Small distributed robots have the potential to be commercialized in greenhouse operations due to their low cost, high efficiency and light weight compared to conventional greenhouse robots. In order to guide the path of these distributed dynamic robots, a positioning system with a centimetre accuracy is needed. While a GPS navigation system does not perform well in such an environment, the passive Spread Spectrum Sound-based Local Positioning System (SSSLPS) using FDMA (Frequency Division Multiple Access) does have the potential to accurately localize robots in such an environment if certain limitations can be overcome. One such issue is the Doppler effect. In this paper a Doppler shift compensation (DSC) algorithm, which applies a carrier frequency detection method, was used for passive SSSLPS (FDMA), and evaluated in terms of its ability to compensate for the frequency shift of the sound signals when measuring distance and position. The results show the applied DSC algorithm can measure distance using a compensated reference signal at 0.1–0.8 m/s constant velocity and 0.06–1.06 m/s² acceleration. The positioning error of the passive SSSLPS (FDMA) mounted on the crawler robot was 50.3 ± 22.3 mm accuracy, while the failed detection rate was 2.6%. These results suggest the applied DSC algorithm can effectively compensate for Doppler shift when using passive SSSLPS with FDMA for dynamic robot positioning.

由于与传统温室机器人相比，小型分布式机器人成本低、效率高、重量轻，因此具有在温室操作中商业化的潜力。为了引导这些分布式动态机器人的路径，需要一个厘米级精度的定位系统。虽然 GPS 导航系统在这样的环境中表现不佳，但如果某些限制，使用 FDMA（频分多址）的无源扩频声音本地定位系统 (SSSLPS) 确实有可能在这样的环境中准确定位机器人可以克服。一个这样的问题是多普勒效应。在本文中，应用载波频率检测方法的多普勒频移补偿 (DSC) 算法用于无源 SSSLPS (FDMA)，并根据其在测量距离和位置时补偿声音信号频移的能力进行评估。结果表明应用的 DSC 算法可以使用 0.1–0.8 m/s 恒定速度和 0.06–1.06 m/s 的补偿参考信号测量距离²加速度。履带式机器人搭载的被动SSSLPS（FDMA）定位误差为50.3±22.3 mm，故障检测率为2.6%。这些结果表明，当使用带有 FDMA 的被动 SSSLPS 进行动态机器人定位时，所应用的 DSC 算法可以有效地补偿多普勒频移。