Aerial Survey Using Drones

Handling lots of data for processes like surveying, progress assessment and volumetric assessment of mines, water bodies etc. which requires immense data processing viz a viz by collecting, sorting, segmenting, analyzing and presenting the data to the user as per requirements within limited time frame; with greater accuracy and minimum manual human intervention. Drones are great at handling the existing problem with greater accuracy and precision which eventually reduces efforts or extends the ability of people to perform tasks beyond their normal capabilities.

A drone survey is photogrammetry, defined as the process of recording, measuring and interpreting photographic images and patterns of electromagnetic radiant imagery and other phenomena. It refers to the use of a drone, or unmanned aerial vehicle (UAV), to capture aerial data with downward-facing sensors. The designated area is photographed several times from different angles, and each image is tagged with coordinates. The height at which the drone is flown, and the sensor size used are the main two variables which will determine the output quality. The objectives of the drone survey are as follows:

·?????? Data acquisition

·?????? Data processing

·?????? Topo drawing

Following are the advantages of a standard GNSS (Global Navigation Satellite System) PPK (Post Processing Kinematics) drone which positions it to be far superior to other conventional surveying techniques:

1.???? Highly accurate image output: Absolute accuracy of a PPK drone is at ±5-7 cm in X, Y and ±8-10 cm in Z axes

?2.???? Processing Time: Lower image processing time as PPK geo-tag enables faster alignment of images and does not rely only on image feature identification-based alignment which consumes a lot more time.

?3.???? Cost: Leasing and operating a PPK drone for surveying costs as low as $65 a day. Considering its speed of surveying and in comparison, to the conventional manual surveying seems prodigiously efficient.

?4.???? Safety: Manual surveying of any water body or a mine has serious consequences from a safety point of view. Even though the average number of fatality and serious accidents has seen a gradual decline over 3-4 decades, the numbers are large to disregard.

?5.???? Resource utilization: While a drone can conduct volumetric assessment of more than 5 pits per day on an average, the manual surveying technique as per industry experts assess only 1 pit a day. This 4X improvement in resourcing is a clear advantage in favor of utilizing PPK drones for volumetric assessment.

Drones are relatively small, very mobile, noiseless, and tending to be less affected by influences such as wind or speed changes. Even though the odds heavily weigh in favor of drones, there are several opportunities for improvement in this space.

1.???? Power Supply- One of the main issues for drones in terms of mobility is that the power sources available are not adequate. There are many types of power supplies applied to drones, however each has their own limitations and strengths such as weight, payload capability, charging & discharging time, size, energy density & power density.

2.???? Data security- The dependence on wireless communication makes drones susceptible to several cyber-attacks. In order to take care of such concerns, following guidelines are being followed:

·?????? Authorization: Assigning privileges to the personnel controlling the drone

·?????? Authentication: Multi-factor authentication using passwords, usernames and biometric authenticators

·?????? Auditing: Tracking down legitimate owners of the drones in case of malicious activities.

3.???? Network connectivity- Though mobile network is well suited for low altitude drone operations, the inconsistent signal strength and service issues in remote areas make connectivity another cause of concern for drone operations.

4.???? Government regulation- There are several regulations for operating civilian drones in India. These are:

·?????? All drones except those in the Nano category (< 250 grams) must be registered & issued a Unique ID (UIN).

·?????? There are specific requirements of various features GPS, RTH, Anti-collision lights, ID Plates, Flight controller, RFID which a drone must have to be flown, which adds to the cost of production

·?????? No Permission No Take off (NPNT) policy- Apart from a no-fly restriction during night skies, drone pilots are required to request permission to fly for every single attempt at surveillance

5.???? Technical Know-how- Drone operations in India are controlled by a license-permission system like driving cars. There is a ‘Unmanned Aircraft Operator Permit’ required in order to pilot a drone.