PAGE Author

All posts by Andrea Schlapbach

German UTM system based on FLARM

Droniq, a joint venture between the German ANSP DFS and Deutsche Telekom, is offering the first operational drone traffic management system in Europe and paves the way for safe and efficient drone operations in shared airspace and BVLOS.

Drones are detected with the help of a drone traffic management system (UAS traffic management system, UTM, U-Space) based on DFS’ air traffic control system and the Deutsche Telekom mobile communications network. For the drone to be detected, the company has developed a special LTE modem with an integrated SIM card, the so-called hook-on device (HOD). After this device is hooked on the drone, it transmits the position of the drone and its identification to the UTM system using the mobile communications network. In addition to basic data, the network can also be used to transfer steering commands and other information.

In the airspace close to the ground, there is currently no radar coverage and airspace users generally fly according to visual flight rules. For this reason, aircraft or helicopters generally use the traffic awareness and collision warning system FLARM which continuously transmits position and other flight data. The devices receive FLARM and forward the data via mobile communications network the UTM cloud. In this way, the drone pilot always receives a precise overview of all flight movements in the vicinity. In addition, the HOD also transmits its own position data via FLARM, so a manned aircraft near a drone with a HOD will automatically receive a warning in the cockpit although he doesn’t even use the UTM.

The first released version of the UTM is available and already being used operationally by companies in the chemical and energy industry. Droniq service covers the entire spectrum for drone flights beyond the visual line of sight.

Camera-Based Non-Cooperative Collision Avoidance

We are working in an InnoSuisse-sponsored research project led by EPFL CVLab on camera-based detection of airplanes. The algorithms automatically detect traffic and draw a red box around another aircraft to indicate that it has been detected. More information to follow!



FLARM joins Swiss U-Space Implementation Group

The Swiss Civil Aviation Authority (FOCA) today has decided FLARM qualifies both as a Supplemental Data Service Providers (SDSP) as well as a future U-Space Service Provider (USP) and thus has accepted our an application to join the Swiss U-Space Implementation group (SUSI).

The U-Space – a European term for Unmanned Traffic Management (UTM) – is a set of services and specific procedures enabling a safe, efficient, sustainable and secure integration of drones into the airspace. These services rely on a high level of digitalisation and automation of functions, which enable complex operations with low human workload. Harmonized standards worldwide are key for a dynamic drone sector, as legal certainty is needed to enable investment.

FLARM receives UK BGA Safety Award

FLARM has been awarded the UK BGA’s Bill Scull Safety Award during AERO 2019. The motivation for the award from the BGA is as follows:

Bill Scull was a very active safety practitioner in gliding. The Bill Scull award is presented annually to a person or organisation for services to gliding safety.

Mid-air collisions have killed 33 UK glider pilots since 1975. Almost all mid-air glider collisions are with another glider, and they mainly happen in the dynamic situations in thermals and around airfields, where other gliders can be hidden from sight behind the glider structure.

In 2004, three Swiss glider pilots applied their engineering expertise to design a system that would alert pilots about an imminent collision and give an indication of the direction in which the threat lay.

Today, most of the active UK glider fleet carries the FLARM system that they invented; we have had no glider-glider collisions since 2014 – the first time that there have been four such years in a row; and there has only ever been one collision between FLARM-equipped gliders.

Having invented the FLARM system and designed the first devices, Urs, Andrea and Urban continued to develop the system to improve its performance, adapt its behaviour for competitions, add functionality to measure antenna performance and find lost gliders and to build in an obstacle database. New versions allowed multiple antennas for better coverage, and detection of powered aircraft equipped with transponders or ADS-B.

FLARM’s complex path prediction algorithms mean that it remains the only collision alerting system that is effective in the close manoeuvring situations such as thermals in which gliders spend so much time.

For devising, manufacturing, sustaining and continuing to develop this exceptional safety system, which has helped prevent collisions and save glider pilots’ lives across Europe, Urs, Andrea and Urban are deserving recipients of the Bill Scull safety award.


HEMS BVLOS Drone with FLARM-based Detect & Avoid

Swiss HEMS-operator Rega presented a new type of aircraft for searching for missing persons: the newly developed Rega drone can autonomously scan large search areas and is equipped with various sensors, such as a thermal camera. As a result, in the future, Rega will have at its disposal an additional device to help it search for people in distress if the helicopter has to remain on the ground due to poor visibility.

“We observed the development of drone technology from an early stage and were always convinced that drones could be of help in particular on search missions,” says Head of Helicopter Operations Sascha Hardegger. However, there is currently no drone system on the market that meets all of Rega’s requirements. In particular, it is not possible to operate a relatively small, lightweight and flexible drone over a distance of several kilometers and for several hours without visual contact with the drone pilot. “As a result, we took the initiative and decided to develop a Rega drone ourselves in collaboration with suitable partners”.

With its three rotor blades, a rotor diameter of just over two meters and a 10 kg payload, the new Rega drone looks like a mini helicopter. During a search mission, it scans large search areas precisely and autonomously (16 km2 in 2 hours with 80 km/h). It is able to independently detect and avoid other aircraft or obstacles, such as helicopters and overhead cables. This is possible thanks to anti-collision systems, coupled with countless data stored in the drone’s in-flight computer, such as digital models of the terrain and obstacle databases. The drone operates without visual contact with the pilot (BVLOS), has an endurance of 3 hours and maximal speed of 120 km/h.

With two redundant GNSS receivers, the Rega drone flies autonomously on a predefined route. It follows the topography of the terrain at an altitude of around 80–100 meters above ground level. In addition, a ground radar is built into the drone. Like many aircraft in Switzerland, the drone is equipped with the FLARM anti-collision system. The FLARM signals are evaluated on board. If necessary, the drone will automatically alter its flight path in order to avoid an impending collision.

Thanks to the FLARM anti-collision warning system, the drone is mutually recognizable electronically by other aircraft from a considerable distance. The drone pilot at the ground control station is constantly connected with the so-called U-space. This is an air traffic management system that is currently being set up to coordinate unmanned aircraft in jointly used airspace. It aims to prevent the drone from getting dangerously close to known air traffic.

For the event that, despite all the precautions described above, the Rega drone does get dangerously close to an aircraft and runs the risk of colliding with it, it is equipped with an active, automatic anti-collision function (detect & avoid, DAA). Based on the signals transmitted by the FLARM anti-collision warning system, the drone autonomously alters its flight path in good time to avoid colliding with the other aircraft. Around 80 percent of all aircraft in Switzerland, including all of Rega’s helicopters, are voluntarily equipped with FLARM, and the system is also becoming increasingly popular with paraglider pilots. This collision avoidance function will soon be enhanced with a built-in radar device to avoid non-cooperative traffic.

GPS Week Rollover

The US DoD GPS system provides essential positioning and timing information to many applications in daily use and aviation including FLARM. As part of the GPS design, the time is encoded in a format which restarts at zero every 1024 weeks (or merely 20 years), next time in the evening of April 6, 2019.

This is currently widely discussed on the aviation community, EASA today has published a Safety Information Bulletin.

The manufacturer of the GPS receiver modules used in all of your end-user products has confirmed to us already in May 2018 that these “modules have been tested and can handle the year 2019 GPS week number rollover without issue”.


New 2019 Obstacle Data Available

Two years ago, we released dramatically improved algorithms on PowerFLARM devices to assess the collision risk with fixes obstacles such as cable cars, antennas and wind turbines. Recently, we have worked hard to improve both the regional coverage, the number of obstacles, its level of detail, as well as the fidelity of obstacle data. These improvements are available for all FLARM devices to give you the best possible protection.

New for this year, we now offer high-resolution databases for the following regions: Austria & Slovenia, France, Germany, Northwest Italy, Northeast Italy, Switzerland, and UK & Ireland. These databases provide the maximum level of detail, as is preferred by regional, low-level, and low visibility operators for example in the helicopter air-work and HEMS/MEDEVAC domains. This is also the best choice for recreational pilots who operate regionally.

An updated European Alps database is also available, covering the entire Alpine region. It has been optimized to accommodate feedback from customers: A massive amount of critical cables throughout the Alps have been added from new data sources. To compensate for the increased data volume, vertical antennas, towers, wind turbines and power lines have been removed (with some regional exceptions). These objects are typically highly visible and do not normally pose a threat to recreational flying. In this database, power lines near airports have also been removed to avoid nuisance warnings during approach and departure, a request regularly raised from fixed-wing flight schools.

Each database is available in our webshop and is priced at EUR 35 (VAT may apply). We also offer periodic (e.g. monthly/AIRAC) large-fleet updates for various regions on request, contact us for conditions and pricing. All databases should be renewed at least annually and expire after January 31, 2020.

Only one database can be stored in the device at a time. Switching between databases is possible via SD card or USB stick, but not recommended in flight. Only one obstacle file must be present on the SD card or USB stick for proper installation during the device booting process. The installation process may erase flight logs, so we recommend retrieving the logs prior to installing a new database. Consult the device manual for specific instructions.

In the future and depending on customer demand, we intend to also cover Benelux, Scandinavia, Spain & Portugal, as well as selected regions of Eastern Europe and North America.

Fully-automated long-range UAV flights

Nice examples of two recent long-range UAV flights across Switzerland using FLARM as the only onboard technology to stay clear of other traffic.

The two independent project – one form ETH Zurich, one from a Locarno-based company – both target a fully autonomous beyond-line-of-sight fixed-wing drone flight in uncontrolled airspace using our FLARM UAV design to detect and avoid manned traffic, to be detectable by manned traffic and to be tracked by professional ground tracking services. FLARM was the only onboard traffic technology, neither ADS-B nor transponders were used.

The Oblivion Aerial project flew in December 2018 over a distance of nearly 100km, crossing the Swiss Alps. For legal reasons, the entire flight was accompanied by a manned aircraft capable of remote controlling the UAV in case required; no approval for the flight was required. Watch the video here.

The ETH Zurich project flew early January 2019, crossed the Lake of Neuchâtel at around 350ft above ground, lasted for a bit more than one hour, ended as planned on a normal airport and had an overall length of about 70km. The flight was unaccompanied. No specific danger zone was established. The flight and operations were approved by the Swiss CAA FOCA according to JARUS SORA standard procedures. Watch an interview here.

SESAR: ADS-B and other surveillance implementation status in Europe

Below condensed excerpts from a May 2018 report covering 56 pages by the European Commission’s SESAR project. We will comment on the findings later as they may be surprisingly disappointing for many GA pilots regarding the purpose, effectiveness and maturity of the ADS-B framework, namely in the context of airliners.


In environments with dense traffic, such as Europe or the continental US, ADS-B has faced challenges. Thus, the term ‘the execution of an ADS-B recovery plan’.


The original variant of 1090ES ADS-B was RTCA DO-260 (also known as version 0); early adopters equipped to that standard in the rushed ADS-B implementation. The original standard was inadequate, and the standard was updated twice to DO-260A (known as version 1) and DO-260B (known as version 2).


EU Regulation (1207/2011, 1028/2014, 2017/386): The last postpones the equipment of ADS-B Out functionality by June 2020 for aircraft with 5.7t MTOW or max TAS > 250 knots.

Since 2010, both US and the EU, have promulgated airborne mandates, which have gone through a series of revisions and postponements to finally converge on the currently applicable scopes (generally medium and heavy commercial traffic in the EU and including GA operating in controlled airspace in the US, several exceptions apply e.g. for state and military aircraft) and deadlines (2020 in both cases). In terms of these mandates, this is referred to as ADS-B Out. ADS-B In is not in the scope of the Regulation. European GA is out of the scope of EU mandate.

Airlines are affected by the misalignment of ADS-B mandates, especially between EU and US. European global airlines must equip their fleet to cope with the US mandate which requires to modify the Multi-Mode Receiver (MMR) by including the WAAS (Wide Area Augmentation System) function. In the US, additionally Selected Availability (SA) Aware MMR`s are required by 2020, and GPS Service Availability Prediction Tool and GPS augmentation WAAS/SBAS by 2025.

Airliner Equipment levels

Many aircraft are not fulfilling the quality requirements defined in the EU Regulation. The retro-fit plans show very few airlines planning to be compliant by 2020. The situation is similar for Regional and Business Aviation: there are no plans to retrofit their fleet, with very few exceptions.

Only around 20% of the EU airliners fleets are compliant with DO-260B, the majority of these are forward-fit on new deliveries. This is in line with the Airbus aircraft equipage rate (21% for A320, 31% for A330/A340). For the long-haul aircraft, 17% of the fleet is equipped, whilst for the short / medium haul aircraft, 21% is compliant with the Regulation. Data shows a consistent equipage level of 20% between mainline carriers and business aviation, with regional carriers falling behind that at 15%.

For the regional fleet, and especially Turboprops, ATR is offering the DO-260B compliance as an option on ATR’s-600 fleet, which is the last certified version. Regarding ATR-500 fleet, a retrofit solution should be certified by end of 2018.

For the long-haul fleet, some airlines are planning to retrofit their aircraft to comply with the Regulation. However, for the medium/short haul fleet, major airlines foresee difficulties to retrofit due to the high number of aircraft needed to be equipped in the short-term.

Technology and Capability

In the short to medium term, Mode S radars offer enhanced performance and substantial RF capacity improvements, whilst multilateration offers a cost-effective alternative to radar with similar performance to ADS-B.

ADS-B as a surveillance technology could not be able to fully replace conventional sensors until all airspace users are equipped and capable.

ADS-B was proven easily eavesdropped and/or spoofed when compared to conventional surveillance sensors. This raises substantial concerns to actors who value operational security or privacy. Technological mitigations are yet to become part of the global standard.

ATC Equipment levels

The current situation on ADS-B receiver installation in Europe is fragmented. Except for isolated areas such as oil rigs in Norway, no country today operates an ADS-B ground infrastructure for enroute surveillance integrated into the ATM system. France and other countries have no ADS-B ground coverage at all. France currently plans to install one single station in the Bordeaux area.

France, Luxembourg and several other countries do not have deployed ADS-B stations at their main airports today. Only a few countries today (mainly Germany and Switzerland) use ADS-B ground infrastructure for airport surveillance on few major airports, integrated into the ATM system.

UK, Belgium, Sweden, Finland and other countries will implement ADS-B ground reception without making operational use of the ADS-B data. In UK, France, Belgium, Italy, Sweden, Finland and other countries, stakeholders may intend to implement ADS-B for validation purposes or for surveillance of airport surface vehicles but there are no plans to integrate ADS-B position in ATC systems and to use it for ATC services.

Radio Spectrum

Radio frequency spectrum is a scarce resource. Management of the spectrum is handled globally by the International Telecommunications Union (ITU) where States are represented. Aviation only has a status as an observer in ITU and is not part of decision making. Aviation is represented by States that often have other priorities to consider.

The aviation spectrum is attractive to telecommunication service providers. Traditionally, it was sufficient for aviation to claim ‘flight safety’ to protect its spectrum, but during the last 20 years, a strong pressure has emerged from satellite service providers, mobile phone industry, broadcast companies etc., demanding access to aviation spectrum. The argument used against aviation is that the reserved spectrum is underutilized because of expected new systems not in operation and low spectrum efficiency due to old and obsolete technologies. The aeronautical band 960-1215 MHz is coming under increasing pressure to allow channel sharing with non-aviation services that by design are not compatible with the aeronautical applications incumbent in the band.

Radio channel saturation largely became a function of traffic density. Both TCAS and ADS-B use random channel access. The practical effect is that when the channel becomes saturated, the operational range of ADS-B in that location is substantially reduced.

Saturation of the 1090MHz channel is a regular occurrence in European airspace. The progressive rollout of the more spectrum efficient Mode S radars in lieu of old Mode A/C units alleviates this issue, but the freed capacity is being taken up by ADS-B with its rigid band usage character. TCAS is a significant contributor to channel congestion and can amount to 50% of radio traffic in a dense environment.

There exists a concrete risk of band oversaturation in the transitionary period when all aircraft are expected to both broadcast ADS-B and reply to Mode S interrogations on the same channel.


The position can be sourced from the aircraft’s inertial platform, i.e. does not need to come from GNSS. Such position quality will start to degrade after some time and the accuracy will be downgraded.

If surveillance is to make itself largely dependent upon GNSS by replacing ground-based surveillance sensors (radar, multilateration) with ADS-B, the shared dependency will lead to a significant common point of failure, since ATC is no longer able to determine aircraft positions. In the absence of an independent positioning source, both the aircraft crew and the ground ATC have effectively become blind. The consensus in the ATM community is that a robust, fully GNSS independent positioning and timing solution of some form will be necessary to provide some level of sustained operational capacity.

GNSS is a relatively fragile system; its weak received power makes it easy to interfere with, obstruct and spoof. Multiple cases of each have been demonstrated in the recent years and the number of interference events has been showing a sharply rising trend.

DO-260B ADS-B uses GNSS as its primary positioning source. The only two operational constellations in existence today being military systems each owned, operated and fully controlled by the US and Russia, and the relative vulnerability of GNSS to interference and spoofing raised unresolved questions of state liability and approval. US GPS and Russian GLONASS are provided realistically on an as-is basis with an expression of commitment from the respective federal administrations. This raises a dilemma concerning the role of national authorizations or approvals of these foreign-power controlled systems for use in the provision of safety of life services such as ATC.