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4222 results about "Observation data" patented technology

Observational data is a valuable form of research that can give researchers information that goes beyond numbers and statistics. In general, observation is a systematic way to collect data by observing people in natural situations or settings. There are many different types of observation, each with its strengths and weaknesses.

Low earth orbit satellite-based satellite-earth differential real-time precise positioning method

ActiveCN107229061ARapid positioningRealize Differential Positioning ServiceSatellite radio beaconingDouble differenceNatural satellite
The invention belongs to the satellite navigation and positioning technical field and discloses a low earth orbit satellite-based satellite-earth differential real-time precise positioning method. A low earth orbit satellite is utilized to broadcast the observation data and real-time orbit data of the satellite-borne GNSS (Global Navigation Satellite System) receiver of the low earth orbit satellite to the ground; and after receiving the differential information broadcasted by the low earth orbit satellite, a ground receiver generates a double-difference observation value consisting of the differential information and a local GNSS observation value and performs pseudorange-based moving base station DGNSS (Differential Navigation Satellite System) positioning and carrier phase-based moving base station RTK (Rea-time kinematic) positioning. According to the positioning method of the invention, the global mobile low earth orbit satellite platform is adopted as a reference station, so that real-time precision differential positioning service in the whole world can be realized, and the method does not depend on the distribution of ground reference stations; and a user can realize differential real-time precise positioning just through using a single receiver, and therefore, the method is free of operating range restrictions, and data communication links are not required to be considered.
Owner:WUHAN UNIV

Estimation method of co-prime array DOA (Direction Of Arrival) angle based on sparse reconstruction

The invention discloses an estimation method of a co-prime array DOA (Direction Of Arrival) angle based on sparse reconstruction, and mainly solves the problems that a prior art is higher in operand, less in identification information source amount and large in passive location evaluated error, and needs more priori knowledge. The method comprises the realizing steps of forming a co-prime array by an antenna receiver; obtaining observation data to spatial signal sampling; receiving data vectors by a virtual array element obtained by observation data; dividing spatial grids to form over-complete bases; receiving a spare relationship between the data vectors and the over-complete bases by the virtual array element to build a spare restraint equation; resolving the spare restraint equation by adopting a convex optimization method to obtain sparest resolution; drawing a magnitude spectrogram by a relative relationship between the sparest resolution and the spatial angle to obtain a DOA angle value. According to the method provided by the invention, the passive direction-finding precision and operating speed can be improved under a condition of low priori knowledge, the number of the recognized information source can be improved, and the estimation precision of a signal direction angle can be improved in a low signal to noise ratio, therefore the estimation method can be used for target reconnaissance and passive location.
Owner:XIDIAN UNIV

Method for assimilating remote sensing data of soil humidity in watershed scale

The invention provides a method for assimilating remote sensing data of soil humidity in a watershed scale. The method comprises the following steps of: improving a watershed runoff producing calculation module and developing a distributed hydrological model which is suitable for assimilating remote sensing soil humidity information and describes a soil hydrodynamic process; introducing a particle filtering sequence data assimilation method of information science, and continuously merging and assimilating new remote sensing observation data in a dynamic operation process of distributed hydrological process numerical simulation so as to acquire updated watershed soil humidity assimilated data during sequential assimilation; feeding the updated watershed soil humidity assimilated data back to a distributed hydrological model platform; and gradually estimating the time and space distribution pattern of watershed soil moisture content. Practices prove that by the method, not only high-precision and physically consistent watershed soil humidity data can be provided for research on hydrology, zoology, environment and agriculture, but also the foundation is laid for performing four-dimensional data assimilation processing on soil humidity data of an upper soil layer acquired by using remote sensing retrieval, and improving the precision of the model.
Owner:NANJING UNIV

Earth face evapotranspiration remote sensing inversion method and system based on MODIS data

InactiveCN103810387AAvoid the requirement for accurate atmospheric correctionReduce uncertaintyMaterial analysis by optical meansSpecial data processing applicationsData aidedObservation data
The invention relates to an earth face evapotranspiration remote sensing inversion method and system based on MODIS data. The earth face evapotranspiration remote sensing inversion method comprises the following steps that (1), a research area is confirmed, relative MODIS data porducts in the research area are achieved and pretreated; (2), a scatter diagram of space change information is built by the utilization of the pretreated MODIS data products, a remote sensing inversion of pixel sized surface evaporation ratio EF is conducted; (3), according to the relative MODIS data products, remote sensing inversions of pixel sized surface net radiation Rn and soil heat flux G are conducted; (4), according to the surface evaporation ratio EF, the surface net radiation Rn and the soil heat flux G, a remote sensing inversion of pixel sized earth face evapotranspiration LE is conducted. The earth face evapotranspiration remote sensing inversion method only needs to input the MODIS data, the problem that the current evapotranspiration remote sensing inversion usually needs more ground observation data to assist is solved, and the earth face evapotranspiration remote sensing inversion method can be used for the evapotranspiration remote sensing inversion in the area with no data or with few data.
Owner:INST OF GEOGRAPHICAL SCI & NATURAL RESOURCE RES CAS

Multi-system dynamic PPP resolving method based on robust self-adaption Kalman smoothing

The invention discloses a multi-system dynamic PPP resolving method based on robust self-adaption Kalman smoothing. The method includes the steps that receiving machine outline coordinates and receiving machine clock bias of all systems are solved through selecting-weight-iteration pseudo-range single-point positioning, and accordingly all positioning error correction values are calculated according to an error correction model in combination with the satellite precise ephemeris and satellite precise clock bias; strict data quality control is conducted on observation data. Due to the fact that dynamic PPP accuracy is easily affected by undetected small cycle slips or the gross error and the like, an observation equation weight matrix is adjusted according to the observation value residual vectors, and the undetected small cycle slips or the gross error and other influence factors are removed; self-adaption factors are determined according to the state predictive information, and thus the influence on parameter estimation of the predictive information is controlled. By means of the method, when multi-system dynamic PPP is conducted through a single receiving machine, the feature that the number of multi-system satellites is increased greatly, on the basis that the stability of the satellite structure is guaranteed, the influence of the gross error is weaken effectively, the dynamic noise abnormity in dynamic positioning is improved, and finally the high-precision and high-stability multi-system dynamic PPP result is achieved.
Owner:SOUTHEAST UNIV
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