Song et al. / J Zhejiang Univ-Sci C (Comput & Electron) 2014 15(4):284-292
284
Coordinated standoff tracking of moving targets
using differential geometry
*
Zhi-qiang SONG
1,2
, Hua-xiong LI
†‡1
, Chun-lin CHEN
1
, Xian-zhong ZHOU
1
, Feng XU
3
(
1
Department of Control and System Engineering, School of Management and Engineering, Nanjing University, Nanjing 210093, China)
(
2
Department of Information, Suzhou Institute of Trade and Commerce, Suzhou 215009, China)
(
3
No. 207 Research Institute, China North Industries Group Corporation, Taiyuan 030006, China)
†
E-mail: huaxiongli@nju.edu.cn
Received Oct. 14, 2013; Revision accepted Jan. 7, 2014; Crosschecked Mar. 17, 2014
Abstract: This research is concerned with coordinated standoff tracking, and a guidance law against a moving target is proposed
by using differential geometry. We first present the geometry between the unmanned aircraft (UA) and the target to obtain the
convergent solution of standoff tracking when the speed ratio of the UA to the target is larger than one. Then, the convergent
solution is used to guide the UA onto the standoff tracking geometry. We propose an improved guidance law by adding a derivative
term to the relevant algorithm. To keep the phase angle difference of multiple UAs, we add a second derivative term to the relevant
control law. Simulations are done to demonstrate the feasibility and performance of the proposed approach. The proposed algo-
rithm can achieve coordinated control of multiple UAs with its simplicity and stability in terms of the standoff distance and phase
angle difference.
Key words: Unmanned aircraft, Standoff tracking, Differential geometry, Coordinated control
doi:10.1631/jzus.C1300287 Document code: A CLC number: TP13
1 Introduction
Unmanned aircrafts (UAs) can be employed in a
wide variety of military and civilian applications
(Nigam et al., 2012; Ping et al., 2012; Acevedo et al.,
2013; Forsmo et al., 2013; Zarea et al., 2013). Mili-
tary forces face great challenges to provide continu-
ous information on a target of interest. Multiple UAs
have the potential to revolutionize military applica-
tions due to their ability to coordinate with each other
in order to achieve common goals. Missions involv-
ing multiple UAs, each equipped with communica-
tion, sensing, computation, and control capabilities,
can be robustly designed to provide better results than
these involving a single UA. For some applications
such as exploration, persistent surveillance, search
and rescue, border patrol, vehicle convoy, and area
coverage, multiple coordinated UAs can provide
more accurate target positioning than a single UA.
Cooperation between multiple UAs can improve
performance in terms of search efficiency, execution
time, and system robustness. In these applications,
target tracking or surveillance is one of the crucial UA
properties required.
It is necessary to acquire exact target position
information, as well as to track and monitor a target
without being detected. This can be achieved by
tracking the target using multiple UAs, keeping a
certain distance from the target and a predetermined
angular separation between UAs. The distance from
the target is called the ‘standoff distance’ and this type
of tracking is known as ‘standoff tracking’. The target
can be stationary or moving. Lawrence (2003) was
the first to propose Lyapunov guidance vector field
‡
Corresponding author
*
Project supported by the National Natural Science Foundation of
China (Nos. 61273327 and 71201076), the Key Pre-research Fund of
the PLA General Armament Department (No. 9140A06050213BQX),
and the Natural Science Foundation of Jiangsu Province, China (No.
BK2011564)
© Zhejiang University and Springer-Verlag Berlin Heidelberg 2014
Journal of Zhejiang University-SCIENCE C (Computers & Electronics)
ISSN 1869-1951 (Print); ISSN 1869-196X (Online)
www.zju.edu.cn/jzus; www.springerlink.com
E-mail: jzus@zju.edu.cn