## 3 Theoretical Analysis
### Range Characteristic between MBS and EGT
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & **Apogee** & **Perigee** & **Ascending** & **Descending** \\  & & & **Node** & **Node** \\ \hline MBS’s sub-point & & & & \\ (MBS locates 30\({}^{\circ}\) W, 30\({}^{\circ}\) S) & 20.3974\({}^{\circ}\) S, 98.8077\({}^{\circ}\) W & 21.5687\({}^{\circ}\) N, 125.1552\({}^{\circ}\) W & 0.0741\({}^{\circ}\) S, 86.9358\({}^{\circ}\) W & 0.1052\({}^{\circ}\) S, 59.3042\({}^{\circ}\) W \\ EGT’s location in 0.1\({}^{\circ}\) look angle & & & & \\ (MBS locates 30\({}^{\circ}\) W, 30\({}^{\circ}\) S) & 14.0429\({}^{\circ}\) S, 98.5044\({}^{\circ}\) W & 37.2064\({}^{\circ}\) N, 125.7875\({}^{\circ}\) W & 5.6218\({}^{\circ}\) N, 96.2608\({}^{\circ}\) W & 5.8745\({}^{\circ}\) N, 51.8339\({}^{\circ}\) W \\ EGT’s location in 0.2\({}^{\circ}\) Koek angle & & & & \\ (MBS locates 30\({}^{\circ}\) E, 30\({}^{\circ}\) N) & 1.0986\({}^{\circ}\) S, 98.4419\({}^{\circ}\) W & 38.4506\({}^{\circ}\) N, 125.9474\({}^{\circ}\) W & 17.5481\({}^{\circ}\) N, 96.8640\({}^{\circ}\) W & 18.3314\({}^{\circ}\) N, 51.2914\({}^{\circ}\) W \\ MBS’s sub-point & & & & \\ (MBS locates 0\({}^{\circ}\), 0\({}^{\circ}\)) & 20.3126\({}^{\circ}\) S, 98.9532\({}^{\circ}\) W & 21.7340\({}^{\circ}\) N & 0.0972\({}^{\circ}\) N, 86.9779\({}^{\circ}\) W & 0.0398\({}^{\circ}\) S, 59.4593\({}^{\circ}\) W \\ EGT’s location in 0.1\({}^{\circ}\) look angle & & & & \\ (MBS locates 0\({}^{\circ}\), 0\({}^{\circ}\)) & 14.1379\({}^{\circ}\) S, 98.9118\({}^{\circ}\) W & 27.3699\({}^{\circ}\) N, 125.2809\({}^{\circ}\) W & 5.7921\({}^{\circ}\) N, 95.8230\({}^{\circ}\) W & 5.9248\({}^{\circ}\) N, 51.4363\({}^{\circ}\) W \\ EGT’s location in 0.3\({}^{\circ}\) look angle & & & & \\ (MBS locates 0\({}^{\circ}\), 0\({}^{\circ}\)) & 1.2075\({}^{\circ}\) S, 98.8328\({}^{\circ}\) W & 38.6006\({}^{\circ}\) N, 125.3594\({}^{\circ}\) W & 17.7037\({}^{\circ}\) N, 96.4098\({}^{\circ}\) W & 18.3666\({}^{\circ}\) N, 50.8652\({}^{\circ}\) W \\ MBS’s sub-point & & & & \\ (MBS locates 30\({}^{\circ}\) E, 30\({}^{\circ}\) N) & 20.2221\({}^{\circ}\) S, 99.0994\({}^{\circ}\) W & 21.8957\({}^{\circ}\) N, & 0.2606\({}^{\circ}\) N, 87.0416\({}^{\circ}\) W & 0.0454\({}^{\circ}\) N, 59.6056\({}^{\circ}\) W \\ EGT’s location in 0.1\({}^{\circ}\) look angle & & & & \\ (MBS locates 30\({}^{\circ}\) E, 30\({}^{\circ}\) N) & 14.2114\({}^{\circ}\) S, 99.3207\({}^{\circ}\) W & 27.5414\({}^{\circ}\) N, & 5.9705\({}^{\circ}\) N, 95.3266\({}^{\circ}\) W & 6.0110\({}^{\circ}\) N, 51.1512\({}^{\circ}\) W \\ EGT’s location in 0.3\({}^{\circ}\) look angle & & & & \\ (MBS locates 30\({}^{\circ}\) E, 30\({}^{\circ}\) N) & 38.7875\({}^{\circ}\) N, & 17.8967\({}^{\circ}\) N, 95.8939\({}^{\circ}\) W & 18.4669\({}^{\circ}\) N, 50.5550\({}^{\circ}\) W \\ \hline \end{tabular}
\end{table} 
Table 1: The MBS’s sub-point and its bore-sight intersection on the Earth’s surface at one approximate apogee (i.e., 19:01:01 24 January 2001), one approximate perigee (i.e., 09:01:01 10 January 2001), one approximate ascending node (i.e., 22:01:01 2 January 2001). The look angles here are all left-looking. generating unequal dual-delay time, which is more obvious once MBS is at the ascending node or the descending node. If the load shown in this paper were deployed in a space-born platform, the discrepancy of dual-delay time would be much smaller, mainly because of the shorter distance from the platform and the EGT, as well as the available stop-and-go mode. MBS has many advantages (long-term, large-scale, unique, etc.) over the space-born platform when conducting Earth observations. Compared with the geostationary (GEO) SAR, the average distance of MBS is about 9.5 times longer; the field of the whole disc of the Earth at such a long distance is just a small angle, around 1.8\({}^{\circ}\), which makes it possible for nearly 50% of the Earth to be observed at a gaze look, when echo reflection characteristics, which can be expressed by incident angle, are ignored. Once incident angle is considered, the field of view (FOV) of MBS is also larger than that of the space-borne platform.