Track-before-detect (TBD) and multi-sensor fusion are two popular methods of weak target detection which can improve the performance by increasing the number of measurements. In this paper, we combine these two methods, proposing a novel multi-sensor track-before-detect (MS-TBD) method for automotive platforms. It can utilize the information from both the spatial and temporal dimensions of the target by jointly processing the measurement from different radars. In particular, the traditional TBD method is often based on an implicit assumption: the presence of targets is unchanged in the sliding window. However, this assumption may not be applicable for automotive multi-sensor systems due to the time-varying fields of view (FOV). To solve the problems mentioned above, we first present an energy accumulation strategy for automotive multi-radar systems and then propose a multiple-hypothesis detection method with the adaptive threshold (AT). It is demonstrated by simulations that the proposed methods show superior performance.

The Bayesian inference has a two-step recursion structure, i.e., prediction and updating, which can be viewed as a dynamic reasoning process. Based on this elegant structure, various multi-target tracking (MTT) algorithms have been invented and successfully applied in many areas. On the other hand, Bayesian inference MTT algorithms are model-based methods that rely on models’ accuracy and first-order Markov assumption. In recent years, the MTT algorithms based on deep learning have received much attention due to their model-free property and the ability to learn from data, although they have issues such as over-fitting, generalization, etc. In this work, we propose a Transformer-based multi-target tracker whose architecture mimics the Bayesian inference, referred to as the Bayesian inference-based Transformer (BAIT) for MTT. To deal with the model mismatch issues, BAIT uses neural networks instead of the pre-assumed motion and observation models while retaining the excellent architecture of Bayesian inference. BAIT can recursively complete accurate predictions and updates via Transformer by refining the estimation of target states in a Bayesian inference-like manner. Thus, BAIT can be viewed as a combination of model-based and data-based methods. The simulation results show that, because of combining the advantages of Bayesian architecture with intelligent data association structure, BAIT is competitive in simple scenarios and achieves superior performance when the data association task becomes complicated.

The swarm targets have shown great potential for both military and civilian applications, driving a high demand for reliable trajectory generation and accurate activity recognition. In this paper, we propose a trajectory generation method and establish an end-to-end deep learning model for dynamic continuous activity recognition of swarm targets. First, we devise an activity transition model of the drone swarm based on a continuous-time Markov chain (CTMC). Subsequently, the minimum snap trajectory generation algorithm is employed to generate the trajectories. After that, to recognize the dynamic continuous activity of targets, we develop an end-to-end neural network model to extract spatial and temporal features for swarm targets detected by radar across multiple frames. Finally, we demonstrate the effectiveness and robustness of our proposed method through simulation results.