Sprint - Test Flight 8 and Data Review 

Really liking the real-time speed of the playbacks instead of the slow mo!

Hey Joe, some tips for your Kalman filter from a controls guy: 1) It looks like you assume 0 uncertainty in your GPS measurements, since your covariance drops to 0 at the GPS updates. Giving this a plausible value will help smooth out the jumps you see in the velocity and position plots. This also becomes pretty important at low speeds where GPS uncertainty is larger compared to your motion. An easy way to find out this info is to either look at the specs for your receiver, or take a log of the GPS speeds and positions at rest and calculate the standard deviation of that data. Note that this may be dependent on GPS signal quality, which your chip probably provides a real-time measure of, but that’s probably not going to matter _too_ much for your purposes. 2) You mentioned at 8:52 that you think you have an error in the covariance plots since x, y, and z axes are identical. But this is actually expected if the estimated process and measurement noise on each axis is identical, the state transition equations are symmetrical (which they should be), and of course your initial covariance estimate is the same. If you look at the the Kalman filter equation to update your state estimate covariance matrix P, you'll see that it is not dependent on either the state or your measurements. So your covariance will be deterministic given a known update rate, and so should only not be identical across axes if you (a) have different noise models for each axis, (b) have additional sensors on one or more axes, or (c) have updates at different times for each axis (which doesn't look like the case). The 'sawtooth' pattern is characteristic of a blended IMU-GPS pair, so that should give you more confidence that you did it right! 3) And as a last note, don't forget to give your covariance variables units too. 🙂 Personally I find it conceptually helpful when looking at variance data to convert them to 3sigma values instead. This means you’d be looking at uncertainty in units of velocity rather than a variance “area” with units velocity squared. 3sig = 3*sqrt(var)

Interesting to see the board temperature decrease as it gains velocity.

" we're about to cross 200'000 subscribers if we haven't already" i look down to the subscriber mark: 200.000 on the mark nice timing

Technician: ... um ... Flight ... we're getting a slight oscillation in the 'Z' axis. Flight Boss: ... hu? ... Oh ... it's ok, that's just J.B.'s signature "Z axis wiggle". Technician: (puzzled frown) you mean he designed it to do that? Flight Boss: ... um ... ... yes ... yes he did ... now pay attention to your board.

Love the overlay with all the data. Not that I really know what the significance of most of them are lol

At 8:40, I had absolutely no idea what was coming, and I didn't even know what it was when you said it. In fact, I didn't understand most of this video, but it's still entertaining enough for me to watch the whole way through.

"Let's say it at the same time, I know what you're thinking, ready, ok, it's" Me: "Another cool graph" Joe: "The process covariance estimates" Me: "Yea, that's exactly what I said"

Congratulations! I watched the entire AVA assembly to this point (many of your other videos as well). Your persistence is contagious. It helps keep me motivated for my own projects. Hopefully, in the near future, they'll be a legitimate sustainable business. As practical and frugal as you are, I really appreciate the effort you put into aesthetic details, from your video editing to your PCB design.

Yes, it’s joey again! Love the rapid launch and video schedule due to the current... *pandemic* Planning on building my own rocket, inspired by you! The reaction control tutorials are very helpful You have definitely been an inspiration to many people :) I also plan to make a liquid fuelled rocket after the practice with homemade (very large) sugar motors.

Fantastic flight! Thanks for not only sharing the video of the rocket, but also breaking down the data in such an easily understandable way. I showed this to my wife (1st time viewer) and she was able to follow along just fine, which is a real testament to just how well you explain things. Good job!

Wow thank you so much Joe that means a lot to me @Aerospacefan46 and also I’m sure Charles definitely passed out by viewing this !!

Always awesome! Very impressive work developing the AVA board, those data records are beautiful.

Fantastic as usual, Joe. Really enjoyed the detailed information about the operation of the flight. As an aside, since I'm working on some pretty over-equipped environmental sensors right now and have sensors on the brain: have you considered the use of magnetometers to aid in orientation sensing? They're available in very small footprints (e.g. NXP MAG3110, which is 2x2mm DFN10) and in my experience they offer pretty decent measurements at nearly 80Hz, which might help you improve your integrator accuracy during alignment correction, and better sense pitch during flight. The noise isn't the best on the MAG3110, at about 0.3uT in practice (so 0.6% error on a standardised 50uT earth field). That translates to about 0.55 degrees of error on an axis if you're normalising to 90 degrees per axis, but you can get more expensive alternatives like the RM3100 that offer incredible resolution and noise floors in the order of tens of nanoteslas. I figure if you've already built the Kalman filter it shouldn't be too much work to add geomagnetic orientation values into the mix and keep the covariances low. Anyway, enough back-seat engineering from me. Good flight and I look forward to future videos :)

You should get that vertical shot from one more angle to triangulate Sprint’s flight angle.

So, we agree: Nothing happens to the board during welding! Greetings from Munich, Tom.

the analysis was super interesting. I'm having a look at this plotting program

can’t wait to see this thing hopefully go 1 kilometer up . Love the work joe 🦀🦀🦀

Congratulations on 200K! Keep up the excellent content!

Congrats on 200k Joe! Well deserved

This data vis and video format is absolutely stunning

By now I have started to back your launches as much as spacex ones. This is more special.

2 videos in 2 days!! and you've reached 200k :D Congrats!! Keep up the good work!!

_"I love it when a plan comes together...."_ 😊😊😊

Hi bps, just love that I don't get giddy watching Sprint onboard vision. No spin - me grin. Well done and look forward to when you Scale UP

I love the people cheering in the background. They sound so excited.

Congrats on a nice flight! I really love your scrappy methods to get the job done, including the use of open source tools.

“joe, why is that?”

Excellent, as always..... Still working on first vehicle, of my long delayed return to rocketry. Nothing fancy.

Awesome! Love that your promoting other rocketry channels. It shows how much your confidence is building.

Congratulations on 200k! Keep up the good work!

Woooooooooweeeeeeeee that was one stable flight 🤭 Also massive thanks for the shoutout! and congrats on 200k :)

Congrats on 200k man

Would you ever use a hybrid rocket motor? (Not sure if you’ve answered this one) also congrats on 200k subs 👍

Happy 200k subs :D

On the topic of servos, the RC helicopter world has several reasonably priced strong lightweight high speed brushless servo manufacturers. I specifically bring them up because the servos on the heli swash plate have to have a consistent response speed. or the models become uncontrollable. BK servos in particular are spectacular.

Congratulations on another successful flight! I love watching the launch with all of the data surrounding the screen!

It's people like you that will blaze the trail once interplanetary travel becomes wide spread. Keep up the great work!

Bravo Joe, Bravo.

Congratulations for 200k, I hope you're doing well.

"May your skies be blue..." gets me every time. Same to you!

amazing footage and analysis - love your videos! salute from germany

Do I spy an RC plane-launched model of Virgin's launcherone in the background?

Thanks prof. Joe. Amazing science, dedication and iterative development. Just a dream! Keep it up!

Sir,great video as always,A AM A NOOB AT THIS STUFF,but here is an idea, maybe use a high res quarature rotary encoder to characterize the servo(or make a lookup table) and use the pot of the servo with an external high speed ADC with a different micro controller for total control over that TVC. Man That KF looks so much better. Best of luck !!! RU-vid lacks content of this caliber and quality and fun and SO MUCH FUN WOW.

loved the tracking animation, really worked.

Good to see the normal uploading back!

Great to see a successful Sprint 8 flight. Looking forward to Sprint 8 and 9. Achieving 1Km. altitude will be amazing. What is your goal after the 1Km flight?

Wow you just hit 200k subs, congrats!

Nice Video and project Congratulations for 200.000

Thanks for showing us this data!! Interesting to see all the data you get back from your flights!

Beautiful, once again proved: Mistakes are no mistakes

200K!!!! Congrats!! 🎊🍾🎉🎈

Dear Joe, I'm a fan of you great job in rocketry ! I have something to ask you I have in my mind since long time. Maybe it is a silly question, but why do you use 2 parachutes instead of 1 ? Rocket weight is not so big to justify this choice , are there other reasons ?

Hey Joe I am from India. Insert A.V.A. into falcon heavy. And your rocket data is so good. Congratulations for success....

Incredible stuff, I love your channel. Would it be possible to determine the wind velocity versus altitude profile during the first half of the flight as you fly? Could that information then be used to target a trajectory that would have the parachutes drift you back to the launch pad?

BEEPIS SPACE. I like that you take this so seriously. The debriefs are awesome

Pretty amazing stuff. Glad to see your system finally working. I know it's been a frustrating journey at times.

*Great. I Wonder How Many Mathematic Awards Did This Guy Achieve*

Does B.P.S stand of Barnard Propulsion Systems?

Well done buddy. I love the data outputs.

Ok this is waaaaaay more satisfying than it should be.

Awesome! Super excited about the progress!

Congrats on 200k!

Love the videos! I am learning from every video of yours that I watch and I am trying to build one myself! Keep it up!

Congrats on 200K Joey!

Love the "xenon" lights you have set up :)

That was sexy, i think i got a chub. Its been real great watching you from the start to now and all you have accomplished! Keep it up!

Hi Joe, Have you thought about using your camera data to map the flight path in a 3d program? I work in CGI so can point you in the right direction and help trouble shoot any problems you may have if you want to go down that route. Cant wait for launch 9

Congratulations on 200k subscribing

Great video, as always! I'm afraid I haven't seen all of your videos, so I don't know if you have ever talked about this before, and thus do not know if you have addressed this concept before, but here goes: So, I've been kind of obsessed with reaction control thrusters lately, specifically after thinking about their use in SpaceX boosters for orientation control during their return to the pad, and especially after watching the recent footage from onboard the fairings orienting during their return to Earth. Seeing the compressed has canisters on the fairings made me wonder if you've ever considered incorporating a similar concept for use in your amazing rockets. It seems, in my layman's understanding of the subject, that you could (presumably) achieve faster orientation control than it's possible to achieve with gimbal motor control alone. I understand, based on what you were addressing in the video, that the limits in the ability of the the motor to correct trajectory seems to stem from the refresh rate of the GPS coordinates, so I don't know if there would be any advantages to developing such a system, but that's part of why I'm asking. I also wonder if it might be more efficient than gimbal control, and if it could theoretically replace that ability. Imagine if you used an onboard compressed gas tank, something like a C02 canister, mounted in the "upper stage," where you would also mount the "thrusters," with electronically controlled valves. I don't know whether this concept is even remotely feasible, I'm really just curious if it's something you've ever considered or explored the logistics of. Anyway, thanks for sharing another amazing video of your fascinating projects. They are always a special treat.

This is so prefect and straight if you have seen his works before this，That is amazing！！

Great feeling when it works

Amazing work! I love seeing stuff like this it really sparks my curiosity!

This man is essentially space X now.

Dude, i didn't understand a word you said. However, the video was AWESOME! Great job!

Really really appreciate it

no one does anything alone. good flying, dude!

One of your videos was shown in a TV program in my country. The rocket fail one!

I came from the Motherboard video. Damn I’m hooked now!

Used to SpaceX launches, the short burntime of the rockets are unsatisfactory. :-) It is over, just at the moment you start to realize it began just now :-) On the other hand, 100 m apogee is nice. Greetings from Munich, Tom.

cant wait to see you build the starship model.

Bravo Elon Joe.....I am learning all the videos of yours that i watch. Greetings from E.Pakistan 🇵🇰🇺🇸🇵🇰🇺🇸🇵🇰🇺🇸

I can't wait flight 9 and 10.

You know... Joey B is a class act!

I like the variable naming convention.

This community is great

Great work Joe !

Have you ever considered trying something like the zenit flyback booster? Or is it too complicated to teach the computer two different flight modes?

Oh yea! Nice job man!

Can you show us room , WHERE YOU DO ALL THIS STUFFS, humble request

6:01 Oh no, it's becoming self-aware!

Looking forward to the longer flights, should be awesome

I want to pursue my dream of launching a rocket like you! I am inspired by your videos!

당신을 응원합니다. I am rooting for you - 대한민국에서 당신의 구독자가. -

200k Subscribers 🚀

AVA computer is working so hard during flight and your brain after flight.

Now it needs to land itself. Great job 👏

Congo for 200k.

Great work and fun! Fantastic.