Low earth orbit (LEO) satellite constellations have the potential to augment global navigation satellite system services. Among the ongoing tasks of LEO-based navigation, providing broadcast ephemerides that satisfy the accuracy requirement for positioning, navigation, and timing is one of the most critical prerequisites. Singularities can occur when fitting broadcast ephemeris parameters in the case of a small eccentricity or small or large inclination. We choose an improved nonsingular element set for the LEO broadcast ephemeris design. We establish suitable broadcast ephemeris models, considering the fit accuracy, number of parameters, orbital altitude, and inclination. The fit accuracy using different orbital altitudes, orbital inclinations, and eccentricities suggests that the optimal parameters are \(\dot{n}\), \(\ddot{n}\), C_rc3, C_rs3, \(C_{\lambda c3}\), and \(C_{\lambda s3}\), together with the basic broadcast ephemeris model. After adding these six parameters, a fit accuracy of better than 10 cm can be achieved with a 20 min arc length and 500–1400 km orbital altitudes. The effects of the number of parameters, orbital altitude, inclination, and eccentricity on the fit accuracy are discussed in detail. Finally, the performance is validated with real LEO satellites to confirm the effectiveness of the proposed method.

低地球轨道 (LEO) 卫星星座具有增强全球导航卫星系统服务的潜力。在基于 LEO 的导航任务中，提供满足定位、导航和授时精度要求的广播星历是最关键的先决条件之一。在偏心率较小或倾角较小或较大的情况下拟合广播星历参数时，可能会出现奇点。我们为 LEO 广播星历设计选择了改进的非奇异元素集。考虑拟合精度、参数数量、轨道高度和倾角，我们建立了合适的广播星历模型。使用不同轨道高度、轨道倾角和离心率的拟合精度表明，最佳参数为\(\dot{n}\), \(\ddot{n}\) , C _{rc 3} , C _{rs 3} , \(C_{\lambda c3}\)和\(C_{\lambda s3}\)，以及基本的广播星历模型。添加这六个参数后，20分钟弧长和500-1400公里轨道高度的拟合精度可以达到10厘米以上。详细讨论了参数数量、轨道高度、倾角和偏心率对拟合精度的影响。最后，通过真实的 LEO 卫星对性能进行验证，以确认所提出方法的有效性。