A Novel Double Cluster and Principal Component Analysis-Based Optimization Method for the Orbit Design of Earth Observation Satellites

Table 2

Eight dimensionless performance indices of the five clustering centers after the first clustering.

Performance indices	Classification
	1	2	3	4	5
Frequency of coverage (FC)	0.12	0.34	0.42	0.93	0.32
Total coverage time (TCT)	0.31	0.27	0.34	0.83	0.23
Average time per coverage (ATC)	0.01	0.43	0.86	0.89	0.77
Maximum coverage gap (MCG)	0.04	0.26	0.72	0.63	0.33
Average coverage gap (ACG)	0.94	0.92	0.54	0.96	0.48
Minimum coverage gap (ICG)	0.02	0.05	0.5	0.9	0.11
Average time interval of TT&C (ATI-TT&C)	0.30	0.15	0.79	0.65	0.84
Average time of each TT&C (AT-TT&C)	0.59	0.04	0.62	0.57	0.61