The common view time transfer and two-way time and frequency transfer methods are currently the main means for achieving time synchronisation at nanosecond level. However, these methods have some limitations in real time and cost, which limit their wide applications in many fields, such as time synchronisation among base stations of the upcoming 5G network. In order to meet the requirements of nanosecond time synchronisation, a low-cost differential timing method is proposed in this paper by changing the manner of generation of traceability model parameters in GNSS navigation messages. The time deviation between GNSS system time and the timing laboratory that maintains Coordinated Universal Time (UTC) kept by timing laboratory named k (UTC(k)) is monitored by receiving the GNSS signal in space with monitoring receivers. The new traceability model parameters are generated with the monitored time deviations and then broadcast to users through the GNSS navigation message. The precision of the one-way timing method can be improved from tens of nanoseconds to the order of several nanoseconds with the proposed method. In addition, there are obvious advantages to carry out this method on the geostationary satellites in the BeiDou navigation satellite (BDS) constellation. The proposed method is verified on an experimental platform based on the UTC(NTSC) time frequency signal and the geostationary satellites in the BDS-3 constellation.

中文翻译：

---

基于修正溯源模型的差分定时方法

目前实现纳秒级时间同步的主要手段是共视时间传递和双向时频传递方法。然而，这些方法在实时性和成本上存在一定的局限性，这限制了它们在许多领域的广泛应用，例如即将到来的 5G 网络的基站之间的时间同步。为了满足纳秒级时间同步的要求，本文通过改变GNSS导航电文中溯源模型参数的生成方式，提出了一种低成本的差分授时方法。GNSS 系统时间与维护由名为 k (UTC(k)) 的计时实验室保持的协调世界时 (UTC) 的计时实验室之间的时间偏差是通过在空间中使用监测接收机接收 GNSS 信号来监测的。新的可追溯模型参数与监测到的时间偏差一起生成，然后通过 GNSS 导航消息广播给用户。采用所提出的方法，单向计时方法的精度可以从几十纳秒提高到几纳秒的数量级。此外，在北斗导航卫星（BDS）星座中的对地静止卫星上实施该方法具有明显的优势。该方法在基于UTC(NTSC)时频信号和北斗三号星座地球同步卫星的实验平台上进行了验证。采用所提出的方法，单向计时方法的精度可以从几十纳秒提高到几纳秒的数量级。此外，在北斗导航卫星（BDS）星座中的对地静止卫星上实施该方法具有明显的优势。该方法在基于UTC(NTSC)时频信号和北斗三号星座地球同步卫星的实验平台上进行了验证。采用所提出的方法，单向计时方法的精度可以从几十纳秒提高到几纳秒的数量级。此外，在北斗导航卫星（BDS）星座中的对地静止卫星上实施该方法具有明显的优势。该方法在基于UTC(NTSC)时频信号和北斗三号星座地球同步卫星的实验平台上进行了验证。