Choosing the right drone for your photogrammetric needs can be a challenging duty, given the multitude of options available in the market. When it comes to photogrammetry, a drone is significant in capturing high quality images from different perspectives, which are later used for the creation of detailed 3D models. Advancements in technology, has made drones more accessible and affordable, making them a popular choice for professionals in various industries. However, with so many options on the market, it’s important to carefully consider your specific needs and requirements before investing in a drone for photogrammetric purposes.
Factors to Consider When Choosing a Drone for Photogrammetry
Level of Accuracy Needed for Photogrammetric Projects
Do you need your measurements to be precise, or just get the job done with a bit more finesse? The level of accuracy you need will determine the type of drone you should pick.
According to Dr. Jad Jarroush, Founder and CTO at Datumate, “The required mapping accuracy also dictates operational parameters. For instance: for accuracy at a 1:250 scale mapping (requiring about 5 cm accuracy with a maximum of 2.5 cm pixel resolution), the user must consider both the camera’s resolution and the number of batteries needed.”
Environmental Conditions and Terrain Characteristics
Is your drone going to be battling hurricane level winds or peacefully cruising through sunny skies? The environment and terrain where your drone will be flying is key in picking the right one.
“Drone operations are highly sensitive to weather conditions. In windy situations, drones may not maintain stability for capturing images with proper overlap, or they might even crash, rendering them unusable. If the weather is too hot, it will badly affect the battery life as well,” says Dr. Jarroush.
Additionally, “The ability of the drone to resist a range of weather conditions such as dust and water are qualities that are useful for outdoor use,” emphasize Reynolds Adongo, Drone Pilot at Axis Drone Surveys.
Budget Constraints and Cost effectiveness
Having considered all the key factors, you will probably want to find that sweet spot between what you can afford and what will give you the best value for your buck. Evaluate the cost breakdown of the drone itself, the camera, and any necessary accessories. Quality drone and camera setup can impact the accuracy and quality of your data, so allocate your budget wisely to ensure optimal results.
Keep upfront costs to factor in long-term maintenance and upkeep expenses. Regular maintenance, repairs, and software updates are essential for keeping your drone system in top condition.
“The total cost, which includes the software, camera, and drone, should be within the allocated funds. Additionally, for continuous maintenance and troubleshooting, dependable customer service and the availability of spare parts is also crucial,” commends Adongo.
Key Features to Look for in a Photogrammetry Drone
Quality of Camera and Sensor Technology
Look for cameras and sensors that can capture crisp, clear images and accurate data. The higher the resolution of the camera, the more detailed your images will be, leading to more accurate 3D models. “Opt for drones with high-resolution cameras capable of capturing detailed images. Camera quality influences photogrammetric model accuracy,” acclaims Felipe Grande, International Business Manager at Aplitop.
“Photogrammetry is heavily reliant on the quality of the input and therefore we can argue that the very first factor to consider is the quality of a drone’s camera,” asserts Kamen Kiryakov, Business Development Manager at MYX Robotics.
Considering the camera’s ability to adjust settings such as aperture, shutter speed, and ISO will ensure flexibility in different lighting conditions. These features can help you capture the best possible images for your photogrammetric projects. Beside, a larger sensor size can capture more light and detail, enhancing the quality of your photogrammetric data.
Ilya Shikov, TOPODRONE CTO, stresses that – “It’s necessary to understand what areas and surface type shall be surveyed. The main deal breaker of the Photogrammetry drone is not a flight time or lifting power, but the Camera itself. Surely, it should have a mechanical shutter, full frame matrix and high resolution capacity of the images.”
“Investing in high-resolution camera or equally, drones with quality optics will enhance the detail and accuracy of the captured data. Key details to consider include sensor size, number and size of pixels, shutter speed and focal length. In addition, to enhance the accuracy of a digital twin, we strongly advise on geotagging all photos. Geotagging adds GPS coordinates to photos, making it easier to integrate the data into GIS (Geographic Information System) software,” comments Kiryakov.
“The resolution and size of the camera’s sensor are very important. Accurate photogrammetric analysis requires high-resolution cameras (usually 20 MP or more) with large sensors because they collect more detail and provide better images,” specifies Adongo.
“Photogrammetry, like the name implies, is based on photographs. So you want a drone that can carry high-quality cameras. Not only that, you need one engineered to fly reliably so that you can make the most of the quality of the camera you are flying with. What makes this possible? The type of drone. Why? Because if you have a small multi-rotor or a classical fixed-wing drone, you cannot carry cameras that are above a certain weight. This is because a smaller multirotor will not have power to lift them, and the fixed-wing is launched and lands in a way that can destroy them,” edifies Emily Loosli, Content Manager at Wingtra.
“What’s left? A vertical take-off and landing (VTOL) tailsitter or hybrid. These kinds of drones can take off and land like a multirotor in a controlled way, but they transition and cruise like an airplane to capture data. This passive-lift-powered cruise flight means they don’t need so much energy to stay aloft. So they can carry good quality cameras, covering large areas,” she clarifies.
Photogrammetry software compatibility is very important. Ensure that the camera you choose is supported by the software you plan to use for processing your data. This will save you time and effort in post processing and ensure seamless integration between your hardware and software.
“Since successful photogrammetry relies on sharp photos that are captured in a very specific configuration, check carefully that the system you are using is easy enough to set up and fly in a repeatable way. Some systems are really complicated. Make sure there is an intuitive workflow and a lot of automation to remove hassles from your data collection experience,” guides Loosli. “Finally look deeper than price tags and flight times. Specifically, look at how efficient the platform actually is and how compatible its data is with any software for processing. Make sure that the support for the platform is well rated. Things can happen in the field or during processing. You will want someone with the passion and expertise to solve your problems as a contact,” she cautions.
Flight Time and Battery Life
Running out of battery mid-flight, is every drone pilot’s nightmare. Make sure your drone has enough flight time and battery life to get the job done without constantly needing pit stops.
“Flight time and range are important factors to consider when choosing a drone. For best results in photogrammetry, a grid flight mission is recommended which consist of multiple horizontal passes with the drone over a given area of interest. The flight time and range will ensure that those flight passes can remain consistent, parallel to each other, equally distanced at similar height and with an overlap of between 80 and 90%,” recommends Kiryakov.
“The flight duration is crucial because it determines how long the drone can stay in the air to capture data. Fixed-wing drones typically have longer flight durations,” says Grande.
“It is usually recommended for Drones to possess extended battery life and reliable flight characteristics. Both battery life and drone stability are paramount in photogrammetric surveys because they complement one another. As the battery life helps extend flight lengths and cover more areas in a single trip, stability guarantees consistent photos,” acclaims Adongo.
Similarly, capitalize in reliable software and tools that can help you optimize your drone missions. Flight planning software can assist in creating flight paths, setting waypoints, and ensuring efficient coverage of the area you want to survey. This leads to better data collection and accurate results.
Data Processing
As you proceed with processing your captured data, select a software that suits your expertise level and project requirements. The different processing techniques available can help you generate precise 3D models from your imagery. Consider factors like processing speed, ease of use, and compatibility with your camera and drone system.
GPS and Navigation Systems
Getting lost is no fun. Your drone needs to know where it’s going and how to get back home safely. GPS and navigation systems are like the drone’s internal compass, guiding it through the skies. “Another key area to consider is the Precision of GNSS on board the drone. Georeferencing of photographs depends on accurate GPS and sophisticated navigation systems. The precise translation of the recorded information to physical coordinates can also be attributed to the accuracy of the GNSS,” Says Adongo.
“GPS accuracy affects the precision of your results. Drones with RTK or PPK technology offer higher geospatial accuracy,” adds Grande.
Regulatory Compliance
Establishing solid compliance protocols keeps things running smoothly and makes the process a whole lot more bearable.
As Adongo indorses, “The drone has to possess the required certifications for use in commerce and conform with local aviation laws. This entails being aware of no-fly zones and securing the necessary licenses or permissions.”
Types of Drones for Photogrammetry
Key Difference Fixed-Wing Drones vs. Multirotor Drones
When deciding between fixed-wing and multirotor drones, it’s important to consider the specific requirements of your project. “Fixed-wing drones usually have longer flight durations and a higher range. They are perfect for comprehensive surveys and mapping vast landscapes because of their aerodynamic efficiency, which enables them to cover big areas in a single trip, unlike the multirotor drones which have shorter flight durations and a smaller range,” remarks Adongo.
“Each type of drone has its strengths and weaknesses, and the choice between a fixed-wing and a multirotor drone will depend on the specific requirements of the photogrammetric project, including the area size, terrain type, image resolution required, and logistical considerations.” Outlines Dr. Jarroush.
Flight and Maneuverability
In comparison, fixed-wing drones can cover long distances efficiently. They are ideal for tasks that involve covering large areas or require long flight times.
Multirotor drones, on the other hand, are more like sprinters, nimble and agile for tight spaces. They are best in maneuverability and are better suited for tasks in confined spaces or that require precise movements. Knowing the strengths and limitations of each type, you can choose the drone that will best meet your project’s needs.
“First of all,” as Shikov notes, “most VTOLs are designed to fly more than an hour with a payload, so it’s a great tool to cover huge areas. However, this is only applicable mostly in flat areas. Since VTOL AGL mode will work as fast as it might be necessary in the steep surface conditions, and in that case it would be necessary to use the multirotor, which is capable of flying directly upward. Secondly, it is a maximum cruising speed of the air vehicle, the VTOL are designed to be used on the high speeds ~19-22m/s, meanwhile multirotors are better for more precise and slow speed operations ~8-12m/s.”
“Fixed-wing drones typically offer longer flight times and greater range than multirotor drones. This is because fixed-wing drones are powered by aerodynamic lift, which is more energy-efficient than the vertical lift used by multirotor. This makes fixed-wing drones ideal for large-scale mapping projects covering extensive areas,” explains Dr. Jarroush. “Multirotor drones excel in maneuverability. They can hover in place, take off and land vertically, and easily navigate tight spaces. This makes them particularly suitable for projects requiring detailed imaging of specific locations or objects, such as construction sites, archaeological digs, or urban environments where precise positioning is crucial.” He adds.
“The general useability of the multirotor is far better than the fixed wing as it is simpler to set up and run,” says Adongo. “They are also excellent at maneuvering and can hover, which makes them perfect for taking close-up pictures of particular locations. The fixed-wing however does not have this capability and it also takes some time to set it up in motion,” he notes.
“There are key differences between fixed-wing and multirotor drones and with both, there are certain advantages and disadvantages. To start with, a beginner in the field of drone and photogrammetry operations will benefit greatly from a multirotor drone compared to a fixed-wing. Multirotor drones are easier to operate, significantly more maneuverable and cost much less than fixed-wing drones,” says Kiryakov.
“The keys differences, however, come from the flight time and altitude that fixed-wing drones have a considerable advantage compared to multirotor drones. They provide greater flexibility when capturing greater and larger areas where a higher altitude is required. They are, however, still significantly less affordable and require greater skills to operate them. We can therefore conclude that multirotor drones are still the preferred choice for photogrammetric applications especially due to their maneuverability and cost effectiveness,” clinches Kiryakov.
Payload Capacity and Endurance
Fixed-wing drones typically have a higher payload capacity than multirotor drones, allowing them to carry heavier cameras or sensors. This makes them suitable for tasks that require specialized equipment or multiple payloads.
“Fixed-wing drones can carry heavier payloads, such as professional cameras or additional sensors,” says Grande.
“Generally, fixed-wing drones can carry heavier payloads compared to multirotors of a similar size. This capability allows them to be equipped with more advanced sensors and cameras, which can be beneficial for high-resolution mapping and other sophisticated photogrammetric needs,” says Dr. Jarroush.
“Compared to multirotor drones, fixed-wing drones often have smaller payload capacity. This may restrict the kind and quantity of sensors that they can hold, while high-end models can still hold sophisticated photogrammetric apparatus. The multirotors can carry more sensors and cameras because they frequently have larger payload capabilities. This adaptability is useful for intricate photogrammetric projects that call for a variety of data-gathering methods,” Observe Adongo.
Coverage Area and Data Collection Efficiency
Maximizing coverage and efficiency are key considerations in selecting the right drone for the job. “Fixed-wing drones rely on passive lift when they collect data—they literally cruise like an airplane. Multirotors are powered for their entire flight by the turning of their rotors and active lift. The implications of this are huge: multirotors must spend many times more energy keeping themselves aloft while fixed-wing drones can cover many times more area on the same size battery,” says Loosli.
“Multirotors are great at what they do: aerial video, aerial photography and inspection as well as package delivery and applications requiring fine control. Fixed-wing drones are simply much more efficient for mapping and repeated mapping because you can cover so much more in limited time windows and get data whenever you need for large areas,” she describes.
Speed and Stability
Fixed wing drones typically rely on motor-driven propellers or jet engines for propulsion. These systems, combined with their aerodynamic design, enable fixed wing drones to reach impressive speeds and maintain stable flight over long distances. Multirotor drones are equipped with sophisticated flight control systems and sensors that constantly monitor and adjust their position and orientation in real-time. This technology allows them to remain stable in various weather conditions and flight scenarios.
“Multirotor drones are able to hover, which provides greater stability for capturing high-quality, static images. This stability is particularly advantageous in photogrammetry for achieving precise image overlap and maintaining consistent altitudes and angles. Fixed-wing drones typically fly faster than multirotor drones. This higher speed allows for quicker coverage of large areas, reducing the time to complete a surveying mission. However, the increased speed can make it more challenging to capture high-quality images without motion blur, necessitating careful planning of the photogrammetric mission,” compares Dr. Jarroush.
Takeoff, Landing and Resistance
Fixed-wing drones require a runway for takeoff, where they gain speed to generate lift and become airborne. Pilots need to ensure a clear and obstacle-free runway for a successful takeoff. They also require a runway for landing, where pilots need to control the speed and angle of approach to land smoothly. Precision and skill are crucial for a safe landing.
Multirotor drones can take off vertically from almost anywhere, making them more versatile in terms of launching locations. Pilots simply need to ensure that the area is clear above and around the drone to avoid any collisions. They can as well land vertically, descending straight down to the ground. Pilots have more flexibility in choosing a landing spot, but they must still maneuver the drone carefully to avoid any mishaps.
“Fixed-wing drones require a large open space for take-off and landing. Multirotor drones, on the other hand, can take off and land vertically, which means they can operate in confined spaces and varied terrains without needing a runway,” complements Dr. Jarroush.
“Operating a fixed-wing drone generally requires more training and expertise due to their more complex launch and recovery processes and their need for flight planning similar to traditional aircraft. Multirotors are often preferred for their simpler, more intuitive control, especially useful in environments where quick deployment is necessary,” he adds.
“Fixed-wing drones can land more safely in case of power loss, as they glide down. Multirotors descend vertically,” tells Grande. “Fixed-wing models can handle stronger winds due to their design. Multirotors are more sensitive to wind,” he adds.
“In cramped or difficult environments, fixed wings need a runway or a catapult mechanism for takeoff and landing may be prohibitive, thus they are less suitable for places with less open space because of this necessity. However, it’s important to note that certain fixed-wing models possess vertical takeoff capabilities, offering versatility in their deployment. With multi-rotors, they can land and take off vertically, taking up very little room. More flexibility is offered by this function in a variety of settings, such as cramped or heavily congested regions,” Adongo indicates.
Parting Shot
Selecting the right drone for your photogrammetric needs is crucial for achieving accurate and reliable results in your projects. Understanding the key factors, features, and considerations, you can make an informed decision that aligns with your specific requirements and budget. With the right drone and camera setup, coupled with effective flight planning and data processing strategies, you can harness the power of photogrammetry to enhance your spatial data collection capabilities and drive success in various industries.
By Dorcas Kang'ereha
