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How Long Will We Keep Using Helicopter Surveys?

Isn’t it time we put safety ahead of tradition in aerial inspections?

Wreckage of the Super Puma helicopter that crashed in Norway recently

OK, yep, we’re biased because we like to think of ourselves as a disruptive force in the aerial inspection and aerial survey sector. But really, how many more manned aviation incidents do we need before we start to close the book on helicopter inspections and surveys?

The recent crash of an EC225 Super Puma helicopter in Norway, killing 13 people onboard, highlights the fact that even with the best of design and the best of maintenance, helicopters are far more likely to cause serious accidents, injuries and deaths than remotely piloted aircraft.

Admittedly, moving relevant survey and inspection work from helicopters to UAVs would not entirely eliminate the risk of helicopter accidents, injuries and fatalities, but everything we can do to reduce these incidents is surely a step in the right direction.

Interestingly (and sadly) this tragic crash had a strong connection with Australia as the cause of the crash is thought to be a gearbox failure, and 12 months earlier the gearbox that was installed in this aircraft was involved in a pre-delivery incident in Western Australia when the truck carrying the gearbox swerved to avoid kangaroos and rolled over. The gearbox showed obvious damage and was returned to Airbus Helicopters for inspection and repair, but was subsequently released to be installed in the EC225 in Norway. We can’t place the blame for the crash on that incident, but it will presumably form a large part of the investigation.

ATSB Statistics for Helicopter Incidents between 2010 and 2019

This chart, from the Australian Transport Safety Bureau (ATSB), shows that between 2101 and 2019 there were almost 200 incidents involving helicopters doing commercial aerial work in Australia. This excludes incidents during pilot instruction, business travel, sport and leisure flights and general aviation activities. This is almost 200 incidents (10 per year on average) just in aerial work where UAVs could be providing a safer service delivery model.

29 of these incidents resulted in serious injuries and 21 resulted in the death of the pilot and/or passengers on board.

Now let me be the first to point out that UAVs (drones or RPAS) are not free of incidents either. Over the same 10 year period, remotely piloted aircraft performing similar aerial work were involved in 146 incidents. Pretty similar, yes? Especially since they’ve only really been doing this kind of work for since 2013 and most of the incidents were in the last 5 years of the 10 year period.

ATSB Statistics for UAV (RPAS) incidents between 2010 and 2019

But the truth of that argument lies in the detail. There were ZERO fatal incidents involving UAVs from 2010 to 2019. None at all. Not only that, but there were ZERO serious injury incidents involving UAVs during the same 10 year period. None. Nada. Zilch. In the interests of full disclosure, there was one incident in the “Survey/Photographic” category in 2014 that caused a minor injury. Just the one.

Can UAVs compete directly with helicopters in aerial work? You bet they can, and they do. Every year, more and more companies walk away from helicopter-based inspection and surveys in favour of UAVs. And it’s happening largely from the top down, driven by the increasing need for publicly-traded corporations to show an increasing commitment to safety in their operations.

At the moment, the artificial limitations imposed by CASA (the airspace regulator) on UAV operations means that UAVs are not entirely able to compete in an even playing field with helicopters. But that’s mainly because CASA and Air Services Australia, who create the rules, say that UAVs, can’t fly near or over people on the ground, can’t fly over busy roads, can’t fly over urban neighbourhoods, can’t fly near towered airports, can’t fly beyond visual line of sight … well mostly, there are safety cases to be made for some or most of these situations, but the requirements are often far more complicated and onerous than those imposed on helicopter pilots. Does that have anything to do with the background of the decision-makers in CASA and Air Services Australia? I could not possibly say.

Helicopter pilots will probably argue that they have to prove that their aircraft are airworthy on a regular basis, and that’s why they don’t have the same rules. That’s true, but it does not stop them from crashing. As there is no model for UAV airworthiness certification in Australia (back to you CASA and ASA), it will take a while to defeat that argument entirely. I believe that UAVs can be made airworthy and that an annual airworthiness inspection program for UAVs would be a positive move. Not sure why it hasn’t happened already.

Helicopter pilots might argue that they have to file flight plans with Air Services Australia so that they won’t conflict with other manned aircraft. That’s true too, but there is nothing at all stopping UAV pilots from filing flight plans, only that the mechanism really doesn’t exist at this time (back to you Air Services Australia). Again, I believe that filing flight plans, at least for Beyond Visual Line of Sight (BVLOS) operations, would be a positive move. Again, not sure why it hasn’t happened already.

Helicopter pilots might argue that they have more regulatory constraints on their flight operations than UAVs, but that’s a fatuous argument because they are both heavily regulated and it’s a fact that helicopter pilots often fly outside the approvals given for their flight plans, especially in respect of altitude, and that a lot of helicopter flights in rural and remote areas don’t have flight plans.

Not only don’t they have flight plans, but often they are not monitoring the ADS-B transmissions of other manned aircraft, and they are not using the aviation radio channels intended to alert other airspace users of their flight paths and intentions. In most cases, small helicopters operating in remote areas don’t transmit an ADS-B signal either, so the only time you can become aware of them is when they fly in fast and low over your head, often taking shortcuts over private property to reduce fuel costs.

Helicopter pilots might even argue (and I might even agree with them) that the sky is made more dangerous now because of recreational drone users who don’t need a license, don’t need any training, don’t bother to read learn how to fly their drones safely, etc. I can’t argue with that as it affects my own work more often than I care to admit, but we don’t just let anyone pop into Hardly Normal and buy a helicopter to fly around the neighbourhood without a license. Nor should we allow it with drones. There are ways for non-commercial pilots to safely fly helicopters and light aircraft through aero clubs and the like, even to build and fly their own aircraft if they so wish. The same is slowly evolving for recreational drone users with mandatory drone registration, mandatory training for commercial use (even of small drones) and greater freedoms for drone club members than for the average drone operator. We just need to regularise the system so they are treated in the same way as recreational manned aircraft pilots.

Anyway, enough of my rants about how unsafe helicopter operations can be (and isn’t that reflected strongly by the fact that about 50% of all helicopter incidents in the 10 year reporting period were cattle mustering and agricultural spraying operations).

Let’s get back to the point.

Yes there are still limitations on how well UAVs can compete with helicopters in commercial inspections, aerial photography and aerial surveying operations, but these limitations are largely (if not entirely) regulatory … not technical … nothing to do with the capabilities of remotely piloted aircraft or their pilots. Just that the rules get in the way.

Even leaving these limitations aside, UAVs can and do compete very well with helicopters in most aerial work. Helicopters are expensive to deploy, expensive to operate and often require multiple crew members to conduct these kinds of operations.

Yes, helicopters can cover a lot ground in a day at 2000 feet than a UAV can at 400 feet, but there are now UAVs more than capable of operating at 2000 feet at well, which can cover the same amount of ground in the same time, at a lot lower cost.

Yes, helicopters can fly all day on a single tank of fuel (well, arguable but let’s agree for the sake of argument), while UAVs are limited to flight times of typically less than one hour. But helicopter fuel is getting much more expensive – fuel costs have almost doubled in the past two years – and UAVs are achieving greater and greater endurance – one US-made petrol/hybrid VTOL (Vertical Takeoff and Landing) UAV has an endurance of more than 10 hours of continuous flight at 60-90 km/h, carrying commercial payloads of up to 7 kgs … and it uses a fraction of the fuel of a helicopter flying for the same period. Not only that, but if it’s petrol engine happened to fail, it has a battery motor backup that can still land it safely with little or no risk of incident.

I could go on and on (you might say I already have), but the arguments for helicopters over UAVs are becoming less and less valid, more and more reliant on archaic rules and regulations which are arguable intended to protect the manned aviation sector.

It will be the UAV sector, as I see it, that eventually manages to create a safer airspace environment where UAVs and manned aircraft can safely coexist. Along the way, it will create a safer environment for manned aviation too, resulting in fewer and fewer manned aviation incidents, especially those resulting in severe injury or death.

This will come about through the promotion of integrated airspace models where UAVs and manned aircraft fly in different altitude layers, rarely risking conflict at all. It will come about through the development of integrated airspace management models where unmanned and manned aircraft are always aware of each other and any potential for conflict can be easily mitigate by real-time communication. But in the end it all hinges on the willingness of government to examine the rules and regulations and objectively decide what needs to stay and what can be relaxed or removed entirely, as is already happening in the USA and Europe for example.

Unmanned aviation will come to dominate the commercial aviation market, from inspection drones to delivery drones, to surveillance drones, to policing drones, to remotely piloted taxis, remotely piloted cargo planes, remotely piloted military aircraft and, eventually, remotely piloted passenger flights. The future is writ large, at least for those of us reading the writing on the wall.

So the next time someone automatically assumes that a helicopter is the best option for your commercial aerial inspection, aerial photography, aerial mapping, aerial LIDAR or aerial survey project, jump in and suggest to them

“Isn’t it time we considered using drones? After all, they’re cheaper and much safer!”

To discuss more about how UAVs can deliver traditional helicopter projects, give me a call on 07 3103 0566 or flick me an email to info@qlddrones.com.au.

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How Much Does LIDAR Mapping Cost?

Can You Afford To Use LIDAR Mapping? Can You Afford Not To?

If you’re wondering whether or not to use LIDAR mapping on your next project, the short answer is “You probably already know you need it” … but how much will you need to pay to get LIDAR mapping?

The broader integration of lightweight LIDAR sensors into commercial drones has made LIDAR mapping a whole lot more affordable. But costs are still often “a piece of string” because there are just so many variables in the equation, like precision level, outputs required, size of area to be mapped, type of terrain, remoteness and more.

As a general rule, we advise our clients to budget for LIDAR mapping at $2500 per day. The actual cost may vary up and down a bit from there, but it’s a good rule of thumb to start considering affordability and value.

The recent availability of DJI’s own L1 LIDAR sensor may drive this rate down at first, but it will quickly (and sadly painfully) become clear that the type of operators who are buying the L1 sensor are almost certainly not the types of operators you want to be relying on for engineering, survey and similar standard data.

The technology (Livox Avia) on which the L1 is based is widely used by commercial drone service providers, but the way DJI has chosen to deploy the technology, at the lowest cost possible, has lead to too many compromises that will have the potential to lead to reduce the quality of the results, in ways you just can’t afford. It’s a great sensor for learning what LIDAR can do, but we don’t see it as a commercially reliable sensor at this point.

We’re more than happy to discuss the costs and cost factors associated with LIDAR mapping and to provide fast, no-obligation estimates for specific LIDAR mapping projects. Just give Tony a call on 07 3103 0566 or send an email to info@qlddrones.com.au with some details of your project and how you think you might want to use the LIDAR data.

Check out our Aerial LIDAR Mapping Service and Drone LIDAR Mapping for Surveyors and Engineers pages to find out more about how Queensland Drones is deploying and delivering fast, accurate LIDAR mapping using drones.

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4 Top Reasons to Choose Drone Surveys

Drone surveys are still a relatively new and not fully understood process for many people, but professionals in the engineering, exploration, surveying and precision agriculture fields are rapidly embracing the advantages of this alternative approach to gathering critical site data.

Where once they had to wait for a traditional surveyor to go out to a site, often spend several days there gathering ground-based measurements, then more days or even weeks compiling and presenting the data in a usable format, these early adopters are getting usable data in just a couple of days.

Even traditional surveyors are increasingly embracing drone surveys as a way of extending their reach and leveraging their time, often using a combination of traditional ground measurements and precise aerial measurements to quickly and efficiently survey large areas. We find ourselves increasingly working with traditional surveyors and partnering with them to certify the data collected from drone surveys.

So why are drone surveys becoming so popular? Why should you be considering drone surveys over traditional ground surveys, or even legacy manned aircraft surveys? Here are the 4 top reasons why drone surveys are taking over…

1. Drone Surveys are Faster and More Efficient

Not every survey should be completed using drones, just as ground surveys are not ideal for every situation. But there are many use cases where drone surveying is proving to be a faster and more efficient method of gathering site data.

As development and resource exploration extends into more and more remote areas of the country, drone surveys make more and more sense from a financial perspective.

The single biggest advantage of drone-based surveying is the speed at which data can be collected over large areas. The drone crew has to travel to and from the site, just as a ground survey crew would do, but once on site they can quickly and efficiently cover very large areas, capturing precision data that can be used as is, or validated against ground control points measured by a registered surveyor.

Where a traditional ground survey might be able to cover 50-100 acres per day, a drone survey can easily cover 500-1000 acres a day and more.

And where a traditional ground survey might collect 5-10 data points per acre, a drone survey is collecting 500-1000 data points per acre!

2. Drone Surveys are Safer

One of the biggest risks in ground surveys is workplace health and safety. In remote areas, especially, there is a big risk that ground survey staff may be injured by falls, vehicle accidents, snake bite or any number of other hazards, and because these sites are typically well away from ambulances and hospitals, help can be a long time arriving.

Contemporary HSSE best practice requires the development and implementation of strategies to minimise the risk of harm for personnel, especially when working on construction or mining sites and in remote areas. Drone surveys are one of the key methods of reducing staff exposure to site risks.

Yes, it’s true that drone survey teams have to work in the same risky or dangerous environments as ground survey teams, but it’s also true that drone survey teams only need access to a few key locations around the site, not to every part of the site (at least not on the ground). So there is inherently less risk in a drone survey.

Where a traditional ground surveyor might need to scramble over rocks or through dense vegetation to reach ground points that need to be measured for an accurate topographical profile, the same data can often be easily and safely captured from the air using drones launched from safe locations, then validated against ground data collected in safer, more easily accessible parts of the site.

This becomes even more critical when surveying large quarries or open cut mines where pit walls can be very difficult to reach and very dangerous to measure. But drone surveys can easily capture every detail of a pit wall or excavation, safely and efficiently, delivering data with much greater detail than traditional approaches.

3. Drone Surveys are Often Cheaper and More Cost-Effective

Are drone surveys really cheaper than ground surveys? It’s a no-brainer, right? If the data can be collected more quickly and efficiently from the air, there must be significant cost savings. Right?

Well yes and no. Anyone who claims that drone surveys can be completed for a fraction of the cost of ground surveys may not know what they are doing. It’s too easy for amateurs to pick up a drone at Harvey Norman and claim to offer aerial surveys, with little or no practical experience and relying on computer programs to automatically process the data (and with little or no idea if it is reliable or accurate, let alone in a usable format).

While this kind of operator might be able to deliver something resembling survey data, any reliance on that data comes with large financial and organisational risks for the purchaser. The data might come cheaply, but the cost of basing construction and engineering decisions on that data can be extremely high … and the operator probably has no professional liability insurance to compensate you for losses incurred through using their data.

Yes, drone surveys are often cheaper and more cost-effective than comparable ground based surveys for the obvious reasons, but they still require a similar level of professional skill, survey design methodology, ground-truthing, data processing knowledge and data verification expertise as a traditional ground survey, so make sure you’re getting that or it may not be as cheap as you think.

Professional drone survey service providers like Queensland Drones use experienced pilots and GIS analysts who understand how the data will be used by the client and can plan and execute their surveys to ensure client expectations are met. Our high quality GNSS RTK and PPK measurement systems mean we can collect and process survey data that can be readily used without surveyor certification. But where that data needs to be relied on for engineering decisions or cadastral purposes, we always work with a surveyor – your or ours – ensure it is reliable and verifiable.

The cost savings from a drone survey are significant, especially when larger and more complex or difficult sites are involved, but drones themselves don’t do surveys.

4. Drone Survey Data can be Just as Accurate as Ground Survey Data

Some traditional ground-based surveyors claim that drone surveys are not as accurate as traditional surveys, but there is little evidence that this is correct … and a growing body of evidence to the contrary.

Most traditional ground surveying still relies on the use of an RTK base station and RTK ground rovers to collect data points using triangulation of satellite data, which is then corrected using either the base position or remote correction signals, or both. Ground survey positions can be more accurate simply because the observation times are much longer – often 30 minutes or more, sometimes several times at the same location over the course of a day. And that’s why ground surveys are so expensive and time-consuming.

It may surprise you to know that professional drone surveys use almost the same measurement systems as ground-based surveys. Our professional mapping drones are equipped with multi-constellation GNSS GPS systems that collect triangulation data from 30-40 satellites every time they capture an image. This data is corrected using a multi-constellation GNSS base station whose position is accurately established either by placing it over a known survey point, using corrections from a remote network or using the same 30-minute or longer observations as a traditional surveyor, then validating the base position after the survey using a remote corrections network. This is a long-winded and complicated way of saying that, done correctly, drone surveys can produce very precise ground measurements.

Because drone survey accuracy is theoretically a factor of ground sampling distance (warning … more technical stuff coming), there are limitations to the precision a drone survey provider can reliably claim. While a ground surveyor may tell you they can measure points to an accuracy of 5mm, these points are often metres apart, sometimes much more, and are “extrapolated” across the ground between the measured points, so while they may be that accurate at the measured points, that may not be true in between.

Nominally, a drone survey can only be accurate to twice the ground sampling distance (GSD) horizontally and three times the GSD vertically. That means if the drone is collecting data at 3cm GSD, the nominal real world precision of the output is 6cm XY and 9cm Z. But even that accuracy can be compromised in many ways by pilot error or processing errors that often go untracked.

Queensland Drones can capture aerial drone survey data at 1cm per pixel and even less. This means our nominal real world precision is 2cm or less X/Y and 3cm or less Z. We use precision “terrain-following” data capture techniques to ensure the GSD is maintained even when mapping sites with large elevation changes. Like a ground surveyor, we do “extrapolate” elevations between data points, but as we are collecting thousands of points per square metre, the precision between those points is usually much better.

Our precision aerial surveys are backed up by measured ground control points and checkpoints. Even with precision PPK image capture and PPK or PPP correction of those image positions down to 1-2cm accuracy, we prefer to have ground data points that can be used to either provide additional corrections where some image distortions may occur, or to validate the accuracy of the captured data. Where these points are measured by a traditional surveyor, the validation often indicates aerial data capture accuracy of 5-10mm at those measurement points.

How to Find Out if Drone Surveys Can Work For You

Drone surveys are not ideal for every situation, just as ground-based surveys are not required for every situation. With more than six years of professional commercial aerial survey experience, our team can help you to decide if a drone survey is right for your particular requirements and if it is the most cost-effective option to get what you need.

Complete the form below, or give us a call on 07 3103 0566 for a no-obligation discussion of your survey requirements.

Go to the full page to view and submit the form.

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5 Tips for using a Drone for Gardening

Modernisation is seamlessly incorporated into our lives nowadays. We can learn anything with a simple video over the internet. We can socialise and provide professional services digitally. We can improve the quality of our lives by simply upgrading to more efficient technology. One of which is gardening.

Gardening isn’t just about choosing the best fertiliser for the home garden or finding the best crops for greenhouses. It also involves the planning phase, which can be difficult without the right tools. A drone’s perspective provides many benefits for gardening, and we’ll show you a few tips in this article.  

Some purists and hobbyists may find this impractical, but drones are an excellent way to help with gardening-related activities. Some large-scale projects use drones to make jobs faster and easier. So, if you’re looking for a tech-savvy approach for your gardening needs, here are 5 ways drones can be useful to you.  

Drones Can Help With Planning And Analysis 

Instead of walking and surveying a vast landscape for gardening, you can use a drone to do that instead. Drones usually come with access to applications like maps so you can get a quick landscape plan. Here are some things worth noting: 

  • It can capture still images and videos of the terrain, which you can use personally or as a marketing tool for landscape gardening proposals.  
  • The applications can also create a finished product using combined stills and videos for easy viewing and planning.  
  • It can help with large scale projects that require a precise operation.  
  • This method of gathering data helps you save money and resources.  
  • A bird’s eye view of the terrain will give you a better chance at implementing the right plan for gardening and landscaping.  

Drones Can Help With Monitoring Small Gardens 

Using drones can also be useful for small gardens. When you plot the regular schedule of drone visits to your garden, you can note observations and identify trends. This way, it will be easier for you to see areas that may need more attention or irrigation. This monitoring process can also serve as a gardening diary, capturing stills of your garden’s development over time.  

>> Need more gardening tips for your dream garden? Our friends from Garden Simply would be happy to help. Go to www.gardensimply.com.

Drones Can Help With Planting, Seeding And Pollination 

In agriculture, drones are now being used to help with seeding. These automated drone seeders are designed to help fast track planting trees in agricultural and large-scale projects. Although this technology is not yet readily available, the question of its accessibility is not when but how soon.  

Drone pollination is also a relatively new process, first used in Japan using a toy drone. Eijiro Miyako, a materials chemist, used a simple drone to pollinate flowers by gluing horsehairs under the device and coating it with gel. Although it can never replicate the complexity and precision of bees, the technology is headed in that direction.  

Drones Can Help With Security In Gardening  

Gardening often involves valuable plants like the best crops for greenhouses. Commercial greenhouse structures often require constant monitoring and security, which a drone can quickly provide. Hard to reach areas can also be easily monitored, allowing gardeners to mitigate any damage efficiently.

Drones fitted with speakers can mimic the sounds of birds of prey to frighten other birds away from your valuable crops or seeds.

The production areas involved in gardening can also use drone security as part of a more efficient method of managing inventory.  

Drones Can Use Infrared And Visual Spectrum To Identify Crop Health 

Drones are commonly used in commercial agriculture to identify crop health issues based on infrared and multispectral imaging, but similar inspections can even be done with a basic camera drone.

This makes it easier for you to spot what needs tending to, especially when the cause for concern is not visible to the naked eye. 

Conclusion 

If you’re open to the idea of cooperating with technology, there are endless opportunities for growth for you as a gardener. But beyond the ease and convenience, using a drone for gardening is a fun way to plan, grow and maintain your garden. And if there’s a device that makes the process easier, you’re hitting two birds with one stone.

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How accurate are drone mapping surveys?

Can Drone Aerial Surveys Meet Engineering Standards?

Drone mapping surveys are being used more and more to support construction, development, mining, agricultural and other commercial activities. Queensland Drones is a trusted provider of precision PPK Precision Aerial Mapping using purpose-built mapping UAVs. We regularly partner with engineers, surveyors and other industry professionals to rapidly deliver survey-grade aerial mapping (especially over larger areas).

So how accurate are aerial mapping surveys using drones? And why does experience matter so much?

It’s pretty easy to buy a drone and fly a site for mapping data. You can process it on an online platform like Pix4D or DroneDeploy and get what looks like fairly good outputs. You can even buy something called Aeropoints that will provide a level of ground control for additional accuracy.

In fact, lots of drone operators think that’s all you need. And some construction companies think the same. But is that enough? And if so, why do US survey authorities insist on aerial mapping being delivered only by licensed surveyors (even if Australian authorities don’t)?

Survey accuracy and reliability are critical if you intend to use the data for engineering or construction purposes. Basing your project on flawed data can lead to major problems and legal liability issues – something most drone operators know nothing about.

There are situations where drone imagery is all you need to inform your project planning or pre-design work, but before you rely on drone-based map to plan earthworks, building foundations or other structural and engineering uses where accuracy is critical, you need to know they can be certified by a registered surveyor.

When we create aerial survey maps, we use industry-standard GIS-grade PPK and RTK survey equipment to level and align the photogrammetric data for maximum accuracy. Where ultimate precision is required, we use ground control points and checkpoints measured by a qualified surveyor.

Some drone operators don’t use PPK/RTK or GCPs at all, but rely entirely on a 3rd party processing platform like DroneDeploy or Pix4D to provide the accuracy. These platforms provide pretty outputs, but not accuracy, and there is literally no way to measure how accurate or inaccurate the results may be. It’s not worth the risk.

But to understand that fully, we need to talk about what accuracy really means.

What does “accuracy” mean for drone survey mapping?

There are two types of accuracy when it comes to drone mapping surveys (or any other kind of survey) – Relative Accuracy (also known as local accuracy) and Absolute Accuracy (also known as global accuracy).

Relative accuracy applies within the model, whereas absolute accuracy applies to where the model fits in the real world (illustration courtesy Delair)

What is relative accuracy?

Relative Accuracy (also called local accuracy) reflects only how accurate the position of one pixel, position or object in the model is to another pixel, position or object in the model. You could measure absolute accuracy with a tape measure or ruler.

High relative accuracy can be useful on it’s own, if the model does not need to be fitted into a geospatial framework. But maps with low relative accuracy and low or no absolute accuracy are just pretty pictures, and should be treated as such.

It’s useful to understand that an “off the shelf” consumer drone like the Phantom 4 Pro or the Mavic Pro relies on public satellite data for its precision, and that data is often only accurate to 3-5m (yes metres) horizontal, while vertical accuracy is almost meaningless. So if your mapping operator is using a drone like this, they are not doing you any favours.

Find out more about relative survey accuracy

What is absolute accuracy?

Absolute Accuracy is a measure of how accurate the latitude, longitude and elevation (or northing, easting and height) of a pixel, position or object in the model are in comparison to their real world position if measured by a survey instrument.

The only accurate way to measure the absolute accuracy of aerial mapping data is with the use of checkpoints (ground control points measured using survey instruments, but not included in the processing of the model). Checkpoints need to be independently measured by an authoritative source.

We have had the absolute accuracy of our final mapping products measured by registered surveyors at 1.5-2cm horizontal, 2.5-4cm vertical, when based on PPK data collection accuracy combined with surveyed ground control points and checkpoints.

Find out more about absolute survey accuracy

How is accuracy measured in drone mapping surveys?

The only established method of checking and proving the accuracy of drone mapping surveys is using independently measured checkpoints.

Checkpoint measurement is the only way to establish absolute accuracy of drone mapping surveys (illustration courtesy Delair)

Absolute accuracy in drone survey data is measured by comparing the observed coordinates (the positions of checkpoints in the model) against authoritative positions (the independently measured coordinates of the same points on the ground).

How accurate should drone mapping surveys be?

There is no such thing as perfect accuracy in drone mapping surveys (and there is contention regarding the extent to which perfect accuracy may exist in traditional survey models). Every step in the process of collecting the data and creating the outputs potentially adds a small error factor to the end result.

The first element that needs to be considered in estimating the precision of drone survey data is the Ground Sampling Distance (GSD) – a measure of the smallest object which would be visible in the original photos, before they are processed into mapping outputs.

For example, we often fly the Swiss-made Wingtra One PPK UAV for highest survey data accuracy, as it’s 42MP mapping camera is capable of achieving a Ground Sampling Distance of 5-8mm per pixel, depending on terrain and flight altitude.  This means an object the size of a 5c piece could be detected in the photos.

GSD is important because it affects the minimum relative accuracy possible within the model, which itself affects the minimum absolute accuracy. If the data is collected, for example, with a Phantom 4 Pro UAV at 120m altitude, the GSD will be about 2.6cm/pixel at best. In practice, this means the best possible relative accuracy in the model would be 5.2cm horizontal and 7.8cm vertical – simply because that’s the closest a person or system could get to identifying the centrepoint of a GCP or checkpoint in the images.

But GSD is only ever relative to the precision of the mapping camera and the height of the UAV above the terrain. The extent to which the UAV is able to follow or reflect changes in the terrain will determine the overall GSD (and therefore the overall relative accuracy) of the model.

Overall relative accuracy GSD will be dependent on the ability of the UAV to follow the terrain during drone mapping surveys (illustration courtesy of Insight PPK)

Most UAVs these days feature some kind of terrain following capability. But sadly, few do it well. Most will establish a waypoint at each end of a grid and will adjust the altitude for those two points. If one point is low (say 100m above sea level) and one point is high (say 200m above sea level), the drone will gradually climb or descend between those two levels – ie, if set at 120m flight altitude, the drone may start a grid line at 220m high and end at 320m high, but will not reflect any variance in the terrain between those two points (e.g. there might be a gully 50m deep  in the middle).  While the GSD at the start and end of the grid line might be 2.6cm/px, over the centre of the gully it might be 4cm/pixel or more.

It is not uncommon in rugged terrain for a survey model configured to be executed at 1.5cm or 2cm per pixel GSD to end up with 15-20cm/pixel final GSD simply due to elevation changes during flight. The only way this can be effectively corrected is using ground control points so the processing system understands the changes in the terrain during flight.

What is survey-grade accuracy?

The term “survey grade accuracy” (sometimes called GIS-grade accuracy”) has no absolute definition, so you have to be careful about accepting this as a quality statement. In general, it implies an absolute accuracy of 10cm or less. But surveyors would argue that engineering-grade surveys should be accurate to within 3cm or less.

In reality, “survey grade accuracy” is what ever the client believes is the minimum error which can be managed in the data. There are really very few cases where 3cm accuracy is an absolute requirement (as distinct from a “nice to have”). It is achievable, but everything comes at a cost.

The larger the mapped area, the less the error in relative accuracy is critical to the outcome. For example, if we assume that relative accuracy is one metre for a given aerial mapping technology and we’re measuring 25km of fence line, an error of 1m or so is not terribly important. But if we’re measuring a retaining wall 10m long, an error of 1m is pretty significant.

What is RMS error in drone mapping surveys?

RMS error is the final calculation of the accuracy of the outputs from drone mapping surveys when all possible sources of error have been factored into the model (not just GSD or GPS error). There are many ways that small accuracy errors can be introduced into a drone mapping survey. For example, if the centre of a GCP is a line 2cm wide (so it can be easily identified in the photos), then positioning that point in the imagery will have a potential error of 1-2 cm just because of the thickness of the line. Add this to the positional accuracy of PPK or RTK (typically 1-2cm at best) and you have a total potential RMS error of 4-6 cm already.

Drone maps created using good quality drone equipment, careful flight planning, commercial grade GPS ground control points and commercial grade processing software can potentially be accurate to around 2-3cm horizontally and around 5-6cm vertically.  Because we prefer to err on the side of caution, we claim our aerial mapping accuracy as <10cm horizontal and <15 cm vertical, which is generally sufficient for most purposes.

Final RMS error is calculated by establishing the X, Y and Z variance between points in the model and points on the ground.

RMS error calculation example

The table above shows data from drone mapping surveys carried out using the French-made Delair UX-11 mapping UAV with 24 independently surveyed checkpoints. It illustrates an overall accuracy of just 12mm horizontal and 51mm vertical. When you think that the surveyor would have struggled to achieve 6mm horizontal precision in the surveying of the checkpoints, this level of final precision is very impressive.

Note always that drone operators are not surveyors. While our mapping can be created at very high levels of accuracy, it should be certified by a surveyor (yours or ours) before being used for engineering purposes.

Contact us for an obligation-free discussion and quote for precision aerial mapping.

Enquire now about precision mapping with PPK UAVs

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blog agriculture

New Ways to Manage Seed Trials and Trial Plots in 4 Easy Steps

Improve Seed Trials using Multispectral Trial Plot Mapping

Modern farming is challenging. Drought, climate change and other natural disasters are cutting farm profits, but you still need to do the best you can with what you have. Which is why seed selection and trial plots are so critical to the success of your crops.

A recent survey by Farmers Business Network identified the biggest seed selection challenges facing farmers as:

  • Needing to save money on inputs (23%)
  • Not knowing how last year’s seeds performed before planting this year’s crops (22%)
  • Pressure to make an early commitment to get seed discounts (17%)
  • Too little information on seed performance (16%)
  • Lack of agronomic expertise (7%)
  • Uncertainty about next year’s crop rotation (6%)

Seed trials are an increasingly popular way to get more certainty about production in a changing environment, but the lack of independent data on seed performance reduces the value of seed trials to the producer. But seed trials and field trial plots are complex, time-intensive and costly to run.

Validating the performance of seed trials or other trial plots by walking the field plot rows throughout the season is the traditional way of assessing comparative performance, but it is still subjective comparison and it’s hard to document the results in a way you can objectively compare.

You need results you can objectively analyse and compare, when you need them to make timely and well-informed decisions. Above all, you want your own independent data and you want to know how it was collected and analysed.

Enquire about our Trial Plots Mapping Services

Multispectral Trial Plots Performance Monitoring Program

Queensland Drones, in conjunction with Delair, Micasense and AgriSpatial, has developed a multispectral trial plots performance mapping program that delivers the objective data you need to make timely and accurate assessment of seed trials and nutrient trials for your growing conditions.

Regular, non-intrusive and biosecurity-safe overflights of your seed trial plots through the growing season provide rapid access to a wealth of knowledge and opportunities to improve seed selection decisions and improve overall crop productivity.

At regular intervals throughout the growing season, Queensland Drones UAV pilots will measure key phenotyping traits and plant responses from the air, using precise, repeatable and standardised data capture that can be benchmarked in time and space, allowing direct comparison plot by plot over the course of the growing season. We are very familiar with farm biosecurity practices and our pilots ensure that your specific biosecurity practices and HSE requirements are incorporated into our Job Safety Assessments.

The historical data collected through this program forms a digital twin of your field that can be examined and viewed from any direction, at any time, to revisit specific plant responses to seasonal conditions and plot treatments. Your digital twin can be configured for different seasons or times in a season and you can integrate this model into your existing farm management platform.

Using fast, quiet fixed wing drones and the latest RedEdge multispectral sensors, Queensland Drones rapidly delivers the data you need to easily visualise your field trial plots in 2D and 3D and instantly assess the differences in performance between seed varieties and nutrient varieties in near real time.

Regular data capture through the growing season supports analysis of key field trials and seed trials data.

Our seed trials and trial plots monitoring program includes four key flights during the growing season (others can be booked as required):

  • The first data capture flight immediately prior to planting supports field vectorisation and an accurate surface model of the bare soil to calculate plant height and biomass throughout the growing season.
  • The second flight, soon after plant emergence, supports vectorisation of microplots, plant counting and gap analysis, while you still have time to sow new seeds if desired. Following this flight, vector data identifying fields, rows and plots can be added to the data set for easy reference.
  • The third flight, towards the middle of the growing season, provides a high resolution orthographic (colour) image of the entire trial field, with sufficient detail to see individual rows, plants, gaps and weeds. This flight includes height variance analysis of individual plants within each trial plot and comparative biomass analysis between trial plots. It also provides a plant health review with NDVI plant vigour and NDRE cholorophyll production comparison by trial plot.
  • The final flight, prior to harvesting, informs success of corrective actions taken after the mid-field flight and yield estimation through biomass calculation to allow direct yield comparison between individual microplots or varietal groups. This data supports harvest planning and can be mapped against actual yield data collected by harvesting equipment to validate and improve calculations for future seasons.

Data from multispectral analysis of field trial plots provides clear comparative data to assess field plot performance (image courtesy of Delair)

Phenotyping of seed trials and other field trials can be easily and rapidly evaluated and compared in near real time, including:

  • Microplot vectorisation (automated identification of microplot boundaries)
  • Field vectorisation (automated identification of trial plot field boundaries)
  • Statistics by trial plot (supports plot by plot performance comparison)
  • Row vectorisation (to automatically determine the dimensions of trial plots)
  • Plant height calculation (to automatically measure and compare plant heights within plots)
  • Plant counts and gap identification (to validate the success of planting and germination)
  • Flowering characterisation (percentage of flowering vs non-flowering plants, particularly for sunflowers and canola)
  • Emergence characterisation (percentage of green/leaf to estimate seedling vigour, especially in early stage crops)
  • Photochemical Reflectance Index (PRI)
  • Stay Green (assessment of crops remaining green late in the season, particularly in sorghum)
  • FCover (the fraction of ground covered by the crop)

The DSM provides a base layer for quantitative measurement of crop vigour (NDVI) and green biomass (MCARI2) in trial plots (image courtesy of Delair)

The data collected by our seed trials and trial plots monitoring program can also inform other farm management activities including field planning, rotation planning, irrigation planning, fertiliser and chemical use, and logistics planning for future seasons to develop sustainable and profitable farm management workflows.

Cholorophyll content (NDRE) helps measure nitrogen retention, Greenness (VARI) is used to isolate soil from plants in analysis, and Photochemical Reflectance Index (PRI) identifies issues like water stress through chlorophyll and carotenoid pigment analysis (image courtesy of Delair)

Data and maps can easily be shared with your team members, advisors, consultants and contractors. You can add annotations, discuss findings, add attachments (like field photos) and make faster, better informed decisions about your field trials.

Row data and microplot data support direct, near real time comparison of trial plot performance (image courtesy of Delair.AI)

Automatic statistical extraction supports direct comparison of key traits row by row or plot by plot, with min/max, average, standard deviation and variance reported for each key phenotype cateregory and for each monitoring flight.

Enquire about our Trial Plots Mapping Services

Do It Yourself Multispectral Drone Mapping

We understand that relying on a external service provide in the long term can be problematic. To help clients who would prefer to fly the drone themselves and monitor their own seed trials and trial plots, we have put together a package that supports this option.

  • A simple, easy to fly multispectral UAV (not as good as ours, but acceptable quality).
  • A comprehensive on-farm coaching service to show you how to get the most from your drone.
  • A cloud-based support system so we can quickly and efficiently process what you capture and give you comparable data and analysis.

We usually require that our clients have one full season of on-farm service data as a baseline before using this option, so you can be confident that what you are capturing from your own drone is comparable with what we would have captured if you continued to use our on-farm service.

Farmers can now capture their own multispectral seed trials and trial plots data with full support from our AgriSpatial data processing team (image courtesy of DJI)

Please give Tony a call on 07 3103 0566 or email info@qlddrones.com.au if you would like to find out more about this option.

Enquire about our Trial Plots Mapping Services

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blog Photography

Aerial Photography Gallery

Here are a few aerial photos we’ve captured along our five year journey so far. Please let us know in the comments below what you think.

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blog

Aerial Landscape Gallery

Queensland Drones regularly provides landscape photography for property developers, rural and prestige real estate brokers, architects, building designers, tourism authorities and event managers. Here are some examples of our work. Click on any image to see it full size in the lightbox.

Check out Drone Photography Services for more information about this service.

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blog

What Is a Contour Survey?

A contour survey is a way to easily visually understand the vertical and horizontal shape (the “topography”) of your land. By understanding the land contours, you can easily visualise or map how water will flow over the property when it rains, where it will collect, where it might erode the soil and many other important water flow characteristics, where to build access roads and how to farm your property along the contours. From this simple base, you can even develop water flow models, stream maps and determine the best places to create dams and silt traps.

Do contour surveys need to be conducted by a registered surveyor?

Well, not all the time. A registered surveyor is required if the contour survey data is being used for construction or engineering purposes, or if the boundary data is being registered on a government cadastral (land title) system. Otherwise, surveyor certification is generally not required. We partner with a registered surveyor (yours or ours) where certification is required.

Are contour surveys by a registered surveyor more accurate than drone surveys?

Well, not really. In theory, a surveyor’s PPK measurement system can achieve accuracy 5mm, but in reality the average accuracy used by surveyors on ground surveys is around 10-15mm, which is very similar to the accuracy achieved by a well-designed drone survey (15-25mm). Ground surveys typically measure around 5-6 points per square metre or less. Aerial surveys can measure 100s of points per square metre. You do the math!

Is a registered surveyor faster and cheaper than a drone survey?

Not at all! The area that a ground survey team can cover in a day can be covered by an aerial survey in 1-2 hours. The area a ground surveyor would take a week to complete can be done with a drone survey in a day or two. Both methods have similar processing times, although drone survey results are usually ready in a few days, while ground survey data can take weeks to process and deliver.

Can precise aerial land mapping only be achieved using LIDAR?

Well, no, not really. We use both Lidar and photogrammetric aerial survey techniques and generally speaking any terrain with less than 50% tree cover can be mapped using a photogrammetric drone mapping camera with a reasonable degree of accuracy.

Standard drone mapping relies on making connections (extrapolation) between visible ground points, just as a traditional ground survey does. Where there are doubts about accuracy due to long grass or thick vegetation, Lidar mapping will generally deliver a better result as it can, to some extent, “see” below the vegetation to the underlying ground levels.

Please feel free to chat with us about this if you have concerns.

Looking to obtain a contour survey of your land? Call us on 07 3103 0566, email info@qlddrones.com.au or complete the Online Enquiry Form so we can discuss your requirements.

Why are contour surveys are so important?

Elevation data is essential for planning your home or any building construction projects, and following the contours of the land is the cheapest way to build roads and tracks through your property. For many types of agriculture, especially tree crops (like mangoes, macadamias, avocados, etc), planting along the contours of the land is the best strategy for maximum yield.

In construction projects, contour mapping is an essential tool to first understand the structure of the site, then calculate how much soil and other material needs to be added or removed to make the structure of the site fit the construction plan, and then to understand and verify how the terraforming of the land fits with the engineering design.

How do you read a contour survey?

In the most basic terms, a contour survey illustrates the elevation differences across your land, in regular intervals, from the lowest point to the highest point. Contour lines join points at the same elevation. The closer together the contour lines are, the steeper the section. The further apart the lines are, the shallower the rise or fall of the terrain.

A contour survey shows the boundaries of the property in a geo-referenced space, with the important contour intervals that show the terrain changes across the property and the location and accuracy of any controls used in the survey.

This contour and elevation map shows topographic data at intervals down to 0.25m (25cm), but we can calculate accurate contours down to 10 cm on lightly undulating land. 

Contour surveying is best illustrated using the image above, which shows the structure of an excavation across a narrow valley with a ridge at each end and a gully in the middle. The gully features a small dam and a marshy wetland around the dam. The tight contours on right side show a steeply rising hill which flattens out in the south-east corner, where a construction site office has been located. To the west of centre we can see that the directions of the slop change and the land again rises to a small plateau. The numbers on the sides represent the “MGA” coordinates. You might be used to latitudes and longitudes, but MGA coordinates are more useful in maps of this kind as they allow direct measurement in metres from point to point. Each MGA pair corresponds to a latitude and longitude and are easily converted using online calculators.

Contour maps are based on elevation data which can also be used to show relative height of ridges and valleys, water flow lines and more.

How do you get a contour survey?

Traditionally, topographical land surveys mean engaging a surveyor who sends a team of people to the site with survey poles and tripods and spend days, or even weeks, walking around every part of the site to measure points of different elevation. You would then wait weeks to see a large map of the site with all the survey results on it.

In the world of aerial contour mapping using drones, this kind of topographical mapping can be done in a matter of hours, or perhaps a day or two, using precision PPK-equipped mapping drones which can cover up to 300 acres of land per hour and still achieve real world precision of 2-3 cm in most cases, equivalent to that delivered by a traditional surveyor but with many more survey points and high-resolution mapping imagery to make the contours easier to comprehend.

An aerial contour mapping survey can identify many features traditional surveying might overlook, like hidden gullies and streams, natural watercourses, old abandoned tracks and areas that could be inaccessible entirely to a surveyor on foot.

To find out more about getting an aerial contour survey for your property or project, complete our simple aerial mapping enquiry form or phone Tony on 07 3103 0566.

Categories
blog

Multispectral Post Emergence Crop Surveys

How to Rapidly Audit your Crop Planting Investment

As identified by McCaine et al (University of Mississippi, 2019), “Plant density estimation during the emergence phase is critical for early-season decision making. Estimation of both crop and weed density is critical for addressing early season issues. Mapping of weeds in crops at any stage can be useful; however, early competition from weeds is frequently most detrimental to yield.”

Planting new crops, especially in times of climate uncertainty, is a risky investment. It pays to make sure your new planting investment has produced the results you expected, and be able to take rapid action to correct any deficiencies while conditions are still suitable for planting.

That’s why Queensland Drones has introduced its Post Emegergence Crop Survey service. Using the latest RedEdge Multispectral drone technology and advanced multispectral analysis tools, we can accurately model the results of new plantings within just a few days of emergence, giving you time to fill gaps, thin out over-plantings and correct nutrient or irrigation deficiencies before it’s too late.

In many crops, the first few weeks after planting are a critical time when new seeds can fail to germinate, new seedlings can die or fail to prosper and weed pressures can cause large parts of new crops to fail.

Plant population data is a strong visual indication of the success or otherwise of each new plant in a crop

Plant emergence mapping provides a visual record of the health and success of each new seedling in an emerging crop, which ones are growing well and which are not, where seeds have failed to germinate entirely, where plants have been sown too closely, and which plants are growing the fastest. The colour bar (left) shows the relative sizes of plants across an area, while the seedling map (right) shows the relative health of each individual plant in the crop.

This information can be integrated into your existing farm management systems to provide a persistent record of the planting which can be compared with mid-season growth, pre-harvest assessment and yield measurement to help identify improvements in planting processes for subsequent seasons. It can also be used to inform claims against contractors engaged to sow your new fields.

Queensland Drones provides on-site mapping services throughout Australia using fixed wing UAV aircraft to cover large areas in a fraction of the time of multicopter drones (e.g. DJI). Our RedEdge Multispectral sensors can deliver mapping imagery to as little as 8cm per pixel ground resolution and cover up to 400 acres per flight. Higher resolution mapping of smaller areas is also available.

Contact us now on 07 3103 0566 to discuss or request a quote

Find out more about RedEdge Multispectral Mapping.

Why Multispectral Mapping beats NDVI

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