Compact navigation systems for unmanned drones of the future
When Unmanned Aerial Vehicles (UAVs) or drones are used to survey industrial
buildings, map terrain, or transport cargo for the logistics sector, they need to
be as lightweight as possible, but carry the greatest possible payload.
Fraunhofer IZM has developed a compact and lightweight navigation unit (IMU)
for such drones, which enables centimeter-perfect accuracy that was previously
unattainable for civilian applications.
The aim of the IMUcompact research project was to develop a unit that can track the
position of autonomous drone systems with pinpoint accuracy. The inertial
measurement unit (or IMU for short) at the heart of the system essentially uses three
gyroscope axes and three acceleration sensors to establish a position in navigation uses
or map terrain with centimeter-level precision, even without a GPS signal. Compact,
low-resolution gyroscopes are now found in most smartphones and smartwatches, for
example to determine the orientation of the screen or camera. Although these socalled
MEMS gyroscopes are also small and lightweight, they are easily affected by
environmental forces like changes in the temperature, humidity, or electromagnetic
fields. This made them less suitable for use on drones, but IMU systems with higher
resolutions used to be no feasible option for industry or commercial use due to their
size and cost.
The interferometric fiber optic miniature gyroscope (IFOG) developed at the Fraunhofer
Institute for Reliability and Microintegration IZM enables a higher level of detail and can
be fitted to a wide variety of carrier drones due to its compactness and low weight.
As IFOGs contain no moving parts and are electromagnetically insensitive, they are far
better suited for use in UAVs than conventional MEMS alternatives.
Exceptional miniaturization, courtesy of an innovative assembly method
A novel assembly method was developed to make sure that the electronic and optical
components of the IMU can be arranged in such a way that a high degree of
miniaturization is achieved without compromising on accuracy. Conventional IMUs only
have a resolution in the range of 25 to 30cm. By comparison, the gyroscope developed
at Fraunhofer IZM now offers an absolute accuracy of less than 10cm. The special
arrangement of the measuring components on a 3D-printed optical bench also gives it
great mechanical strength for industrial applications, all while keeping the weight very
low. In addition, the researchers developed an application-specific circuit board, with a
robust and compact design.
Photogrammetric measurements from the air
One of the first practical applications of the new IMU is photogrammetry with UAVs.
Photogrammetry is the technology for measuring and identifying physical objects using
a combination of 2D images and 3D measurement methods such as LIDAR. In this case,
the weight of the IMU must not exceed 5 kg. Possible applications for drone-based
photogrammetry include the automated surveying of factory buildings, the technical
monitoring of offshore wind turbines, or automated stocktaking in agriculture and
livestock farming. Drone-based photogrammetry can also make an important
contribution for damage assessments in disaster areas, especially when large areas are
affected by unexpected environmental events. Providers of online mapping services also
use photogrammetric methods to create digital 3D maps, although this often required
the cost-intensive use of aircraft or gyrocopters with the necessary measurement
technology on board.
Strong partnership between research and industry
"As experts in the assembly and interconnection technology of optical fibers, we were
able to work with our project partners and develop a demonstrator that combined an
IMU with a GPS system and a powerful integrated circuit to create a complete,
integrated solution. The next step is to optimize this prototype in order to further
advance the civilian use of autonomous drone systems," project leader Dr. Alethea
Vanessa Zamora Gómez and developer Christian Janeczka proudly summarize the end
of the project. The IMU could be used in other carrier systems such as marine, aerial, or
other autonomous vehicles and even AI-based logistics networks for even greater
automation.
In addition to Fraunhofer IZM, the IMUcompact project included IGI - Ingenieur-
Gesellschaft für Interfaces mbH, IntraNav GmbH, and MILAN Geoservice GmbH as
associate partner. The project was funded by the Federal Ministry of Education and
Research for a period of five years until March 2023 under funding code 13N14758.
(Text: Yannic Walter)
Wissenschaftlicher Ansprechpartner:
Dr. Alethea Vanessa Zamora Gómez l phone +49 30 46403- 7995 l alethea.vanessa.zamora.gomez@izm.fraunhofer.de |
Fraunhofer Institute for Reliability and Microintegration IZM I Gustav-Meyer-Allee 25 | 13355 Berlin | www.izm.fraunhofer.de |
Originalpublikation:
https://www.izm.fraunhofer.de/en/news_events/tech_news/compact-navigation-systems-for-unmanned-drones-of-the-future.html
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