Tools for Finding Problems in the Data or Processing

Topics to be covered

• Postfit editing • Sky plots of residuals • CVIEW interactive data viewer • Common failure modes 28-Apr-20 GAMIT/GLOBK Tutorial 6 2

Skyplots

• To make them – Check that GMT software is installed – Include following command in autcln.cmd

• POST phs_res_root DPH – Will create DPH files • Examples: • HOLC in California • Results from /dell3/tah/glob99 using display 28-Apr-20 GAMIT/GLOBK Tutorial 6 3

HOLC skyplots

28-Apr-20 GAMIT/GLOBK Tutorial 6 4

CVIEW

• an interactive viewer of GPS data • allows editing and cycle slip repair • seldom used now • autcln works well on most data • useful for diagnosis when autcln fails • example use of cview • To retain C-files to read with cview, use -e option in sh_gamit.

• Examine /dell3/tah/iap02/013r 28-Apr-20 GAMIT/GLOBK Tutorial 6 5

Failures

• Reported in the GAMIT.fatal files • Most common modes of failure – setup errors – receiver and antenna information – bad apriori coordinates – tables out of range • Examples – fatal errors in yesterday's tutorial 28-Apr-20 GAMIT/GLOBK Tutorial 6 6

Summary

• Examine sky plots – phase residuals help evaluate quality • Examine GAMIT.fatal

– diagnose upstream problems 28-Apr-20 GAMIT/GLOBK Tutorial 6 7