828 results about "Satellite system" patented technology

The invention relates to a monitoring and prewarning system and a monitoring and prewarning method for geological disasters. The monitoring and prewarning system for the geological disasters comprises a plurality of global navigation satellite system (GNSS) monitoring stations 1, a continuous operational reference system (CORS) 2, a 3rd-generation (3G) wireless network or wireless bridge 3, a microwave communication system 4, a monitoring and prewarning server 5, a monitoring and prewarning central computer 6 and the like which are arranged in a monitored area. Each GNSS monitoring station 1 comprises a global positioning system (GPS) receiver 11, a 3G network transmission component 12, video monitoring equipment 13, a microwave communication transmission component 14, a power supply 15 and the like. In the method, the aims of forecasting and prewarning possibly initiated geological disasters automatically in real time can be fulfilled by setting the GNSS monitoring stations in areas liable to the geological disasters, monitoring ground surface displacement in real time by the CORS, performing real-time ground surface displacement monitoring on the geological disasters, such as collapse, landslide, debris flow, surface collapse, subsidence, ground fissure and the like, which can be caused by ground surface displacement, combining remote video monitoring, performing data processing on monitoring information, and automatically issuing prewarning information.

The present invention discloses a method for increasing the channel capacity of a communications network, comprising a plurality of one-way TDMA transmitters sharing said channel, and at least one compatible receiver, by reducing transmission collisions among said transmitters. This is achieved by coupling a Global Navigation Satellite System (GNSS) decoder, such as a GPS receiver, to each transmitter, and limiting transmissions to discrete time slots, determined by timing signals provided by said GNSS. Further, this basic set of time slots is divided into several sub sets, and each transmitter selects a sub set of time slots according to its geographic location, in order to enable reusing time slots in spaced apart areas, as frequencies are reused in cellular networks. Then, each transmitter selects its own transmission time slot, from said sub set, in a way that statistically minimizes collisions among nearby transmitters. The present invention does not intend to ensure collision-free communications, yet is projected to reduce the transmission collision rate among simplex in nature transmitters, which have no means to detect other transmissions, or discover if a transmission was successful. One embodiment of this invention is related to distress radio beacons in satellite based Search and Rescue (SAR) systems, such as Cospas-Sarsat.

A global navigation satellite system-tracking (“GNSS-tracking”) device and method for determining one or more positions of the GNSS-tracking device utilizing a user-plane service is disclosed. The GNSS-tracking device may comprise: charging and tracking modules adapted to be disengagably coupled together, wherein the tracking module comprises (i) tracking circuitry for determining at least one position of the tracking module using the user-plane service in a satellite positioning system, and (ii) a chargeable source for supplying power to the tracking circuitry when disengaged from the charging module, and wherein the charging module is operable to charge the chargeable source when the charging module is coupled to the tracking module.

The invention discloses a multi-mode multi-frequency global navigational satellite system receiver radio frequency front end device. The device comprises a low-noise amplifier, a power divider, and multiple radio-frequency signal processing circuits, wherein the low-noise amplifier, the power divider, and the multiple radio-frequency signal processing circuits are connected in sequence. Each radio-frequency signal processing circuit comprises a first radio-frequency switch, a radio-frequency filter bank, a second radio-frequency switch, a radio-frequency amplifying module, a lower frequency mixing module, an intermediate frequency filter module, an intermediate frequency amplifying module, and an automatic gain control unit, wherein the first radio-frequency switch, the radio-frequency filter bank, the second radio-frequency switch, the radio-frequency amplifying module, the lower frequency mixing device, the intermediate frequency filter module, the intermediate frequency amplifying module, and the automatic gain control unit are connected in sequence. The lower frequency mixing module comprises a lower frequency mixing device and a local oscillating generating module which are connected with each other. A control unit is connected with the first radio-frequency switch and the second radio-frequency switch of each radio-frequency signal processing circuit and the local oscillating generating module of the lower frequency mixing module. The device can flexibly select intermediate frequency inputting from various combination frequency ranges of a quad-mode 11 frequency range, and therefore functions of collecting in the same module and processing navigation system intermediate frequency signals of four system satellites are realized, namely a global position system (GPS), Glonass, Galileo, and Big Dipper.

A method of processing global navigation satellite system (GNSS) data includes identifying one or more GNSS satellites servicing a predefined area, receiving at least one of GNSS almanac data or space-based augmentation system (SBAS) data for the satellites servicing the predefined area, determining the performance of the GNSS satellites servicing the predefined area using the almanac data or SBAS data, and applying a performance rating to the predefined area based on the performance of the GNSS satellites.

The invention provides a high-precision point positioning method and a high-precision point positioning system for a global navigation satellite system (GNSS). The method comprises the following steps: prestoring an observed value positioning equation with commonality for a compass navigation satellite system, a GPS, a GLONASS and a Galileo satellite navigation system, and interconvertible parameters of coordinate systems and time systems of the various satellite navigation systems into a storage module of a double-frequency GPS receiver; receiving signals of the various satellite navigation systems by the double-frequency GPS receiver through an antenna, and converting the signals into digital signals by a signal converting unit; reading the interconvertible parameters in the storage module and the observed value positioning equation by a data processing unit to process the digital signals; finally obtaining a high-quality PVT result; realizing the combination use of observed quantities and ephemerides of the various satellite navigation systems; and sending the PVT result to a field data acquisition device for recording. The method and the system realize the compatible high-precision point positioning based on the compass navigation satellite system/the GPS/the GLONASS/the Galileo satellite navigation system, and can provide point positioning position information with higher quality.

A method is provided for estimating parameters useful to determine the position of a global navigation satellite system (GNSS) receiver or a change in the position thereof. The method includes the steps of: obtaining at least one GNSS signal received at the GNSS receiver from each of a plurality of GNSS satellites; obtaining, from at least one network node, precise satellite information on: (i) the orbit or position of at least one of the plurality of GNSS satellites, and (ii) a clock offset of at least one of the plurality of GNSS satellites; identifying, among the obtained GNSS signals, a subset of at least one GNSS signal possibly affected by a cycle slip, the identified subset being hereinafter referred to as cycle-slip affected subset; and estimating parameters useful to determine the position of the GNSS receiver or a change in the position of the GNSS receiver using at least some of the obtained GNSS signals which are not in the cycle-slip affected subset, and the precise satellite information.

The invention pertains to the monitoring of the integrity of position and speed information arising from a hybridization between an inertial reference system and a satellite-based positioning receiver. The invention relates more precisely to a navigation apparatus known in the art by the name INS/GNSS system (for “Inertial Navigation System” and “Global Navigation Satellite System”) hybridized in closed loop.

The invention provides a high-precision time-frequency source capable of being tamed to a time-frequency standard in real time. The high-precision time-frequency source can obtain a first time-frequency clock difference sequence generated by a reference side and a global navigation satellite system (GNSS) remotely and in almost real time, and comprises a tamed side; the reference side generates N time-frequency signals of a to-be-calibrated clock; according to the N time-frequency signals and a satellite signal, a second time-frequency clock difference sequence is generated; according to the first time-frequency clock difference sequence and the second time-frequency clock difference sequence, a third time-frequency clock difference sequence between N time-frequency signals of a reference time-frequency source and the N time-frequency signals of the to-be-calibrated clock is obtained; according to the third time-frequency clock difference sequence, a relative frequency difference sequence is computed and acquired; and through the third time-frequency clock difference sequence and the corresponding relative frequency difference sequence, the to-be-calibrated clock is monitored and calibrated. The high-precision time-frequency source capable of being tamed to the time-frequency standard in real time can easily trace time performance and frequency performance of the reference time-frequency source (generally, the time-frequency standard, including a national time-frequency reference) in any laboratory, can trace the time and the frequency back to the International System of Units, and is relatively high in reliability, accuracy and stability.

The invention discloses a parallel navigation satellite signal tracking method based on GPU (graphics processing unit) and a system thereof. The method comprises the following steps: constructing a multichannel carrier tracking loop and a pseudo code tracking loop on CPU(central processing unit)-GPU, wherein the CPU is in charge of data reading, loop phase discrimination and control functions and the like, and the GPU is in charge of the relevant calculation and integral summation functions of a great quantity of data sequences; after the GPU finishes the integral summation calculation, adopting a two-stage binary tree calculation structure; calculating an error by a carrier phase discriminator and a CA (certification authority) code phase discriminator on the CPU; and controlling a local carrier phase and a CA code phase to correct to realize the tracking. According to the invention, the defects of poor flexibility and black box operation of a hardware receiver system and the defect that various navigation satellite signal systems can not be supported are overcome. Meanwhile, the processing speed and precision of a software receiver can be enhanced, the cost of the software receiver is lowered, and a GNSS (global navigation satellite system) software receiver can track the multichannel navigation satellite signal in real time.

The present invention provides a system, method and computer program for a GNSS receiver that is operable to provide an ultra fast Time To First Fix (TTFF). The invention is implementable without requiring the decoding of a navigation message transmitted by GNSS satellite systems. The system of the present invention may comprise a parameter obtaining means, a clock obtaining means and a Fast TTFF engine. The parameter obtaining means may obtain satellite parameters of one or more GNSS satellites. The clock obtaining means may obtain a clock for estimating a GNSS time tag. The Fast TTFF engine may be linkable to a signal interface that is operable to provide I/Q samples from a GNSS antenna. The Fast TTFF engine may comprise a measurement generation utility, a coarse search utility and a fine search utility. The measurement generation utility may compute the Doppler frequency shift and the code phase of the one or more GNSS satellites based on the I/Q samples.

The present invention relates to providing navigation guidance for mobile users, using Global Navigation Satellite Systems (GNSSs) for applications where the user position needs to be determined in real time while meeting the navigation requirements, especially integrity requirement, for the given application. The present invention assists in providing guidance with a high availability of integrity function by trading accuracy for integrity for two different types of navigation applications. A first type of application requires a capability of detecting an occurrence of multiple satellite signal faults; the first embodiment of the invention provides this capability with a high availability of integrity, using two or more independent GNSSs. A second type of application requires a capability of detecting an occurrence of a single satellite signal fault; the second embodiment of the invention provides this capability with a high availability of integrity, using any one or a combination of GNSSs. The detecting and deriving of both methods are (i) in position domain and (ii) determinative of mobile user safety.

The present invention discloses a portable personal communication device with an extendable helical antenna. This helical antenna is made of an elastic conductive spring, configured to change its height over a ground plane and along the antenna axis, mainly having two positions: a stowed position where the antenna is pressed down between the ground plane and a rigid cover, achieving a low profile; and an operational position where the rigid cover is removed and the antenna is extended by its own spring force, to a higher height, improving antenna gain. Normally, a second planar antenna may be placed over the same ground plane, not exceeding the footprint of the helical antenna, thus utilizing a compactly small volume and yet achieving a considerable electromagnetic decoupling between the antennas, due to their different radiation patterns. According to one embodiment, these antennas are installed in a Personal Locator Beacon (PLB) for Search and Rescue (SAR) of people in distress, where the planar antenna is coupled to a Global Navigation Satellite System (GNSS, such as GPS) receiver, and the helical antenna is coupled to a VHF/UHF radio.

A system and method for determining timing offset errors in a low earth orbit satellite system based upon Doppler and Doppler rate of change is provided. A user terminal determines first and second timing offsets respectively associated with first and second satellite beams from respective first and second satellites. Next, the user terminal determines the Doppler and Doppler rate of change associated with the first and second satellite beams. A timing offset is estimated from the measured Doppler and Doppler rate of change and is then compared with the user terminal's own determined timing offset. If the comparison does not produce a value within a predetermined threshold, a beam identification error is declared.

The invention relates to an ADS-B (automatic dependent surveillance - broadcast) autonomous anti-false object spoofing method. The ADS-B is based on a GNSS (global navigation satellite system), ground-air data links and other advanced techniques, and is a novel ground-air surveillance system which is being globally popularized by ICAO (international civil aviation organization). Because of the opening and sharing characteristics of working frequency, signal format and communication protocol of the ADS-B, the application of the system will be easily subject to artificial malicious spoofing and attack by wireless amateurs or illegal persons, a false target is formed, the management of ATC (air traffic control) areas is disordered, the normal aviation flight order is seriously disturbed, and the severe hidden hazards on safety are caused. The system comprises an ADS-B ground base station host, an anti-false target processing auxiliary machine, an BD/GPS (Beidou global positioning system) antenna, an ADS-B receiving antenna, an anti-false target direction measuring antenna, a PC (personal computer) (optional), an BD/GPS satellite, and an aircraft.

Disclosed is a method for achieving space-based autonomous navigation of global navigation satellite system (GNSS) satellites, and relates to the field of satellite navigation technologies. The method includes the following steps: optimizing a DRO, and establishing a dynamic model of an earth-moon space satellite orbit; establishing measurement links, by a low earth orbit (LEO) data relay satellite, with an earth-moon space DRO satellite and a GNSS respectively, and measuring an inter-satellite distance for modeling and linearization; adopting an extended Kalman filter (EKF) method to process inter-satellite measurement data, and autonomously determining a position and velocity of the global navigation satellite system without depending on the ground measurement and control support.

The invention relates to a gravity satellite formation orbital stability optimization design and an earth gravity field precision inversion method on the basis of disturbing inter-satellite distance principle, in particular to an orbital stability optimization design method for a four-satellite system (FSS). In order to guarantee the stability of the four-satellite system, the quantity of satellite orbits is optimally designed, orbital semi-major axes, orbital eccentricities, orbital inclinations and right ascensions of ascending nodes keep unchanged, the difference of arguments of perigees each pair of satellites and the difference of mean anomalies of the pair of satellites are 180 degrees respectively, an initial argument of perigee of each satellite is arranged at the equator, an initial mean anomaly of each satellite is arranged at a pole, and the ratio of the semi-major axis of each elliptical orbit of the four-satellite system to a semi-minor axis of the elliptical orbit of the four-satellite system is 2:1. The gravity satellite formation orbital stability optimization design and the earth gravity field precision inversion method have the advantages that an earth gravity field is precisely and quickly inverted on the basis of a disturbing inter-satellite distance process; and the orbits are high in stability owing to the method, the earth gravity field computation precision is effectively improved, the gravity field inversion speed is increased to a great extent, and requirements on the performance of a computer are low.

The invention discloses a satellite health state multistage fuzzy evaluation method based on an AHP-entropy weight method. The method includes: constructing a system weight system comprising a subjective weight, an objective weight and a comprehensive weight, providing the accurate comprehensive weight for the fuzzy comprehensive evaluation method by adopting an analytic hierarchy process and an entropy weight method, providing the subjective weight by adopting the analytic hierarchy process, providing the objective weight by adopting the entropy weight method, and obtaining the subjective andobjective combined comprehensive weight from the subjective and objective weights through an optimization function; constructing a system evaluation system comprising a factor discourse domain, a comment set, a membership function, an evaluation matrix and multi-stage fuzzy evaluation; and comprehensively evaluating the use state of the on-orbit satellite, evaluating each layer of elements through a membership principle of fuzzy comprehensive evaluation, and then sequentially recursively evaluating the overall health state from bottom to top by adopting a multi-stage fuzzy comprehensive evaluation method. The method improves the safety and reliability of a satellite system, reduces the effective life cycle operation cost, and guarantees the smooth completion of an in-orbit satellite task.

A global navigation satellite system (GNSS) receiver using phase lock loops for strong GNSS signals and (AFC) loops for weak GNSS signals on a satellite-by-satellite basis. The phase lock loops or the AFC loops associated with particular GNSS satellites generate frequency feedback adjustments for tracking the carrier frequencies of the incoming GNSS signals in order to determine pseudoranges for calculating a location fix. The transition from an AFC loop to a phase lock loop is controlled for each GNSS signal depending on location quality parameters including a history of previous loop transitions, knowledge of whether a transition is in-progress, and a conditional PDOP where the pseudorange from the GNSS signal is removed from the computation of the location fix.

The invention discloses a compatibility capturing method of a multi-mode GNSS (Global Navigation Satellite System) combination receiver. The capturing method comprises the following steps of: carrying out corresponding capture process on a satellite signal within coherent integration accumulation time and non-coherent integration accumulation time; adopting a fuzzy logic algorithm in the capture process, dynamically adjusting the coherent integration accumulation time and the non-coherent integration accumulation times according to a carrier-to-noise ratio and a carrier speed; and within the coherent integration accumulation time, carrying out the secondary sampling on a middle frequency signal of the acquired satellite signal, i.e. all data are decomposed into a plurality of groups, and the data points in each group are at one pseudo-random code element, and subsequently the Fourier transform, the Fourier inversion, the DCT (Discrete Cosine Transformation), the IDCT (Inverse Discrete Cosine Transform), the mode value square and threshold judgment process are carried out. With the adoption of the capturing method, the defects that signals cannot be captured as an existing capturing method is low in sensitivity and likely to be interfered are overcome, and satellite signals can be captured normally when a GNSS signal is shielded and strong environment noise exists.

Disclosed is a technique that can provide one or more countermeasures against spoofers. A beamformer can control an antenna pattern of a CRPA to generate a survey beam. The survey beam is swept across space to determine a characteristic signature based on carrier-to-noise ratios (C/No) for particular space vehicle signals. Matching C/No signatures can be used to identify the existence of spoofers and invoke a countermeasure, such as nulling.

The invention discloses a system efficiency comprehensive evaluation method of a navigation constellation, which comprehensively considers different interruption types such as short-term planned interruption, short-term unplanned interruption, long-term interruption and the like, and various factors such as average interruption interval time of a satellite, satellite development time, reliabilityof a carrier rocket, inter-satellite logic relation, spatial signal precision and the like, utilizes a generalized random Petri network to construct a single-rail availability model, utilizes random faults and loss faults to construct a single-satellite multi-parameter reliability model, utilizes a combined weighting method based on a game theory to construct a single-satellite capability model, utilizes a weighted product method to construct a single-satellite system efficiency model, comprehensively considers single-satellite system efficiency and inter-satellite logic relation, and utilizesa Bayesian network to develop navigation constellation system efficiency modeling, so that the system efficiency comprehensive evaluation of the navigation constellation can be realized; and the system efficiency comprehensive evaluation method of a navigation constellation method can provide quantitative basis for top-level design and running state evaluation of the satellite navigation system,and can be expanded to be applied to series constellations such as communication, remote sensing and the like.

The invention provides a GNSS+INS+odo (global navigation satellite system+inertial navigation system+odometer) combined navigation system, which can solve the problems that at present in a combined navigation system of the vehicle-mounted field, vehicle-mounted easily outputtable odometer information can be effectively utilized to amend a GNSS+INS system so as to achieve a better positioning effect, and when the odometer information output of part of a vehicle-mounted system has low priority in vehicle-mounted master control scheduling and is likely to be discontinuous, a GNSS+INS combined navigation system can be directly adopted, and related amendment module can be started to achieve better positioning output. Without adding the vehicle-mounted system hardware cost, the combined navigation system performs adaptive adjustment of relevant algorithm module through reasonable use of sensor information, can output a good positioning result with or without a odometer, and for end-users, the cost performance is greatly enhanced, thus being easy for industrialization development.