December 3-4, 2003 Green Bank GBT PTCS In Progress Review EMS/LRF Update Richard Prestage

2 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.....”

3 From June 16 th 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

4 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: 5 th September

5 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.