I'm a big fan of the Marvelmind indoor positioning system, which is inexpensive, accurate (2cm) and quite easy to use. They've now put together a tutorial page on how to use it with drones, both PX4 and Ardupilot:
Marvelmind Indoor "GPS" supports PixHawk with ArduPilot and PX4
– Marvelmind and ArduPilot – link to ArduPilot.org
– Marvelmind and PX4 Integration Manual – step by step guidance with settings and screenshots for Mission Planner, PixHawk and the HW connectivity
– PixHawk and Marvelmind Integration Manual – step by step guide for PixHawk, ArduPilot and Marvelmind integration for drones
Build indoor positioning system for quadcopters properly
There are quite many, but rather basic aspects that have to be taken into account to successfully fly indoor:
– Autonomous copter settings manual – basic and practical recommendations for setting up of Indoor “GPS” system for usage with autonomous copters/drones indoor and outdoor
– Placement Manual – practical advises and examples of how to mount the Marvelmind Indoor “GPS” system to achieve the best performance in different applications and configurations
– Check the slides about drones
– Check the slides about Precise Z
– Help: Z-coordinates for copters – long explanation – YouTube explanation how to place the stationary beacons properly to get good Z accuracy. If you can’t use the advises, because your environment doesn’t let you, use the Precise Z configuration with 4+2 stationary beacons
Examples of precise indoor positioning and navigation for drones
Precisely (±2cm) tracking DJI Phantom quadcopter indoor in 3D (XYZ)
– Precise tracking in X,Y,Z (XY view + XZ view + YZ view)
– Raw data and post-processed data from Dashboard’s Player – notice, that today the same is available not in the post-processing, but in the Real-Time Player
– The DJI eco-system is closed, at least, the Phantom and Mavic series. Thus, it is possible to track the Phantom, but not fly autonomously indoor (without deeper hacking)
Precisely (±2cm) tracking DJI Phantom quadcopter outdoor in 3D (XYZ)
– Precise (±2cm) tracking in XYZ (XY view + XZ view + YZ view) – the same as above, but outdoor
– In this demo and in the demo above, the same Precise-Z configuration consisting of 4+2 stationary beacons is used. See more in the Placement Manual
Fully autonomous flight indoor
– Small copter is flying fully autonomously relying on Marvelmind Indoor “GPS”
Indoor tracking small and micro-drones
Recommended Marvelmind configurations for drones
The minimum configuration for the drone tracking would be any NIA set with 3D capability. For example, 3 stationary beacons + 1 mobile beacon + 1 modem and Non-Inverse Architecture (NIA) or Multi-Frequency NIA (MF NIA) would be already OK for the drone.
See the Products page for different starter sets options.
However, just 3 stationary beacons would have little resiliency against obstructions. Any occlusion of any stationary beacon – non-line of sight/hearing situation – will lead to no tracking or erroneous tracking. Very much ike in GPS: “no satellites visibility = no GPS coordinates = no tracking”.
Thus, we recommend, at least, N+1 redundancy for stationary beacons. And that is why our starter sets for 3D consist of 4 stationary beacons.
Even better is to have 2N redundancy with fully overlapping 3D submaps. That would be either 3+3 or 4+4 stationary beacons. The system would automatically choose the best submap for tracking. That kind of system is very resilient and with proper placement of the beacons, you can fly even in complex rooms with columns, for example, without issues with tracking.
The key for the great tracking is to provide proper coverage at any flight point, i.e. the mobile beacons on the drone must have 3 or more stationary beacons belonging to the same submap with clear direct line of sight/hearing within 30m.
Proper placement is the key usually and particularly important to drones, because they require 3D; the drones are fast; and the mistakes may be particularly costly. What to pay attention to?
– The single most important requirement for good tracking or autonomous flight – provide clear line of sight/hearing visibility from the mobile beacons on the drone to 3 or more stationary beacons
– Don’t rely on magnetometers indoor. Use the Paired Beacons configuration for Location+Direction
– Place stationary beacons so that angles from the mobile beacons to the stationary beacons would be 30 degree or more. See a longer explanation in the video
– Use the Precise-Z configurations when not possible to achieve proper angles to the stationary beacons otherwise