60results about How to "Reduce cross-correlation" patented technology

A system comprises a plurality of acoustic transmitters, mounted inside the streamers, adapted to transmit broadband signals having low cross-correlation between the signals of different transmitters; a plurality of acoustic receivers, mounted inside the streamers, adapted to receive the signals from the transmitters; at least one processor adapted to cross-correlate the signals received at the receivers with copies of transmitter signals to determine identities of the transmitters of the received signals and to determine travel times of the received signals; and a main processor adapted to convert the travel times to distances between the identified transmitters and the receivers and to determine relative positions of the streamers from the distances.

A method that is sub-optimal, but easily implemented, for cross correlation mitigation of GPS signals. It involves adaptive modification of the locally generated code used to detect a weak signal so that the new code is orthogonal to the jamming signals currently being tracked. The method employs simple constraints to achieve the orthogonalisation rather than a direct orthogonalisation performed using matrix inversions.

It is an object to provide a sequence allocating method that, while maintaining the number of Zadoff-Chu sequences to compose a sequence group, is configured to make it possible to reduce correlations between different sequential groups. This method comprises the steps of setting a standard sequence with a standard sequence length (Nb) and a standard sequence number (rb) in a step (ST101), setting a threshold value (Xth(m)) in accordance with an RB number (m) in a step (ST103), setting a sequence length (N) corresponding to RB number (m) in a step (ST104), judging whether ]r/N-rb/Nb]<=Xth(m) is satisfied in a step (ST106), including a plurality of Zadoff-Chu sequences with a sequence number (r) and a sequence length (N) in a sequence group (rb) in a step (ST107) if the judgment is positive, and allocating the sequence group (rb) to the same cell in a step (ST112).

The invention discloses a wavelet constant modulus blind equalization method in a MIMO (Multiple Input Multiple Output) system from the aspect of reducing?inter channel?and inter signal?correlation, so as to overcome defects that the traditional constant modulus blind equalization method in the MIMO system is weak in inter channel interference inhibition ability, slow in the convergence rate and large in steady-state errors. According to the method, singular value decomposition is used for reducing the correlation of channel output signals; an orthogonal wavelet base function is used for carrying out orthogonal wavelet transformation on MIMO channel output signals and autocorrelation of input signals of a blind equalizer is reduced; on the basis of fully considering the inter channel correlation, a cost function of MIMO system constant modulus blind equalization algorithm is redefined, and cross-correlation of output signals of the blind equalizer is reduced; and a variable step size function is used for controlling a blind equalization?weight vector?updating process, the convergence rate quickened, and the steady-state errors are reduced.

The invention discloses an LFM pulse train signal waveform design method based on pulse width agility. The method comprises the steps: setting different pulse widths for different pulses in an LFM pulse train with the same bandwidth, so that each pulse signal has different modulation rates, and the cross correlation between the pulses is reduced so as to effectively improve the range gating characteristic and the folding clutter resistance of the generated LFM pulse train signal and achieve the purpose of suppressing range ambiguity and resisting folding clutter.

The invention provides a signal processing method and device. The method comprises the step that in frequency domain resources of a comb tooth structure, reference signals mapped on the frequency domain resources of different comb teeth can be generated by different sequences. That is to say, the reference signals on different frequency domain resources can be generated by adopting different sequences, so that the performance of the reference signals transmitted on the frequency domain resources of the whole comb tooth structure is improved.

The invention discloses an airborne equipment electromagnetic compatibility grading method based on an unascertained measurement theory. The method comprises the following steps of S1, measuring the grading evaluation indexes of the electromagnetic compatibility of airborne equipment, and building a grading evaluation index set; S2, establishing a measurement function of grading evaluation indexes by applying an uncertain measurement theory; S3, solving a single index evaluation matrix of the electromagnetic compatibility of the airborne equipment; S4, solving a grading evaluation index weight of each electromagnetic compatibility by using an information entropy method; S5, solving the comprehensive attribute measure of each airborne device; S6, solving quantitative grading or classification of the electromagnetic compatibility of the airborne equipment on the airplane; and S7, obtaining the electromagnetic compatibility design priority and design weight of the airborne equipment. According to the method, the cross correlation of evaluation indexes is low, the evaluation indexes can be measured and examined, the evaluation indexes can serve as a priority strategy for system-level electromagnetic compatibility index distribution, and a theoretical basis is provided for quantitative design of electromagnetic compatibility of the whole aircraft system.