X/Ka Celestial Reference Frame Improvements: Vision to Reality
Abstract
In order to extend the International Celestial Reference Frame from its S/X-band (2.3/8.4 GHz) basis to a complementary frame at X/Ka-band (8.4/32 GHz), we began in mid-2005 an ongoing series of X/Ka observations using NASA's Deep Space Network (DSN) radio telescopes. Over the course of 47 sessions, we have detected 351 extra-galactic radio sources covering the full 24 hours of right ascension and declinations down to -45 degrees. Angular source position accuracy is at the part-per-billion level. We developed an error budget which shows that the main errors arise from limited sensitivity, mismodeling of the troposphere, uncalibrated instrumental effects, and the lack of a southern baseline. Recent work has improved sensitivity by improving pointing calibrations and by increasing the data rate four-fold. Troposphere calibration has been demonstrated at the mm-level. Construction of instrumental phase calibrators and new digital baseband filtering electronics began in recent months. We will discuss the expected effect of these improvements on the X/Ka frame.
- Publication:
-
Proceedings of the Sixth General Meeting of the International VLBI Service for Geodesy and Astrometry
- Pub Date:
- December 2010
- Bibcode:
- 2010ivs..conf..285J
- Keywords:
-
- Celestial Reference Frame;
- Reference Frame;
- ICRF;
- astrometry;
- VLBI;
- Deep Space Network;
- X/Ka-band;
- quasar;
- Active Galactic Nuclei