted towards the Earth by said satellites, and which comprises a processing unit intended for verifying the integrity of said received positioning signals, using position information that is separate from said signals for this purpose.

Abstract: The invention relates to a network element comprising a controlling element for forming assistance data relating to two or more signals transmitted by a reference station of at least one navigation system; and a transmitter for transmitting the assistance data via a communications network to a device. The device comprises a positioning receiver for performing positioning on the basis of two or more signals transmitted by a reference station of the at least one satellite navigation system; a receiver for receiving the assistance data from the network element; and an examining element configured to examine the received assistance data to find out information relating to the status of the two or more signals. The information comprises indication on the reference station the signal relates to, and the status indicates the usability of the signal.

Abstract: Disclosed herein is a system for detecting manipulation of a global time source such as a Global Navigational Satellite System (GNSS) signal and mitigating against such manipulation. A plurality of receivers with geographical diversity receive GNSS signals, and calculate a time signal to be distributed to consuming devices. The receivers also communicate calculated time signals with other receivers. The receivers compare the time signals, and when a difference between the time signals exceeds a predetermined threshold, the receivers indicate that manipulation is likely. Such indication is shared across the network of receivers. The indication is further shared with consuming devices of the time signal from the compromised receiver. A second time signal that is not compromised may be shared with the consuming devices and/or used by the consuming devices. The consuming devices may modify their behavior when in receipt of the indication.

Abstract: A system and method for monitoring integrity of a Global Navigation Satellite System (GNSS) are provided. Integrity of a GNSS location is assessed based on a comparison of the GNSS location with one or more locations received from at least one other GNSS. Integrity of the GNSS location is also assessed based on a comparison of the GNSS location with one or more locations obtained from signals generated by one or more known located emitters. Integrity of the GNSS location is also assessed based on a comparison of the GNSS location with historical data, which may include contextual information of recent GNSS locations of a user equipment, measurements made by an inertial navigation system of the user equipment, and prior measurements made by the user equipment during similar paths. An integrity warning is outputted when one or more of the integrity assessments indicate a loss of integrity of GNSS.

Abstract: Systems and methods for detecting and displaying cycle slips are provided. In one example method, a first L1 signal and a second L2 signal may be received. The coarse/acquisition code from the L1 signal may be extracted and may be monitored to detect a phase shift in the code. In response to detecting a phase shift in the code, a data bit of the L1 signal may be monitored for a predetermined length of time to detect a change in the data bit. A cycle slip may be detected in response to detecting a change in the data bit during the predetermined length of time. In another example, a cycle slip may be detected in response to detecting a change between a phase of the L1 signal and a phase of the L2 signal.

Abstract: A method for detecting the distortion of a GNSS signal transmitted by at least one GNSS satellite and received by at least one GNSS receiver is disclosed, where the distortion is caused by a GNSS signal generation defect. Initially, at least one autoregressive parametric model of the GNSS signal is determined at the output of a correlation stage of the GNSS receiver. Next, at least one linear prediction error e(n) between the output signal of the correlation stage and the autoregressive parametric model is computed. The linear prediction error is compared to a detection threshold and the distortion of the transmitted GNSS signal is decided when the linear prediction error exceeds the detection threshold.

Abstract: Methods and devices for the analysis of global positioning system (GPS) data are described. The methods and devices comprise several metrics to analyse GPS data, such as tracking coverage, signal to noise ratio, multipath noise, positioning and receiver clock, troposphere and data noise.

Abstract: A first position of a satellite is calculated at a first time in dependence on received orbit data corresponding to an orbit path of the satellite. Anan orbit path of the satellite is modeled from the first position at the first time to a second time to determine a second position of the satellite at the second time. A third position of the satellite is then calculated at the second time in dependence on the received orbit data. The second position and third position are compared to determine a validity of the orbit data.

Abstract: A method for modelling integrity of a filtered global navigation satellite system, by calculating component navigation system error distributions for a set of fault conditions and a fault free condition, and determining overall navigation error distribution by forming a mixture distribution from these component navigation system error distributions. The mixture distribution may be determined by weighted summation of navigation system error (NSE) distributions with weightings determined according to prior probabilities for the fault conditions. Once the overall NSE mixture distribution is determined in this way, it can be used to derive one or more statistical quantities relevant to the integrity of the navigation system such as the probability of exceeding given alert limits in a desired coordinate geometry.

Abstract: In a method of Global Navigation Satellite System (GNSS) reference station integrity monitoring, network Real Time Kinematic (RTK) information is accessed for a location associated with a GNSS reference station. At least one aspect of GNSS information local to the location of the GNSS reference station is compared with a corresponding aspect of the network RTK information. The results of the comparing are monitored for indication of occurrence of compromise to operational integrity of the GNSS reference station.

Abstract: Provided is a method of detecting GPS clock signal jump, comprising a data obtaining step of obtaining GPS carrier phase measurements from a GPS receiver and satellite orbits from IGS to detect the GPS clock signal jump; a GPS clock bias calculating step of eliminating errors included in the data obtained from the data obtaining step and calculating GPS clock bias; a Teager energy calculating step of applying a Teager energy operator to the GPS clock bias calculated with respect to each satellite in the GPS clock bias calculating step and calculating Teager energy to determine whether the GPS clock jump is occurred; and a GPS clock jump detecting step of checking whether a Teager energy is larger than a threshold value. Therefore, the present invention can effectively detect the GPS clock signal jump in real-time.

Abstract: Example embodiments disclosed herein provide for a method for detecting a fault in a receiver for a satellite navigation system. The method includes calculating a plurality of measurement residuals corresponding to a position solution and combining the plurality of measurement residuals to form a test statistic. The method also includes calculating a threshold corresponding to the test statistic, wherein calculating the threshold includes selecting the threshold to be a value from a non-central chi squared distribution of possible test statistics that corresponds to a desired probability of false alarm. The test statistic is compared to the threshold and if the test statistic is larger than the threshold, performing at least one of: outputting an alarm indicative of a fault in the position solution and discarding the position solution.

Abstract: Methods and apparatus for implementing a receiver autonomous integrity monitoring (RAIM) algorithm are provided. The RAIM algorithm is for determining an integrity risk in a global navigation satellite system (GNSS) by processing several ranging signals received from satellites of the GNSS. The algorithm involves determining several integrity risks at an alert limit for different fault conditions of the ranging signals, and determining an overall integrity risk at the alert limit from the determined several integrity risks.

Abstract: A submarine homing system includes an acoustic emitter configured to emit an acoustic signal comprising at least two narrow-band tones, each narrow-band tone having a respective predetermined center frequency. An acoustic receiver is configured to receive the acoustic signal from the acoustic emitter, and produce one or more receiver signals. A processor is operatively connected to the acoustic receiver. The processor is configured to process the receiver signals to calculate a direction between the acoustic receiver and the acoustic emitter.

Abstract: In a method for reducing the adverse effect of clock frequency jumps on a user-position determination device in a global navigation system, a plurality of space vehicles each having a clock, transmit position determination information to the position determining device. If a sufficient number of such navigation signals from a first group of space vehicles having clocks in which no jump occurs are available for this purpose, and if a calculated integrity risk is acceptable, position determination is performed using those navigation signals. If not, however, the position determination device receives navigation signals from space vehicles of a second group with clocks in which jumps can occur. The latter signals are combined with signals from the first group in a manner which takes into account possible jumps, and the process is repeated.

Abstract: The present invention relates to a method for detecting and excluding at least one pseudo-range measured between a satellite and a receiver for receiving signals transmitted by different satellites of a radio-positioning constellation when said pseudo-range is faulty, characterized in that said method includes the steps of: (a) determining an estimation of the position of the receiver from the pseudo-ranges measured by the receiver, (b) estimating, from the thus-estimated position, biases in the measured pseudo-ranges; (c) processing the thus-obtained biases in order to derive a value representative of the probability of a fault for each pseudo-range; (d) preselecting, on the basis of the resulting values, a given number of pseudo-ranges which are most likely to be faulty; (e) determining, for each combination of pseudo-ranges from among the thus-preselected pseudo-ranges, a value of a test variable representative of the likelihood the combination is faulty; (f) selecting, on the basis of the values of the th

Abstract: In a baseband process circuit unit, a demodulation unit demodulates a received satellite signal which carries a navigation message to obtain a demodulated data. Further, an error bit detection unit detects an error bit from among the demodulated data using a parity code included in the demodulated data. An inconsistent bit detection unit detects an inconsistent bit by comparing the demodulated data with prescribed comparison data. An adoption determination unit determines whether or not to adopt the demodulated data, based on a difference between the error bit and the inconsistent bit. In addition, a correction unit corrects the demodulated data, in a case where the demodulated data is determined to be adopted by the adoption determination unit.

Abstract: A system and method are disclosed which may include providing a plurality of communication devices having access to the internet and respective GPS systems operable to communicate with a GPS satellite system; and each communication device transmitting a signal, indicative of GPS communication disruption, over the Internet to a back end system whenever (a) its GPS system is turned on; and (b) energy received through a GPS antenna of said communication device is below a level enabling a minimum signal to noise ratio needed for decoding GPS signal data.

Abstract: A method and a system calculates the low probability events for the evaluation of the precision performance of a satellite navigation system, and makes it possible to certify the precision performance of a satellite navigation system for high levels of requirement by modelling events of low probability on the basis of the implementation of the theory of extreme values conjointly with the use of a chart for evaluating precision performance.

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: The present invention relates to a method for protecting a radionavigation receiver user in relation to aberrant pseudo-range measurements. In the method, a measurement error is detected by a statistical estimation scheme based on calculating the residuals of the measurements.

Abstract: According to a first aspect, the invention relates to a method for checking the integrity of position information output by a satellite (GNSS) positioning device (1) including a bank (3) of Kalman filters each producing a navigation solution (dX0, dXi, dXn) from raw measurements of signals transmitted by the satellites, characterized in that the method comprises the steps of, for each filter in the bank: (i) correcting the navigation solution produced by the filter according to an estimate of the impact of a failure of a satellite on the navigation solution; (ii) calculating a cross-innovation reflecting the deviation between an observation corresponding to a raw measurement from a satellite not used by the filter and an a posteriori estimate of said observation from the navigation solution produced by the filter and corrected in accordance with step (i); and (iii) performing a statistical test of the cross-innovation in order to declare whether or not the satellite, the raw measurement of which is not used b

Abstract: The present invention relates to a method for determining a protection space in the event of two faulty measurements of a pseudo-range between a satellite and a receiver for receiving signals transmitted by various satellites in a radio-navigation constellation, characterized in that said method includes the steps of: (a) determining, on the basis of the pseudo-ranges measured by the receiver, a test variable representative of the likelihood of a fault; (b) estimating, for each pair of pseudo-ranges from among the pseudo-ranges measured by the receiver and from the expression of the thus-obtained test variable, a set of minimum-bias pairs detectable for a given missed detection probability; (c) expressing, for each pair of pseudo-ranges, the estimated set of detectable minimum-bias pairs in the form of an equation defining an ellipse associated with the pair of pseudo-ranges in question; (d) expressing the equation of each ellipse in parametric coordinates and expressing each detectable associated minimum-bia

Abstract: A method and a system verifies the precision performance of a satellite navigation system that can certify compliance with a level of precision whatever the observation conditions, notably as regards satellite geometry, and is a performance verification tool for the design, verification and qualification of a satellite navigation system.

Abstract: Provided is a method and apparatus for a pseudo range verification of a global navigation satellite system (GNSS) receiver, more particularly, a method and apparatus for the pseudo range verification of the GNSS receiver by comparing the pseudo range for a measurement calculated in the GNSS receiver and the pseudo range for a verification generated depending on a position of the GNSS receiver.

Abstract: Provided is an apparatus for monitoring a malfunctioning state of a global positioning system (GPS) satellite, the apparatus comprising: an orbit computing unit to compute an orbit of a geostationary satellite; a data receiver to receive GPS data from the GPS satellite; a data correction unit to correct an error in a clock error value of the GPS data; a first computing unit to compute a data pseudorange between the GPS satellite and a base station based on the corrected GPS data; a second computing unit to compute a geographical distance between the GPS satellite and the base station; and a determining unit to determine a malfunctioning state of the GPS satellite by comparing the data pseudorange and the geographical distance.

Abstract: A system and method for compensating for faulty satellite navigation measurements. A plurality of measurements in a system is received for a measurement epoch. A Kalman filter is used to calculate a state of the system for the measurement epoch based on the plurality of measurements, wherein the state of the system for the measurement epoch is calculated using a first closed-form update equation. A faulty measurement is detected in the plurality of measurements for the measurement epoch and a revised state of the system for the measurement epoch that compensates for the faulty measurement is calculated, using the calculated state of the system for the measurement epoch as an input to the revised state calculation, and using a revised closed-form update equation comprising the first closed-form update equation modified with respect to the faulty measurement.

Abstract: Apparatus and methods are provided for use in a receiver that receives global positioning data from one or more satellites above the Earth's surface. The apparatus and methods involve detecting a change in at least one parameter associated with the receiver and determining if the change in the at least one parameter is to be treated as erroneous. As a result of determining if the change in the at least one parameter is to be treated as erroneous, a further action may be performed. Determining if the change is to be treated as erroneous may include, for example, detecting changes in more than one parameter and determining if the changes are coincident. Detecting a change in at least one parameter may also enable the receiver to predict the presence and magnitude of multipath components of signals, predict changes in an environment local to the receiver, predict large errors in position estimates determined by the receiver and modify an acquisition and tracking strategy used by the receiver.

Abstract: Example embodiments disclosed herein provide for a method for detecting a fault in a receiver for a satellite navigation system. The method includes calculating a plurality of measurement residuals corresponding to a position solution and combining the plurality of measurement residuals to form a test statistic. The method also includes calculating a threshold corresponding to the test statistic, wherein calculating the threshold includes selecting the threshold to be a value from a non-central chi squared distribution of possible test statistics that corresponds to a desired probability of false alarm. The test statistic is compared to the threshold and if the test statistic is larger than the threshold, performing at least one of: outputting an alarm indicative of a fault in the position solution and discarding the position solution.

Abstract: A method and apparatus for directly estimating depleted ionosphere delay in a GPS receiver and using the estimate for improved navigation precision in satellite based augmentation systems.

Abstract: A method and apparatus for determining protection levels in a satellite navigation system includes the following steps: (1) determining an integrity risk at the alert limit for a plurality of application situations—for example, starting from approaches in category I (Category I precision approach) up to the operation “oceanic enroute;” (2) determining an interval of the alert limits between the largest set of alert limits which produces too high an integrity risk, and the smallest set of alert limits which produces an acceptable integrity risk; and (3) carrying out an interval nesting for the interval of the alert limits that was determined in the previous step, the integrity risk between the horizontal and the vertical being divided in the same way as it is obtained from the relationship between these integrity risks in the largest set of alert limits.

Abstract: A method for estimating an integrity risk in a satellite navigation system includes receiving a plurality of navigation signals at a user system from at least one satellite, the plurality of navigation signals including data relative to the integrity of the satellite navigation system; and estimating the integrity risk using the data in the at least one user system. The estimating further includes forming a plurality of intervals of an integration variable of an integral function, estimating a maximum of the integrity risk for each interval, comparing the maximum of each interval to find an overall maximum of all the intervals; and using the overall maximum as an estimate of the integrity risk.

Abstract: Methods and apparatuses are provided that may be implemented in various electronic devices to possibly reduce a first-time-to-fix and/or otherwise increase the performance or efficiency of a device in determining its current estimated position. In some embodiments, it may be determined whether current estimated position is valid based, at least in part, on pseudorange measurement information and pseudorange predicted information, and such determining may include obtaining a sum-of-squares of an a-posteriori measurement residual associated with the pseudorange measurement information and the pseudorange predicted information.

Abstract: A method for detecting the distortion of a GNSS signal transmitted by at least one GNSS satellite and received by at least one GNSS receiver, said distortion being caused by a GNSS signal generation defect, includes at least the following steps: a step for determining at least one autoregressive parametric model of the GNSS signal at the output of a correlation stage that said GNSS receiver includes; a step for computing at least one linear prediction error e(n) between said output signal of the correlation stage and said autoregressive parametric model; at least one step for comparing the linear prediction error to a detection threshold; and, a step for deciding on the distortion of the transmitted GNSS signal in the case where the linear prediction error exceeds said detection threshold.

Abstract: For amending navigation data of a global navigation system, navigation signals are received from a space vehicle, and a predicted clock phase offset of the clock signal sent from the space vehicle is estimated and stored in a memory. The clock phase offset difference between the current estimated clock phase offset and a previously estimated clock phase offset times (T1) is then computed and stored. An earlier computed phase offset difference between a previously estimated clock phase offset and a further previous estimation for said clock phase offset is obtained, wherein the time interval between the current measurement epoch and second earlier epoch is at least T1. The difference between the computed clock phase offset differences is derived, and compared with a given threshold value. If the latter difference is greater than the given threshold value, an integrity risk signal is generated and transmitted to other devices for position determination.

Abstract: This disclosure relates to the field of space and can be used for radio navigation determinations using man-made satellites of the Earth, in particular, for monitoring the integrity of a system without participation of ground control segment facilities and monitoring stations allocated globally. The apparatus includes: enhancement of responsiveness of a user's notification about navigation signal uncertainty; reduction of costs for solving the problem of the system integrity monitoring due to absence of ground control and monitoring complexes allocated globally; exclusion of complementary radio links; improvement of system integrity monitoring certainty; growth of reliability.