DV05 Metrology System Issues and Tracking


TIP Last Update: JeffMangum - 11 September 2009

Issues Tracked

  • Update ACU metrology interface software
    • 2009-09-11: Waiting to schedule.
  • Use Commanded El Rather Than Previous Elevation While Blanking Metrology
    • 2009-10-08: Proposed to eliminate problem with 0.8 arcsec "jumps" in azimuth position when fast switching in elevation near El = 60 degrees. Problem is that since there is a Y-offset to the tiltmeter that can be large on some antennas (such as DV05 and DV02), if one uses the previous elevation when calculating the metrology delta just after a blanked motion one gets the following differential position when the commanded position is subsequently used: T1YOffset*(tan(61.5)-tan(60)) = 0.11*T1YOffset. For T1YOffset = 12.5 arcsec (which is the current value for DV05), we get a 1.4 arcsec jump, which when projected onto the sky becomes 1.4*cos(El) = 0.7 arcsec. If one uses El = Commanded El during metrology blanking then you don't get a jump.
    • 2009-10-09: Klaus confirms that the solution proposed is the correct one to solve this problem. Vertex will make this change to the ACU software on DV05, we will test it, then the final solution will be implemented on DV06.

Associated JIRA Tickets

Metrology Sensor IDs

  • Tiltmeter: SN 8214
  • Linear Sensor: SN??

Metrology System Calibration Constants

Date SN Pad AN0 (arcsec) AW0 (arcsec) SA2 (arcsec) SA3 (arcsec) phi2 (deg) phi3 (deg) NPAE (arcsec) Comments
1 February 2009
8214
SEF2
+13.7
+33.7
+0.55
+132.44
-0.12
+181.58
 
Acceptance values
16 September 2009
8214
SEF2
+12.96
+32.95
+0.148
+0.149
+21.07
-35.22
...
Recalibration/optimization

Tiltmeter Metrology System Calibration Offsets

Date SN Pad TiltXOffset (arcsec) TiltYOffset (arcsec) Tiltmeter Blanking Time (sec) Tiltmeter Filter Time (sec) Comments
 
8214
SEF2
-25.79
-11.8
2.0
1.0
Acceptance values

Linear Sensor Metrology System Calibration Offsets

Antenna Pad LS Offset 1A (mm) LS Offset 1B (mm) LS Offset 2A (mm) LS Offset 2B (mm) Comment
 
SEF2
+0.095
+0.029
+0.104
+0.168
Acceptance values
16 September 2009
SEF2
+1.8
-1.8
-2.1
+2.1
Recalibration/optimization

-- JeffMangum - 2009-09-11
Topic revision: r7 - 2009-11-05, JeffMangum
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