Fig.1

Typical foreign avian radars

Fig.2

Typical avian radars in China［1］

Fig.3

Typical foreign UAV detection radars

Fig.4

Schematic diagram of the passive radar system［18］

Fig.5

China Mobile 5G-A integrated sensing UAV detection system［20］

Fig.6

Micro-Doppler characteristics of flying birds and UAV targets obtained from field measurements［23］

Table 1

Classification methods for flying birds and UAV targets based on radar

Fig.7

RCS sequence diagrams of various low and slow small targets［38］

Fig.8

Motion characteristics of UAV and flying bird targets［38］

Fig.9

Typical photoelectric sensors［47］

Fig.10

Typical photoelectric image data

Fig.11

Typical optoelectronic detection systems

Fig.12

IdentifiFlight system sensor and target image database［48］

Table 2

Classification methods of birds and UAV targets based on optoelectronics

Fig.13

Examples of visible light image recognition results of bird targets in different scenarios［59］

Fig.14

Examples of infrared image detection and recognition results of UAV targets in different scenarios［70］

Fig.15

Examples of CUB-200-2011 dataset［78］

Fig.16

Examples of UAV dataset released by AVSS2021［82］

Fig.17

Examples of bird dataset released by MVA2023［83］

Fig.18

Typical radio direction finding system

Fig.19

Typical software interface for radio direction finding system［91］

Fig.20

Typical deployment diagram of TDOA system［93］

Fig.21

Typical UAV signal time-frequency diagram［95］

Fig.22

Bird voiceprint monitoring systems

Fig.22

Typical bird voiceprint images［109］

Fig.24

SkySentry UAV acoustic detection system［110］

Fig.25

Syllable detection and annotation results after unsupervised clustering of Lonchura striata repertoire［108］

Table 3

Characteristics of multi-source data and their role in fusion detection

Fig.26

Flow chart of multi-source heterogeneous detection data fusion of flying birds and drones in the airport clearance area

Fig.27

Diagram of multi-attribute decision process

Fig.28

Flowchart of multi-sensor data fusion scheme