As a typical multi-radar data association metrics

the association method

which is based on the chi-square statistic metrics

is an effective way used for multi-radar data association in the current information fusion fields. It is found that

however

the correct probability of multi-sensor data association decreases as the radar measurement error decreases

when the target moves in a hypersonic way. In view of the strange phenomenon

the data association model

which is based on the chi-square statistic metrics

is established firstly by the linear frequency modulated radar. Then the influence of target hypersonic movement on multi-sensor data association is further discussed

and the conclusion is that the associated judgment function (subjected to the non central chi square distribution) is contradicted against the existing associated judgment threshold (subjected to the chi square distribution). Finally

the strange phenomenon above

which is proposed in this paper

is explained by using the statistic theories

and an important conclusion is correspondingly drew that the existing data association approaches

which are based on the chi-square statistic metrics

have a great disadvantage on multi-sensor data association of hypersonic target. Simulation results show that

the happening of the strange phenomenon above is reasonable

when the target moves in a hypersonic way.