The Time of Flight (TOF) system of the Solenoidal Tracker at RHIC (STAR) at the Relativistic Heavy Ion Collider (RHIC) consists of two different subsystems: the start detector and the stop detector. Described in this thesis is the design, construc tion, and operation of a new start detector for STAR. This new start detector, called the Upgraded Pseudo Vertex Position Detector (upVPD) provides many improvements to the old start detector, called the Pseudo Vertex Position Detector (pVPD). The upVPD is expected to have better efficiency per event and better start timing and primary vertex location resolution compared to the pVPD, which will improve the performance of the STAR TOF and STAR Trigger systems. Timing offsets and the slewing effect smear the raw data read-out by the detectors and require offline calibration. The general approach and a few possible algorithms for such calibrations are also described. The analysis results from both the pVPD and the upVPD detectors are presented. Additional cosmic ray tests of the upVPD detectors were also performed, and the calibration results from these data are also discussed.