Wang Zhongguo, Lu Fan, Wang Dabao, Zhang Xiao, Li Jionghui, Li Jindong
Institute of Remote Sensing Satellite, China Academy of Space Technology, Beijing 100094, China.
Beijing Institute of Spacecraft System Engineering, Beijing 100094, China.
Sensors (Basel). 2022 Jul 20;22(14):5423. doi: 10.3390/s22145423.
Nowadays low Earth orbit (LEO) Earth observation (EO) satellites commonly use constant coding modulation (CCM) or variable coding modulation (VCM) schemes for data transmission to ground stations (G/S). Compared with CCM and VCM, the adaptive coding modulation (ACM) could further improve the data throughput of the link by making full use of link resource and the time-varying characteristics of atmospheric attenuation. In order to comprehensively study the data transmission performance, one new index which could be utilized as a quantitative index for the satellite-to-ground data transmission scheme selection, the transmission efficiency factor (TEF) of LEO satellites is proposed and defined as "the product of the link availability and the average useful data rate". Then, the transmission efficiency of CCM, VCM and ACM at typical G/S with different weather characteristics at Ka-band is compared and analyzed. The results show that ACM is more suitable for the G/S with moderate and abundant rainfall. Compared with the CCM of MCS 28, for Beijing G/S and Sanya G/S, ACM not only improves the transmission efficiency with the TEF increased by 3.62% and 24.51%, respectively, but also improves the link availability with the outage period reduced by 82.47% and 75.18%, respectively.
如今，低地球轨道（LEO）地球观测（EO）卫星通常采用恒定编码调制（CCM）或可变编码调制（VCM）方案向地面站（G/S）传输数据。与CCM和VCM相比，自适应编码调制（ACM）通过充分利用链路资源和大气衰减的时变特性，可进一步提高链路的数据吞吐量。为了全面研究数据传输性能，提出并定义了一种可作为卫星到地面数据传输方案选择定量指标的新指标——LEO卫星的传输效率因子（TEF），其定义为“链路可用性与平均有用数据速率的乘积”。然后，对Ka波段不同天气特征的典型地面站的CCM、VCM和ACM的传输效率进行了比较和分析。结果表明，ACM更适合降雨适中且丰富的地面站。与MCS 28的CCM相比，对于北京地面站和三亚地面站，ACM不仅提高了传输效率，TEF分别提高了3.62%和24.51%，而且提高了链路可用性，中断时间分别减少了82.47%和75.18%。
