passive tracking

例句：

1. 1. The company uses passive tracking to monitor its employees' activities.
   该公司使用被动跟踪来监控其员工的活动。
2. 2.The police are using passive tracking technology to catch the criminal.
   警方正在使用被动跟踪技术来抓捕罪犯。
3. 3. The researchers developed a passive tracking system that could detect the location of the target.
   研究人员开发了一种被动跟踪系统，可以检测目标的位置。