Fig.1

Schematic diagram of flight mechanics for wing drones and birds"

Fig.2

Schematic diagram of horizontal projection of representative drone tracks"

Fig.3

Schematic diagram of horizontal projection of regular smooth and typical oscillation tracks"

Table 1

Definition of weighting factors"

Fig.4

Schematic diagram of random forest fundamental principle"

Fig.5

Bird surveillance radar systems of CAAC"

Fig.6

Schematic diagram of bird surveillance radar system and experimental deployment in BeiHai FuCheng airport"

Fig.7

Distribution of the first and second principal components in feature space of three types of target tracks"

Table 2

Fuzzy matrix for recognition rate of five-fold cross validation for three types of targets"

Table 3

Fuzzy matrix for recognition rate of five-fold cross validation for bird and drone targets"

Table 4

Fuzzy matrix of recognition rate for three types of targets"

Table 5

Fuzzy matrix of recognition rate for bird and drone targets"

Table 6

Comparison of the correct recognition rate of bird and drone targets using classification methods in this article and [19]"

Table 7

Fuzzy matrix of five-fold cross validation based on new fusion training set"

Fig.8

Random forest model Gini exponential distribution-three types of target recognition"

Fig.9

Random forest model Gini exponential distribution-bird and drone target recognition"