76 results about "Pseudolite" patented technology

The invention relates to a space-ground integrated Beidou high-precision positioning method applied to urban canyons, and belongs to the technical field of navigation positioning. The method comprises the following steps: deploying a pseudo satellite base station, calibrating coordinates of the base station through carrier phase difference, and monitoring the number of Beidou visible satellites; a master pseudo-satellite is determined, timestamps and ephemeris data are broadcasted to slave pseudo-satellites through Beidou short messages, and the slave pseudo-satellites are combined with bidirectional ranging data to correct a local clock to realize high-precision synchronization; receiving Beidou and pseudo-satellite signals by a user terminal, screening effective observation values through a shielding judgment mechanism, substituting the effective observation values into a non-difference observation equation in combination with pseudo-satellite reference difference data, and resolving a fusion result through an elastic coupling mode; and finally, multi-path interference is identified by using pseudo-satellite double antennas, and historical data is called to construct an error model to correct a fusion result. The space-ground integrated positioning of Beidou and pseudo satellites in an urban canyon scene is realized, the centimeter-level positioning precision is stably output, and the high-precision positioning requirements of urban traffic, surveying and mapping and the like are met.

The invention relates to an ephemeris broadcast and time synchronization method for Beidou pseudolite deformation monitoring, and belongs to the technical field of satellite positioning. The method comprises the following steps: constructing a linearization error equation based on a pseudo-range observation value, and solving a clock error correction amount in combination with a robust iterative algorithm to improve the time synchronization precision; analyzing ephemeris parameters of the Beidou GEO satellite, calculating earth-fixed coordinates of the Beidou GEO satellite, and rotating and adapting the earth-fixed coordinates; establishing an affine transformation relationship between the pseudo-satellite coordinates and GEO ephemeris, and generating optimized pseudo-satellite ephemeris data; and a time synchronization protocol is designed, and clock skew is compensated through bidirectional timestamp interaction of the main base station and the pseudo satellite. According to the method, nanosecond synchronization of the pseudo-satellite and the real satellite is realized, the ephemeris parameter redundancy problem of the static pseudo-satellite is optimized, multi-system cooperative work is supported, and the deformation monitoring reliability and precision under the complex terrain are remarkably improved.

The invention relates to the technical field of clock synchronization, in particular to a high-precision clock synchronization method and system based on Beidou satellite navigation, and the method comprises the steps: a pseudo satellite master station receives a Beidou signal, carries out the processing of capturing, tracking and the like, solves the transmission time and transmission delay, and adjusts a local clock to obtain the local receiving time; the 1PPS pulse is corrected, so that the rising edge of the 1PPS pulse is aligned with the whole second time of the local receiving time; and the master station completes time service by taking the 1PPS as an anchor point, adjusts the telegraph text transmission time delay, and broadcasts time service information to the slave station. And the slave station receives the telegraph text resolving time, calculates the transmitting time and synchronously transmits the telegraph text with the master station, so that the time synchronization of the ground-based pseudo satellite system and the Beidou is realized. According to the method provided by the embodiment of the invention, the unification of the ground-based pseudo satellite system and the Beidou time reference is realized, the problem that the existing system cannot unify the time reference with the Beidou is solved, high-precision time synchronization is ensured, and indoor and outdoor seamless positioning is supported.

The present invention specifically discloses a method for optimizing the layout of indoor pseudolite base stations based on the minimum GDOP configuration, which relates to the technical field of indoor positioning. The method includes: S1. Defining the scenario and the number of base stations, setting the population size, and initializing the population based on minimizing the geometric dilution of precision GDOP; S2. Collecting the number of visible satellites and horizontal dilution of precision data, calculating the objective function value, storing the non-dominated solutions according to the Pareto dominance relationship, and determining the initial optimal position of the particle swarm; S3. Updating the inertia weight using a piecewise adaptive linear decreasing strategy, and updating the particle velocity and position; S4. Recalculating the particle objective function value, updating the individual and global optimal positions, and updating the external archive; S5. Checking whether the termination condition is satisfied, and if not, continuing the iteration; S6. Outputting the finally obtained non-dominated solution set. This method effectively improves the performance of the indoor pseudolite positioning system and provides a new way for optimizing the layout of base stations.

The invention relates to a positioning method, a positioning device and a readable storage medium, and relates to the technical field of satellite navigation. The positioning method is applied to a receiver, and the receiver receives a pseudo satellite signal sent by each target satellite in a plurality of target satellites simulated by a pseudo satellite base station; wherein the number of the target satellites is at least four, and the target satellites are satellites which are invisible at the position where the receiver is located; for each pseudo-satellite base station, determining auxiliary positioning information of the pseudo-satellite base station according to the pseudo-satellite signal corresponding to the pseudo-satellite base station; wherein the auxiliary positioning information comprises the base station position of the pseudo satellite base station and the clock skew, and the clock skew is the skew between the clock of the pseudo satellite base station and the local clock of the receiver; and determining the position of the receiver according to the auxiliary positioning information of the pseudo satellite base station.

The invention relates to a Beidou pseudolite signal simulation generation method, which comprises the following steps of: setting a pseudolite private frequency band so as to avoid same-frequency interference with a real Beidou satellite signal; high-precision clock synchronization is carried out to ensure that the pseudolite and the Beidou atomic clock are highly synchronized; and the transmitting power is dynamically adjusted to adjust the transmitting power in real time, the near-far effect is inhibited, and the signal coverage range is optimized. Through collaborative optimization of frequency spectrum planning, clock synchronization and power regulation, the positioning availability is improved and the elevation precision is optimized in a complex environment, and a complete enhanced positioning solution is provided for a Beidou system in scenes such as automatic driving, tunnel navigation, mountains and canyons.

The invention discloses a Beidou pseudo satellite fusion positioning method and system in a tunnel. The method comprises the steps that a tunnel is divided into multiple sections of visible sub-areas, a relative coordinate system is established, Beidou signals are introduced into the tunnel through Beidou pseudo satellites, a common commercial receiver can still have the Beidou signal positioning capacity in the tunnel, meanwhile, according to the environment in the tunnel, a directional antenna is adopted, the multipath effect is reduced, and the positioning accuracy of the Beidou signals is improved. An infrared distance measuring device is arranged in a specific area, the vehicle driving direction and Doppler errors are judged, single pseudo satellite positioning is achieved through Doppler, and final coordinate output is achieved through the relation between relative coordinates and map coordinates.

The invention relates to a positioning method, a positioning device and a readable storage medium, and relates to the technical field of satellite navigation. The positioning method is applied to a receiver, and comprises the following steps: receiving a pseudo satellite signal for simulating each target satellite in a plurality of target satellites; wherein the target satellite is a satellite which is invisible at the position of the receiver; determining a pseudo satellite base station corresponding to each target satellite according to the pseudo satellite signal; for each pseudo-satellite base station, determining whether a target pseudo-satellite signal corresponding to the pseudo-satellite base station is credible; and under the condition that the target pseudo-satellite signal is credible, determining the position of the receiver according to the target pseudo-satellite signal.

The present application discloses a GNSS pseudo-satellite system for generating and broadcasting time-frequency synchronized GNSS pseudo-satellite signals based on a GNSS system. The system includes at least one main base station and at least three sub-base stations. Any one of the at least one main base station includes a main base station GNSS signal processing unit, a main base station time-frequency synchronization unit, a main base station signal generation unit, a main base station synchronization reference signal receiving unit, a main base station loop processing unit, and a main base station reference signal generation unit. Any one of the at least three sub-base stations includes a sub-base station time-frequency synchronization unit, a sub-base station signal generation unit, a sub-base station synchronization reference signal receiving unit, a sub-base station loop processing unit, and a sub-base station reference signal generation unit. The signals emitted by the main base station and sub-base stations of the GNSS pseudo-satellite system of the present application have time-frequency synchronization characteristics, which can help the user terminal achieve accurate dynamic positioning.

This invention discloses a pseudo-satellite indoor positioning optimization method based on ergonomic robust Kalman filtering, comprising the following steps: obtaining the initial positions of all positioning base stations; setting the verification information parameters in the ergonomic robust Kalman filter model; obtaining positioning route data passing through the initial positions of all positioning base stations; inputting the positioning route data into the ergonomic robust Kalman filter model for processing to obtain the optimized positions of the positioning base stations; obtaining the optimal verification information value by comparing the optimized positions with the initial positions; setting the optimal verification information value as the model verification information for this positioning, and starting the positioning process. This invention combines the idea of ​​the ergonomic algorithm with the robust Kalman filter algorithm, thereby effectively solving the problem of ensuring the optimality of verification information in the robust Kalman filter algorithm model during actual positioning, thus further improving the accuracy of the algorithm and obtaining a better filtering effect.

The application relates to a space-ground integrated Beidou high-precision positioning method applied to an urban canyon, and belongs to the technical field of navigation and positioning. The method comprises the following steps: deploying a pseudolite base station, calibrating the base station coordinates through carrier phase difference, and monitoring the number of visible Beidou satellites; determining a master pseudolite, broadcasting timestamp and ephemeris data to a slave pseudolite through a Beidou short message, and combining two-way ranging data to correct a local clock to realize high-precision synchronization; then a user terminal receives Beidou and pseudolite signals, screens effective observation values through a shielding discrimination mechanism, combines pseudolite reference differential data into a non-difference observation equation, and solves a fusion result through a loose-tight coupling mode; finally, the pseudolite double-antenna is used to identify multipath interference, historical data is called to construct an error model, and the fusion result is corrected. The space-ground integrated fusion positioning of Beidou and pseudolites in the urban canyon scene is realized, stable centimeter-level positioning precision is output, and the high-precision positioning demand of urban traffic and surveying and mapping is met.

The application discloses a discontinuous random time hopping pulse pseudolite signal tracking method based on carrier phase correction, and belongs to the field of satellite navigation auxiliary enhancement. The method first down-converts the received pseudolite signal to an intermediate frequency by using a receiver local oscillator; then carries out effective time slot signal interception and invalid time slot interference cutting on the pseudolite signal converted to the intermediate frequency by using a random time hopping pulse generation and control module in the receiver; then generates a carrier phase correction value of the signal in the effective time slot by using the pulse position information provided by the random time hopping pulse generation and control module and the carrier Doppler information fed back by the rear end; then further generates a cosine and sine result of the carrier phase correction value, and uses the result to continuously correct the carrier phase instantaneous value in the effective time slot; finally, the method realizes accurate tracking on the pseudolite signal after carrier phase correction by using a delay lock loop and a phase lock loop.

The invention belongs to the technical field of pseudo satellite positioning, discloses an indoor pseudo satellite signal carrier-to-noise ratio positioning method based on a commercial smart phone, and solves the core problem through innovative design. The invention provides a positioning technology based on Bayesian reasoning alternating optimization dynamic estimation. According to an attenuation relationship between a carrier-to-noise ratio observation value and a distance base station, maximum posteriori estimation (MAP) is calculated through Bayesian reasoning, and an alternating estimation strategy is adopted to iteratively optimize an attenuation coefficient and a position until the attenuation coefficient and the position converge, so that the change of the attenuation coefficient is effectively dealt with, and the performance difference between smart phone devices is relieved; compared with a traditional weighted centroid method, the average positioning precision is improved by 30%. The technology provided by the invention is not only suitable for smart phones with different performances, but also can be used. The technology provides a universal solution for high-reliability positioning of the smart phone under the same-frequency interference condition.

This invention proposes a pseudo-satellite base station layout optimization method suitable for urban lifeline monitoring, belonging to the field of deformation monitoring. The method determines the urban lifeline areas to be monitored based on existing city maps and analysis of relevant GNSS signal strength and positioning accuracy. It also analyzes system measurement errors in positioning scenarios to determine the constraints on base station layout, using GDOP (Geostationary Descent Point)... w Evaluation metrics were established, and a mathematical model of the base station geometric layout was built in the positioning area. The Monte Carlo algorithm was used to solve the mathematical optimization model with Cramérault lower bound (CRLB) constraints, thus initially determining the current optimal layout of base stations in the positioning area. These models were then used as superior individuals in a population, and an improved genetic algorithm was used to obtain the optimal base station layout. This invention makes the deployment of pseudo-satellite base stations in urban environments more flexible and accurate, improving base station signal coverage and quality, system positioning accuracy, and enhancing the efficiency of urban lifeline monitoring.

The invention discloses an indoor high-precision positioning method realized by backstepping after indoor Bluetooth beacon coarse positioning, which comprises the following steps: acquiring navigation auxiliary data sent by a Bluetooth beacon system, and calculating by using signal intensity data of a broadcast message received from the Bluetooth beacon system to obtain a summary coarse positioning position of a terminal; after the terminal and the Bluetooth beacon system finish time synchronization, calculating a terminal receiver clock error based on the navigation auxiliary data, and reversely calculating a virtual pseudo-range from the terminal to a satellite based on the navigation auxiliary data, the summary coarse positioning position and the terminal receiver clock error; and the terminal receives the position system information block from the network side, analyzes the position system information block to obtain RTK differential data, performs differential positioning calculation by using the virtual pseudo-range, the RTK differential data and the summary coarse positioning position, and outputs indoor positioning coordinates. According to the invention, the Bluetooth facility is used for relaying satellite data and constructing a virtual observation value, and low-cost extension of an outdoor RTK high-precision positioning algorithm to an indoor scene is realized on the premise that pseudo-satellite hardware is not needed.

The present invention discloses an indoor dual-antenna positioning method based on carrier phase difference optimization. The method first installs two pseudolites indoors to transmit signals and messages in a GPS standard format. A dual-antenna receiving terminal is installed on a device that requires positioning information. A carrier phase reference error from the receiving terminal to the pseudolites is then obtained. During the positioning process, the receiving terminal receives pseudolites' message signals. The carrier phase differences between pseudolites 1 and 2 and receiving antennas A and B are calculated based on the carrier phase conditions. The distance differences between the pseudolites and receiving antennas A and B are calculated using the carrier phase differences. An optimization model is established to minimize the residual error between the measured carrier phase difference and the theoretically calculated carrier phase difference. The optimization algorithm is then used to solve the position data of the dual-antenna receiving terminal, thereby achieving indoor positioning.

The invention discloses a pseudolite indoor positioning method based on Chan and SQP. The method comprises the following steps: 1) a pseudo satellite receives a signal and outputs a carrier phase value; 2) a pseudo satellite indoor positioning model based on Chan and SQP algorithms; 3) analyzing a model positioning error; and 4) after removing the positioning error, correcting the carrier phase positioning observation value by using the model. According to the indoor pseudo-satellite positioning method based on Chan and SQP, the positioning value obtained through the Chan algorithm serves as the initial solution of SQP for iteration, and the indoor carrier phase positioning precision of the pseudo-satellite is improved by reducing errors. Aiming at the problem that a Chan algorithm non-line-of-sight (NLOS) error is relatively large during indoor positioning and the NLOS error can cause a multipath effect during positioning, an SQP is utilized to carry out iterative correction on a Chan positioning value, and establishment of a positioning model is completed without depending on any external data. The algorithm is applied to a pseudo-satellite end, positioning errors are reduced, the positioning precision of pseudo-satellites is improved, and subsequent superposition errors are avoided. According to the method, result divergence caused by NLOS is overcome, and meanwhile, the indoor positioning precision of the pseudo-satellite is effectively improved.

A High Altitude Pseudo Satellite (HAPS) aircraft is disclosed for maintaining the span-wise shape of the wing and maintaining total bending and torsion loads. The aircraft including at least one aeroelastic span loaded fixed wing having an aspect ratio greater than 15 and wing loading less than 6 kg / m2, the wing having a plurality of spoilers distributed across the span of the wing and each spoiler being chordwise located adjacent the center of pressure of the wing. The HAPS aircraft further includes a control system for controlling the spoilers, and sensors which determine the amount of lift at points or regions along the wing span, the pitch and roll at points or regions along the wing span, the bending and torsional strain at points or regions along the wing span, or the absolute speed and roll and pitch angle of the wing.

The invention relates to a pseudo satellite navigation and positioning method under weak geometric configuration, and belongs to the technical field of pseudo satellite positioning, and the method comprises the following steps: under the condition that the layout of a pseudo satellite base station is limited and is in weak geometric configuration, after the fixed motion track of a pseudo satellite receiver is broken, laying the pseudo satellite base station along the broken line track; when the pseudo-satellite receiver moves to one track line segment in the broken line track, establishing a pseudo-satellite positioning first error equation set according to signals transmitted by a plurality of ground-based pseudo-satellite base stations which are received at the same time; taking the trajectory equation of the trajectory line segment as a motion constraint condition, and adding a motion trajectory horizontal error equation at the approximate coordinate of the pseudo satellite receiver into the first error equation set to obtain a pseudo satellite positioning second error equation set; and iteratively solving the second error equation set to obtain a pseudo-satellite single-point positioning result, and calculating an HDOP value of the second error equation set. According to the method, the parameter position solving precision is improved under the weak geometric configuration, and the availability of the positioning service is enhanced.

The invention belongs to the technical field of tunnel positioning, and discloses a tunnel high-precision positioning system based on fusion of leaky coaxial cables and pseudo satellites, and the system comprises a conduction unit which generates BDS / GPS dual-system navigation signals; the main control clock unit is configured with a dual-mode clock taming module and generates a local carrier signal homologous with a main clock; the leaky coaxial cable is made of a radiation type low-smoke halogen-free flame-retardant polyolefin sheath material; the indoor and outdoor integrated positioning terminal realizes indoor and outdoor positioning by combining the signal transmission characteristics of the leaky coaxial cable; and the comprehensive management platform supports real-time trajectory tracking, electronic fence alarm and multi-dimensional data analysis, and provides real-time monitoring and safety management. According to the tunnel high-precision positioning system based on fusion of the leaky coaxial cables and the pseudo satellites, random errors caused by asymmetric paths in traditional Ethernet synchronization are overcome through the deterministic time delay characteristic of a physical transmission medium, and therefore the synchronization precision superior to that of a traditional industrial Ethernet is achieved.

The present invention discloses a method, system and related components for positioning a pseudolite in a reduced dimension under an occlusion scenario. The method includes: obtaining the three-dimensional coordinates of the pseudolite in a reference rectangular coordinate system under the occlusion scenario; fixing one of the horizontal axis coordinates of the receiver in the reference rectangular coordinate system in combination with map matching according to the linear movement trajectory of the receiver, and determining the z-axis coordinate of the receiver in the reference rectangular coordinate system according to prior information; wherein, a plurality of pseudolites are arranged along the target horizontal axis direction under the occlusion scenario; based on the three-dimensional coordinates of the pseudolite and the z-axis coordinate and one of the horizontal axis coordinates of the receiver, the target horizontal axis coordinate of the receiver is solved by using the least squares algorithm. The present invention obtains positioning initial information through map matching to identify the positioning range, and then reduces the dimension of the positioning state quantity by reducing the number of coordinates to be solved, thereby improving the positioning accuracy and reliability.

The present invention relates to the field of positioning and navigation, and in particular to a Beidou information positioning method for use in tunnels. The present invention provides a method for obtaining communication transmission parameters when a vehicle communicates and transmits with a pseudo-satellite group in each positioning area at predetermined intervals, obtains a multipath effect characterization value, and adjusts the transmission power according to the multipath effect characterization value. This method achieves a real-time evaluation of the strength of the multipath effect of electromagnetic communication in the tunnel, and adaptively adjusts the transmission power based on the evaluation result, thereby improving the ability to resist the multipath effect in the complex electromagnetic environment in the tunnel, improving the accuracy of satellite positioning in the tunnel, and reducing positioning delay. The present invention considers the communication signals of different vehicles and the multipath effect characterization values ​​at corresponding moments, sets corresponding correction intervals for different vehicles, and selects different positioning strategies according to the location of the vehicle, thereby improving the positioning accuracy when the positioning system interacts with different vehicle models.

A high-altitude pseudo satellite (HAPS) aircraft having aeroelastic span loaded fixed wing(s) 1, aspect ratio greater than 15, wing loading less than 6 kg / m², and spoilers 6’ distributed across the wi

This invention provides a method, system, and device for deformation monitoring at indoor monitoring points, applied in the field of communication technology. The method includes: receiving a monitoring station and a reference station respectively analyzing and processing preset BeiDou signals emitted by each pseudosatellite to obtain and transmit first target analytical parameters and second target analytical parameters; determining a double-difference observation equation based on the target analytical parameters among multiple pseudosatellites, the approximate coordinates of the monitoring station, and the calibration coordinates of the reference station; fixing the double-difference integer ambiguity of the double-difference observation equation for each epoch to obtain the target integer ambiguity corresponding to the double-difference observation equation for each epoch; solving the double-difference observation equation based on the target double-difference ambiguity to obtain the target monitoring coordinates corresponding to the monitoring station within a preset time period; and determining the displacement of the target monitoring point based on the target monitoring coordinates. This invention achieves millimeter-level precision deformation monitoring of monitoring points in indoor or shaded environments.

The present disclosure discloses a vehicle-mounted satellite, inertial navigation, and pseudolite fusion positioning system and method, comprising: a pseudolite navigation positioning system for obtaining pseudolite data of a vehicle; a satellite navigation positioning system for obtaining GNSS satellite data of the vehicle; an inertial sensor for obtaining inertial navigation data of the vehicle; a fusion positioning module for positioning the scene where the vehicle is located according to the GNSS satellite data of the vehicle; when the vehicle is in an open scene, obtaining the positioning information of the vehicle through the GNSS satellite data and the inertial navigation data of the vehicle; when the vehicle is in a completely shielded area, obtaining the positioning information of the vehicle through the pseudolite data and the inertial navigation data of the vehicle; when the vehicle is in a semi-shielded area, obtaining the positioning information of the vehicle through the GNSS satellite data, the pseudolite data, and the inertial navigation data of the vehicle. Continuous and accurate positioning of the vehicle is realized.

The present application relates to a pseudolite deployment optimization method based on the geometric characteristics of GDOP values. The method includes: determining the deployable space for pseudolites based on the elevation cutoff angle at which users receive satellite signals, the radius of the target area, and the deployable altitude range; calculating the radius of a circle at the maximum deployable altitude based on the maximum deployable altitude in the deployable space; and obtaining the pseudolite geometric layout that minimizes the GDOP value of the central user based on the radius, the number of pseudolites, and the pseudolite observation matrix of the central user in the target area; obtaining the measurement matrix corresponding to the user based on the position coordinates of the user in the target area and the pseudolite geometric layout; obtaining the optimal altitude of the top pseudolite based on the measurement matrix and the deployable altitude range; and deploying pseudolites based on the pseudolite geometric layout and the optimal altitude of the top pseudolite. This method can improve the positioning accuracy of users in the target area and quickly optimize pseudolite deployment.

The embodiment of the invention provides a positioning method, device and system, and relates to the technical field of satellite positioning. The positioning method comprises the following steps: receiving a pseudo satellite signal sent by a pseudo satellite base station; analyzing the pseudo satellite signal to obtain a navigation message containing pseudo satellite positioning information and positioning auxiliary information; determining the position of the receiver according to the pseudo satellite positioning information and the positioning auxiliary information; wherein the positioning auxiliary information comprises equipment delay information of the pseudo-satellite base station transmitting the pseudo-satellite signal. Therefore, the pseudo-satellite signal generated based on the satellite modulation technology can realize long-distance reliable transmission, and the positioning precision of the receiver can be improved by carrying the positioning auxiliary information in the pseudo-satellite signal.

The application discloses a pseudolite navigation message management method, system, device and storage medium. The method comprises the following steps: obtaining a navigation message request of a pseudolite positioning system based on a preset communication protocol; generating a first navigation message according to a navigation message type in the navigation message request; and sending the first navigation message to a running control system in the pseudolite positioning system based on the preset communication protocol, so that the running control system sends the first navigation message to a terminal for positioning. In this way, the required navigation message is flexibly configured for the terminal of the pseudolite positioning system according to the navigation message type requested by the pseudolite positioning system. Meanwhile, the first navigation message is sent to the running control system in the pseudolite positioning system based on the preset communication protocol, and the terminal obtains the first navigation message from the running control system, that is, the terminal obtains the first navigation message through a network transmission mode. This mode shortens the time for the terminal to capture the first navigation message, and thus accelerates the initial positioning of the terminal.

The present invention belongs to the field of joint navigation technology and provides a vehicle-mounted dual-antenna tightly coupled positioning method and system in complex environments. Based on PPP-RTK, PL and INS multi-source heterogeneous data, a PPP-RTK / PL / INS tightly coupled integrated model is constructed to improve the reliability of navigation parameter estimation in complex scenarios. A multi-source data tightly coupled filtering model is designed based on robust adaptive filtering to improve the model's ability to resist gross errors in complex scenarios, thereby obtaining reliable navigation parameters. An ambiguity fixing scheme is designed based on the characteristics of GNSS satellite and pseudo-satellite constellations, assisted by INS-derived prior information, to improve the convergence speed of navigation parameters in complex scenarios.

A method for avionic positioning includes computing a position estimate of the aircraft based at least in part on data corresponding to a signal from each of a plurality of global navigation satellites and data corresponding to a signal from each of at least one pseudolite. A clock of a computing device for computing the position estimate is synchronized to time of the global navigation satellites, and the clock has a timing error less than one microsecond per twenty-four hours.