The drones are coming.
The drones are coming. (Vol 95)
On the 24th August 2012 Peter Elliott, along with his team and pilot, died in a light air crash in East Kalimantan while conducting an airborne geophysical survey for a coal project. It is hoped that the new drone technology will eventually provide a full array of airborne surveys, such that further tragedies will be avoided. The traditional aerial surveys involve a tedious permitting process, along with various cost components, and scheduling issues (weather, plane availability) that are barriers to exploration projects conducting airborne geological surveys. Drones are revolutionizing the field of airborne and conventional ground survey programs.
This article provides a short introduction to the Indonesian drone industry catering to the exploration and mining industry.
Why Use Drones.
Traditional satellite imagery provides medium to high spatial resolution over vast areas. Satellite can be limited by cloud cover and satellite availability, and is reasonably costly when only looking at a small area. Airborne photography, radar imagery and LiDAR that can penetrate tree canopy, are used to define the terrain surface over moderately large areas such as a 10,000 Ha tenement. Airborne surveys are subject to availability of suitable aircraft, weather, and requires considerable permitting and costs. Drones can now readily provide airborne surveys over moderate areas (say up to 4,000Ha), and only subject to shorter weather interruptions. In many cased drone surveys are the most economical, effective and readily available aerial survey option. Conventional ground surveys continue cover limited areas, and may still be the most reliable method for some heavily forested areas, along with the ability to provide selected quality control for airborne surveys.
Drone regulation.
The principal Indonesian regulation that governs the Unmanned Arial Vehicles (UAV) Law was first issued on 12th May 2015 through the Minister of Transportation decree with No 90 / 2015. Further decrees include 163 of 2015, 180 of 2015 and more recently PM 47 of 2016 that mentions some 16 regulations relating to drone safety and use. Under these decrees it is prohibited to operate UAV in restricted areas and in no-fly zones or within 15 km from airstrips and airports. UAV flying altitude must be limited to a maximum of 150m. If you want to fly higher or over certain government areas, then a flight plan must be submitted at least 14 days prior to the flight. Small UAVs (< 2kg) can be used for hobby/recreational purposes while heavier UAV’s (up to 7 kg) should obtain special flight permits from the General Director of the Department of Civil Aviation. Drone pilots and their aircraft that intend to fly for photography / videography (Category 2 drones) should be registered and have a letter from their institution stating the reasons and use of the imagery. Pilots will also have to carry emergency equipment such as a fire extinguisher, are to report accidents and have valid insurance etc. UAV’s may not go closer than 50 meters to third parties and should be within sight (4.8km) of the pilot. Some provinces (e.g. Bali) have further rules for drones. Breaches of these regulations can be met with fines or prison. Indonesia has their own specific set of rules about how to properly travel with a drone. These rules may vary according to each airline.
ESDM regulation.
The ESDM regulation – KEPMEN 1827 on good mining practice includes requirements [ E.1.b).2.ii] for explorers to include a survey review where drones may be applicable;- “Remote sensing as intended include: satellite images, digital air photos, and / or other airborne data; using spatial and spectral resolutions each at least 7 (seven) meters and 5 (five) channels (band) and Results remote sensing using data with age maximum 5 (five) years;”
Drone surveys can be carried out by the exploration company or an appropriate service company. Drone service companies typically are registered with the Ministry of Aviation, but not necessarily registered as a Mines Department service provider, nor with the ASPINDO mining services association.
Selecting a drone.
There are a number of technical parameters that need to be considered prior to flying a UAV: the required resolution of the orthophotos, the flight height, the overlap between the photos, the lens and camera characteristics. These parameters are important because they affect the resolution of the obtained images, the time spent on site, the post-processing time and effort for the production of the final report. The resolution of the final orthomosaic photos significantly affects the amount of information that can be extracted and the use of automatic feature detection algorithms. Currently, most UAV’s are equipped with GNSS receivers and/or other sensors (e.g., Inertial System sensors, etc.). Telemetry facilities are frequently deployed for data transmission and management in almost real time when an immediate reaction is necessary.
The fixed wing is faster and therefore, can cover large areas while the copter gives better resolution images as it can fly at lower heights. Helicopter drones are cost and time effective only if it is used for surveys limited to small areas.
Drone technology for exploration.
Photogrammetry builds upon the old technique of aerial photos viewed through a stereoscope to gain a 3D perspective from the overlapping 2D photo images. Now digital photography and various computer data processing can build a 3D model of the surface. This approach allows error estimates and suitable coordinate system to be embedded from the outset. However, the software often has complexities and error intolerance that can present difficulties for inexperienced users. The requirements for collection of suitable imagery and control data can be arduous. There are a number of freely available software packages, web-based software services and various commercial packages to support this photogrammetry approach.
There are a number of packages that seek to merge digital images of rock surfaces, geological trenches etc with the photogrammetry surface models. These geological packages seek to interpret bedding, faults and some other geological parameters to help develop geological models. As a young Australian geologist working in the outback so long ago, it was the dream to have a tame kangaroo to hop over to some hard to reach hill and bring back some samples in its pouch. Todays geologist can stop dreaming of kangaroos and have a drone in their kit. Certainly, this technology would have come in handy the other day when I was half way up a very steep mountain, and could not continue up to examine the uppermost cliff face.
Hyperspectral imaging is a new and promising technique for drone based geological mapping. Sensors in the visible and near-infrared spectral range (VNIR) of the electromagnetic spectrum have been preferably used on drones due to their low weight and size. In contrast, short wave infrared (SWIR) sensors exceed the payload capacity of most lightweight aerial platforms. The most prominent material absorption features in the VNIR spectral range originate from green vegetation, while only a few mineral groups, mainly iron oxides and some rare earth elements that show typical absorption features, raising the need for a careful data processing. Some European test programs have tended to use hyperspectral imaging for regional mapping.
LiDAR (Light Detection and Ranging) sensors use laser light to scan the ground and measure the ranges of what bounces back. The laser light can find gaps in the foliage and thus measure the land surface below the tree top surface. Internal sensor errors may be associated with the performance index of the laser head, and there may be external issues related to the vibration of flying platform, load capacity, atmospheric conditions safety, etc. Not all UAVs can be used as LiDAR carriers. Typically, fixed wing drones have less vibrations, but selection of the motor and drone design are still a factor to be considered. When compared with photogrammetry, LiDAR is a much better mapping technology as photogrammetry can have limitations for areas of strong shadows, poor contrast, or featureless surfaces. Photogrammetry also requires you have access to the site to survey your ground control points, which is a time-consuming task.
Drone Makers and Contractors.
Ex-President Habibie’s dream was to build an Indonesian aircraft manufacturing industry in Bandung. This industry never real took off, though the Bandung universities established learning centres in support of this dream. Today Bandung seems to be the centre of a new Indonesian aircraft industry – building drones. There are a number of Indonesian manufacturers including PT. Global Inovasi Informasi Indonesia, PT. Aero Terra Indonesia, BPP Teknologi, Lapan and PT. Mandiri Mitra Muhibbah. The main developers seem to cater to the military, research, agriculture industry, with some mines trailing drones mostly for pit and stockpile mapping. PT. Aero Terra Indonesia is one of the more popular builders for the forestry and mining industries.
Many of the key drone components (motors, batteries, camera / sensors) are imported, though such drones are subject to “local content” criteria. Software packages are typically imported as a one-off payment or as annual subscriptions.
There are a number of drone service providers to the mining industry including the private companies of Top Aerial, PT. Aero Geosurvey Indonesia and PT. TechnoGIS, PT. Earthline, UAV Indonesia, and State-Owned Companies of PT. Surveyor Indonesia, PT. Sucofindo, PT. Biro Klasifikasi Indonesa.
At the recent Indonesian Mining exhibition, the Parrot Group using a SenseFly fixed wing drone was seeking to enter the Indonesian drone market. These drones are well made and with good sensors. Some European made drones tend to be smaller than some of the Indonesian models, making them more susceptible to Indonesia’s strong winds. Other international drone makers and contractors are looking to the Indonesian market.
The Indonesian experience.
The drone industry started in Indonesia around 2010, catering for the agricultural industry which only required moderate accuracy and was less concerned about built up areas and associated safety factors. By 2016 the use of drones was being trailed in some mining sites, where a greater degree of accuracy and higher safety concerns were required. Now the drone industry is trying to break into the oil & gas industry where even higher demands are placed on accuracy and safety. Several mining companies are trailing drones, and find that drones are suitable for some tasks, but do not replace all satellite / airborne surveys or ground surveys.
A typical drone contract requires a clear scope of work, to set out the accuracy, deliverables and safety factors. The contract is often US$ 10-25/Ha for a established mining project that covers an area typically less than 30Ha – 3,000Ha Ha. There are no government permit fees. A permit can take up to 6 weeks to obtain, though a single permit can cover a 6-month multiple flight period that is good for monthly surveys of mine development etc. Transporting the drone on a commercial aircraft can have safety issues for the drone batteries, that may go by air freight or even sea freight. The drones typically set a prearranged flight plan that can have multi elevation sections in response to hills, but typically do not have terrane following surface height software and sensors. If the battery becomes too weak, or the camera is not functioning well, then sensors can bring the drone back to base. Flight time is often less than 1 hour for battery life.
The field survey requires a registered pilot (graduate surveyor) and a ground engineer (geodetic engineer). The field survey may take about 2 days, and a further week is required in the office to process the data. The final model is delivered in typical geological software (Micromine, Global Mapper, Surpac etc) as per the client’s specifications.
Indonesian drones typically use Photogrammetry for convenience and cost. LiDAR is available in Indonesia and there are some research articles on their use in the forestry sector. LiDAR sensors can cost Rp 2 billion and require the drones to be more stable, fly more slowly at a lower altitude, while processing time can be twice that of photogrammetry. The benefit of LiDAR over photogrammetry is that lasers can penetrate vegetation giving much higher accuracy in data. This allows the scaling at 1:500. Typical photogrammetry provides maps at 1:2,000. The Jakarta company Top Aerial has both photogrammetry and LiDAR drones.
Hyperspectral imaging has not been tried in Indonesia.
In Australia some drones are downed by large eagles, though Indonesian birds sometimes follow a drone to see what it is. However Indonesian drones are sometimes lost due to sudden strong gusts of winds, particularly in hilly areas. Fixed wing drones can operate in winds of 30 – 60km / hr, but side winds above 30km/hr create too much “crabbing” and flight safety issues.
Drone Development.
The drone industry is largely made up of young entrepreneur engineers, wherein research is active in design and construction of the drone, sensors and software. The global trend is to carry heavier loads to allow for radiometric and other traditional airborne survey sensors. Indonesian companies are open to joint research with foreign parties, and the Netherlands has an ongoing research project in the agriculture sector. One Indonesian drone builder is developing a drone mounted magnetic sensor that may be trailed for mineral mining in 2019.