3results about How to "Estimated range is large" patented technology

The invention relates to the field of satellite navigation, and discloses a low earth orbit satellite signal capturing and tracking method and a signal processing method, comprising the following steps: periodically receiving a low earth orbit satellite signal of at least one time slice, and carrying out carrier separation on the low earth orbit satellite signal to obtain a stripped signal corresponding to the low earth orbit satellite signal; processing the stripped signal and a locally stored pseudo-random code sequence so as to find an amplitude maximum value of the stripped signal in a frequency domain, and calculating Doppler frequency after determining that the stripped signal is successfully captured according to the amplitude maximum value; and transferring the successfully captured stripped signal to a tracking channel, tracking the stripped signal regularly, and returning to the previous step. According to the invention, signals with relatively large Doppler frequency offset can be efficiently captured in real time for low-orbit signals, the number of navigation satellites which can be captured by the system at the same time can be greatly increased, and the system efficiency and the system coverage rate are improved.

The invention relates to the technical field of radar signal processing, and provides a generalized Pareto distributed radar sea clutter parameter estimation method, which comprises the following steps of: obtaining a plurality of pieces of generalized Pareto distributed clutter data; constructing a fitness function based on an accumulative distribution function and a probability density function of the generalized Pareto distribution clutter data, and substituting the fitness function into a genetic algorithm; a global optimal particle of the generalized Pareto distribution clutter data is iteratively solved by combining a genetic algorithm and a particle swarm optimization algorithm, and when the number of iterations reaches a preset value or the global optimal particle keeps algebra equal to a preset algebra in the iteration process, iteration is stopped, and an optimal parameter value of generalized Pareto distribution is obtained; wherein the optimal parameter value is a global optimal particle when iteration is stopped, and the global optimal particle is a parameter enabling the fitness function value to reach the maximum; the parameter estimation method does not depend on a complex mathematical estimation expression, the parameter estimation precision is high, and the estimation range is wide.

The application discloses a low-orbit satellite Doppler estimation demodulation method and equipment. It relates to high dynamic synchronization technology and is suitable for application in low-orbit satellite communication. The application takes a satellite beacon as a pilot signal, quickly locks the satellite beacon through a phase discrimination method, and extracts a current Doppler frequency shift; then, according to the beacon frequency and the carrier frequency of the symbol rate of the received signal, the Doppler frequency shift of the received signal is determined; finally, through frequency down-conversion, the low symbol rate signal is converted into a baseband signal, and then timing recovery, carrier recovery, demapping and the like are carried out, so as to complete demodulation. The application is suitable for high dynamic conditions of low-orbit satellites, has a large Doppler estimation range and high precision.