WWF's Conservation Innovation Awards

Gathering votes
Gathering votes

The Drone Ranger – an aerial wildlife tracking system

Locating and monitoring wildlife is fundamental to conservation projects. During my prior experience developing wildlife tracking equipment as a Wildlife Telemetry Consultant for Sirtrack, I know first-hand the difficulties involved in tracking animals – including the drawbacks of ground-based VHF tracking. Walking (or crawling!) around with an antenna can be time-consuming and labour-intensive, made even worse by difficult terrain, thick vegetation, and large distances.

 We have developed a radio-equipped drone which can track multiple VHF transmitters at the same time. During a pilot study in the Sub-Antarctic we trialled this system to successfully track endangered yellow-eyed penguins, and to locate their nests hidden in thick scrub. See here for a video summary, including some footage of the Drone Ranger in operation tracking penguins:


 As a group of post-graduate students and researchers from the University of Canterbury and Massey University, we are seeking funding to further develop our system so it can be utilised by other conservation projects.

What conservation problem are you trying to solve?

Tracking animals is a critical requirement of many wildlife management programmes and research studies, and is important for monitoring individuals and populations. However, locating animals can be inefficient, time-consuming and expensive depending on the species and habitat involved.

VHF radio tracking is commonly used in wildlife studies, and while it is often cheaper and more accessible than other forms of electronic tracking, radio tracking from the ground can be labour-intensive.

Many animals can disperse further than the detection range of their transmitter, and ground-based tracking can be hindered by large distances, difficult terrain and topography, and thick vegetation.

Radio tracking from the air can improve detection range, the size of the search area, and minimise the effects of topography or vegetation on the signal, however using aircraft can be prohibitively expensive for many projects, and is impractical in many areas.

How are you going to solve this conservation problem?

We have developed the Drone Ranger system; a small drone equipped with a multi-frequency VHF radio receiver which can simultaneously track and map multiple transmitters from the air.

It is a lightweight, portable and cost-effective system, and can be carried into the field and operated by one person. Its multi-rotor design allows vertical take-off and landing without the need for a runway, and it can fly a pre-programmed search mission using the on-board autopilot, or under manual control.

Camera drones are not suitable for tracking cryptic species, or those hidden beneath vegetation, underground, or in other situations where visual location is not possible.

VHF telemetry is commonly used to monitor wildlife, but ground tracking can be affected by terrain and vegetation.

Our solution is to fit a multi-frequency VHF radio receiver to a drone to improve tracking results, and to allow the benefits of aerial tracking to be available to a much wider group of wildlife and conservation projects.

What makes your idea new and unique?

Other drones have been proposed which can track a single VHF transmitter at once, however these have limited practicality, as this means they can track just one animal at a time.

In the worst-case scenario a single-frequency receiver could track only one transmitter per flight, or else it must use a complicated method of frequency scanning to check through a list of target frequencies one at a time – which introduces the possibility of other signals being missed (and this problem can be exacerbated by the number of frequencies to scan, the time spent listening for each, and the speed of travel).

The Drone Ranger can monitor multiple VHF radio signals simultaneously, and can track over 30 different transmitters during a single flight.

Early field trials have proven its worth under extreme field conditions in the subantarctic Auckland Islands, where it provided significant efficiency gains tracking endangered yellow-eyed penguins to locate their nests.

Who will use your idea, and how will they benefit?

This system will be useful for conservation researchers, government agencies, non-profit groups, and professional organisations.

It is particularly useful to anyone who already undertakes VHF radio tracking of wildlife, as it not only offers considerable savings in time and effort compared to standard ground-based tracking methods, but is considerably cheaper than radio tracking using aircraft.

Due to the lower cost and comparatively longer battery life of VHF transmitters, aerial radio tracking using the Drone Ranger system offers advantages for tracking greater numbers of animals compared to other technologies such as GPS or satellite (Argos) tracking.

The Drone Ranger system would be equally useful for tracking and monitoring endangered natives and invasive pest species, so would be a useful tool to Predator Free NZ and other conservation initiatives.

What tasks or activities do you need investment for? How would you spend a $25,000 grant?

The following improvements are needed to make the system more accessible to conservation projects:

  • Refine the hardware design to improve ruggedness and reliability, and streamline manufacturing processes, including the development of additional prototypes.
  • Create an accompanying software program with a graphical user interface to simplify work flow and improve the ease of use for programming frequencies, downloading data, and analysing signals.
  • Many VHF radio transmitters are also capable of broadcasting additional information from on-board sensors, including activity, mortality, chick/egg timer programming, or temperature sensing. Once implemented on the Drone Ranger, this functionality will allow the system to detect not just position information, but also the status of the animal being tracked.

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List five other ideas posted in the challenge that excite you. Why?

1) Self-resetting trap for Possums and Rats

Great idea, and should go a long way towards winning the Battle for the Birds! This could be a great opportunity to collaborate! The Drone Ranger has a multi-frequency radio receiver onboard, so if the traps could broadcast a radio signal the drone could download information from them as it flies overhead, including what kills they have made and whether they need servicing. This could be useful for monitoring traps in the back country where it’s hard to get to.

2) Restoration Drone for Polluted Waterways

Great idea for restoring wetlands and waterways. Plus drones are cool!

3) Hihi Feeder

A good idea for helping this endangered species, and hihi need all the help they can get! This could be another good opportunity to collaborate too! The Drone Ranger’s multi-frequency radio receiver could be set up to download information remotely from feed stations, including which birds have visited, and whether the station needs need refilling. This could be useful if you had a lot of stations to check, or if they were in the back country where it’s hard to get to.

4) DNA diagnostics

DNA analysis in the field would be a really useful tool

5) X-Specs

This looks like a good way to collect lots of environmental data in support of research, and another great opportunity to collaborate. The Drone Ranger’s multi-frequency radio receiver could also detect other radio signals such as information from sensor pods as it flies overhead.

How could you improve your idea?

The Drone Ranger provides a complete tracking system from data collection to scientific analysis, but we would like to streamline the data management process by improving the software UI for configuring the system and analysing the data.

At present the system requires a reasonably tech-savvy user, so we plan to create a more rugged, reliable, and user-friendly solution suitable for large-scale use.

The next planned enhancement is recording information from programmable transmitters e.g. activity, mortality, temperature, and chick/egg timer.

We also hope to include the use of larger drone platforms (multi-copter and fixed-wing) so it is suitable for a wider range of conservation projects. A larger drone would have increased range and flight time, and would also offer increased payload capacity so it could carry additional equipment (such as a camera) with less effect on flight performance.

There is also scope for the Drone Ranger to become a multi-purpose conservation tool. In discussions with other contributors on this site (including NZ Auto-Traps, X-Specs, and Hihi Feeder) we have identified several collaboration opportunities! The Drone Ranger already includes a multi-frequency radio receiver and wifi so it could be used to remotely download data from their traps, sensor pods, and feed stations in the field, without needing to visit the sites in person. Useful for saving time, and retrieving data from difficult locations in the back-country!

edited on Oct 13, 2017 by Chris Muller

Brent Beaven Oct 6, 2017

Conceptually a fantastic idea and coming from a wildlife background, and having spent hundreds of hours tracking wildlife, I can see the benefit and cost savings that this will bring.
We are now only have one week left to get these refined for judging. Can we get a bit more specific. What part of this is the innovation? Did you build a new type of drone? Have you created a completely new receiver that is multi-frequency? Or is it taking two systems and combining them into one working unit? Getting that clarity will be important for judging this compared to the other entries.
Good work so far...let's use the time left to get this entry as good as it can possibly be.


Chris Muller Oct 7, 2017

Hi Brent, yes the innovation is the multi-frequency radio receiver we have developed which can scan many frequencies at the same time. This is a huge advantage over single-frequency scanning receivers which can only listen to one frequency at a time, and therefore have to step through the list checking each in turn. This means much longer and slower flights while the drone hunts for each transmitter individually, and/or the possibility of missing signals during a general search! With our system, one pass over an area can monitor all the transmitter frequencies simultaneously, and the recorded data file allows easy analysis of signal strength and corresponding position data for each transmitter.

The system is not specific to the drone platform and could be fitted to a variety of different drone types depending on mission requirements (e.g. range, flight time etc). For the first version we selected a small, easily portable, and cost-effective quad-copter platform which would have maximum usefulness for the widest number of conservation projects. But the sky is the limit (no pun intended!)

The Drone Ranger has already been field tested on wildlife research in a challenging environment. It provided significant savings on time and effort during my own research tracking yellow-eyed penguins in the subantarctic, freeing up time and personnel from labour-intensive ground searching for other tasks. The average time to find a nest was reduced from 5-6 hours using ground searching to under 24 minutes (including the time to attach transmitters to penguins, and set up the drone). I'm planning on publishing these results in a peer-reviewed scientific journal, and am always keen to hear from other researchers who can see applications for this technology in their own projects...


Inge Bolt Oct 7, 2017

Yep, we need one


Inge Bolt Oct 7, 2017

How did DRONE COUNTS get on last year, have they released any results? Are they worth contacting / collaborating with?


Chris Muller Oct 7, 2017

Hi Inge, yes I have contacted the folks from DroneCounts, and we are always open to collaboration in the future!
The biggest advantage of our system is that we have already solved the problem of how to monitor all your transmitter frequencies at the same time. The alternative method of sequentially scanning each frequency one after the other means signals can be missed during a search, so we have developed a multi-frequency receiver which can monitor many transmitter frequencies at the same time. This makes search flights much quicker and more efficient.
The Drone Ranger has already been field-tested under challenging conditions in the subantarctic and performed well – although we have lots of ideas for improvements and enhancements!


Philip Solaris Oct 7, 2017

Hi, Philip Solaris from Dronecounts here. I saw a question about the Dronecounts project on this page so thought I should respond. We completely redesigned our system that won last year's WWF award as we found that the antennas required, and accompanying weight, precluded fixed wing, long range operations and shortened endurance. We feel that long range capability is essential if wanting to acccess remote locations and to ensure that humans (or their machines) don't interfere with the test subjects (wildlife). Most importantly we completely moved away from simply locating tracking units and instead built into the new system the ability to capture and transmit a (customisable) range of additional data such as three axis accelerometer information. All the location and sensor data is recorded on the tracking unit itself so that you get a history of data rather than just momentary location. You can then upload all this data to short range or longe range drones. Recent tests show the system can currently upload data from the ground units from over a kilomotre away but version 2 (the production version) will have an upload range of up to 10km. We have spent a year developing this completely new system from the WWF award money and have a fantastic platform that has now been built and entering field trials this week !

Hope this answers the question.

FYI . we are going to enter an expansion capability to this unit soon. It will be called X-Specs.


Inge Bolt Oct 8, 2017

Well done, glad you guys have overcome some of the practical issues. Sounds really good, with massive capability. Sounds like the skyranger principle for the data, hopefully coupled with a great flying machine. wicked technology for conservation tool box!


Philip Solaris Oct 9, 2017

Thanks Inge. The Dronecounts system (now known as the Seekatron) takes a findamentally different approach to the original prototype idea of VHF tracking. We had developed the original idea to the point where we could pick up multiple signals and triangulate positions rapidly but ultimately we were frustrated by not being able to get the system onto small long range UAV systems, which most remote and large area searches require.

We kind of had a eureka moment, turned the problem on its head.stripped it down, started from the basics and have made something that no one else has. In the process we realised that positional / location data was just one of the many data sets we could capture with the new system. Not only that but we can also acquire a range of historical data from the target subject. So, we don't hunt for signals anymore. We simply fly within a couple of km of the target and upload the data. Without the searching task requirement we can now cover huge areas very quickly.

What we are now looking at doing is expanding the connectivity network with the X-Spec proposal we have put forward in this WWF round. This aims to connect other devices such as traps,water samplers, etc, to the information network. All of which we can upload via the drones, even in the most remote locations.


Jennifer Mcguire Oct 9, 2017

Great to have that feedback.


View all replies (3)

Chris Muller Oct 10, 2017

Thanks everyone for your comments. There have been a couple of questions asking about the differences between the Drone Ranger and other VHF tracking drone proposals…

One major advantage of the Drone Ranger over other systems (including last year’s winner DroneCounts) is that we already have a complete system, all the way to using the data for scientific research!
The Drone Ranger has been successfully field tested on an actual wildlife research project tracking yellow-eyed penguins in challenging conditions in the Sub-Antarctic. It cut months of bush-bashing down to a few days of search effort looking for nests, and we are planning to publish the data in a peer-reviewed scientific journal.
Check out the video here:

Other aerial VHF systems with single-frequency receivers (such as DroneCounts) have a significant limitation that they can only track one frequency at a time. For example, if you have 30 animals to search for then the receiver needs to scan each frequency for a minimum of 2 seconds (since many wildlife VHF transmitters only beep once every 2 seconds), meaning it will take a full minute to check them all. To allow for weak signals it would be recommended to listen for a longer time, say 4-5 seconds per frequency to make sure a signal has a chance to be detected if it is there. This would require 2.5 minutes to complete a scan of all 30 frequencies.
If the drone flies at 20km/hr then it can travel over 800m in 2.5 minutes, meaning this is the distance that is travelled before each frequency can be checked again. The faster it flies during a scan the more chance there is of missing something. If the drone passes over any other transmitters in that time they won’t be detected if the receiver isn’t listening on their frequency.
To absolutely guarantee that no signals are missed during a search, a single-frequency receiver must either make a separate flight to search for each transmitter, or it must remain stationary every time it completes a scan of all the frequencies (2.5 minutes in the example above) then move to the next location to scan from, and so on.
Some aerial VHF tracking projects have developed complicated scanning algorithms to try and get around this limitation by reducing the number of frequencies being scanned for (I believe SkyRanger works out where it is and prioritises the frequencies of the animals which are expected to be in that area), but there is still a risk of missing frequencies, especially if animals have moved away from their usual area.
In example scenario above, the bottom line is that by using a scanning receiver to track 30 transmitters each one can only be monitored for ~3% of the time, and if you need to track more transmitters this percentage reduces even further.
The Drone Ranger avoids this problem entirely by using a multi-frequency receiver to monitor all your frequencies simultaneously, meaning it can search at top speed and each transmitter frequency will be monitored for 100% of the time!

The Drone Ranger provides position data in the field so field teams can go straight to the animal’s location if needed.
Unlike other systems the Drone Ranger also collects a data file as it goes, making it straightforward to import the location data into a GIS for analysis and actually use it for scientific research. For example, this makes it possible to analyse position data in different times and locations, and to compare the results of different surveys. Since an animal’s location can change continuously, finding it once is not necessarily enough!
The Drone Ranger collects signal data very efficiently since it can cruise overhead during a search, so it can also be used for monitoring as well as locating animals. One morning flight and one evening flight over the penguin area was enough to detect which birds had gone to sea foraging and which were still on their nests, providing info on foraging duration and nest attendance. Collecting this information would have taken much longer if the drone had to check each bird’s frequency one at a time, and because of the time delay between scans this would not represent a simultaneous comparison.


Jamie McAulay Oct 10, 2017

This is super rad! Aweosome stuff!


Chris Muller Oct 10, 2017

Hi Jamie, thanks for your support!


Jennifer Mcguire Oct 10, 2017

This is really going to make a difference and funding will be able to go much further. Great thinking. Well done.


Chris Muller Oct 10, 2017

Hi Jennifer, thanks for that. Appreciate your support!


Jennifer Mcguire Oct 11, 2017

I'm really interested to see how this progresses. Best of luck!


View all replies (2)

Joanne Jackson Oct 12, 2017

Hey Chris. How are you resolving the limitations around rotary drones payload and flight times?


Chris Muller Oct 12, 2017

Hi Joanne, good question! You are correct that multi-copters can have less range than fixed-wing drones, although they do have other advantages.
We specifically chose a small multi-copter drone for the penguin project for several reasons: it is compact and light (fits in a backpack!) and quick to assemble in case we need to crawl through the bush with it, and the vertical takeoff and landing proved useful when operating from forested areas.
We found that the current drone platform provides around 10-15 min flight time, and a range of around 2km per flight. This was ample for monitoring each ~150,000 square metre penguin breeding area, and with a quick battery change it could search several areas at a time if needed.

However, some projects will have different requirements and the key innovation of the Drone Ranger is the technology, including the multi-frequency radio receiver and the onboard datalogging computer. This could be fitted to different drone platforms as needed to tailor the system to different requirements, including using a larger drone platform to give longer range and flight time.
A larger drone would also offer increased payload capacity so it could carry additional equipment (such as a camera) with less effect on flight performance.
(We’re also considering how we can use the onboard wifi receiver to download data from other types of device which may be in the field, and this wouldn’t require any additional payload capacity!)
One of the aims we have in applying for the Conservation Innovation awards is to further develop the system, including using larger drone platforms (multi-copter and fixed-wing) so it is suitable for a wider range of conservation projects.


Becky Wilson Oct 13, 2017

The idea has been progressed to the next milestone


Becky Wilson Oct 19, 2017

Kia ora Chris

Some great thinking here in response to queries about your idea.

One technical question that has come up is around the sensitivity of the receiver. Current multi-frequency receivers have lower sensitivity than their single counterparts, which means they have to be used at lower altitudes. This poses problems for projects in large forested and mountainous environments.

What is the sensitivity of your receiver? Have you cracked this issue, so that the drones can pick up signals effectively in areas they need to fly higher?

Your technology definitely has potential application for small areas with difficult terrain and colony species like penguins. How would it go for larger ranging species?


Chris Muller Oct 19, 2017

Hi Becky, thanks for the feedback. That’s a good question!
The system can pick up 2-stage VHF transmitters from a range of at least 105m away, which is the largest distance we have documented so far. This would allow a horizontal separation of over 210m between flight lines during a search.
A higher altitude would be expected to increase the coverage area on the ground, up to a point. We have evaluated the system under field conditions at altitudes between 30-50m, mainly because these altitudes proved sufficient, and the wind is usually quite strong in the subantarctic so flying higher than this reduces flight efficiency for a small drone. The same altitudes were also successful for detection of transmitters in beech forest in Canterbury during testing.
We are confident that signals could be detected at distances and altitudes greater than these if needed, and I am currently planning some comprehensive testing to document the antenna profile and corresponding detection ranges at different altitudes and distances.
We have the ability to adjust the antenna to fine tune it if needed, and a larger drone platform would allow increased flight time and range when tracking species with larger home ranges.
I’d be interested to follow up with you regarding the desired altitude and detection distance for the species and habitat/s you had in mind.