search project is started in Hungary to evaluate the
feasibility of the Forerunner UAV concept and this
article is the first publication summarizing the initial
findings of the development.
Considering the literature about following and/or
supporting a ground vehicle (GV) by an aerial vehi-
cle several solutions can be found. First, there are
solutions helping the remote operator of the GV with
the aerial images taken by the UAV on demand of the
operator (Cantelli et al., 2013) or with continuously
streamed video (Harik et al., 2015). Second, solutions
utilizing aerial images in pre-planning of GV route
(Zoto et al., 2020) can be found. Third, there are so-
lutions on-line supporting the unmanned ground ve-
hicle (UGV) in path planning by processed informa-
tion from the UAV images (free paths, obstacles etc.)
(Lakas et al., 2018), (Peterson et al., 2018). Another
related source discusses the tracking of an UGV by a
UAV considering changes in UGV speed and heading
but constant UAV speed (Lee et al., 2003).
Considering the forerunner concept here the UAV
needs to fly in front of the EGV to have images about
forthcoming obstacles or threatening vehicles in ad-
vance. As nowadays the emergency vehicle drivers
navigate by their own GPS and probably they sud-
denly modify the route (especially in intersections)
based on their knowledge about the area its advisable
to plan and follow the route on-board the EGV and
follow the EGV with the UAV. So from the above lit-
eratue review the following of the GV by the UAV
(Lee et al., 2003) and the support of the GV opera-
tor (who is on-board the EGV in this case) through
streamed video (Harik et al., 2015) are the closest to
our concept but variable UAV speeds should be con-
sidered and the UAV must fly in front of the EGV.
This paper is an introduction of the basic concepts
considered in the design and development of the Fore-
runner UAV solution. Section 2 summarizes the hard-
ware system and the ideas for the cooperative control
concept between the EGV and UAV. Section 3 sum-
marizes the computer simulation concept of the over-
all forerunner system including the EGV, the UAV, the
camera sensor model and the related virtual 3D en-
vironment. Section 4 deals with the communication
issues regarding position and route data communica-
tion between the EGV and UAV and the streaming of
video from the UAV to the EGV. Section 5 gives an
overview about the planned simulation and real life
test scenarios to evaluate the pros and cons of the fore-
runner concept and demonstrate its basic capabilities
and finally Section 6 concludes the paper.
2 SYSTEM CONCEPT
In our approach, the UAV supplements the EGV to
extend its sensing capabilities. The aerial vehicle has
to be autonomous and has to follow or get ahead of the
EGV as the circumstances require. For example if the
EGV has to go through a crowded city center, it is ad-
vised for the drone to stay ahead relatively close to the
EGV in order to inspect the upcoming intersections.
On the other hand, in a highway or motorway scenario
the drone can get further ahead to identify obstacles,
providing the driver with extra time to safely reduce
speed.
Both of these cases prove that the UAV is not nec-
essarily following its companion rather leading the
group. However, the EGV is the one that dictates
the route. This problem can be solved if the UAV
knows the proposed path of the EGV. Therefore, at
the start of the journey, the destination, the planned
route and the initial course has to be sent to the drone.
Of course, this is not a final decision the EGV can al-
ter its route due to heavy traffic or other reasons, so
the UAV has to adapt to the emergency vehicle when-
ever it is necessary. To achieve this, the drone is com-
manded to stop at every intersection and wait for the
emergency vehicle, meanwhile scanning the environ-
ment for possible hazards. After it is evident which
way the EGV is going (from communication or the
motion of the EGV) the drone starts to go to the same
direction.
To be able to observe the surroundings of the
emergency vehicle, the UAV has to be equipped with
a camera preferably attached with a gimbal to en-
able independent movement relative to the drone. The
whole concept relies on the perception of the cam-
era, therefore it has to be carefully selected. The im-
age processing is highly dependent on the point of
view of the camera. Its task is to identify pedestrians
and vehicles and their position on the ground. The
current state of development suggests, that bounding
box (YOLO (Rekha B. S., 2020)) based identification
could be carried out real-time on the computer aboard
the drone.
From the above concept it is obvious that there has
to be some kind of communication between the UAV
and the EGV. Not only the planned route and course
has to be sent at the beginning but during move-
ment several data (including velocity and change of
plans) must be transmitted from the ground to the
aerial vehicle serving as the base of the cooperative
control. On the other hand, the UAV sends the risk
alerts, raw and/or (pre-)processed camera image to
the ground to help the driver. The place where im-
age processing is carried out is going to be deter-
mined by the performance of the on-board computer
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