Please select the most similar patent number from A, B, C and D. Which number is?
A method for using multiple feature values of a high-frequency satellite-ground link to determine whether it is sunny or rainy at a given time, comprising: removing, by filtering, a rapid signal change caused by noise of a satellite-ground link and scintillation, then extracting multiple feature values including a standard deviation, a trend, a maximum value, a minimum value, an average value, a skewness, a kurtosis, and information entropy, and selecting the optimal time window by means of adjustment, and finally using a classification algorithm to determine whether it is sunny or rainy at a given time. The present invention can accurately distinguish a sunny period from a rainy period by using a high-frequency satellite-ground link signal, and can monitor the large-range distribution of sunny days and rainy days in real time, having a great significance in terms of further improving the rain detection accuracy of a satellite-ground link, and improving the levels of monitoring of urban water logging and flood prevention and early warning.
A: A rapid-converging ultrahigh-frequency microwave rainfall data discretization method. The method comprises: discretizing each link in an ultrahigh-frequency microwave network into a plurality of segments of short links; taking the central point of each short link as a virtual station, and determining a central station and a side station in each link; and performing estimation for a virtual station on each link, performing calculation, by means of IDW, by using rainfall intensity estimators of all central stations of other links except the link, correcting a calculation result, and performing successive iteration until an iteration termination condition is met, so as to complete discretization. The method is more scientific and realizes a higher convergence speed. Aiming at the features of an ultrahigh-frequency microwave network, only a central station participates in optimization calculations, so that errors introduced to a model after station discretization are greatly reduced. Accordingly, during a rainfall data processing process, only the central station is used, such that the arithmetic speed is not limited by the number of virtual stations.
B: A method for automatically detecting a free vibration response data segment of a high-speed rail bridge when a train passes, comprising: first, determining, on the basis of the maximum value of a moment at where the absolute maximum value of a vibration response vector of each measuring point is found, a test response to be decomposed; then, utilizing iterative variational mode decomposition to extract a single-frequency modal response from the test response, and utilizing the Hilbert transform to fit an envelope amplitude of the modal response; and finally, marking a vibration characteristic of each moment as an attenuated vibration or a non-attenuated vibration on the basis of the characteristic of amplitude attenuation of a single-frequency free vibration, and making the longest structural response data segment complying with an attenuated vibration requirement as a detected free vibration response applicable in modal identification. The method implements the effective detection of a free vibration data segment without requiring human participation and carries great significance with respect to real-time accurate modal analysis of high-speed rail bridges.
C: A transformer monitoring apparatus based on non-electric-quantity comprehensive characteristic information. The transformer monitoring apparatus comprises: a transient oil pressure characteristic quantity measurement module, a transient oil flow characteristic quantity measurement module, a transient acceleration characteristic quantity measurement module, a signal conditioning and collection module and a digital processing and analysis module, wherein the transient oil pressure characteristic quantity measurement module, the transient oil flow characteristic quantity measurement module and the transient acceleration characteristic quantity measurement module are all connected to the signal conditioning and collection module, and the signal conditioning and collection module is connected to the digital processing and analysis module. Further disclosed is a transformer monitoring method based on non electrical quantity comprehensive characteristic information. According to the apparatus and method, by means of comprehensively using a plurality of pieces of non-electric-quantity transient characteristic information inside a transformer, an action oil pressure value, an action oil flow value and an action acceleration value of a running state of the transformer are calculated, and by means of comparing with a preset non-electric-quantity start threshold, an alarm threshold and an early warning threshold, the real-time monitoring and reliability evaluation of each non-electric-quantity safety level inside the transformer are realized. The apparatus is independent of a power grid, and has the advantages of a simple structure, easy implementation, being reliable and accurate, etc.
D: Disclosed is a method for processing satellite position velocity data based on a satellite earth station, comprising the following steps: S1) obtaining satellite GNSS data at a certain moment; S2) obtaining ephemeris data, and calculating the position velocity of a satellite at the moment; S3) calculating a position velocity deviation value of the calculated position velocity and the position velocity measured by the GNSS under a geometric inertial coordinate system; S4), training based on a neural network, and constructing a mapping relationship of &#34;satellite position velocity-position velocity deviation value&#34;; S5) compensating for the ephemeris-calculated position velocity of the satellite with the position velocity deviation value output by the neural network in regions that the mapping relation relationship is already constructed; and S6) converting the output position velocity deviation value to a geometric fixed coordinate system with the geometric inertial coordinate system. According to the present invention, precise position and velocity data of the satellite can be obtained. In addition, when beacon signals or received signals are absent, a Doppler shift value is estimated in real time, so that Doppler shift of uplink signals is compensated in real time.
Answer: A