Cai Bai-gen

Study on adaptive GPS/INS integrated navigation system

A GPS/INS integrated navigation system based on the theory of multi-sensor data fusion is presented in this paper. Error models for the inertial measurement unit are generated and included in the extended Kalman filter for INS. An improved decentralized Kalman filter is developed to eliminate obvious error of GPS data and reduce the load of calculation. An adaptive federal Kalman filter is used to fuse the data from GPS and INS to provide smoothed and continuous positioning data against the presence of GPS blockages or communication dropouts and the unbounded INS errors growing with time. The results demonstrate that the performance of the adaptive GPS/INS integrated navigation system is better than that of using only GPS of INS.

A GNSS Based Slide and Slip Detection Method for Train Positioning

Real-time positioning is an important part of the modern train control system. An efficient method to improve the positioning accuracy and reliability is the multi-sensor integrated positioning system, and GNSS is introduced to the existing train positioning based on odometer (ODO) in this paper, where the accuracy and error source of train positioning based on ODO are analyzed, and an effective slide and slip detection method is proposed with the integration of GNSS and odometer. Experimental results demonstrate the proposed method could realize the detection of slide and slip with high positioning accuracy.

The Research and Realization of Vehicle Detection System Based on Wireless Magneto-Resistive Sensor

To deal with various traffic situations, traffic information collection, transmission and process is key technologies in ITS system. The development and application of traffic information collection system is widely used in developed country, while it is just at the very beginning stage in our country, possessing broad application foreground. In this paper, wireless magneto-resistive sensor network node is designed for traffic information collection system, and a set of traffic information collection algorisms for system is proposed, including traffic flow detection algorism based on low pass filter, vehicle speed detection algorism and vehicle recognition algorism. HMC1052 form Honeywell and NVE GMR magneto-resistive sensor collecting sample database are adopted in simulation, whose results proves that traffic information collection node could help to obtain information accurately, as traffic flow, vehicle speed, roadway occupancy rate, etc.

Research and analysis of ETCS controlling curves model

Basic principle, composition and classification of European Train Control System (ETCS) are introduced. Train Traction model and Brake model of ETCS controlling Curves are studied, which includes increasing and decreasing curve model. At last, the application and development of ETCS in high-speed railway are introduced, which could be as reference of Chinese train control system controlling curves model.

A Novel Vehicle Detection Method Based on Wireless Magneto-resistive Sensor

In recent years, vehicles detection base on the magnetic effect is a major hot spot in the field of vehicles detection. This paper has studied and realized a wireless magneto-resistive sensor based vehicles detection system, and improved the vehicle detection algorithm. The thesis has used a testing algorithm based on iterative optimal wavelet threshold used to focus on testing whether vehicles passing by. For the speed detection, the traditional algorithm of speed detection has been improved; a new speed detection method which is based on clock synchronization has been used. In that way the error of speed detection will be minimized. The effectiveness of the algorithms has been tested by using the vehicle detection signals of wireless magneto-resistive sensors. Experimental result shows that, the vehicle detection algorithms are available for the vehicles detection and the speed measurement.

Research of MRM-Based CTCS-3 Level Train Operation Control System Simulation Support Technology

Train operation control system is one complex system with some feature like real-time and distributing, aim at different application purpose and operation process of system lifecycle, the emphasize point and level of detail is different. In this paper, MRM-based Simulation Support Technology and it’s application was studied, the modeling theory and method was studied systematically; the Aggregation-Disaggregation problem and settle method of MRM model run together in distributing simulation was studied, solving the couple consistency problem of MRM model; design the distributing and interactive simulation system structure base on HLA, the simulation support technology base on different level resolution was studied. Aim at practical demand of Chinese railway development, the modeling method base on MRM and modeling system structure aim at different simulation motivation was studied, the MRM modeling of key subsystem and parts of Train operation control system was studied, combine with practical work pattern of key parts, study the simulation of constructed model.

Early warning system for potential train collisions: Enhancing safety levels of high-speed trains

Collision avoidance support for high-speed trains is a major safety target for railway operators. This paper presents a new concept for a train collision early warning system (TCEWS) that addresses the problem of train-to-train collisions. Similar to existing collision avoidance systems used by railway networks, the TCEWS approach allows drivers to “see” its neighborhood leading target train and have up-to-date and accurate knowledge of the traffic situation in the vicinity. However, the system architecture and operational principles of TCEWS have certain differences. The core idea is to build a system that is independent of the current railway signaling-based systems, e.g. the Chinese Train Control System level-2 or level-3. With additional sensors and prior information from the electronic track map database, the Global Navigation Satellite System is able to provide the ability for train state detection and collision risk assessment without relying on Automatic Train Protection or other existing train-borne equipments. Wireless communication enables the state of the train to be monitored and an early warning to be issued due to cooperation between the train and trackside facilities. The system components and working principles of the TCEWS are detailed in this paper, and the characteristics and advantages are summarized by comparisons with collision avoidance systems in railway and other transport modes. Implementation and field test of TCEWS on the Hankou–Yichang Railway are introduced and analyzed. It is demonstrated that the TCEWS has sufficient capability to be a “safety overlay” system on top of existing railway signaling systems, and has huge potential in ensuring safety levels of high-speed railways using the Global Positioning System, the BeiDou Navigation Satellite System or other global navigation satellite systems.

Location-based Cooperative Vehicle Collision Avoidance for Unsignalized Intersections: A Multi-sensor Integration Approach

Safety assurance of vehicles is of great importance to improve the road transportation, especially at the unsignalized intersections. To eliminate safety threat that is mostly caused by vehicle-to-vehicle collisions, technologies and methodologies of cooperative vehicle infrastructure system provide sufficient capabilities for a vehicle to share relevant information with other connected neighborhood vehicles, then identify and avoid potential collisions. In the design of collision avoidance solution, precise vehicle location is the most essential but enabling factor to support vehicle situation perception and collision avoidance decisions, which promotes location-based solutions for collision avoidance using real-time information of enhanced location from connected vehicles with wireless communication links. In this paper, a multi-sensor integration approach is presented with a GPS/DR structure where lane-level roadmap database for assistance is also integrated. A four-stage framework is designed to accomplish effective conflict resolution and safety assurance. Key issues including multi-sensor fusion with map match and the location-based collision avoidance mechanism are discussed. Simulation with field data in a real intersection environment is carried out, and the results demonstrate the feasibility and effectiveness of the proposed approach with low-cost and simple configuration.

Multi-sensor based vehicle autonomous navigation for vehicle infrastructure integration: Concept and simulation analysis

Vehicle autonomous navigation is crucial for the implementation of vehicle infrastructure integration, which is a prospective trend of intelligent transportation systems. The integration of multiple on-board sensors and even the support from V2V and V2I communication are critical to maximize each of their benefits. This paper discusses the concept of multi-sensor based vehicle autonomous navigation for vehicle infrastructure integration. Based on the present location relevant applications, functional and performance requirements of vehicle autonomous navigation system are summarized, the system structure and the vehicle dynamic model are designed, and issues of time-space synchronization and the employed filtering strategies are briefly investigated. Simulation and analyses indicate its potential of fulfilling the various performance requirements of vehicle infrastructure integration scheme by multi-sensor data fusion.

Research of System Modeling and Verification Method Combine with UML Formalization Analysis and Colored Petri Net

Because of complexity of CTCS-3 train control system, interworking testing and function evaluation could not be operated directly on the system, which means that deep research on modeling and simulation of train operation control system should be carried out. This paper proposes a modeling and verification method based on UML and colored Petri net. On the basis of analysis of advantages and disadvantages of UML modeling, colored Petri net is used as formal specification of UML modeling, which improves scalability of formal method and make up for the deficiency of UML, as lack of analysis of model and verification method. Aiming at sequence diagram, dynamic model of UML, colored Petri net is suggested as a modeling method. Sequence diagram of communication between on-board and RBC during conversion from CTCS-3 to CTCS-2 is designed and transformed into colored Petri net model. Based on information interaction between objects to each other, colored Petri net model of onboard and RBC is obtained. Using CPN tools, the model is simulated and analyzed boundedness and deadlock of model. Thus, correctness of model is verified.