Technical system design and construction of China's HJ-1 satellites

Figures & data

Figure 1.  In-orbit status of the HJ-1A satellite.

Figure 2.  In-orbit status of the HJ-1B satellite.

Figure 3.  In-orbit status of the HJ-1C satellite.

Figure 4.  Comparison between a single false color image of HJ-1 satellites and that of Landsat TM.

Figure 5.  True color mosaic of the land surface of China based on the CCD data of HJ-1A (left) and HJ-1B (right).

Figure 6.  True-color composite mosaic of China based on the combination of two days’ CCD data from HJ-1A and HJ-1B.

Table 1. Parameters of univariate statistics of data samples from HJ-1 CCD and Landsat TM.

Band	HJ-1	HJ-2	HJ-3	HJ-4	TM-1	TM-2	TM-3	TM-4
Mean	40.87	133.52	133.27	137.66	107.52	129.29	128.30	127.70
Standard error	0.03	0.31	0.31	0.28	0.10	0.33	0.33	0.30
Median	42.00	141.00	139.00	140.00	111.00	137.00	138.00	122.00
Mode	44.00	155.00	127.00	153.00	115.00	147.00	154.00	255.00
Standard deviation	6.60	59.75	61.23	54.99	19.71	63.55	63.45	58.12
Variance	43.54	3569.56	3748.52	3023.98	388.37	4038.99	4026.07	3378.46
Kurtosis	0.04	−0.82	−0.80	−0.24	0.73	−0.78	−0.70	−0.10
Skewness	−0.40	−0.20	−0.20	−0.16	−0.20	−0.30	−0.41	0.46
Maximum	79	255	255	255	255	255	255	255

Table 2. Covariance matrix of data samples from HJ-1 CCD and Landsat TM.

Band	HJ-1	HJ-2	HJ-3	HJ-4	TM-1	TM-2	TM-3	TM-4
HJ-1	43.53
HJ-2	368.90	3569.46
HJ-3	365.89	3584.81	3748.42
HJ-4	140.63	1610.76	1701.09	3023.90
TM-1	114.82	1018.96	1011.53	330.74	388.36
TM-2	368.26	3471.20	3515.69	1412.60	1213.71	4038.89
TM-3	355.79	3461.07	3553.41	1364.79	1180.10	3987.11	4025.97

Figure 7.  Composition of the ground systems of HJ-1 satellites.

Figure 8.  General structure of the Environment Application System of HJ-1 satellites.

Figure 9.  Task-driven operation mode adopted by the Environment Application System.