tag:blogger.com,1999:blog-4237678261594285909.post1512753945975164673..comments2024-01-05T22:40:53.671-05:00Comments on Sailboat Instruments: Improved magnetometer calibration (Part 1)Unknownnoreply@blogger.comBlogger17125tag:blogger.com,1999:blog-4237678261594285909.post-29051460929304640032018-11-04T01:55:04.279-04:002018-11-04T01:55:04.279-04:00I'm working with the HMC5883L, I succeeded to ...I'm working with the HMC5883L, I succeeded to convert the raw data to degrees but I don't know much about the calibration and how to know if the device is really pointing to the north.R1S8Khttps://www.blogger.com/profile/00073144089750117217noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-943780081388544682017-10-17T18:07:15.746-04:002017-10-17T18:07:15.746-04:00Use Total Intensity aka TMI aka TF aka field aka t...Use Total Intensity aka TMI aka TF aka field aka total field value for your location. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-15074771177489145432017-03-21T02:49:52.503-04:002017-03-21T02:49:52.503-04:00Might be drifting temperature effects over the tim...Might be drifting temperature effects over the time period? Fluxgates do drift with temperature changes. Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-22324720210192351522017-01-24T01:20:32.895-05:002017-01-24T01:20:32.895-05:00Hi Merlin, thanks for this great blogPost. I am tr...Hi Merlin, thanks for this great blogPost. I am trying to find the value for the Norm of the Earths Magnetic Field. Your link is a 404 but i tracked it down here: https://www.ngdc.noaa.gov/geomag-web/#igrfwmm<br />The issue is that this outputs 8 fields, but none of them are called 'norm'. <br /># (1) Date in decimal years<br /># (2) Declination in decimal degrees<br /># (3) Inclination in decimal degrees<br /># (4) Horintensity in nanoTesla (nT)<br /># (5) Totalintensity in nanoTesla (nT)<br /># (6) Xcomponent in nanoTesla (nT)<br /># (7) Ycomponent in nanoTesla (nT)<br /># (8) Zcomponent in nanoTesla (nT)<br />What do you suggest i use as 'norm' for the MagCal input??<br />thxDav-ohttps://www.blogger.com/profile/01891636529832030130noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-39236224275315947052016-07-22T01:26:47.158-04:002016-07-22T01:26:47.158-04:00I am in the office,so there are computers and stee...I am in the office,so there are computers and steel inside the concrete skeleton,guess maybe the problem here.maninblackhttps://www.blogger.com/profile/06334739813883197068noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-25401112852971042602016-07-22T00:36:46.108-04:002016-07-22T00:36:46.108-04:00Definitely not normal if the environment has not c...Definitely not normal if the environment has not changed.Merlinhttps://www.blogger.com/profile/00901116173524809046noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-68862822062714526062016-07-21T22:26:28.714-04:002016-07-21T22:26:28.714-04:00Hi,Merlin
I've done lots of times,after the c...Hi,Merlin <br />I've done lots of times,after the calibration seems very effective,but as time goes by(2~3hours) I found that magnetometer would become inaccurate even in the same environment,is that normal? Do I need to calibration maybe every couples of hours? maninblackhttps://www.blogger.com/profile/06334739813883197068noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-30532642849163307562016-07-21T21:55:49.903-04:002016-07-21T21:55:49.903-04:00In practice, I only rotate the compass around 3 mu...In practice, I only rotate the compass around 3 mutually perpendicular axis, as this is enough to define an ellipsoid of measurements. Using 10 degrees steps for each measurement is quite enough. It is particularly important that the compass does not move during the accelerometer measurements, as any vibration will affect the results (hence the 'static' recommendation). I fix the compass to a wooden peg <br />leaning on a support to make the measurements.Merlinhttps://www.blogger.com/profile/00901116173524809046noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-51709530895231819242016-07-20T02:05:14.539-04:002016-07-20T02:05:14.539-04:00Hi,I want to ask a question of the procedure 1,
re...Hi,I want to ask a question of the procedure 1,<br />record a set of "static" measurement by positioning the compass in a large number of orientiations covering a whole sphere. How to record static measurement when position whole orientations to cover a whole sphere when rotate the compass? and how many sets should I record is enough? maninblackhttps://www.blogger.com/profile/06334739813883197068noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-18769009328598784342014-08-25T09:20:35.178-04:002014-08-25T09:20:35.178-04:00Thank you! This post is an excellent tutorial for ...Thank you! This post is an excellent tutorial for calibrating magnometer such <a href="http://www.vcc2gnd.com/2014/02/HMC-5883L-Digital-Compass-Magnetometer.html" rel="nofollow">HMC-5883L sensor</a>.Anonymoushttps://www.blogger.com/profile/11637356692031540669noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-34754701420180469992013-09-02T11:34:53.800-04:002013-09-02T11:34:53.800-04:00Really interesting subject, as I struggled with th...Really interesting subject, as I struggled with this for some time now with little luck. Ellipsoid fitting is not an easy task...<br />Anyway - in order to see what the output would be when applying the correction matrix on the data provided in your sample, I wrote a small program that applies the correction and plots the data.<br />However I didn't get the perfect sphere I had hoped for and wonder if I made something wrong.<br />I could publish the application and results here If I only knew how to attach files and pictures...Anonymoushttps://www.blogger.com/profile/16586964472364030860noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-81129006645020439362013-01-21T12:38:06.071-05:002013-01-21T12:38:06.071-05:00i asked silly questions!i completed it!thanx a lot...i asked silly questions!i completed it!thanx a lot !!!this calibration technic offered me the only correct results :)!!!!Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-25930761489715257432013-01-21T12:19:51.096-05:002013-01-21T12:19:51.096-05:00a i found it !!!just 2 last questions!!!!
double h...a i found it !!!just 2 last questions!!!!<br />double hm;<br />double* A_1 = new double[3*3];<br /> <br />for(i = 0; i < 9; i++)<br /> A_1[i] = SQ[i] * hm / hmb;<br /><br />what does hm stands for?<br /><br />and :<br /><br />***Calculate A to permit comparison with MagCal***<br /><br />what does the part of the code do here?calcualtes A-1?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-22865675391512234522013-01-21T11:30:27.105-05:002013-01-21T11:30:27.105-05:00thanx!when you say i have to complete you mean to ...thanx!when you say i have to complete you mean to do the last 5 steps?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-44560421043433437702013-01-21T10:52:16.606-05:002013-01-21T10:52:16.606-05:00See :
https://sites.google.com/site/sailboatinstru...See :<br />https://sites.google.com/site/sailboatinstruments1/presentation<br />for a link to a Matlab implementation of the Li's<br />ellipsoid fitting algorithm. You will to complete with the calculation of the correction matrix as shown in:<br />https://sites.google.com/site/sailboatinstruments1/proofMerlinhttps://www.blogger.com/profile/00901116173524809046noreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-72381489371105125602013-01-21T09:53:52.300-05:002013-01-21T09:53:52.300-05:00hello!!!amazing post and excellent!is the source c...hello!!!amazing post and excellent!is the source code of the algorithm for the calibration available for matlab!since i am most familiar with it!thanx :)Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-4237678261594285909.post-5027431240867503902011-11-21T00:57:05.948-05:002011-11-21T00:57:05.948-05:00Hi, probably our entry may be off topic but anyway...Hi, probably our entry may be off topic but anyways, I have been surfing around your blog and it looks very professional. It’s obvious you know your topic and you appear fervent about it. I’m developing a fresh blog plus I’m struggling to make it look good, as well as offer the best quality content. I have learned much at your web site and also I anticipate alot more articles and will be coming back soon. Thanks you.Calibrationhttp://bestandards.comnoreply@blogger.com