Research And Implementation Of Train Integrity Monitoring Method Based On Moving Baseline Solution

Each carriage of the train is connected by the coupler draft gears.As the train moves forward,frequent acceleration and braking will cause physical deformation such as tension and extrusion of the coupler,resulting in permanent mechanical damage and risk of decoupling.Therefore,in order to ensure the traffic safety,it is necessary to monitor the train integrity in real time.At present,in the CTCS-2 and CTCS-3 train operation control system,the track circuit and other ground equipment are used to realize the train integrity monitoring,but the cost of construction and maintenance is high.With the development of global navigation satellite system(GNSS),it is proposed to use satellite positioning based on on-board equipment to achieve the train integrity monitoring in the next generation of train control system(NGTC).This will minimize the use of wayside ground equipment.Therefore,this paper proposes a train integrity monitoring method based on the GNSS moving baseline.The relative positioning function model of double-difference carrier phase is constructed to calculate the length of moving baseline in real time.In order to further improve the accuracy of baseline solution,the research and implementation of multi constellation joint solution and on-line ambiguity fixing method are carried out.At the same time,an altitude angle constraint dispersion algorithm for selecting reference satellite is proposed.Finally,a simulation platform for train integrity monitoring of moving baseline is built.To evaluate the performance of the proposed train integrity resolution method,a real train test was carried out on the Beijing-Shenyang high speed railway.The main work of this thesis is as follows:(1)The train integrity monitoring method based on the moving baseline solution is innovatively introduced,and the relative positioning model of double difference carrier phase is established to solve the baseline.According to the length of the moving baseline solution and the reference train length,the train integrity state can be judged.(2)For the single constellation system in the railway satellite signal limited environment,the number of available satellites is small and the positioning accuracy is low.In order to improve the observability of the system,a first-order Markov acceleration model is established to optimize the system model of moving baseline.(3)A real-time integer ambiguity fixed algorithm for multi constellation is studied.On the basis of the ambiguity floating-point solution,the resolution accuracy of moving baseline is further improved.A reference satellite selection algorithm based on the altitude angle constraint dispersion is proposed,which makes the satellite have the best distribution structure and ensures the accuracy of baseline solution.The real-time integer ambiguity of single epoch can be fixed quickly to ensure the need of real-time monitoring of train integrity.(4)A train integrity monitoring platform based on GNSS moving baseline is built.According to the field data of Beijing-Shenyang railway,the train integrity monitoring method of moving baseline is tested and verified.In addition,the display interface of baseline length,train status,satellite status and train real-time track is designed.The experimental results show that the proposed method can effectively improve the calculation accuracy of train length.There are 58 pictures,13 tables and 60 references.