[romanzubenko]

During the hackathon the team only did a simulated flight, not a real flight, so take the results on effectiveness with a grain of salt. In any environment with significant seasonal changes, localization based on google maps will be a lot harder.

[logtempo]

Each 5 days, a satellite from sentinel mission take a picture of your location. It's 8 days for landsat mission. Those are publicly available data (I encourage everyone to use it for environment studies, I think any software people that care about the future should use it).

It's obviously not the same precision as the google map, and it needs update, but it's enough to take in account seasonal change and even brutal events (floods, war, fire, you name it).

[lordswork]

Where can you find this data?

[palmfacehn]

https://earthexplorer.usgs.gov/ https://landsat.gsfc.nasa.gov/data/data-access/

[logtempo]

There is also https://apps.sentinel-hub.com/eo-browser/ that regroup landsat and sentinel under the same interface.

[Faaak]

https://dataspace.copernicus.eu/

[josefresco]

Hmm used the links shared below but the picture of my home is at least 4-6 months out of date. What am I missing?

[logtempo]

I don't know where you live, but the default search at https://apps.sentinel-hub.com/eo-browser/ use sentinel-2 (the true color), 100% maximum cloud coverage (which mean any image), and the latest date.

So you should be able to find the tile of your region at a date close to today, definitely not 4-6 month.

[ynniv]

Satellite images can be taken on a dependable schedule, but the weather doesn't always provide a clear view of the ground.

[fnordpiglet]

Occurred to me that in a war or over the water this wouldn’t be useful. But I think it will be a useful technology (that to be fair likely already exists), in addition to highly accurate dead reckoning systems, when GPS is knocked out or unreliable, as secondary fall back navigation.

[krisoft]

> in a war … wouldn’t be useful

Why do you say that? Navigational techniques like this (developed and validated over longer timeframes of course) are precisely for war where you want to cause mayhem for your enemies who want to prevent you from doing that by jamming GPS.

This is not just an idea but we have already fielded systems.

> over the water this wouldn’t be useful

What is typically done with cruise missiles launched from sea that there is a wide sweep of the coast mapped where it is predicted to make landfall. How wide this zone has to be depends on the performance of the innertial guidance and the quality of the fix it is starting out with.

[hef19898]

Well, landmarks have a tendency to change quickly in a war zone. Making whatever map material you have useless, or close to useless.

All the navigational methods predating GPS still work perfectly fine so.

[heisenbit]

For the human eye maybe. For a computer using statistics less so. Extracting signals under a mountain of noise is a long solved problem - all our modern communication is based on it.

[littlestymaar]

You can get new satellite imagery ever day… (be it military ones if you're a major power, or just commercial one like your average OSINter)

[hef19898]

Sure. And then you have to upload those new, and vetted, imagines to all your drones. Other nav data is much more stable.

Mind you, military hardware is not your smartphone, OTA updates are usually not a thong for various reasons.

The approach for sure is interesting so.

[krisoft]

That is all really interesting speculation, but I'm not describing a system which could be, but one which is already available and fielded. In cruise missiles it is called DSMAC.

Here are some papers: https://secwww.jhuapl.edu/techdigest/Content/techdigest/pdf/...

https://apps.dtic.mil/sti/tr/pdf/ADA315439.pdf

[Zetobal]

Yes, that's also how it works right fucking now.

[magicalhippo]

Well if you combine it with dead reckoning, I guess even a war torn field could be referenced against a pre-war image?

I mean, a prominent tree along a stone wall might be sufficient to be fairly sure, if you at least got some idea of the area you're in via dead reckoning.

[KaiserPro]

You can't use visual key-points to navigate over open water.

You can use other things like Visual Odometer, but there are better sensors/techniques for that.

What it can do, if you have a big enough database onboard, and descriptors that are trained on the right thing, is give you a location when you hit land.

[Tostino]

That's exactly what the comment you replied to was describing.

[TeMPOraL]

> You can't use visual key-points to navigate over open water.

No, but you can use the stars. Even during the day.

[KaiserPro]

true, but that requires an accurate clock, and specialised hardware. Ideally you also need to be above the clouds as well.

[jnwatson]

For only $300 plus shipping from Ali Express you get a high accuracy inertial navigation system. Only weighs 10 grams.

The future is scary. It is now straightforward and inexpensive for lots of folks to construct jam-resistant Shahed-style drones. https://www.aliexpress.com/item/1005006499367697.html

[Animats]

And for a little less, you can buy the original, from Analog Devices.[1]

Those things are getting really good. The drift specs keep getting better - a few degrees per hour now. The last time I used that kind of thing it was many degrees per minute.

Linear motion is still a problem, because, if all you have is accelerometers, position and velocity error accumulates rapidly. A drone with a downward looking camera can get a vector from simple optical flow and use that to correct the IMU. Won't work very well over water, though.

[1] https://www.analog.com/en/products/ADIS16460.html

[sigmoid10]

>Linear motion is still a problem, because, if all you have is accelerometers, position and velocity error accumulates rapidly.

An INS will usually need some kind of sensor fusion to become accurate anyways. Like how certain intercontinental ballistic missiles use stars (sometimes only a single one) as reference. But all these things are based on the assumption of clear sight and even this google maps image based navigation will fail if the weather is bad.

[Animats]

10^-5 degrees/hour drift was achieved in the 1970s, for ICBMs, at very high cost.

[pjc50]

The laser ring gyro? It'll be fun when those start showing up on Aliexpress.

[deno]

Sold by "Peace Dove Grocery Store."

[ufocia]

Sounds expensive.

[dilyevsky]

“High accuracy”

[Modified3019]

For oceans, they could use juvenile loggerhead turtles: https://www.reed.edu/biology/courses/BIO342/2011_syllabus/20...

[mytailorisrich]

Being able to nagivate using only a map stored locally sounds extremely useful in a war.

[dwighttk]

Don’t we have basically this but it looks at stars?

[Zetobal]

I guess if it's really a possibility for military use they won't use google maps...

[RecycledEle]

So the article is fraud.