Moving target indication

About: Moving target indication is a research topic. Over the lifetime, 2653 publications have been published within this topic receiving 32435 citations.

Performance bounds on MIMO radar with optimized coded constant modulus waveforms

Abstract: A multiple-input, multiple-output (MIMO) radar system uses multiple, spatially diverse transmitters and receivers with separable, independent waveforms with the goal of enhancing resolution and, thus, improving performance. Key to the achievement of these performance benefits is the degree to which the transmitted waveforms may be separated on receive, e.g. the correlation properties amongst the waveforms. A previously defined correlation metric useful for designing “good” waveforms is simplified and its global minimum prescribed for M coded constant modulus waveforms each consisting of N chips and shown to be equal to M-1 (independent of the number of chips). The theory is validated using random phase waveforms as well as optimized waveforms using a previously defined iterative procedure (“CAN”), which is shown to effectively achieve the derived minimum bound. An important consequence of this large level of correlation residue for an optimal waveform set when used to perform a ground moving target indicator (GMTI) function in an airborne radar observing distributed clutter is that the rank of the resulting MIMO interference covariance is increased beyond that of an idealized orthogonal waveform set leading to significant degradation in the clutter mitigation performance, as shown through simulation. An approach to mitigating this effect through the use of partially optimized waveforms tailored to the scenario of interest is demonstrated to achieve the performance of an idealized orthogonal waveform set.

Doppler-aided target tracking in heavy clutter

Abstract: Target tracking in clutter uses measurements of uncertain origin. In addition to target detections, in every scan the sensor returns clutter measurements. Standard target tracking in clutter most often uses the position measurements only. The tracking then becomes clutter limited, and beyond a limited clutter measurement density target tracking algorithms do not perform. Using the Doppler information of each measurement can significantly increase these limits. Previous publications used Doppler measurements either to improve the data association probabilities only, or to improve trajectory state estimates only. Whilst it helps, it often is not enough. This paper extends popular Integrated Probabilistic Data Association to use Doppler information in the track update step both to enhance the Data Association probabilities, and to improve trajectory state estimation. A simulation study shows that this approach may provide reliable automatic target tracking in the case of severe clutter.

Airborne Moving Target Indication of ground and maritime targets with SmartRadar

Abstract: SmartRadar is a multi-channel radar technology demonstrator aimed for airborne and spaceborne ground surveillance and reconnaissance applications. SmartRadar (an acronym for Scalable Multipurpose Aerospace Radar Technology) is engineered by Airbus Defence and Space. An X-Band variant of SmartRadar applying a multi-channel active electronically scanned array antenna (AESA) was integrated into a wing mounted pod and EASA certified for world-wide operation on a Lear Jet 35 aircraft. Due to its flexible design SmartRadar allows the development and demonstration of various state of the art advanced radar modes such as imaging by means of High Resolution Synthetic Aperture Radar (SAR), or target detection by means of Ground Moving Target Indication (GMTI). Also Maritime Surveillance modes and target tracking are available. Already in 2011 the on-board processing of high resolution SAR images in near real-time was demonstrated. In 2012 and 2013 the space-time-adaptive processing (STAP) of three channel GMTI data in real-time and on-board the pod was shown successfully in several flight campaigns. Recently also the detection of maritime moving targets became a customer demanded mode. One of these modes is the so called Maritime MTI (MMTI) mode which is the equivalent of the GMTI mode, i.e. coherent processing and clutter suppression by means of STAP is applied. This paper gives some insight into the GMTI/MMTI mode and STAP processing relevant issues. Results of the flight trials in 2013 emphasize the sensor's capabilities. The SmartRadar Pod System is property of the German MOD (BAAINBw). The authors gratefully acknowledge BAAINBw for funding this work.

Maximum a Posteriori Based Approach for Target Detection in MTI Radar

Abstract: We propose a sparse recovery approach to detect moving targets in clutter. In presence of clutter, the target space is not sparse. We propose a simple way to estimate the clutter region. We then enforce sparsity by modeling the clutter as a single extended cluster of nonzero components. This done by solving a sparse signal recovery problem with partially known support within a maximum a posteriori estimation framework. The resulting algorithm is applied in angle-Doppler imaging for moving target indication in an airborne radar. Our approach has a number of advantages including improved robustness to noise and increased resolution with limited data.

Motion Parameter Estimation of Doppler-Ambiguous Moving Targets in SAR-GMTI

Abstract: In an along-track interferometric SAR system, the discrete sampling of moving target signals can give rise to two types of ambiguity: Doppler ambiguity, and interferometric angle ambiguity. These ambiguities lead to ambiguities in target velocity estimation. Range cell migration of moving targets is unambiguous in target velocity. Hence, it can be used for resolving the ambiguities in target velocity estimation mentioned above. The wave number domain algorithm as well as the chirp scaling algorithm is adapted to moving target signals. In order to focus moving target signals with arbitrary velocities both approaches are extended to arbitrary Doppler frequency ands. Moving target signals distributed over two neighbouring PRF bands are especially difficult to detect and analyze because the sgnal splits into two parts. It is shown that the two parts appear at different positions in the SAR image and have different ATI phases. They show up as two weaker targets since the energy is split between them. It is demonstrated how the two targets can be identified as possibly the same target, and how they can be properly focussed by adaptation of the SAR focussing algorithms.