| Date: | 1995-12-14 00:00:00 | |
| Sender: | Andrew Sinclair, Mike Pearlman <[Mailed Mike <PEARLMAN@cf1.harvard.edu>]> | |
| Subject: | [SLR-Mail] No. 5: Changes to CSTG SLR FORMAT - Please take note | |
| Author: | ||
| Content: | ******************************************************************************** SLR Electronic Mail 1995-12-14 00:00:00 UTC Message No. 5 ******************************************************************************** Author: Andrew Sinclair, Mike Pearlman Subject: Changes to CSTG SLR FORMAT - Please take note Subject: Changes to the SLR CSTG NORMAL POINT FORMAT Dear Colleagues, At the CSTG SLR Subcommission Meeting held in Berne on December 5-7, it was decided not to make a major revision to the SLR CSTG Normal Point Format at this stage. However two small changes are needed and should be introduced immediately by the stations. The SLR CSTG Normal Point Format, also called the Quick-Look Format, is the format used by the SLR stations to transmit their on-site formed normal points. It is described in the SLR Newsletter of the SLR Subcommission of the CSTG, April 1990. The changes adopted at the meeting are: 1. HEADER RECORD, columns 21-24. Wavelength of the laser. At present the units are 0.1 nm. In the future the units will be either 0.1 nm or 1.0 nm, depending on the data value, as follows: value 3000 to 9999 units 0.1 nm value 0001 to 2999 units 1.0 nm So 0.5321 microns will give "5321" (no change from present) 1.0641 microns will give "1064" This wavelength modification is necessary to accommodate systems which are ranging at wavelengths at greater than 1 micron. FOR SYSTEMS OPERATING BELOW I MICRON THERE IS NO CHANGE, and so there is no loss of compatibility with existing data. It is considered that wavelengths lower than 0.3000 microns or greater than 2.999 microns are unlikely to be used for laser ranging. If a quoted data value of 1064 is misinterpreted as being a wavelength of 0.1064 instead of 1.064 microns, then the range error will be 8 metres or greater, and so should be easily detected. The reduced precision of the least significant figure for wavelengths greater than 1 micron is not important. It would make at most a range error of 0.1 mm. 2. NORMAL POINT DATA RECORD, column 48. Data release indicator. At present this character is unused. It will be used as follows: value "0" first release of the data value "1" replacement release of the data, if necessary. Occasionally stations wish to release a corrected or updated version of their field generated normal points for certain passes. To ease the data handling procedures at the Analysis Centers we have been requested to flag sequentially the successive data releases. Please note and implement these format changes immediately. CSTG SLR Subcommission Steering Committee 1995 December [Mailed From: "Mike" ******************************************************************************** |