Diverse Multiple-input Multiple-output Radar Research Articles

Aperture Synthesis Imaging of Ionospheric Irregularities Using Time Diversity MIMO Radar

AbstractAperture‐synthesis images of ionospheric irregularities in the equatorial electrojet are computed using multiple‐input multiple‐output (MIMO) radar methods at the Jicamarca Radio Observatory. MIMO methods increase the number of distinct interferometry baselines available for imaging (by a factor of essentially three in these experiments) as well as the overall size of the synthetic aperture. The particular method employed here involves time‐division multiplexing or time diversity to distinguish pulses transmitted from different quarters of the Jicamarca array. The method comes at the cost of a large increase in computation time and complexity and a reduced signal‐to‐noise ratio. We discuss the details involved in the signal processing and the trade space involved in image optimization.

Joint polarisation and frequency diversity for deceptive jamming suppression in MIMO radar

The joint exploitation of polarisation and frequency diversity is considered here as a way to improve the deceptive jamming suppression capability in multiple-input multiple-output (MIMO) radar. The authors explore a special polarisation and frequency diverse MIMO (PFD-MIMO) radar system here. In the PFD-MIMO radar system, polarisation and frequency diversity are employed in the transmit array, and two-dimensional vector sensors are adopted in the receive array to measure the horizontal and vertical components of the received signals. To fully explore the potential of the PFD-MIMO radar system, the transmitting polarisation and frequency increment are both optimised by maximising the output signal-to-interference-plus-noise ratio. The simulation results demonstrate that the PFD-MIMO radar is more robust and exhibits a better performance for deceptive jamming suppression than the frequency diverse array MIMO radar and polarimetric MIMO radar. Moreover, improved deceptive jamming suppression performance is achieved when the transmitting polarisation and frequency increment are both optimised.

Adaptive detection with conic rejection to suppress deceptive jamming for frequency diverse MIMO radar

With traditional radar systems, it is not easy to classify and suppress the intended false targets, especially in case of the mainlobe deceptive jamming. In this paper, the deceptive jamming suppression issue is formulated as a problem of detecting the presence of target signal while rejecting potential deceptive jamming under the multiple-input multiple-output (MIMO) radar with frequency diverse array (FDA) as the transmit array. The problem at hand is settled by resorting to the generalized likelihood ratio test (GLRT); at the design stage we define the sets where the false target and true target lie in. Since FDA-MIMO radar provides controllable degrees of freedom in both range and angle domains, the sets are range–angle related. This implies that both range and angle properties can be used to suppress the false targets. Based on the detector, a two-pulse scheme is proposed to guarantee high rejection probability of deceptive jamming. At the analysis stage, the performance of the detector is assessed in comparison with the conventional MIMO scenario and other detectors. The performance assessment shows that the proposed solutions are effective in the presence of electronic countermeasure (ECM) systems, especially when facing mainlobe deceptive jamming.

Deceptive jamming suppression with frequency diverse MIMO radar

Simulated false targets cannot be easily discriminated and suppressed with traditional radar systems, especially for the mainbeam deceptive jamming. In this work, we explore the multiple-input multiple-output (MIMO) radar with frequency diverse array (FDA) as the transmit array and study its ability to suppress the deceptive jamming in joint transmit–receive domain. In FDA-MIMO radar, the steering vector is dependent on both range and angle. This implies that the false targets can be suppressed due to the mismatch in either range or angle. In particular, even the mainbeam deceptive jamming can be handled with the FDA-MIMO radar. The effectiveness of our proposed scheme in suppressing jamming under different scenarios is demonstrated via computer simulations.

Target statistical correlation characteristic for spatial–frequency jointly diversity multiple-input multiple-output radar

In diversity multiple-input multiple-output (MIMO) radar system, the mutual correlation of target echo signals in its diversity channels is an important concern for designing signal processing algorithms. The target temporal, spatial and frequency correlation characteristic is studied at the background of a diversity MIMO radar with multiple widely separated radar sites all capable of working at multiple carrier frequencies. With a two-dimensional round-shaped scatterers centre target model, the correlation coefficient of target echo signals in any type of diversity channel pair (DCP) is proved to be a function of the target size and the equivalent frequency interval. The theoretical correlation coefficient is verified by numerical experiments. The correlation coefficient of target echo signals often depends on the target location, which is shown for two typical DCP types.

Target spatial and frequency scattering diversity property for diversity MIMO radar

Statistical multiple-input multiple-output (MIMO) radar, e.g., frequency diversity MIMO radar (FDMR) and spatial diversity MIMO radar (SDMR), can exploit signal diversity to improve target detection performance. The statistical property of target echo signals received in diversity channels is an important concern in designing signal processing algorithms for an FDMR and an SDMR, which is studied in this paper by using a round shaped scatterers centre target model. A uniform formula is derived to estimate the correlation coefficients of target echo signals in diversity channels for both an FDMR and an SDMR. The theoretical correlation coefficients are testified by numerical experiments.