http://openluna.org/wiki/index.php?title=Sensor_corrections&feed=atom&action=historySensor corrections - Revision history2024-03-29T13:49:00ZRevision history for this page on the wikiMediaWiki 1.20.3http://openluna.org/wiki/index.php?title=Sensor_corrections&diff=437&oldid=prevSnyder at 17:15, 23 April 20092009-04-23T17:15:55Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A is a vector of acceleration, and  </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>A is a vector of acceleration, and  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>W is vector of rotations.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>W is vector of rotations.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>These assorted corrections can all be rolled up at system initialisation and represented by:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>These assorted corrections can all be rolled up at system initialisation and represented by:</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Wgood = Cgyro * (<del class="diffchange diffchange-inline">Sc</del>*Wm - <del class="diffchange diffchange-inline">Vc</del>)  </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"> </ins>Wgood = Cgyro * (<ins class="diffchange diffchange-inline">Sw</ins>*Wm - <ins class="diffchange diffchange-inline">Vw</ins>)  </div></td></tr>
<tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>( <del class="diffchange diffchange-inline">similar for the Acc </del>)</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"> Agood = Cacc * </ins>(<ins class="diffchange diffchange-inline">Sc*Am - Va</ins>)</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Where <del class="diffchange diffchange-inline">Vc </del>is a vector for offset correction and Sc is the rolled up scalar corrections</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Where <ins class="diffchange diffchange-inline">Vw </ins>is a vector for offset correction and</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Sc is the rolled up scalar corrections</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>It may make sense to rearrange this equation to simplify the math when considering the  </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>It may make sense to rearrange this equation to simplify the math when considering the  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>accuracy of the assorted variables (16 bits or more).     </div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>accuracy of the assorted variables (16 bits or more).     </div></td></tr>
</table>Snyderhttp://openluna.org/wiki/index.php?title=Sensor_corrections&diff=436&oldid=prevSnyder at 03:11, 23 April 20092009-04-23T03:11:50Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">3) Additional data shaping.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The numbers reported by the accelerometers and gyros are probably not in convenient units.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">each measurement needs to be multiplied by a scalar, and possibly offset by another scalar.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">While we are at the shaping, Accelerations and Angular rates are nice numbers to have, but what is really</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">needed is the angular displacement and velocity change during the measurment interval. another scalar multiplication. </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">And of course just because you measure the angular rate at x deg/sec per bit change, doesn't mean that this is what you want to do your trig functions in nor store in variables. another scalar.</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">These assorted corrections can all be rolled up at system initialisation and represented by:</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Wgood = Cgyro * (Sc*Wm - Vc) </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">( similar for the Acc )</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Where Vc is a vector for offset correction and Sc is the rolled up scalar corrections</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">It may make sense to rearrange this equation to simplify the math when considering the </ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">accuracy of the assorted variables (16 bits or more).    </ins></div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Back to [[Inertial Navigation]]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Back to [[Inertial Navigation]]</div></td></tr>
</table>Snyderhttp://openluna.org/wiki/index.php?title=Sensor_corrections&diff=433&oldid=prevSnyder at 02:28, 22 April 20092009-04-22T02:28:47Z<p></p>
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<tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>2) Other corrections TBD.</div></td></tr>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Back to [[Inertial Navigation]]</ins></div></td></tr>
</table>Snyderhttp://openluna.org/wiki/index.php?title=Sensor_corrections&diff=432&oldid=prevSnyder: New page: 1)The accelerometer and gyroscopic sensors will (probably) be arranged in three orthogonal direction (XYZ) Actual manufacturing will undoubtedly have some misalignment and will need corr...2009-04-22T02:27:47Z<p>New page: 1)The accelerometer and gyroscopic sensors will (probably) be arranged in three orthogonal direction (XYZ) Actual manufacturing will undoubtedly have some misalignment and will need corr...</p>
<p><b>New page</b></p><div>1)The accelerometer and gyroscopic sensors will (probably) be arranged in three orthogonal direction (XYZ)<br />
Actual manufacturing will undoubtedly have some misalignment and will need correction. During manufacturing and test, the misalignment shall be measures and a correction matrix will be generated.<br />
<br />
The misalignment correction to the measured numbes (Vector Vm) will just be <br />
<br />
Vgood = C * Vm<br />
<br />
for example <br />
Wgood = Cgyro * Wm<br />
Agood = Cacc * Am<br />
<br />
where C is a 3x3 matrixes , <br />
A is a vector of acceleration, and <br />
W is vector of rotations.<br />
<br />
<br />
<br />
2) Other corrections TBD.</div>Snyder