Engineering survey of the Environment and Disaster Monitoring and Forecasting Small Satellite Constellation

Figures & data

Table 1. Important parameters of the orbit of HJ-A and HJ-B.

Orbit height/km	Orbit angle/°	Orbit period/min	Nodal period/min
649.09	97.996	97.56	97.68
Trajectory distance between adjacent nodal period/km	Minimum trajectory distance/km	Retrace period/d	Cycle number per day/cycle
2709.5	700	31	14 + 23/31

Table 2. Technical specifications of the sensors on HJ-A, HJ-B, and HJ-C.

Satellite	Sensor	Spatial resolution (m)	Width (km)	Wave bands
HJ-A	CCD	30	single 360; double ≥720	4
	HIS	100	50	115
HJ-B	CCD	30	single 360; double ≥720	4
	IRS	B1-B5:150; B4:300	720	4
HJ-C	SAR	5	40	1
		20	100

Figure 1.  The structure and composition of DRAS at the ‘2 + 1’ phase.

Figure 2.  Operation flowchart of DRAS.

Figure 3.  Structure and composition of DRAS at the ‘4 +4’ phase.