Drone Localisation - Week 10

Question 1

What is drone localisation an application of?

Answer 1

SIFT local feature detection

Question 2

What are the circumstances were GPS is rendered useless for drones?

Answer 2

Poor or non-existent satellite visibility
- For example in a valley or ‘urban canyon’

Multi-path reflections
- Signals bounce off buildings causing GPS mis-calculation

GPS spoofing
- Satellite signals being recieved and re-transmitted after a delay

GPS Signal blocking
- A signal is transmitted at a higher power than the received satellite signals to prevent them from being recieved

Question 3

Describe the drone visual localisation proof of concept

Answer 3

Know rough location of drone (e.g. is in a town)
Get an image of the town with google maps and an image with the drone

Use ORB feature detector to match the drone image with the google image

ORB produces a homography H that maps the image taken by the drone to the google image

If the registration (matching) was done accurately the centre of the drone and it’s centre in google maps should line up

Question 4

Problems with the proof of concept

Answer 4

Still need GPS because of these issues:

• Feature detector parameters need to be tuned for different images
• Images cannot always be matched
• If the aerial image covers a larger area, there are more opportunities to find drone image features in the wrong place
• Many other difficulties such as weather conditions, not being perfectly downward-facing, features changing in images etc…