面向BDSBAS电文认证的OTAR播发策略设计

星基增强系统（SBAS）是向用户提供完好性信息的广域增强系统，涉及生命安全领域。为了提高SBAS系统的抗欺骗能力，基于椭圆曲线数字签名算法（ECDSA）提出面向北斗星基增强系统（BDSBAS）的电文认证设计方案。根据国内商用密码标准椭圆曲线（SM2）算法进行相应参数设计和电文排布方案，并描述了空中密钥更新（OTAR）的电文播发策略。为了进一步对试验方案进行验证，采用蒙特卡罗OTAR仿真器，基于3种播发调度算法进行仿真试验，通过调整权重对不同情况下OTAR电文接收时间进行分析。仿真结果为具体情况下OTAR电文方案播发调度的选择提供了重要参考依据。 

Design of message authentication and OTAR broadcast strategy for BDSBAS

Satellite-based Augmentation System (SBAS) relates to the field of life safety through a wide-area augmentation system that provides integrity information to users. To improve SBAS's ability to resist spoofing, firstly, based on the Elliptic Curve Digital Signature Algorithm (ECDSA), this paper proposes a message authentication design scheme for BeiDou Satellite-based Augmentation System (BDSBAS). According to the domestic commercial cryptographic standard elliptic curve (SM2) algorithm, the corresponding parameter design and message distribution scheme are carried out, and the message distribution strategy of Over the Air Rekeying (OTAR) is described. In order to further verify the test scheme, this paper uses Monte Carlo OTAR simulator to carry out simulation tests based on three broadcast scheduling algorithms. By adjusting the weights, the receiving time of OTAR messages in different situations is analyzed. The simulation results provide an important reference for the selection of broadcast scheduling of OTAR message schemes in specific situations.