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ABSTRACT: Proposed next-generation radar systems will have multiple transmit apertures with complete flexibility in the choice of the signals transmitted at each aperture. Here we propose the use of multiple signals with arbitrary cross-correlation matrix R, and show that R can be chosen to achieve or approximate a desired spatial transmit beampattern. Two specific problems are addressed. The first is the constrained optimization problem of finding the value of R which causes the true transmit beampattern to be close in some sense to a desired beampattern. This is approached using convex optimization techniques. The second is the problem of designing multiple constant-modulus waveforms with given cross-correlation R. The use of coded binary phase shift keyed (BPSK) waveforms is considered. A method for finding the code sequences based on random signaling with a structured correlation matrix is proposed. It is also shown that by restricting the class of admissible waveforms one reduces the set of possible signal correlation matrices.
IEEE Transactions on Aerospace and Electronic Systems 02/2008; · 1.10 Impact Factor
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ABSTRACT: Motivated by problems in waveform-agile sensing systems, we consider the application of an optimal measurement selection technique to discrete-time Kalman and extended Kalman filters. The optimal linear measurement is selected prior to taking the observation at each step of the filter. The measurement is described through a measurement matrix B that depends on the prior state covariance, the available energy, and the observation noise variance. The tracking performance of this method is compared to that obtained using other measurement techniques. Our simulations suggest that the performance improvement is most pronounced when the dimension of the state space is large, there is a large eigenvalue spread in the prior covariance, and the signal-to-noise ratio is low.
Waveform Diversity and Design Conference, 2007. International; 07/2007
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ABSTRACT: Multiple-Input Multiple-Output (MIMO) radar has been shown to provide enhanced performance in theory and in practice. MIMO radars are equipped with the ability to choose freely their transmitted waveforms at each aperture. In conventional radar systems Woodward's ambiguity function is used to characterize waveform resolution performance. In this paper we extend the idea of waveform ambiguity functions to MIMO radars. MIMO ambiguity functions are developed that simultaneously characterize the effects of array geometry and transmitted waveforms on resolution performance. Overall resolution performance is shown to be governed by a space-time covariance function that can be controlled by the system on transmit using waveform diversity. Visual examples are provided to illustrate the resolution enhancement possible using MIMO technology
IEEE Journal of Selected Topics in Signal Processing 07/2007; · 2.88 Impact Factor
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ABSTRACT: A MIMO radar system is a radar system with multiple transmitters, each driven with its own signal, coherently with all the other transmitters. In this paper we consider the problem of using this flexibility to transmit wideband signals and control the spatial distribution of transmitted power. We show how the power distribution is a function of the signal cross-spectral density matrix (CSDM), and formulate the problem of determining the CSDM that generates a desired spatial beampattern subject to power constraints on the transmitters. Convex optimization techniques are used to find the numerical solution of the resulting optimization problem.
Computational Advances in Multi-Sensor Adaptive Processing, 2005 1st IEEE International Workshop on; 01/2006
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ABSTRACT: Proposed next-generation radar systems have multiple transmit apertures with complete flexibility in the choice of the signals transmitted at each aperture. Here we propose the use of multiple signals with arbitrary cross-correlation matrix R and show that R can be chosen to achieve or approximate a desired spatial transmit beampattern. This leads to the constrained optimization problem of the finding the value of the R, which causes the true transmit beampattern to be close in some sense to a desired beam-pattern. This is approached using a gradient search in the space of Cholesky factors of R.
Signals, Systems and Computers, 2004. Conference Record of the Thirty-Eighth Asilomar Conference on; 12/2004
