drone survey

Drone Surveys: HexCam even more accurate with P4RTK

You may not realise it but you’ve probably seen a surveyor at work. You might have paid for a building surveyor to inspect a house you’re hoping to buy whilst hoping they don’t find any dream shattering cracks in the walls.  Or you may have seen surveyors walking around fields, on building sites or next to the road holding a long pole with what looks like a frisbee on the top. Surveying has traditionally been a ground based activity with a lot of legwork, or has involved climbing up scaffolding or looking out of cherry pickers to inspect hard to reach areas such as rooftops.

Drones are already reducing the risks to surveyors and other trades working at height by essentially acting as remotely controlled flying tripods carrying high resolution cameras. High quality video and still images can be beamed back to a surveyor standing safely at ground level and can also be carefully reviewed offline to see if any repairs or a more targeted close-up inspection are needed.

Drone images, captured in the right way and with the right equipment, can now be used for something far smarter. Take enough overlapping images from the right height and the right angles, and powerful software can now be used to produce high quality 3D models called “point clouds” which in turn can be used to generate surveying drawings. How does this happen? Each photo taken by the drone has a ‘geolocation’ (GPS coordinates and height above the ground) hidden within the file and the software uses this information to help locate thousands of points within each image to build up the 3D picture.

The problem with ‘standard GPS’ used in things like smartphones, sat-navs and in most drones, is that it’s not particularly accurate. Fixed locations can appear to wander from one day to the next by up to ten meters and that’s no good for surveyors used to working to sub-centimeter accuracy. One solution is to set out lots of ‘Ground Control Points’ or ‘GCPs’ and locate these precisely using very accurate and expensive surveying equipment. These points then appear in the photos and the software, as it knows their exact surveyed position, will ‘tie’ everything to the GCPs dramatically improving the accuracy of the 3D model. But this still relies on someone doing lots of leg work setting out and measuring GCPs, and the drone’s position (and hence each photo’s geolocation) is still controlled using standard GPS.

So how is expensive surveying equipment able to fix a point on the ground so accurately? Surveyors use a positioning system known as ‘RTK’ or  ‘Real Time Kinetic’. It takes the standard ‘wandering’ GPS signals from multiple satellites, monitors them over time and, using some very clever algorithms, works out the real accurate position. Until now, putting such RTK positioning into drones has been extremely expensive but recent developments in drone technology mean that we can now access high accuracy RTK positioning at much more affordable prices and using much smaller drones.

HexCam can now survey large areas to the same accuracy as traditional ground-based RTK equipment with only a minimal need for Ground Control Points. Site survey times can be cut dramatically and there’s no longer a need to stick that pole in the ground every 10 meters. In fact the drone effectively gives a reading every few centimeters.

As an example, HexCam recently surveyed a 300 hectare site using RTK drone technology.  Traditional surveying methods would have taken approximately 20 days. With the RTK drone,  we captured the data within 2 days, confident in the knowledge that the results were accurate to the same standard.

Drone usage for surveying also removes the need to trudge or drive over rough, environmentally sensitive or perhaps even dangerous terrain, making affordable surveying possible in these tricky environments.  

If you’d like to know more about how RTK positioning helps us to provide accurate drone-based surveying then please contact info@hexcam.co.uk or call us on 01603 327676.


5 Considerations When Selecting a Drone Operator

Drones are becoming a commonly used tool in many business sectors with new applications emerging all the time.  The number of companies and individuals advertising their services as commercial drone operators is also increasing steadily with many of these thousands of operators making claims about their experience and capabilities in an effort to stand out from the crowd. So how should you go about choosing a commercial drone operator to ensure that you get the level of service and experience that your particular application requires?

  1. Permission for Commercial Operation (PfCO)
    Firstly the basics. Anyone selling their services as a commercial drone operator must hold a current Permission for Commercial Operation (PfCO) from the Civil Aviation Authority (CAA) and you must check that they hold this permission. The award of a PfCO demonstrates that the operator has the necessary flight skills, understands all the relevant airspace and flight safety rules and regulations and understands everything, including weather forecasting and equipment limitations, that will enable them to operate safely.
    As well as asking to see the operator’s PfCO, you should also check the details yourself against the CAA’s own live register, known as CAP1362, which can be found at https://publicapps.caa.co.uk/cap1361. There have been many reports of rogue operators forging CAA PfCOs and of others, when asked, not even knowing what a PfCO is! It’s worth remembering that knowingly employing a drone operator without PfCO could leave you open to charges of vicarious liability should something go wrong.
    As part of the PfCO application process, operators have to demonstrate to the CAA that they have adequate, drone-specific, Public Liability insurance in place. You should always ask to see evidence of this insurance and check also that it covers the requirements of all stakeholders for your specific site or project location.

  2. References, Risk Assessment and Method Statements
    A reputable drone operator should be able to give you references from satisfied clients as well as case studies covering the particular application you are considering such as; mapping and surveying, close up asset inspection or more creative productions. Additionally you should be able to ask for example Risk Assessments and Method Statements to reassure yourself that Health & Safety is taken seriously.

  3. Caution:  Grand Claims Ahead!
    Always be suspicious of grand marketing claims such as “we’re the only operator able to work at night”. By default, all PfCOs now issued by the CAA allow operators to work at night with the correct procedures in place.
    Some operators may hold what is known as an Operating Safety Case (OSC) which allows them to work closer to buildings and people or perhaps higher or further from the pilot.
    This can be absolutely essential for some applications but is not always needed, so it’s worth making yourself familiar with what is permitted under a ‘standard’ PfCO. Operators with a standard PfCO can fly up to a maximum height above ground of 400ft (121m) but must keep the drone within 500m and within Visual Line of Sight (VLOS) of the pilot at all times.
    The drone has to be kept 50m away from people or property that are not under the operator’s control except during take-off and landing when this separation can be reduced to 30m.

  4. Start With The End In Mind
    An experienced drone operator will always start by agreeing a clear brief of the end results that you’re looking for. This will clearly be different for a creative filming project compared to a high resolution, high accuracy mapping project and some operators who may specialise in one application might not be able to deliver exactly what you need in terms of accuracy for example.
    The ‘deliverable’ will have a huge impact on the choice of drone equipment to be used, the method of flying, camera settings and even the time of day images should be captured.
    It’s hardly ever a case of simply  ‘getting some snaps’ and then throwing these into a magic piece of software.
    Quality control starts at the very beginning of project planning and a clear understanding by the drone operator of the processes and quality control involved in different workflows is essential, particularly in applications such as detailed mapping and surveying.

  5. Membership of Trade Bodies
    As the number and technical capability of drones increases rapidly, legislation is normally slow to catch up. Events such as ‘Gatwick’ in December 2018 can however lead to rapid step changes in legislation and it’s important that operators keep themselves informed of such changes and are aware of how they might be affected. Being a member of a trade body such as ARPAS-UK can help operators stay informed and membership should offer a degree of confidence to someone selecting an operator.

A basic introduction to the rules covering flying of drones for both commercial and noncommercial use, including new restrictions for drone flights close to aerodromes,  is given in the ‘Dronecode’ available at dronesafe.uk.

More detailed guidance covering the commercial operation of drones can be found on the CAA’s website:

https://www.caa.co.uk/Commercial-industry/Aircraft/Unmanned-aircraft/Small-drones/Regulations-relating-to-the-commercial-use-of-small-drones/

MIPIM 2019: In Cannes with KingFisher APS

March is just around the corner and with it comes the 30th edition of MIPIM in Cannes, France. We are teaming up with KingFisher APS at this world leading property event.

MIPIM is a four day event for the international property market, attended by industry influencers. The property market is facing some challenges in the coming years with growing populations and the growing need for smart cities. Technology is emerging faster than ever and solutions for sustainable growth is high on the agenda. This annual event attracts 26,000 participants from 100 countries to network, share knowledge and come to learn from each other.

KingFisher APS is a leading commercial drone operator, based in London, with a wealth of experience in the property market. Drones offer a safe solution to gather accurate information in the property sector, with very low carbon emissions.

If you are attending MIPIM 2019, we would like to hear from you. Let’s talk about how we can work together to build our future together.

CAA grounding the DJI Inspire 2 and DJI M200 series

On the 31st of October, The CAA published a safety notice, restricting the use of the DJI Inspire 2 and the DJI M200 series. The restriction stated that all SUA (drone pilots) are not allowed to fly these drones over or within 150m of congested areas, until further notice. Since then, DJI Global have been working closely with The CAA to get these restrictions lifted.

For us at HexCam, we were able to speak with KingFisher APS (our London-based collaborator) and arrange for the Inspire 2 to be swapped for the Phantom 4, that was located at our Norwich offices. This meant that operations continued undisturbed and our clients haven’t had to reschedule any of the drone mapping, inspections and surveys we’ve committed to. Here Andy is flying the Inspire 2, well out of the way of any humans in a rural location, testing the batteries.

Stay abreast of the restrictions here: https://t.co/4xKlfBQTo3

Map of Australia

Back in January 2018, we performed a condition drone survey of The Map of Australia with KingFisher APS for Historic England and Savills. It was with delight that we saw the progress this week. The project had many supporters and volunteers, helping to restore it in time for the centenary of Armistice Day.
80 people attended the service on Sunday, 11th November, some reading extracts of diaries and letters written home by soldiers from WWI.

We will remember.

UK Construction Week: NEC Birmingham

This week we were invited by KingFisher APS, to join them in Birmingham at the UK Construction week, to talk about the uses of drones in the construction industry.

Construction and building sites are often complex environments that poses risks to humans. Drones offer a safer and more accessible way to survey and inspect in these environments. It is also a much safer way to work at height (with taller structures). Aerial imagery and data is processed easily and made available to clients, typically within a day or two. This allows the client to take focused course of action, pin-pointing where they want humans to go.

KingFisher APS is one of our key collaborators, who has recently won the award for Best Business for Tech and Innovation, at the Croydon Business Awards 2018. Congratulations, Adam!

We had a successful three days with Adam in Birmingham and we have met lots of new people to work with.