4 results about "Ephemeris" patented technology

The invention provides an ionized layer delaying estimation method of a Beidou navigation satellite system. The method comprises the followings steps: a step of roughly calculating longitude and latitude: enabling a Beidou navigation satellite receiver to calculate a satellite position and a pseudo-range according to a satellite ephemeris to receive rough longitude and latitude position information of the receiver; a step of calculating longitude and latitude of a breakthrough point: calculating longitude and latitude information of the breakthrough point of a participating positioning satellite according to the obtained rough longitude and latitude position information and participating positioning satellite position information; an ionized layer delaying correction step: determining a grid point containing the breakthrough point and ionized layer correction delaying information containing the breakthrough point according to grid ionized layer delaying information sent by a GEO (Geostationary Earth Orbit) satellite of the Beidou navigation satellite system and the longitude and latitude information of the breakthrough point; and a step of calculating accurate longitude and latitude: revising an observation equation of the Beidou navigation satellite receiver according to the ionized layer correction delaying information of the breakthrough point and calculating the accurate longitude and latitude. With the adoption of the technical scheme, the grid ionized layer delaying information of a GEO satellite ephemeris of the Beidou navigation satellite system can be used for reducing ionized layer errors and the navigation positioning precision is improved.

The invention provides a method and a device for retrieving an atmospheric water vapor content. Through acquiring BDS observation data and downloading ephemeris data IGU from an IGMAS, ephemeris datafor retrieving are acquired based on the ephemeris data IGU; based on the above information, coordinate information of an observation station is acquired, total tropospheric zenith delay above the observation station is acquired, and based on the coordinate information of the observation station and a saastamoinen model, zenith dry delay is calculated and acquired, and the zenith dry delay is subtracted from the total tropospheric zenith delay to obtain zenith wet delay; and according to a conversion coefficient, a liquid water density and the zenith wet delay, atmospheric precipitation is calculated. On the premise that the ephemeris data meet the precision requirements of retrieving the atmospheric water vapor content by the BDS, real-time retrieving of the atmospheric water vapor content by BDS observation can be realized, the atmospheric water vapor content measurement precision is improved, and the method and the device are applicable to conditions with a large altitude differencebetween the observation station and a reference station.

The invention discloses a space-ground combined orbit calculation method for navigation constellation measurement and control management. The method comprises: designing a space foundation whole network orbit calculation process for avoiding normal equation rank depletion, using a long-term forecast ephemeris as virtual observation for constraint, and combining traditional foundation S-band measurement data and a Ka inter-satellite link weighted fusion algorithm to calculate the space-ground combined orbit of the navigation constellation measurement and control management; and comprehensivelyprocessing traditional ground-based S-band tracking data and inter-satellite link bidirectional distance measurement to obtain a precise ephemeris product for supporting navigation satellite measurement and control management and inter-satellite link management.

The invention discloses a satellite selection method for a multi-satellite navigation system based on a satellite selection template. The satellite selection method comprises the basic steps of importing broadcast ephemeris files and observation data of satellites, and calculating the location for observing the satellites and an azimuth angle and an elevation angle of the line-of-sight direction;removing satellites with the elevation angle being lower than a cut-off elevation angle to obtain the number of visible satellites; if the number of visible satellites is greater than a satellite selection number, building a satellite selection template with the satellite geometric structure approaching to the optimal by taking proportional distribution of satellites with a high elevation angle and satellites with a low elevation angle and symmetric distribution of the satellites in the azimuth as a principle; determining the step size of rotation and a rotation interval of the satellite selection template; searching a group of actual satellites which are the closest to the template satellites in the rotating process of the satellite selection template, and calculating weighted PDOP valuesof the actual satellites; enabling a satellite combination corresponding to the minimum weighted PDOP value in the whole rotating process to act as a satellite selection result; and if a certain navigation system only has one visible satellite in the satellite selection result, removing the satellite. The invention provides a satellite selection method with good effects for multi-constellation integrated positioning.