Research On The Methods For Analyzing Transmitting Time Delay Of Tactical Datalink And Its Influences On Operational Effects

Tactical datalink is basically used for message transmitting between nodes in combats. Timeliness of message transmitting is of great significance to the operational effects. Tactical datalink should provide commanders with accurate and reliable messages in a timely way to assist in their decision making in combats. Backgrounded with tactical datalink currently used in our army and the US army, this dissertation studies the time delay of tactical datalink and its influence on the air-to-air operational effects. The main achievements are as follows:(1)The message generating model using Acyclic-Continuous-Phase-Type(ACPH) distribution is proposed. A closed form EM algorithm for data fitting using ACPH distribution is presented. Compared with traditional algorithms, the proposed one is numerically stable at both low and high order and can provide good fitting for abrupt, smooth and unknown message data. An random number generating algorithm for ACPH distribution is also given. According to our experiment results, the failure probability curve and probability density curve of the generated numbers are very close to those of the ACPH distribution. The mean and variance of the two are nearly the same and the relative error can be omitted. The proposed algorithms of data fitting and random number generating are able to meet the requirements in establishing the message generating model in tactical datalink.(2)Based on an analysis of the message transmitting process of TDMA datalink, we propose to analyze the time delay of different types of message transmitting with ACPH/D/1/K, where we use ACPH1+ACPH2/D/1/K to analyze time delay with high priority and ACPHA/SA/1/K—ACPHB/SB/1/K for the time delay of relay transmitting. Using Padéapproximations, an algorithm for the analysis of waiting time distribution and packet loss rate is given. Examples show that such indexes as waiting time, packet loss rate and mean time delay from the proposed algorithm are close to those of simulation results', which proves that our algorithm can be used in TDMA datalink time delay analysis.(3)We provide a hierarchical protocol model for tactical datalink simulation. A simulation platform for simulation and analysis of the time delay of tactical datalink, TDL-DSAP, is developed. The procedure for message format converting is given. Based on the platform, we analyze the time delay and its influencing factors of polling protocol based tactical datalink and multinet tactical datalink. We also investigate the impacts of the message generating model on the time delay. Simulation results indicate that message delay, response time and delay variation are significantly influenced by such factors as network topology, number of nodes, message format converting, message transmitting method, message generating model, re-transmit strategy of nodes and so forth. Relations between the factors above and time delay are discussed. Principles for controlling the message delay are forwarded.(4)By analyzing the impacts of tactical datalink system on operational effects and information superiority, we also study how tactical datalink system influences the operational effects of air-to-air combat. A procedure for the analysis is presented, in which we should first analyze the air-to-air combat process supported by datalink, then establish the combat model and lastly calculate the indexes of operational effects of the entire combat task. We investigate the combat process of beyond visual range air combat with tactical datalink, analyze the mechanism of tactical datalink time delay affecting beyond visual range air combat. We also modify the first shot probability model and the kill rate model in beyond visual range air combat. Demonstrations show that modified models are able to reveal the influences.