Therefore, the ABW model is usually used to establish an a priori analytical model to compensate for the empirical model, such as the extended CODE orbit model (ECOM), which was developed by the European Center for Orbit Determination (CODE) based on historical orbits accumulated over time [15]. This family of models was proposed to compensate for the lack of accuracy of the analytical model, and it was later found that good accuracy could be achieved by using the model alone. The ECOM model uses three constants and nine period terms in a Sun-oriented reference frame to describe the SRP acceleration. A simplified ECOM1 model with five parameters is usually estimated [16]. The ECOM1 is simple in a form and has good utility for GPS satellites with a cubic structure, but shows shortcomings for the rectangular satellites of GLONASS, Galileo, BDS, and QZSS. Therefore, [PERSON] et al. (2015) developed a modified ECOM1 model that includes additional terms, known as the ECOM2 model, which was employed by the CODE AC since the beginning of 2015 [17]. For the BDS-3 satellite, the key factor affecting SRP modeling is its body structure. However, the officially released satellite data are very limited. According to the official data, the bodies of CAST and SECM satellites are rectangular in structure [18]. On this basis, it is deduced from the satellite structure diagram that the BDS-3 CAST satellites are not a simple box-wing structure, but a T-box-wing structure [19; 20]. Moreover, some of the CAST and SECM satellites carry search and rescue (SAR) antennas [21], making them subject to self-shadowing. These special structures lead to systematic errors in the orbital solutions of the conventional SRP model that vary with the \(\beta\) angle. Studies focused on the SRP modeling of BDS-3 MEO satellites. On the one hand, an a priori box wing model of the BDS-3 MEO satellite was calculated on the basis of BDS-3 MEO satellites to compensate for the ECOM model [22]. Further, the optical parameters of the satellites are adjusted, and a rectangular priori model is proposed to effectively eliminate the systematic bias in the orbit [8]. Moreover, the optical parameters are calibrated taking into account yaw bias, self-shadowing, radiator emission, and thermal radiation of solar panels under the assumption of a T-shaped structure [19]. On the other hand, ECOM2 was proven to achieve better performance than ECOM1 in the normal yaw mode without the a priori model [23]. Removing parameter \(D_{\text{c2}}\) in the ECOM2 model or adding parameter \(D_{\text{s}}/D_{\text{c}}\) in ECOM1 could improve the orbit accuracy [24]. More detailed work was carried out in [25], where different subsets of the ECOM model were fitted using the SRP acceleration computed by the box wing model. They identified eight parameters for the BDS-3 MEO satellites and nine parameters for the IGSO. However, the above studies are limited to relying solely on L-band ground observations to adjust the SRP parameters without considering the contribution of ISL observations to the SRP parameter estimation. It was shown that the introduction of ISL observations can improve the estimation of the ECOM1 and ECOM2 models [26]. As a result, ISL reduces the \(\beta\) angle-dependent systematic errors in the radial direction of the orbit due to the imperfect SRP model and thus improves the quality of the precise clock offsets [27; 28]. However, the systematic errors in the orbit cannot be eliminated by introducing ISL observation. Furthermore, ISL observation is not publicly available, and ordinary users cannot directly collect it to improve orbit determination accuracy. Therefore, it is the best choice to introduce the ISL observation to establish an a priori SRP model so that it can improve the orbit determination accuracy at any time. In this paper, we consider combining the L-band ground observation and ISL observation to refine the SRP model of the BDS-3 MEO satellite. The effects of the SAR panel are considered.