The differential code biases (DCBs) of the global positioning system (GPS) receiver onboard low-Earth orbit (LEO) satellites are commonly estimated by a local spherical symmetry assumption together with the known GPS satellite DCBs from ground-based observations. Nowadays, more and more LEO satellites are equipped with GPS receivers for precise orbit determination, which provides a unique chance to estimate both satellite and receiver DCBs without any ground data. A new method to estimate the GPS satellite and receiver DCBs using a network of LEO receivers is proposed. A multi-layer mapping function (MF) is used to combine multi-LEO satellite data at varying orbit heights. First, model simulations are conducted to compare the vertical total electron content (VTEC) derived from the multi-layer MF and the reference VTEC obtained from the empirical ionosphere model International Reference Ionosphere and Global Core Plasmasphere Model. Second, GPS data are collected from five LEO missions, including ten receivers used to estimate both the satellite and receiver DCBs simultaneously with the multi-layer MF. The results show that the GPS satellite DCB solutions obtained from space-based data are consistent with ground-based solutions provided by the Centre for Orbit Determination in Europe. The proposed normalization procedure combining topside observations from different LEO missions has the potential to improve the accuracies of satellite DCBs of Global Navigation Satellite Systems as well as the receiver DCBs onboard LEO satellites, although the number of LEO missions and spatial–temporal coverage of topside observations are limited.

低地球轨道（LEO）卫星上的全球定位系统（GPS）接收器的差分代码偏差（DCB）通常是通过局部球面对称假设与已知GPS卫星DCB一起从地面观测中估算出来的。如今，越来越多的LEO卫星配备了GPS接收器以精确确定轨道，这为估算卫星和接收器DCB提供了独特的机会，而无需任何地面数据。提出了一种利用LEO接收机网络估算GPS卫星和接收机DCB的新方法。多层映射功能（MF）用于组合轨道高度不同的多LEO卫星数据。第一的，进行了模型模拟，以比较从多层MF得出的垂直总电子含量（VTEC）和从经验电离层模型“国际参考电离层”模型和“全球核心等离子层”模型获得的参考VTEC。其次，从五个LEO任务中收集GPS数据，其中包括十个接收器，用于与多层MF同时估计卫星和接收器DCB。结果表明，从天基数据获得的GPS卫星DCB解决方案与欧洲轨道确定中心提供的地基解决方案一致。