What is Indoor Drone Flight Technology?

How can drones fly stably, accurately locate themselves, and safely avoid obstacles in indoor environments without GPS signals? Here, we will help you understand indoor drone flight technology and drone applications.

The biggest challenge for drones flying indoors is weak or completely absent GPS signals. Traditional satellite-based navigation methods fail, so other sensors and algorithms must be used to achieve positioning, obstacle avoidance, and stable flight.

6 Core Technologies for Indoor Flight

1. Visual Positioning and SLAM Technology

Visual Odometry: Calculates the drone's relative motion by continuously capturing images using an onboard camera.

SLAM (Simultaneous Localization and Mapping): Builds an environmental map in real time while flying and determines the drone's position within the map.

Common algorithms include Visual SLAM (V-SLAM), LiDAR SLAM, and Visual-Inertial Odometry (VIO).

Multiple cameras or fisheye lenses enable 360° perception, improving robustness in complex indoor spaces, as seen in the EVO Max series.

2. Optical Flow Sensors

Downward or sideways optical flow cameras detect the movement speed of ground textures to calculate horizontal displacement and velocity. Even in low-light or low-feature environments, they assist in hovering and low-speed flight, making them a common solution for consumer and lightweight indoor drones.

3. Range and Altitude-Holding Sensors

Ultrasonic Sensors: Measure altitude above the ground for precise altitude hold.

Time-of-Flight (ToF) Sensors / Infrared Ranging: Quickly acquire distance information, suitable for close-range obstacle avoidance.

Millimeter-Wave Radar: Operates in smoke, dust, or low-light conditions, with strong anti-interference capabilities.

LiDAR (Light Detection and Ranging): High-precision 3D point cloud mapping, primarily used in industrial or autonomous inspection indoor drones.

4. Inertial Measurement Unit (IMU) and Sensor Fusion

An IMU composed of accelerometers, gyroscopes, and magnetometers provides attitude and acceleration data over short periods. Through algorithms such as Kalman filtering, it is deeply fused with visual, optical flow, and ranging data, enabling stable flight and reducing drift even when GPS fails.

5. Omnidirectional Obstacle Avoidance System

In confined spaces with numerous obstacles, the more coverage from the drone's forward-looking, backward-looking, vertical, horizontal, and other multi-directional visual or radar sensors, the better. In addition, real-time path planning and automatic obstacle avoidance algorithms, GPS-free return-to-home, and dynamic obstacle avoidance further ensure flight safety.

6. Other Auxiliary Technologies

AI and Computer Vision: Recognizing semantic information such as doors, corridors, and people to achieve more intelligent navigation.

Illumination and Low-Light Enhancement: Active supplemental lighting or high-sensitivity algorithms to cope with dark or drastically changing lighting environments.

Miniaturization and Anti-interference Design: Reducing propeller noise, improving motor response, and adapting to confined spaces.

Read More: Autel Drone Enters Attitude Mode For Indoor Driving

Challenges and Countermeasures of Indoor Flight

Both quadcopter drones and FPV drones face significant risks and challenges when flying indoors.

Indoor flight typically relies on multi-sensor redundancy or pre-mapped architecture, as well as high frame rate perception and rapid decision-making during flight.

Indoor FPV drones are usually very small and lightweight, with short flight times of around 10 minutes. Professional indoor inspection drones, on the other hand, possess more reliable computer vision and LiDAR mapping technologies, robust collision-resistant designs, and can assist in operations indoors, under bridges, in tunnels, and other similar environments.

The newly launched Autel EVO III series can navigate flexibly in confined spaces without lighting, possesses strong GNSS-denied environment flight capabilities, and is fully capable of performing indoor operations.

Summary

The key to indoor drone flight is "multi-sensor fusion + real-time mapping and positioning + intelligent obstacle avoidance." Currently, there is still a lack of professional indoor drones in scenarios such as warehouse inventory, indoor security, building inspection, and emergency search and rescue. Indoor flight represents a significant expansion direction for drone applications.