Precise (±2cm) Indoor Positioning System for Drones

Table of Contents

Using Marvelmind Indoor "GPS" for drones and quadcopters

Marvelmind indoor positioning system or Marvelmind Indoor “GPS” is widely used for drones or quadcopters in many different ways:

– Guiding autonomous drones indoor and outdoor

– Tracking drones indoor

– Automatic landing or landing assistance

– Drones shows

Marvelmind Indoor "GPS" supports PixHawk with ArduPilot and PX4

Marvelmind Indoor “GPS” supports both 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

It is possible to track even micro-drones (less than 100g) with the help of Mini-TX beacons.

 

Starter Set NIA-SmallDrone is specifically designed for these kind of 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.

Overall the best and the safest choice, when you are not sure what to choose or what exact experiments you will run, but you want to have the greatest flexibility and the greatest performance at the same time.

Configuration:

https://marvelmind.com/product/starter-set-super-mp-3d/

https://marvelmind.com/product/super-beacon/ – additional mobile beacon for the Paired Beacons configuration to have both location and direction. See more about the Paired Beacons demo

The set is designed for micro-drones (<100g). It can be well used for larger drones as well, but the ultrasonic pulses (and the range) on Mini-TX is smaller than the same of Super-Beacons or Beacons HW v4.9. Though, it is easily 15-20m, which is sufficient for the majority of real cases.

Configuration:

https://marvelmind.com/product/starter-set-nia-03-smalldrone

An advanced version of the “Starter Set Super-MP-3D + Super-Beacon – Location+Direction on the drone” option.

 

The Precise-Z, which physically consists of 2 additional stationary beacons on gives a possibility to have precise Z coordinates in all ranges of Z.

See more:

Placement Manual – Precise-Z slide
Video explanation about Z and placement of beacons

 

Configuration:

https://marvelmind.com/product/starter-set-super-mp-3d/

https://marvelmind.com/product/super-beacon/ – additional mobile beacon for the Paired Beacons configuration to have both location and direction. See more about the Paired Beacons demo

https://marvelmind.com/product/super-beacon/ – additional stationary beacons for Precise-Z feature

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