The UK has a highly developed Space business that is a little below the radar but lower still is the drone industry, very much in its infancy and one the government are anxious to grow, in a controlled fashion. SenSat launched in 2015 who focus on drone enterprise applications, give us an insight into the way they are used, the rules and regulations that make drone flights as safe as possible and the future possibilities.

The current UK laws permit drones to fly 500m away from a pilot, limiting the data capture to 1km per flight, but recognising their expertise, SenSat have been granted special regulatory permissions to fly 12km away, known as Beyond Visual Line of Sight (BVLOS). The 500m limits imposed on the majority of the industry represent a regulatory barrier rather than a technical barrier, with most drones carrying technology that allows at least 3km flight distances. The UK government recognised this and set about to propose new laws that unlock the economic potential of drones, especially when flying BVLOS known as Pathfinder.

What is Pathfinder?

In 2017 the Department for Transport set out the Pathfinder Programme, a series of partnerships between government and industry in key sectors, testing and trialling how drones can be ambitiously used to improve services across a range of sectors.

The aim is to tackle barriers to allow drones to be safely and efficiently flown beyond visual line of sight, enabling their full potential to be realised. This will allow UK businesses to maximise the opportunity that using drones presents, delivering benefits for the public. PWC (Price Waterhouse Cooper) estimates that within the next decade up to £42bn of economic impact could be unlocked through the use of drone technology within the United Kingdom.

The ability to fly further enables faster data capture, which in turn provides more robust and timely data sets that can be used to inform better decisions on civil infrastructure projects. For example, using drone data we can track closely the amount of soil that has been moved during the construction phase of new roads. This is a crucial metric for the progress of a project and reflects on the cash flow to a significant degree. The current method involves manual measurement made by people walking down the length of the construction project and usually takes around six weeks. New BVLOS drone data techniques can achieve the same information in under two hours, allowing us to quantify physical changes more frequently.

These projects can provide huge benefits to the quality of life; however, their delivery and operations can be disruptive. SenSat's Infrastructure Pathfinder contribution, looks to reduce this disruption by capitalising on the use of drones to provide consistent and regular data.

Why were SenSat chosen?

Over a two-year period, SenSat safely executed commercial drone flights totalling over 14,000km under both Visual Line of Sight (0.5km) and Extended Visual Line of Sight (1.5km) operations. The exemption allowed SenSat to work with the Civil Aviation Authority to learn from significant operational experience and build upon this to develop BVLOS operations. In addition, SenSat's 28 infrastructure clients provided commercial validation of the data and a clear business case to upscale efficiency.

This proved an attractive offering to Costain, partner on the Infrastructure Pathfinder. To date SenSat has been involved in multiple projects with Costain ranging from highways upgrades to National Grid electricity line schemes. BVLOS takes this an order of magnitude further and lowers the cost barrier to entry from using frequent data. To put the numbers into perspective, SenSat recently scanned the entire 162 km route of High Speed 2, a £56bn rail project connecting London to Birmingham. If SenSat were restricted to a 500m operational limit it would take approx. 462 individual flights. However, with their 12km BVLOS exemption SenSat can now capture the same amount of data in just seven flights, feasibly delivering entire route data sets multiple times per week.

How have SenSat got from 500m to 12km?

The operational processes for achieving BVLOS all stem from lessons learnt whilst operating at 500m and 1500m respectively. Although the technical complexity of the aircraft and airspace management changes when operating beyond visual line of sight, the supporting safety procedures have all evolved from a grassroots level during earlier stages of operation. By following this staged approach, SenSat were able to provide substantiated evidence and documentation to the Civil Aviation Authority who granted a 12km exemption in February 2018. The selection finalised with the Delair DT18 which lent itself well to long range operations on the Pathfinder project, completing multiple 12km flights in Ditchling, East Sussex.

Early stage feedback and interactive  sessions were crucial. This ensured operations were conducted in accordance with current laws and other airspace users were respected during the entire process of the trials.

Methods used to ensure safe flight execution

To safely execute the flights a number of key operational elements were required to support the 12km initial trials.

BVLOS operations do not maintain visual line of sight, so we must use other technology to proxy airspace awareness and understand what is happening 12km away. In order to safely execute these flights, we must assess the technical capability of the chosen hardware system and build upon real flight experience at EVLOS to create safe operating practices. This is largely fed by understanding risks and knowing how to mitigate them, many of which will have been experienced during our 14,000km of EVLOS operations. As an example, using radio antennas to communicate with the drone during EVLOS, we may see signals weaken if the drone passes behind a tree as seen from the ground station. When flying BVLOS it is critical to maintain constant uplink and downlink communications with the drone, so we needed to find a solution that wasn't affected by trees. The answer is to use cellular 3G signals to communicate with the drone, regardless of distance and regardless of signal obstacles.


The Pathfinder Initiative positions itself as a catalyst for scaling beyond visual line of sight flights in a safe way. By making long distance flights a go to solution for clients, SenSat has the ability to deliver large scale surveys in a fraction of the time that other operators are able to achieve with 0.5km or 1.5km permissions. As a result, the cost of drone captured data is reduced by up to 90%.

This has two interesting effects on the market today as most of the services are controlled by companies delivering medium sized areas (1km) at medium to high cost (£10,000) and at medium frequency (once per month). The introduction of BVLOS puts negative price pressure on these services, allowing end users to purchase more data (20km) at a lower cost (£1,300) with high frequency (once per day). This leads to commoditization of data which in turn supports business models that favour high volume low margin operations. How this will alter the make-up of companies delivering drone services is to be seen, but it is clear that a huge economic opportunity looms just around the corner and is now approximately 12km closer.

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