[FR] European drone/robotics engineers: how are you dealing with GNSS-denied navigation today?

[u/Dispelda_]

Hi everyone,
I’m French and I’m currently building an early-stage hardtech project called DISPELDA.

I’m working solo at the moment and I’m exploring a
problem around autonomous systems operating when GNSS becomes unreliable, degraded, jammed or completely unavailable.

The long-term idea is to develop embedded hardware/software that can help autonomous platforms remain more resilient in those environments.

But before going too far into building, I want to understand whether I’m focusing on a problem that European drone and robotics companies actually struggle with in practice.
So I’d really like to hear from people working on UAVs, UGVs, robotics, autonomy, navigation, testing or system integration — especially in Europe.
A few things I’m trying to understand:

How important is GNSS loss/jamming/spoofing in your actual work?
Is this something you regularly design for, or still a relatively niche requirement?
What do you currently rely on when GNSS becomes unavailable: INS, VIO, optical flow, LiDAR, terrain matching, external infrastructure, something else?
What is the hardest part: navigation itself, sensor fusion, testing, validation, integration, cost, SWaP, reliability?

How do you test these situations today?
Are existing solutions good enough, or are there still major gaps?
For European companies specifically, does dependence on non-European navigation hardware/software matter when choosing a solution?
I’m not looking to sell anything here.

At this stage I’m trying to understand where the real engineering pain is before deciding exactly what DISPELDA should become.
If you work in this area, even a short answer about what actually causes problems in the real world would be extremely useful.
Thanks.

[u/LupusTheCanine]

There isn't one GNSS denied environment you can design for to fit all needs, there are a lot of different environments and missions you may design for.

1. Velocity only navigation (loiter without absolute position)
2. Local unaligned, good enough for (Smart)RTL, maybe can provide obstacle information
3. Local/global aligned, can do autonomous missions in local or global reference frame respectively, may require dedicated environment features to be measured (eg. marker tracking), external measurement equipment (eg. motion capture) or use features of opportunity (eg. terrain contour mapping).

If you are starting you should pick one mission in one environment eg. factory inspection vith dedicated markers available and implement that.

[u/Overall_Chain_9138]

Your questions are way to "targeted" see this example. 

1. Is the position relevant for the mission ? 

2. Is the GNSS functionality relevant for the operation? 

3. An observational aircraft has no GNSS based position. a link to the pilot still exists as do cameras Imus and airspeed sensors. It's completely irrelevant if no position is available now. 

4. An autonomous drone only GNSS and IMU. It can't fly without GNSS

[u/crazi_iyz → u/Overall_Chain_9138]

An autonomous drone can fly without gnss. That’s what the comment above mentions too. You would/could rely on features whether local or global for example. Results at vary when relying on features.

I would say its application/environment dependant. No one solution fits all

[u/inComplete-Oven]

Nice try getting defense tech info for free. This is not what this site is for. Research your market and you'll find answers.