Rules for operation of small-scale UAV are a limiting factor for success of the UAV technology. The capacity and responsibility to regulate UAVs rely on different bodies internationally (e.g. European Aviation Safety Agency (EASA) in Europe, Federal Aviation Administration (FAA) in the USA, Civil Aviation Administration (CAAC) in China, Directorate General of Civil Aviation (DGCA) in India). The International Civil Aviation Organisation (ICAO) aims to coordinate global interoperability and harmonisation of UAVs rules (Hayes et ah, 2014). The rapid development of small UAV civil applications worldwide, coupled w'ith a fair number of incidents, calls for tightening up the rules and regulations for small UAV flights. Specific rules are being established for light vehicles, and the responsibility to regulate flights of vehicles below 150 kg concerns national or state authorities. Regulations typically require education and training of operators and pilots. In Europe, beyond national level, there is a consortium funded by the European Commission (the Unmanned Aerial Systems in European Airspace (ULTRA)) working to develop a master plan for the insertion of RPAS in the European air transport system. Despite differences in essential aspects concerning platform categories (EASA, 2015), national rules typically impose some kind of restriction to fly the UAVs in certain localities (e.g. airports) and over certain heights (-125-150 m) and distances (i.e. line of sight). Some sort of certification and insurance is also required for commercially based flights.

The expansion of UAV applications will impact the airspace, but other industry areas will also be affected and need regulations and adaptation too. Radio frequencies for communication of UAV with the ground CS require sufficient band width. The International Telecommunication Union (ITU) has not yet allocated such bandwidth to UAVs, and they may have to use different radio frequencies in every country (Everaerts, 2008), something to be considered by international operators and manufacturers. Since regulations are these days changing fast, updated information should be consulted in the regulators’ webpage.


UAVs are expected to play an important role in the inspection, monitoring, and maintenance of oil and gas pipelines, because unmanned vehicles are likely to do anything the energy companies don’t want to send people to do (e.g. dangerous operations). Oil and gas companies are looking into incorporating UAVs as part of their Intelligent Pipeline Management initiatives. A number of feasibility studies have taken place, but only a few examples are already in an operational phase.

Considerations for Specifications of a UAV System for Monitoring Oil and Gas Pipelines

To configure a UAV system for a specific monitoring mission, a range of factors have to be considered (Table 12.3). First of all, the type of task (e.g. inspection of infrastructure, detection of leakage, follow-up of spillage) and the kind of information to be acquired (e.g. images of the pipelines, environmental indicators like temperature or vegetation status). Furthermore, the weather and day or night conditions may limit the sensor capability (Table 12.2); the physical characteristics of the environment (e.g. accessibility, terrain roughness, distance to target pipeline) also impose limitations to certain systems or configurations.

The characteristics of the mission flight - time, distance, area, and height - require thorough planning and are crucial for selection of a platform. Although capable of higher flights (400-600 m, depending on system of communication with the CS), small UAVs fly at lower altitude (100-150 m) due to law and regulation restrictions and during a time (~20-25 minutes) limited by the power provided by the battery life. When the pipeline monitoring mission requires surveillance and mapping of an extensive area, fixed-wing UAV platforms capable of long flights in a reasonable time, such as Trimble Gatewing X100, are more useful. In practice, it is advisable to maintain constant altitude during the data capture phase (either stills or video), in order to get consistent imagery and to minimise the need for complex post-processing of the data. Most UAV platforms are now very stable, and the height or altitude can easily be monitored through the use of an altimeter, where a reading can be displayed on a first-person view (FPV) monitor and controlled with a standard controller and

TABLE 12.3

Considerations for Selection of UAV System for Oil and Gas Pipeline Monitoring

Observations needed

The pipeline system can be monitored by direct detection of hydrocarbon leaks or indirectly by monitoring indicators or surrogates of leaks (e.g. change in soil or vegetation condition).

Terrain conditions

Flat terrain simplifies UAV navigation.

Constant height and speed are the best option for easiness of data processing. Alternatively, to monitor pipelines in heterogeneous conditions, an adaptable navigation system is necessary'.

Flight distance

A strategic design of the flight aims for efficiency and cost savings. Flying distance and flying time depends on the characteristics of the network of pipelines to monitor (e.g. length, connections, risk points).

One-w'ay flight along the pipeline route w ith recovery stations at both ends (or in intermediate stations) is superior to return flights.


The type of platform to choose depends on what is required of the exercise:

  • • Flying the entire pipeline from one end to the other on a regular basis would require an autonomous fixed-w'ing UAV carrying one or more sensors or a video camera.
  • • Hot-spot inspection or monitoring would be better suited to an N-copter deployed at intervals along the pipeline.


The sensor or sensors should be optimised for the monitoring task. These should be functional or adaptable regardless of weather conditions.

Payload weight

The platform must carry' the sensor and auxiliary equipment (e.g. GPS and INU for navigation).

Data processing

Processing of data acquired to generate useful information usually involves:

  • • Geometric correction. An exact spatial correspondence of features captured in images w ith reality and other data sets is crucial.
  • • Radiometric calibration. Reliance of repetitive surveys is based on perfect radiometric calibration of measurements.


National regulations control the options for use of one type of UAV or another.

Currently the use of UAVs is still relatively restricted. As a result of a more pressing demand for applications, it is expected to be developed further.

even with a mobile phone app. For hot-spot inspection missions, e.g. to monitor the state of a pipe joint or a new structure, where high-resolution imagery is required, the flying height may be only around 5-10 m over the ground. In those cases, requiring manoeuvrability, rotary-wing platforms with hover capacity are preferred.

Environmental conditions (e.g. strong wind, extreme temperatures) may restrict the flight of some UAV platforms. Further, most platforms are not waterproof, and consequently, their sensors can only be flown in dry conditions. This is especially true for most electric powered UAVs; if a UAV gets caught in the rain, it is generally best to land as soon as possible. Small N-rotor platforms are recommended to fly only up to a light breeze, and although they can be flown in a moderate breeze, the aerial imagery captured may be compromised by the instability of the yaw, pitch, and roll of the platform. Light rain and drizzle are tolerable although the rain may spoil the shots.

The data acquired by UAVs, most times images, can be visually interpreted with aerial photointerpretation techniques. Digital image processing software, much of it now low cost, can also be used to geo-correct and mosaic the photographic prints or images together as the basis for onscreen interpretation and the mapping of thematic information for subsequent input to a GIS. Image processing (e.g. geometric and radiometric corrections) can be performed with standard or specialised DIP software. Furthermore, there is now a small range of UAV-dedicated software packages available, specifically aimed at UAV image acquisition and correction, which have similar functionality and better price. A few examples of UAV-dedicated software are listed in Table 12.4.

Advantages and Limitations of UAVs for Monitoring Pipelines

UAV technology has some advantages over other methods (e.g. manned airborne platforms, ground surveys) for oil and gas pipeline monitoring tasks (Table 12.5). The economic cost, operational safety, and freedom of use are some important factors. Ground surveys are much more expensive, and aerial surveys are also less secure and flexible. Other important benefits of small UAVs are

TABLE 12.4

Some Software Solutions for Processing of UAV-Captured Data

Software (Company Website)



Automatically combines raw images captured by lightweight UAVs to produce accurate measurements and visualisation of the environment, enabling timely, on-demand local 3D mapping. Automatically turns many images into accurate, 2D maps (orthomosaics) and 3D models (digital elevation models)


Provides photogrammetric tools for both UAV operators and conventional manned aircraft operators. EnsoMOSAIC creates orthomosaics, 3D models, XYZ point clouds from images, GPS positions and camera calibration parameters. Calibration of camera. Output products are ready to open in any GIS software.


Free and open source software. Geometric rectification of oblique aerial images and generation of orthophotos. Provides high flexibility of input /output formats and it is compatible with GIS software.

AgiSoft Photoscan Pro

Allows generation of high-resolution georeferenced orthophotos (5 cm accuracy with GCP) and detailed DEMs. Fully automated workflow enables processing thousands of aerial images on a desktop computer.

TABLE 12.5

Main Advantages and Disadvantages of Using UAVs for Monitoring Oil and Gas Pipelines



Safety in operations. Operational risk is reduced

Legal constraints:

  • • lack of regulation
  • • restriction of use in certain areas
  • • restricted size for free flight

High temporal and spatial resolution data

Specialist expertise required

Programmatic flexibility:

  • • use when convenient (weather)
  • • on-the-fly change of schedule

Small scale of operation:

  • • only small platforms permitted for civil use
  • • limitation to carry specialised sensors due to weight

Access to difficult areas and perspectives

Economic cost:

  • • inexpensive insurance
  • • reduced human expenses

Lack of standards

Environmentally friendly: less noise, emissions, pollution, and disturbance

Imagery' of very high spatial resolution

Lack of collision avoidance technology

related with weather conditions. Surveys based on conventional aerial platforms are restricted by wind, clouds, and other climatological agents, while UAVs are very flexible, benefiting from below cloud flying altitude and short-term change of plan. The low-height flight provides for high spatial resolution images. Small UAVs can fly in temperatures of -33°C and in 50 km/h winds offering a safe alternative to manned flights in storms and arctic climates and can also make observations in difficult environments where traditional aircraft cannot access. The cost per hour of UAVs can be low enough to make the return on investment very favourable. Since there are no crew members onboard, the vehicle safety concerns are alleviated and insurance costs are reduced, further improving the benefits of this approach. There is a wide range of geospatial and geophysical sensing and imaging technology (Table 12.2) that can now potentially be mounted onto UAVs, its use depending on the platform.

Currently the greatest limitation for use of UAVs lies in the absence of legislation and regulations to operate in airspace non-segregated from manned aircrafts airspace (Skrzypietz, 2012). This restriction is supported by security reasons, based on a UAV’s lack of on-board capability to sense and avoid other aircraft.

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