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  • Don Kelly's Avatar
    02-16-2018, 09:56 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Want to run an implementation idea by the group... I'm on travel for couple days, so limited ability to code. But I've got the Ver10 modified and ready to test with the simple 6-state Kalman and GPS. To start off,...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-14-2018, 09:59 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    quick update... All routines built and they compile (woo-hoo!!) - cTrans.h (coord transformation) - kfINS6State.h (contains kfInit, kfProp, kfUpdate, and kfReset) Now the debugging and testing starts... if anyone...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-14-2018, 03:26 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Step 1 (coordinate transformations library) done. I ended up just adding on several to Brian's previously built ones. They all compile fine, I will need to circle back and add some test cases to double-check the...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-13-2018, 09:34 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Quick update...I'm porting the Matlab code over to arduino in four chunks - Coordinate transformations - KF Initialization - KF Propagation - KF Update I was working on the four coordinate transformations today,...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-12-2018, 01:30 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Just studied your threading code. Really impressive! Wow!! As i port the ins/gps KF over from matlab, i’ll build it as a separate tab/function so it can be called easily. I’m thinking i’ll build a...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-12-2018, 02:51 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, I'll take a look at your zip file Mon. Sounds interesting! I'll port the Matlab test code over to the arduino Mon or Tue. After looking more at the accel data, and how noisy it is, I'm thinking there are...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-11-2018, 09:55 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Got the Kalman running in Matlab with the collected GPS and IMU data. I'm running the filter in ECEF coordinates, so GPS LLA, GPS velNED, and accNED are all converted to ECEF then processed in the filter. The six filter...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-10-2018, 05:51 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's a release of a version that writes both GPS and IMU data to serial port. It sends the following to serial: UTC (seconds of day), dt, fix, LLA values, velNED values, PRY values, accelNED values I'm using...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-10-2018, 04:01 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    EDIT to last post... After looking at the PDFs Mike sent, using UTC (rather than iTOW) is the way to go. Brian's uBlox library parses out the components (weeks, hrs, min, s, ns) of UTC, but looks like I'll need to...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-10-2018, 03:07 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Thanks, I'll read those PDFs. It turns out iTOW is a "long", so must do (float iTOW)/1000.0 to put it in float seconds. Duh, I shouldn't have missed that... So, even though I have the uBlox set to 5Hz, now...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-10-2018, 02:23 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Thx. Think I found it... in u-center there's a rate setting under configuration, and you can set to 200ms (5Hz). so now my velocities are changing at 5Hz, but time (.iTOW) still stays the same for 5 readings, the entire...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-09-2018, 11:31 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    My uBlox is sending data at 5Hz, but the data is only changing at 1Hz. So it prints out the same numbers 5 times in a row. Anyone run across this? Is there a setting in the uBlox u-Center interface that makes the data...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-09-2018, 11:17 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    A quick update... I'm running a uBlox and one of the AHRS algorithms, and am now streaming GPS data and IMU data at 5Hz to serial. I need to add a few other terms to the stream, and then I'll go out and collect some...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-09-2018, 02:55 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's V9. It has a DCM tab added, and then I changed the output to print out 9 terms, PRY, 3 accel NED-body, 3 accel NED-inertial (with gravity removed). Don
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-09-2018, 02:51 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Let me send out V9 right now, pretty much V8 but with the DCM tab added. Don
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-09-2018, 01:52 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Don't think I saw the GPS isr code, so an example would be great. The next thing I'm planning over the next couple of days is to modify a sketch to capture the following data: - From IMU (~100Hz): pitch, roll,...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-08-2018, 10:35 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Yay, success... Got routine that puts out accel in NED-inertial (with gravity removed). Turns out I had made a couple dumb mistakes in the DCM. Will post once I get it cleaned up, maybe later tonight. So I believe...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 10:55 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    The sensitivity of the magnetometers to external metal and magnetic fields makes AHRS a bear! Unless the device is out in open space I suppose... This would tend to make me think that keeping PR and Y in separate...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 08:36 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's an AHRS Filters Version8, all I did was simplify the serial print so that it just prints PRY now. I decided to just leave the sketch as just a "single-filter-select" sketch for now so I can go ahead and see if...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 02:30 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Yes, I'm guessing something like this approach is the way to go, if the AHRS outputs quaternions. If it's an Euler AHRS, I think a DCM rotation is applied. I'll give it a try. I'll need to figure out what...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 01:53 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, I was taking the accel values (NED-body) directly out of your MPU9250 library, removing gravity, then using a DCM (using PRY from AHRS) to transpose the accel values to NED-inertial. I thought that would work,...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 01:10 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I'm also looking forward to integrating in GPS soon, which I think Brian is investigating options right now. My vote would be to start with a simple loosely-coupled KF running after the AHRS. Then later moving to a more...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-07-2018, 12:35 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, I'll create us a "final" MPU9250_Filters (version 8) that will allow the user to select some number (maybe 3?) of filters and then compare them using TelemetryViewer. How's that sound? I've also just set...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 08:53 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, In Brian's code, the L _* Q_ *L_.transpose() is the accumulated process noise term added at each propagation step. Sometimes this whole term is written as the process noise "Q", but in his case he has fixed...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 08:36 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Here's V7. I added the Mahony (which looks to be a slight variant of what you already had as AHRS), and verified its PRY output is correct. I also went through and cleaned up the code a bit (spacing, adding...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 04:56 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Not clear on what you mean by Kris iterates the filter 10 times before the next update. Does he set dt = 0, and then just loops through the filter 10 times? On the sampling side, I need to get into that deeper. I...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 04:41 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Shall I add the original Mahony filter in as MARG 2? I have a version from the Madgwick site, which is what Kris was using as well I believe. EDIT: Just saw your other note... yes, a filter restart is a good...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 04:19 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Will do. Just went thru all the MARGs, signs look great. the MARG 3 values have right sign, but (like you mentioned earlier) they don't settle down. I'll take a look at that today, along with adding some comments and...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 04:00 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, are you ok with me making a couple of tweaks to your V6 to make a V7? the INT pin is hard-wired to PIN 14 in the IMU setup tab, and I thought I'd insert some more comments perhaps. Am stepping through the MARG...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-06-2018, 03:45 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Downloading your latest, will look at it this morning. I need to check out Kris' STmicro IMU. How do you like it? Joop Brokking appears to have gone to an ST-based flight controller design as well in his...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-05-2018, 07:03 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Just ran through Ver5, and it looks like the MARG 3 signs are correct, but the pitch and yaw values aren't starting at 0 for me. For MARG 4, the sign on roll and yaw are backwards now. MARG 6 looks great now! ...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-05-2018, 01:40 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Yesterday was drone work, today i’m tied up with another project. But tues and wed are pretty open so i’ll hit it hard again then. Anxious to try your new version!! Looks like you’ve made even some more progress...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-04-2018, 03:39 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Really nice!! Impressive to see it come together as a pretty complete library! I took a quick look and MARG 0,1,3, and 5 are all working well here. I see a couple of tweaks needed. I think I can look at it...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-04-2018, 12:51 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I'm done now! Just poured a glass of wine... time to kick back for the evening! Don
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 11:52 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, The Madgwick seems to work on the first release of your code (when I input the sensors as NWU), but a sign is off in the second release. I noticed on your second release of the code, the getYawPitchRollRad has...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 10:38 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, I think your discovery may be correct. I just negated the y and z terms for the Madgwick and I think it's aligned now to yaw pitch and roll... So it does seem Madgwick is using a NWU convention. Need to put it...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 10:25 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, That might be the trick! ... if Madgwick is using a NWU (North West Up) frame. That frame is rarely used in the aerospace apps that I've been involved with, but not difficult to transform to/from. It's been a...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 10:19 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's a link to my memo on alignment, too large to upload to this forum... https://www.dropbox.com/s/dw0z71jrdksepz8/MPU9250%20Axes%20Alignment%2C%20DKelly%2C%20020318.pdf?dl=0
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 10:14 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Attachment here:
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 10:07 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's a sketch and a memo that discusses how to verify that a MPU9250 is aligned and producing sensor outputs consistent with a NED body frame (per Brian's library). I wanted to document it for myself, so I could...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 09:18 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, On my SparkFun MPU92050 board, there's a NED axis labeled for the accel and gyro axes. For a NED body frame, usually what's assumed is - X points through nose of aircraft - Y points through right wing - Z...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-03-2018, 02:52 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, you're using INT on pin 14, I'm using INT on pin 1. That might be it... Don
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 10:13 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I just tried MadgwickAHRSupdateIMU(gy,gx,-gz,ay,ax,-az) ...and it gave me a NED solution for PRY but rotated in the horizontal by 90 deg. So it's almost like the Madgwick filter wants the inputs in ENU. enough...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 09:31 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, I'm getting sign errors in the outputs of the four MARG filters in your latest sketch, much like I was getting yesterday with the Mahony and Madgwicks I was running. For example, for MARG 1 and 0 I'm getting -...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 08:30 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, thx for the paper. The author shows an algorithm for yaw from magnetometers in a nice form, so I may add that to my complementary filter routine so that I'll have both PR and PRY versions, sort of like I've seen...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 07:46 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's the sketch with the complimentary filter... all working with Brian's MPU9250 library. Note that this complementary filter just uses gyro data to estimate pitch and roll, and accel data to offset gyro drift. I...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 03:46 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Awesome!! I just pulled in Joop's complementary filter and am getting it ported over to work with Brian's MPU9250 library. Joop's version was designed for reading the raw MPU6050 registers and then converting those...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-02-2018, 02:40 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, That'd be fantastic! Tomorrow I'll work on the simple Complementary Filter I used on my first drone, it's from Joop Brokking, works very well, no mag inputs. I've had frustrating day with Madgwick and Mahony....
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-01-2018, 10:53 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Thats the kind of thing i was starting to pull together: Complementary, Mahony (w and w/o mag), Madgwick (w and w/o mag), EKF Euler, EFK Quaternion... I had Winer's Mahony and Madgwick working using a different MPU9250...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-01-2018, 09:59 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, you mentioned "I have the madgwick, Mahoney and DCM filters broken out into header files that you can just call. If you want I can post them then you can just call them." I've been fighting most of the day with...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    02-01-2018, 01:58 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Congrats Mike! Glad you got it working. Am still debugging my Mahony and Madgwick... if mine doesn't work tomorrow I may ask for yours! :) Logging the CSV files (rather than using SD card) sounds like a great idea....
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-31-2018, 08:21 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Tim, I was thinking of seeing how they look side-by-side, if the processor can handle it. Then I'd have them there to compare later too if needed as we add bias states and GPS inputs. I haven't tried logging to this...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-31-2018, 07:12 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Thx for the RTK links, Mike. Good info there! I'm going to spend a couple of hours this afternoon and resurrect my Mahony and Madgwick code (Winer's code originally) and get it working using Brian's MPU9250 library....
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-31-2018, 01:52 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, Very cool paper. Great find. Nice comparison to Mahony and Madgwick. I could see some cool applications of this approach. For example, the authors claim this gives a very good pitch and roll estimate with noisy...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-31-2018, 03:24 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I let the Euler EKF run overnight a couple of times, and it seems like the innovation means (which are y-hx in accel and the one mag) had drifted a bit, but not too badly. So am thinking that eventually adding back in...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-30-2018, 01:01 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Sounds like a really good approach. My only caution would be to do it in "baby steps" vs. a couple big steps. So perhaps we could bite off just 1-2 things at a time...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-29-2018, 11:04 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    One thing that might be interesting to try (if the T3.6 can handle the processing) would be to run the Euler EKF that we have now in parallel with the 4-state quaternion EKF. So with each void loop, we would - read...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-29-2018, 07:28 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, So it sounds like your thoughts are to go back to a quaternion AHRS scheme, get that working well, and then integrate in GPS measurements. If so, sounds good to me! I'm thinking for most applications outdoors...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-28-2018, 03:05 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, I ran the latest version all night, seems to have run fine. What are your thoughts on next steps? Are you thinking about re-visiting the quaternion 4-State or 7-State and get that going, or using this Euler...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-28-2018, 12:04 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, One thing that I see on the plots that looks a bit odd is that when I move roll and yaw, the three Q values (from both LQL' calculations) remain fairly consistent. But when I raise pitch, Qa(0,0) and Qh(0,0)...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-27-2018, 10:33 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    That did it... it's back cycling again...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-27-2018, 08:07 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, I ran your new code and for me it blows up after a couple of iterations. Guessing it's something with _t or _dt. If I get a chance later on today will see if I can start back with the old timing code snippets...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-26-2018, 10:04 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Is the FTDI board so that you can power the uBlox with 5V? I have been doing that or connecting a second USB to the uBlox to get 5V. I tried tapping off 3.3V from the T3.6 to power the uBlox, but it wasn't enough. It...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-26-2018, 08:47 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    thanks Mike, it's very cool to see the behavior of the innovations in real-time, very insightful. auto tuning (via system identification) would be a really cool R&D project. I would be interested in doing some of that,...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-26-2018, 04:54 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's an interim release of what I've been working on. This version does NOT have the Q updating capability yet, but it has these changes: 1) I added the QuickStats library, and use it to calculate mean and std of...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-26-2018, 01:43 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Am still making progress with my coding, taking longer than i thought with other stuff going on. Am tweaking the TelemetryViewer dispay now with the additional parameters, then will add in code for the real-time setting...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-25-2018, 06:41 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Nice Mike! I hope to take a look at it later tonight. I've got my version of the sketch calculating mean and sigma of the innovations using the QuickStats library. Works like a champ. Working on getting those values...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-25-2018, 03:18 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I'm now able to send commands from a second T3.6 (via second computer) to the T3.6 with the EKF. So suspect tomorrow sometime I'll be up and running with being able to adjust Q and R in real-time while viewing...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-24-2018, 08:13 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Yes, had the yaw correction, but I didn't have that roll mod you mentioned, so I've added that. I've noticed that if the sketch runs for a very long time (like hours), when I come back and look, pitch and roll are at...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-24-2018, 07:21 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    looks right! I didn't have the roll with that mod, so just added it and it seems to be working.
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-24-2018, 02:36 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Very cool! Thanks!!!! Will check this out tomorrow to see if I can replicate. This will be very powerful if we can see the KF or EKF performance in real-time, and then actually be able to tweak Q (or R) in the...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 09:03 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Oops, sorry, that was Tim on last post...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 08:44 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Tim, Probably dumb question here... but here goes... TelemetryViewer can't be run with the Serial Port open. So I'm not seeing how we'd 1) wire it up, and 2) how we'd view a serial display to send the commands....
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 08:18 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    holy cow... I just turned off my 5Hz plotting loop to see if TelemetryViewer could handle plotting the full 100Hz serial port stream (SRD=9), and it's plotting it all I think. Whoa... data's going by FAST.... ...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 07:34 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Just noticed that in Brian's latest version of the code, he commented out the "-_inertialEuler(2,0)" part of the yaw calculation. So in that version yaw (yh_(0,0)) is really reading out the raw (or noisier) heading. So...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 04:58 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's a couple of (very!) early observations from looking at the TelemetryViewer plots: - Two of the Q values (LQL') jump up by a factor of two with pitch movements. Q stays pretty much steady with roll and yaw...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-23-2018, 03:22 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Here's a version of Brian's code that pulls out 18 parameters to serial port for viewing at 5Hz in TelemetryViewer. I also included the layout for TelemtryViewer, along with a screen shot. Here's a summary of what...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-22-2018, 09:58 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Thanks Mike, that's it. For anyone interested, here's what I'm typically seeing with the SRD settings on the Teensy3.6 SRD=9, 101Hz for gyro and accel, 97Hz for mag SRD=4, 196Hz for gyro and accel, 93Hz for mag ...
    464 replies | 23064 view(s)
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    01-22-2018, 09:10 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Tim, my test was very simple. I commented out the Serial.print lines in the ino file, added a simple counter each for the accel, gyro, and mag sections of the code, and then just printed those counters out at 1Hz. So I...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-22-2018, 08:48 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    I just put in some counters to see how fast the various stages of the Euler EKF were running. The propagation stage kicks off with: if (gyroUpdated_) Likewise the accel update stage kicks off with: if...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-22-2018, 04:20 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, In your propagation step for yaw, you're using the already-propagated-by-dt values of pitch and roll to propagate yaw by dt. Maybe it's such a small difference that it doesn't matter, but it seems like the...
    464 replies | 23064 view(s)
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    01-22-2018, 03:29 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Flew it around much more aggressively, and got it confused. suspect it's more euler singularities crossed. had to restart... Brian, got an idea to throw out... since this version seems stable at modest "flight",...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-22-2018, 03:15 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, Got your Euler EKF up and running this morn. VERY nice work! It seems very stable so far, even when I "fly" around the board. I see one hiccup, probably an "Eulerism" as you mentioned. Roll jumped to 360+...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-21-2018, 09:35 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Great! Will check it out tomorrow. Looking forward to it!! Don
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-19-2018, 11:20 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Ooops, sorry... missed that...
    464 replies | 23064 view(s)
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    01-19-2018, 10:11 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, What are your thoughts on trying the approach from the Watson thesis? For his h(x) equation, he does a transformation on the magnetometer measurements that supposedly isolates pitch/roll from yaw. Also, his h(x)...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-19-2018, 01:43 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Mike, Yes, it is sort of getting into the realm of adaptive filter. But I really refer to it as building in "smarts," verses making it truly adaptive. But the more smarts built in, the more adaptive it becomes. I've...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-19-2018, 02:41 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Brian, Some rambling on tuning... This is a bit of a different beast, especially with the use of quaternions, but here's some thoughts... I've had a relatively simple approach to tuning KF applications over the...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-19-2018, 01:55 AM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Thanks Mike, will check those links out.... Here's something cool... I started up the 7-State, messed around ("flew") with the board for a bit, then went off for dinner for a couple hours. When I came back, heading...
    464 replies | 23064 view(s)
  • Don Kelly's Avatar
    01-18-2018, 11:12 PM
    Don Kelly replied to a thread uNav AHRS in General Discussion
    Tried to follow the Teensy suggestions on connecting the SPI to the Sparkfun MPU9250, but not working. Here's what I've tried (assuming MOSI is SDA, MISO is AD0, SCK is SCL, SS is CS: SparkFun9250 Teensy3.6 VCC ...
    464 replies | 23064 view(s)
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GNC, drones, engineering software, optimal estimation
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