Chaotic Signal Processing And Its Pplication In Radar

Signal reconstruction, noise suppression and synchronization of different signalscan be realized by chaotic signal processing. Therefore, chaotic signal processing hashuge value in radar, communication and so on.Chaotic radar, using chaotic signal as the transmitted signal, has some excellentcharacteristics such as low probability of intercept, high range resolution and velocityresolution, good anti-jamming, simple generation, small realization cost and so on.This thesis studies the problems of traditional chaotic signal processing methodssuch as imprecise parameter estimation, synchronization sensitive to noise and so on. Inchaotic radar, this thesis studies the problem of difficult to coherent, high cost and soon.The main results and contribution of this thesis are:1. A high precision method for estimating the initial condition of chaotic signal isgiven. A smaller error estimation value can be got at low signal-to-noise ratios (SNR) byusing the given method.2. A high precision method for estimating the parameter of one-dimensionaldiscrete chaotic system is given. The estimation error of the given method is smallerthan that of the traditional methods.3. Three chaotic synchronization methods are given respectively. First, a newsynchronization control method for chaotic system, which only needs one scalar timeseries of the master system to reach the synchronization, is given in this thesis. Second,a new method of fast synchronization of chaotic master-slave systems is given. Thegiven method can make the fast synchronization between master system and slavesystem. The synchronization time only costs one step iterating time. Third, a chaossynchronization method for master-slave chaotic system under parameter mismatch isgiven. The slave system can synchronize to the master system when the parameters ofthe systems are changed randomly. The synchronization still can be realized even theparameter error is large. 4. An improved quasi-orthogonal coherent reception noise radar system is given. Inthe quasi-orthogonal coherent reception system, it has nearly the same effect as that ofthe ideal coherent reception radar system, and the delayed transmission reference signalis not required. This can solve the problem that the delay lines of wideband signal aredifficult to be realized.5. A method for measuring the target velocity is given. First, the relation betweenthe target velocity and the scaling parameter of the chaos-generating system is given.Then, a new method for scaling parameter estimation of the chaotic system is offered.After the scaling parameter being estimated, the target velocity can be got according tothe relationship between the target Doppler shift and the scaling parameter of chaoticsystem.6. A method for measuring the target range is given based on a class of6-orderhyperchaotic systems. In this method, a sinusoidal signal is added into the transmittedsignal. The delay time of the echo signal can be obtained by comparing the phase of thesinusoidal signal in the transmitting part and the receiving part after synchronization.Thus, the target range resolution can be got from the delay time of the echo signal.7. A coherent reception noise radar system, which is founded on matched filter, isgiven. The feature of this radar system is: the transmitted signal template can beobtained using shift register and it does not require the delayed transmitted signal whichis realized by using the delay lines when implementing coherent detection through thematched filtering. The given radar system has more simple structure and lower cost thanthat of the traditional noise radar.