Reach M+, getting fix is really difficult

Ah! Makes sense.
But can’t you then mount the M+ on the roof of the car instead, preferably 20-30 cm above the roof?

I need the location of the pedestrian in front of the car as a ground truth for pedestrian detection systems.

Oh, that sort of usecase, interesting.
So basically scared that the radar will see the pedestrian too if you have all that metal on you?

I have also experimented a little and found that it can help to have the antenna tight to the ground plate. Just looking at your picture it looks like it might be slightly above the metal shield. Nice pic! :slight_smile:

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We are scared that our data will be not realistic.
Think about recording pictures of pedestrians all in yellow coat. Any algorithm would learn that a pedestrian wears yellow :smiley: Same for radar. I can try if it actually matters, I do not know, but radar is pretty sensitive. Any non metal ground plane alternatives?

Thanks! There is no ground plane here :slight_smile:

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Sorry! I missed that part. I’m not sure what to suggest in that case… Ground plates not only make a huge difference, they can make THE difference, if you know what I mean. You should try it with a ground plate just to see if that’s the problem. Then you can eliminate that if it still doesn’t work.

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+1 for the ground plane being a must. Even a small one will help.

This would be more complicated to do, but you could mount the antenna/groundplane beside the head on the opposide side that the car approaches from. That way the car cannot see the antenna or ground plane.

Maybe similar to this, where you substitute the camera in the picture for the GNSS antenna and ground plane:


Thanks for the replies. Will this really change the performance?
I have read that the thickness does not metter and aluminium foil would work. Is that true? Because I doubt that will be picked up by radar.
So a 10cmx10cm, paper with aluminium foil on it, would that fit the requirement?

Well, let’s turn it around :wink:
The purpose of the groundplane is to reject signals, basically reflect any signals below the horizon.
We know that tin-foil can do the trick.
Radar being radiowaves, “just like” gnss signal (different frequencies, yes, but still similar concept), it will react just the same. So whether you use tin-foil or a metal plate should be the same.


I will worry about the radar side, my question is rather if the tin foil would be enough.
The radar is similar in a sense, but, just like you said, very different frequency, and would see the tin foil from the “side”, so the cross section would be very small.
So you think tin foil would be enough and would help?
Thanks, Andras

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Anything more than nothing will help :wink:
I suggest you try it out. Remember to get the cable inside through the plate just after it has exited the antenna. Also mind how you bend the cable. Make a nice equally graduated bend of the cable.

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Yes, it will change the performance. I would recommend stiff paper so that the ground plate is flat and smooth. Yes, aluminum foil will work.
And yes 10cm x 10cm would fit the requirement.


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