A government-funded research project in Germany looks into the possible use of miniature UAVs by public authorities such as the police, fire and emergency services
Air Shield was a research project funded by the German Federal Ministry of Education and Research in the field of ‘civilian safety research’ which relates to the protection of sensitive infrastructures and general population from manmade threats and natural disasters. The project, taken up over 2001-11, proposed the use of autonomous flying robots for reconnaissance purpose and aiding in the forecasting and prevention of emergency situations. The mobile MUAV (miniature unmanned aerial vehicles) equipped with lightweight sensors were to collect relevant data/information from the incident scene, which would be processed into tangible and actionable information. Siegen-based VTOL UAV manufacturer microdrones was a partner in the project.
The idea was to relay this information, represented as the visual and/or spatial landscape of the incident scene, to the relevant authority, which was expected to enhance their mission management capabilities and decision process.
One of the emerging challenges in managing situations such as fire or gas leakages is the combating and containment of the disaster event. Th is can be achieved efficiently if the disaster managers are provided with timely and detailed information of the situation not only at ground level but also at greater heights. The project was mandated to provide critical data by means of aerial surveillance with the use of UAVs (or UAS)of the disaster area and deliver important information which would then be analysed to devise and implement effective and appropriate action plans.
Fire brigade personnel in Germany are currently provided with special handheld devices that can only measure the concentration of different pollutants at ground level but are unable to survey and quantify the level of contamination carried in the atmosphere by winds and/or ascending columns of smoke. Such a measurement is critical to the safety of outlying communities that could be affected by these aerial pollutants.
A consortium under the aegis of AirShield comprising three industrial partners, five research institutions and one end-user was formed. The Communication Networks Institute at TU Dortmund was coordinator for the project.
Aims & objectives
The essential challenges can be summarised:
- MUAV platform: High load, long hours of operation, stability in bad weather situations
- Lightweight sensors: Minimum weight-high measurement accuracy despite miniaturisation of the measurement instruments
- Communication and operation: High reliability of the communication system, small delay for the transfer of control information, high data rate for the transfer of information in real time
- Geoinformation and decision support: Clear representation of the propagation forecast, inclusion of geographic data and weather forecasts
Solution & project results
A three-staged solution approach was chosen for the realisation of the AirShield project. The first stage contained the “flying units” consisting of flying robots and gas measurement devices. These flying units moved on predefined routes along the concentration gradient of the aerosol and sent the acquired measurement data to the ground station at regular time intervals.
The second stage was the invocation of the geo-decision support system located on ground inside the mission control centre. Here, the data received from the drones were evaluated, linked to topological and geographical information and finally presented to the user in a tangible descriptive form.
The connection between the first two stages was characterised by a highly reliable communication system. On one hand this consisted of the so-called ‘inter MUAV links’ between the individual flying robots of a swarm, while on the other hand there were ‘MUAV to ground station links’, which guaranteed the communication of the swarm with the mission control centre. For sustaining both kinds of communication, stateof- the-art procedures and processes were used.
The validation of the AirShield system under conditions similar to a real-life mission was the goal of an elaborate test. A delegation of the AirShield team travelled to the Rotterdam International Safety Center, a training ground located on the far edges of the Rotterdam harbour. Because of the remote location of the site it was possible to light up even large fires with significant smoke emissions without bothering or endangering residents. For the first time the opportunity arose to emulate major incidents and to evaluate the gaseous pollution sensors and the performance of MUAVs under influence of intense smoke and heat.
One aspect of the test was to check the real-time transmission of measurement data coming from the individual sensors to the embedded PC system in the air, down to the communication server on the ground and finally reaching the user interface. Another key aspect was to assess the specific effects of heat stress on the electronic components of the flight platform. For these tests, a total of three bins with surface areas of one, five and nine square metres were filled with a liquid combustible and lit up. The burning time of each test was between two and five minutes. Two of the four vehicles that usually constitute the AirShield swarm were used for test flights, one of which had a special suction pump to ingest sample gas from atop of the rotor blade plane.
The test proved that the AirShield system is in large parts capable of accomplishing the tasks of the NBC-Scout directly alongside the smoke cloud. In proximity to the cloud, substantially heightened concentrations of CO and H2S were measured as well as a significant decrease of the oxygen level. The results could be seen in realtime on the system’s graphic user interface.
Microdrones’s sb4-1200 was found to be the only VTOL MUAV in its class to have officially passed a fire test and was declared reliable VTOL MUAV for the use of public authorities. Products and services used for the project were a GfG Microtector II G460, custom-built ARM microcomputer with mission control, Gumstix microcomputer with mesh network communication control and AirShield ground system.