Research On Passive Sensors Information Fusion And Its Application

There are some main aspects of information fusion for passive sensors, which are in an urgent need to be solved and have got systematically studied in this dissertation. Those aspects are: self adaptive tracking problem for a single passive sensor with bearing-only measurement, data association for image-based sensor with noisy background, measurement pretreatment method for multi-passive-sensor tracking system, optimal deployment of sensors, fused tracking precision assessment and tracking algorithm. In addition, the situation and threat assessment (STA) problem has also been studied as well. The main contents and results in this dissertation are as follows.1. Self adaptive tracking algorithm for maneuvering targets by high-sampling-rate bearing-only passive sensor is investigated. The two dimensional bearing-only tracking (BOT) model is established, followed up by the MGEKF (Modified Gain Extended Kalman Filter) which is applicable to targets with uniform motion and to maneuvering targets. The MGEKF is employed in the state estimation and the target acceleration vector is periodically calculated in a recursive manner, which is of adaptability for maneuver at low computational cost, with simple model, without noise assumption or model switching.2. Data association and tracking algorithm in small targets tracking by single image-based passive sensor are well studied. Image overlapping is prevalent when targets are far from sensor and the targets density is relatively high, even if the false measurement density is not so serious. To cope with the image overlapping, a multi-assignment method ?is established based on one-to-one two-dimensional (2-D) assignment. As for the long distance tracking of single small target by infrared image sensor, as long as the tracker could offer feedback information, i.e. the predicted location and distribution of target, the sensor would use Bayes detection. As a result, a variable greyscale threshold is implemented in image filtering, reducing the number of candidate measurements, which is in favor of the PDAF-based tracking method. All the parameters needed in PDAF are derived and the method is verified by simulation.3. Measurement pretreatment method for multi-passive-sensor tracking and optimal deployment of sensors are considered. The former is to reduce computational complexity of association to make real-time calculation possible. Ghost measurements elimination is the most difficult problem in multi-passive-sensor data association that prevents itsapplication to a great extent. To that end, a set of effective solution is proposed to reduce the Ghosts number. Optimal sensors deployment is well investigated based on certain suppositions. Different suboptimum sensor distributions for different target distributions are established.4. The fused tracking algorithm for multi-angle-only-sensor system is studied, which is a weakness in current information-fusion research. First, the CRLB is used to analyze the tracking precision by two sensors from different platforms, considering bandwidth influence. Second, the constant velocity model is applied to the EKF tracking in a single site manner. Calculation and simulation validates the significance of two passive sensors tracking. The applicability of MGEKF in multi-angle-only-sensor case is investigated and proved. Moreover, the adaptive fusion filtering method with respect to abnormal measurement and communication failure is also studied, bringing about the new concepts of sensor availability matrix and fused tracking gate. Fused filtering methods are established for measurement with or without spurious responds respectively.5. Some investigation has been carried out at the situation and threat assessment (STA) level. The STA, which is a focal point in multi-sensor information fusion and the highest level of information fusion is hard for implementation. Different application background demands different fusion objectives. Although the STA has been studied for rather a long time, a mature and universal theory has not yet...