“…Distributed guidance laws can be applied to guide multi-missile or multiple unmanned aerial vehicles (UAVs) system to encircle or attack a target simultaneously and to guide underwater multi-UAV system to capture a target cooperatively in Chen and Ren (2018), Dong and Hu (2016) and Wang et al (2017). In these scenarios, target acceleration can be broadly categorized into three types, namely known acceleration in Zhou and Yang (2016), Hou et al (2015), Wang et al (2015a,b), Bing et al (2017), Zhou et al (2017), Jeon et al (2010), Wang et al (2015), Sun and Xia (2012) and Kang et al (2018), unknown acceleration but with known upper bound in Kim et al (2019), Zhou et al (2018) and Hull et al (2012), and unknown acceleration but observable in Ding and Zheng (2016). When the target acceleration is unknown but the upper bound is known, researchers usually utilize the adaptive coefficient method to cancel the disturbance caused by the unknown acceleration in Zhou et al (2018) and Hull et al (2012).…”