Completely new, and have had my R&S up a couple of days, and still learning. Today, I got the opportunity to capture something on both the Shake and Boom side that I thought was interesting. I was listening to something with headphones on, and completely missed a low Helicopter flyover till my youngest daughter tapped me on the shoulder and asked if I’d seen the large black helicopter. Intrigued, I opened up my Automatic Dependent Surveillance Broadcast (ADSB) system, which I have on another standalone RPi, and there was indeed a low flyby from a US Customs and Border Patrol Sikorsky S76B leaving the FBI facility about 20 miles from here:
That got me wondering what the Shake and Boom saw, and it appears I captured the flyover on both, and was able to extract some data from each showing the approach, flyover, and passing, including what I think are plots of doppler:
I think it’s pretty neat that I can combine both of these interests and derive interesting data within just a few days. The RShake is a great device! At the least, I know the signature of the S-76B now for the future!
Having done some passive sonar work earlier in my Navy career to track submarines, the s-curve on your plot is a classic doppler shift. Fun fact, if you know the fundamental frequency that the aircraft is putting out, you can do some math to calculate it’s speed and distance relative to your sensor. This is still one of the primary techniques used to passively track submarines.
Really cool insights. Since, I have captured quite a few more, and the S-curve appears with each pass, different depending on speeds. Thanks for sharing.
I was able to capture a helicopter passing overhead today on my Boom. For some reason, the Shake didn’t pick it up so well. He was low enough that I could almost read the tail number. I found out on Flightradar24.com that it was a private owner Bell 206B.
I just found this post and it’s great to see other folk with the same interests. I also have another Pi setup as an ADS-B receiver which feeds to FlightRadar24. I’m new to the Shake and noticed this unusual output when a police helicopter was over the house attending a nearby incident yesterday. I’d aldo be interested to know how you generate your graphs. As a newbie all I can find at the moment is the one attached to my post.
Yes, helicopters appear very clearly if close to where the Shake is located. I live close to the local HMCG helipad, and I get many of those on my instruments.
Regarding the graphs, the ones posted above your message come from a software called SWARM, which was produced by the United States Geological Service (USGS). You can see an example of a clear helicopter transit from my 3D Shake with those charts here:
However, as stated, since that software is no longer maintained, we have developed our own data visualization tool, DataView. You can access it here for your Shake: Data View: Raspberry Shake Data Visualization Tool
And this is an example of another helicopter transit I captured, using the graphics from DataView:
This is all very interesting. I’m loving this new way to see what’s going on in the world. I live near pylons and the electricity company often inspect them with helicopters so now I know how to see when they’ve been when I’m out
Sorry for the late reply. Yes, it’s interesting what can be seen, and like a sonar operator, you get to know the signatures. I can see when rush hour starts on the highway a few miles away, or when wind makes the trees around me vibrate! I prefer seismic events however!
You might be interested in this document that I put together.
Of course, to be completely accurate, the helicopter really should pass directly overhead, but it is still reasonably accurate even when it does not.
