Citation: Kang, J.-G.; Kim, T.; Kwon,
L.; Kim, H.-D.; Park, J.-S. Design and
Implementation of a UUV Tracking
Algorithm for a USV. Drones 2022, 6,
66. https://doi.org/10.3390/
drones6030066
Academic Editors: George
Nikolakopoulos, Pablo
Rodríguez-Gonzálvez and
Diego González-Aguilera
Received: 11 February 2022
Accepted: 1 March 2022
Published: 2 March 2022
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Article
Design and Implementation of a UUV Tracking Algorithm
for a USV
Jong-Gu Kang *, Taeyun Kim , Laeun Kwon, Hyeong-Dong Kim and Jong-Sang Park
Maritime Technology Research Institute, Agency for Defense Development, Changwon 51678, Korea;
taeyun@add.re.kr (T.K.); lukwon@add.re.kr (L.K.); kimhd@add.re.kr (H.-D.K.); jsang723@add.re.kr (J.-S.P.)
* Correspondence: kangjg@add.re.kr
Abstract:
In a departure from the past, unmanned underwater vehicles (UUVs) and unmanned
surface vehicles (USVs) are increasingly needed for complementary cooperation in military, scientific,
and commercial applications, because this is more efficient than standalone operations. Information
sharing through acoustic underwater communication is vital for complementary cooperation between
USVs and UUVs. Normally, since USVs have advantages in terms of wide operational boundaries
compared to UUVs, they are efficient for tracking UUVs. In this paper, we suggest a UUV tracking
algorithm for a USV. The tracking algorithm’s development consists of three main software models:
an estimation based on an extended Kalman filter (EKF) with a navigation smoothing method, guid-
ance based on multimode guidance, and re-searching based on a pattern. In addition, the algorithm
provides a procedure for tracking UUVs in complex acoustic underwater communication environ-
ments. The tracking algorithm was tested in a simulated environment to check the performance of
each method, and implemented with a USV system to verify its validity and stability in sea trials.
The UUV tracking algorithm of the USV shows stable and efficient performance.
Keywords:
tracking algorithm; unmanned underwater vehicle; unmanned surface vehicle;
complementary cooperation; acoustic underwater communication
1. Introduction
Until now, the operating concepts of unmanned surface vehicles (USVs) and un-
manned underwater vehicles (UUVs) have been individually researched by connecting
them to manned systems through a network to perform missions. In other words, USVs and
UUVs acquire controlled and measured information over remote communication with each
control center, and perform missions such as surface or underwater surveillance [
1
,
2
]. How-
ever, complementary cooperation between USVs and UUVs has recently been emphasized
due to extensions of their range of operation [
3
]. In this complementary cooperation, the
USV needs high performance (e.g., duration, velocity, payload, and navigation accuracy)
compared to the UUV [4,5].
Previous methods of tracking UUVs have been proposed [
6
–
10
]. For example, Petter
Norgren showed a tracking algorithm based on an estimated UUV position with acoustic
modem telemetry and a mission plan [
7
]. José Melo’s research presented an estimation
of a UUV’s position using two beacons over an acoustic underwater communication and
a continuous–discrete Kalman filter for the UUV motion [
10
]. However, these studies
are not sufficient for a complementary cooperation mission between a USV and UUV
based on acoustic underwater communication. In an underwater environment, sound
waves have been used for acoustic underwater communication. The sound waves have a
low-frequency bandwidth and a sound speed. Moreover, the sound waves cause a delay,
which spreads due to multipath reflections and frequency shifts as a result of the Doppler
effect [
11
–
13
]. These limitations induce a loss of acoustic underwater communication, and
cause long transmission times. In these situations, USVs need a tracking algorithm to follow
UUVs stably.
Drones 2022, 6, 66. https://doi.org/10.3390/drones6030066 https://www.mdpi.com/journal/drones
