DOI

https://doi.org/10.34331/cpops.2022O001

J-STAGE Advance published date: June 9, 2023

DEVELOPMENT PROGRESS OF A LONG-RANGE VERTICAL TAKEOFF AND LANDING UAVShort Communication

DEVELOPMENT PROGRESS OF A LONG-RANGEVERTICAL TAKEOFF AND LANDING UAV FOR
THE IMPROVEMENT OF SHIP-BASED CETACEAN
SIGHTING SURVEYS
Taiki KATSUMATA* and Takashi YOSHIDA
Institute of Cetacean Research, 4–5 Toyomi-cho, Chuo-ku, Tokyo 104–0055, Japan*Corresponding author: katsumata@cetacean.jp

Key words:

aerial survey, cetacean, drone, unmanned aircraft systems, unmanned aerial vehicle, VTOL-UAV/ASUKA.

Estimating the abundance of cetaceans is critical to the conservation and management of those species concerned. Abundance estimates are based primarily on sighting data collected during shipboard
sighting surveys. However, these useful and standardized survey methods have their limitations. In
some cases, surveys may not be able to entirely cover the cetacean distribution areas, such as coastal
areas with high density of ﬁshing gear, or pack ice areas in polar regions. To improve the abundance
estimates in such undersurveyed areas, in 2019 we started developing an unmanned aerial vehicle(UAV) which was subsequently given the name of ASUKA (Matsuoka and Yoshida, 2021). The newaircraft would have to combine the following four characteristics. First, be able to takeoﬀ and land
vertically, allowing deployement from and to conﬁned spaces on the research ship’s deck. Second, beable of long ﬂight time required to cover large survey areas. Third, be able to carry suﬃcient payload
for installing a camera or cameras, which can capture a wide range with a high resolution to detectand identify cetacean species. The ﬁnal point is the UAV’s resistance to windy conditions. Because
cetacean sighting surveys are conducted oﬀshore, an aircraft that can operate in windy conditions isrequired.
After repeated trials with ﬂight tests at sea in 2019 and 2020, the ASUKA Mk 4 was completed in2021. In March 2021, ASUKA Mk 4 achieved an autonomous ﬂight distance of 51 km from a research
vessel in the North Paciﬁc. Then, in March 2022, it autonomously ﬂew 104 km in 1 hour and 20 minutes at an altitude of approximately 110 m, setting a new Japanese record for distance traveled in asingle ﬂight by a small UAV (Fig. 1). In addition, a preliminary ﬁn whale (Balaenoptera physalus)ﬁeld survey oﬀ Abashiri, Hokkaido (Fig. 2) and another for ﬁnless porpoise (Neophocaena sunameri)in Mikawa Bay, Aichi, were conducted. Equipped with a Sony DSC-RX0M2 camera, ASUKA Mk 4
successfully detected both target species. In the near future, the ASUKA Mk 5 (Fig. 3 and Table 1),
developed as a commercial model, will be used in actual whale research in the Antarctic Ocean to conduct aerial visual surveys in areas of pack ice where vessels cannot navigate.
UAVs are increasingly being used to observe and study marine mammals, including cetaceans. AGoogle Scholar search (https://scholar.google.com) on the number of articles containing “UAVs” and“marine mammals” showed that it quadrupled from 2012 to 2021. In addition to visual surveys of marine mammals, UAVs have been used for photogrammetry, photo ID, and tagging (Leslie et al., 2020;
Ryan et al., 2022; Murakami et al., 2021). This suggests that UAVs are replacing helicopters andsmall aircraft that require airﬁelds for takeoﬀ and landing, and that UAVs are becoming a necessary
survey tool. Cetacean research using UAVs has already begun (e.g., Hodgson et al., 2017), and they
are being used for various observational purposes in polar regions (e.g., Funaki et al., 2014; Angliss etCetacean Popul. Stud. (CPOPS), Others
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KATSUMATA AND YOSHIDA

Fig. 1. VTOL-ASUKA (Mk 4 Type 2)during vertical take-oﬀ from the research
vessel in Mikawa Bay on 27 March 2022.

Fig. 2. An underwater ﬁn whale photograph taken by ASUKA (Mk 4 Type 2) oﬀ Abashiri, Hokkaido, on 27 May 2022.
The approximate ﬂying altitude was 80 m.
Table 1. Speciﬁcation of the newly-developed
VTOL-UAV in 2022.
ItemFig. 3. The latest VTOL-UAV aircraft (ASUKA
Mk 5) developed in 2022.

ASUKA Mk 5*

Overall length
1,904 mm
Wingspan3,335 mm
Overall height
843 mmBody weight22.9 kg
Cruising range
Over 100 km
Maximum
160 km/h
speed(Long-range ﬂight cruising speed 80 km/h)
Payload5 kg maximum(104 km range achieved with a 2 kg payload)Seaworthiness Regular operation at 25-knot wind speed
Level ﬂight maintained at 40-knot windspeed* The acronym ‘Mk’ and ‘Type’ followed by a number
indicate the UAV prototype series identiﬁer.

al., 2018). In addition, in anticipation of the widespread use of UAVs, methods have been developed
for abundance estimation using digital data captured by cameras (Borchers et al., 2020). Given theabove, it is highly probable that abundance estimation of marine mammals using data obtained withUAVs will become more widespread. Accordingly, we anticipate that ASUKA, which can take oﬀ
from and land on a ship and has a long-range, and suﬃcient payload capacity, will be used in visualand various other surveys.
Acknowledgements

We thank the Fisheries Agency of Japan for granting research permits and funding for developing and implementing theUAV project. We also thank Drs. Hiroto Murase, Koji Matsuoka and Yoshihiro Fujise for their assistance with survey designand logistical support.

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DEVELOPMENT PROGRESS OF A LONG-RANGE VERTICAL TAKEOFF AND LANDING UAVReferences
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Received: November 26, 2022Published online: June 9, 2023

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