December 3-4, 2003 Green BankGBT PTCS In Progress Review

EMS/LRF Update

Richard Prestage

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Goals

• From April CoDR:

“….EMS/LRF…will be available as a GBT surveying tool, allowing us to measure critical dimensions and characterize the antenna with considerably higher accuracy and convenience than is possible with conventional surveying techniques”.

• Panel Report:

“…Careful measurements of simpler performance aspects are needed to evaluate if the LRF are useful in other modes of operation.....”

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From June 16th PTCS Project Meeting

• EMS Objectives– “Production” Use, 1mm or better

– Characterization of LRF accuracy

– Develop EMS/Wit/Matlab frameworks for experiments

– Feed Arm Tip Survey

– Subreflector Survey

• Schedule– EMS Framework (completed)

– Test data set collection beginning early July, repeated at intervals

– Prototype trilateration EMS code August, developed with July data

– Completed FA survey tool September

– Prototype SR survey tool September

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Actual Schedule

• EMS sufficiently complete to execute experiments: late May.

• EMS Refinements for real-time trilateration results: August.

• LRFs ready for basic trilateration experiment: end August

• First “successful” trilateration experiment: 5th September

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Results

• EMS prototyping/characterization tool resounding success.

• LRF trilateration results c.f. traditional survey showed significant discrepancies.

• April to September: ~two staff years of effort.

• Clearly would not be able to make any significant performance contributions for Winter 03/04.

• Temperature sensors and traditional approaches were showing great promise.

• Postpone further LRF work until Spring 2004.