Fig. 1. Aerodynamic shape and surface temperature distribution of hypersonic gliding vehicle under typical operating parameters. (a) Surface mesh; (b) surface temperature distribution

Fig. 2. Schematic diagram of observation angle of infrared satellite to hypersonic vehicle

Fig. 3. Spectral radiance of four typical backgrounds

Fig. 4. Relationship among signal-to-noise ratio of detector, observation angle, and working band at different orbital altitudes. (a) Orbital altitude is 550 km, and observation angle is located in xoz plane; (b) orbital altitude is 1600 km, and observation angle is located in xoz plane; (c) orbital altitude is 550 km, and observation angle is located in yoz plane; (d) orbital altitude is 1600 km, and observation angle is located in yoz plane

Fig. 5. Relationship between detection probability of infrared satellite to hypersonic vehicle and observation angle under background of forest land at different orbital altitudes. (a) Orbital altitude is 550 km; (b) orbital altitude is 1600 km

Fig. 6. Effective detection coverage of infrared satellite to hypersonic vehicle

Fig. 7. Three-dimensional map of Walker constellation generated on the basis of seed infrared satellites

Fig. 8. Coverage time ratio varying with latitude at different orbital altitudes. (a)--(c) Orbital altitude is 550 km; (d)--(f) orbital altitude is 1600 km