Instrumentation for Creating KHz SLR Timing Systems

The instrumentation provides basic tools for creating SLR timing systems operating at repetition rate up to a few KHz. There is a test setup to simulate the process of ranging to various satellites and to evaluate capabilities of this instrumentation for the KHz system design. The simulation of the CHAMP laser ranging at 2 KHz repetition rate is considered as an example. Test results show that the proposed instrumentation offers sufficient performance to be used in the KHz SLR systems. Timing system architecture As known, increasing the SLR repetition rate up to KHz provides a variety of essential benefits. Currently there are a few SLR stations which already use this technique or will have it in the near future. However KHz SLR usually need essential upgrading of SLR equipment, including the timing system for satellite range measurement. In view of that we propose an instrumental basis to create various KHz SLR timing systems adapted to the specific user requirements. There is the well-known custom timing system for KHz SLR at Graz SLR station [1]. In general terms, architecture of timing systems based on the proposed instrumentation and principles of their operation are similar. But there are distinctions in some essential details. Specifically, in our case the specialized hardware is offered as two compatible stand-alone devices (Event Timer A032-ET and Range Gate Generator). PC interacts with these devices and coordinates their operation via standard parallel ports working in the EPP (Enhanced Parallel Port) mode (Fig.1). Figure 1. Timing system architecture As for the application software, it should be custom-made according to the specific application requirements with the reference to the sample program (source code written in C). This program defines device-specific software functions which can be directly built in the user software to support the interactions with hardware. In this way the instrumentation can be used as a basis for various timing system designs.