I. Pathfinder surveys: VLBA Calibrator survey 1 (VCS1); PI: A. Beasley; VLBA BB023; S/X bands; 11 segments; since 1994.08.12 through 1997.08.27. Reference: \citet{r:vcs1} Paper: Beasley, A.J., Gordon, D., Peck, A.B., Petrov, L., MacMillan, D.S., Fomalont, E.B., & Ma, C., "The VLBA Calibrator Survey - VCS1", 2002, Astrophys. J. Sup., 141, 13 VLBA Calibrator survey 2 (VCS2); PI: E. Fomalont; VLBA BF071; S/X bands; 2 segments; since 2002.01.31 through 2002.05.14. Reference: \citet{r:vcs2} Paper: Fomalont, E., Petrov, L., McMillan, D.S., Gordon, D., Ma, C., The Second VLBA Calibrator Survery: VCS2, 2003, Astron. J., 126, 2562 VLBA Calibrator survey 3 (VCS3); PI: L. Petrov; VLBA BP110; S/X bands; 3 segments; since 2004.04.30 through 2004.05.27. Reference: \citet{r:vcs3} Paper: Petrov, L., Kovalev, Yu.Y., Fomalont, E., and Gordon, D., The Third VLBA Calibrator Survey -- VCS3, Astron. J., 2005, 129, 1163 VLBA Calibrator survey 4 (VCS4); PI: L. Petrov; VLBA BP118; S/X bands; 3 segments; since 2005.05.12 through 2005.06.30. Reference: \citet{r:vcs4} Paper: Petrov, L., Kovalev, Yu.Y., Fomalont, E., and Gordon, D., The Fourth VLBA Calibrator Survey -- VCS4, Astron. J., 2006, 131, 1872 VLBA Calibrator survey 5 (VCS5); PI: Y. Kovalev; VLBA BK124; S/X bands; 3 segments; since 2005.07.08 through 2005.07.20. Reference: \citet{r:vcs5} Paper: Kovalev, Yu.Y., Petrov, L., Fomalont, E., and Gordon, D., The Fifth VLBA Calibrator Survey -- VCS5, Astron. J., 2007, 133, 1236 VLBA Calibrator survey 6 (VCS6); PI: L. Petrov; VLBA BP133; S/X bands; 2 segments; since 2006.12.18 through 2007.01.11. Reference: \citet{r:vcs6} Paper: Petrov, L., Kovalev, Yu.Y., Fomalont, E., and Gordon, D., The Sixth VLBA Calibrator Survey -- VCS6, Astron. J., 2008, 136, 580 VLBA Calibrator Densification 7 (VCS7); PI: L. Petrov; VLBA BP171; C/X bands; 17 segments; since 2013.02.08 through 2013.08.01. Reference: \citet{r:wfcs} Paper: L. Petrov, "The wide-field VLBA calibrator survey -- WFCS", 2021, The Astronomical Journal, 898 (1): 51. VLBA Calibrator Densification 8 (VCS8); PI: L. Petrov; VLBA BP177; C/X bands; 10 segments; since 2014.01.07 through 2014.02.23. Reference: \citet{r:wfcs} Paper: L. Petrov, "The wide-field VLBA calibrator survey -- WFCS", 2021, The Astronomical Journal, 898 (1): 51. VLBA Calibrator Densification 9 (VCS9); PI: L. Petrov; VLBA BP192; C/X bands; 99 segments; since 2015.08.07 through 2016.09.07. Reference: \citet{r:wfcs} Paper: L. Petrov, "The wide-field VLBA calibrator survey -- WFCS", 2021, The Astronomical Journal, 898 (1): 51. Study of the population of steep-spectrum compact radio sources, 1st part (VCS10-CX); PI: A. Popkov VLBA BP242, BP245P, BP245Q, BP245R, BP245S, BP245T; C/X bands; 20 segments; since 2019.07.24 through 2020.03.17. Reference: {} Study of the population of steep-spectrum compact radio sources, 2nd part (VCS10-SX); PI: A. Popkov VLBA BP245U, BP245V, BP245W, BP245X, BP245Y, BP245Z; S/X bands; 6 segments; since 2020.03.02 through 2020.03.23. Reference: {} Completion of Surveys for a Gravitational Lens Search to Explore Dark Matter (VCS11); PI: T. Readhead; VLBA BR235; C/X bands; 18 segments; since 2020.09.11 through 2021.02.16. Reference: {} Reaching completness of the VLBI-selected AGN sample North of -40 deg (VCS12) PI: L. Petrov VLBA BP252; C/X bands; 53 segments; since 2021.09.21 through 2022.12.02 Reference: {} Northern Polar Cup Survey (NPCS); PI: Y. Kovalev; VLBA BK130; X band; 3 segments; since 2006.02.14 through 2006.02.23 Reference: \citet{r:npcs} Paper: Popkov, A.V., Kovalev, Y.Y., Petrov, L., Kovalev, Y.A., "Parsec-scale properties of steep and flat spectrum extragalactic radio sources from a VLBA survey of a complete north polar cap sample", (2021), Astronomical Journal, 161(2), 88 (20pp). A systematic search for inspiraling, binary, and recoiling black holes in nearby galaxies (V2M); PI: J. Condon; VLBA BC191, BC196, BC201; X band; 94 segments; since 2010.07.15 through 2012.06.05. Reference: \citet{r:v2m} Paper: Condon, J., Darling, J., Kovalev, Y.~Y., Petrov, L., "VLBA observations of a complete sample of 2MASS galaxies", (2013), NARIT Conference Series, NCS Vol 1 Proceedings of APRIM2011. The VSOP Pre-launch VLBA Observations (VLBApls); PI: H. Hirabayashi; VLBA BH019; C band; 1 segment; 1996.06.05. Reference: \citet{r:vlbapls} Paper: Fomalont, E.B., Frey, S., Paragi, Z., Gurvits, L.I., Scott, W.K., Taylor, A.R., Edwards, P.G., Hirabayashi, H., "The VSOP 5 GHz Continuum Survey: The Prelaunch VLBA Observations", J. Supp. Ser., 131:1, 95--183. BB041; PI: T. Beasley; VLBA BB041; S/X bands; 2 segments; since 1995.06.25 through 1995.02.16. Reference: {} Compactness of Weak Radio Sources at High Frequencies; PI: W. Majid; VLBA BM252; X-band; 2 segments; since 2006.11.06 through 2006.11.13. Reference: \citet{r:majid09} Paper: Majid, W.A., Fomalont, E.B., Bagri, D.S., "Compactness of Weak Radio Sources at High Frequencies", (2009), in 'Approaching Micro-Arcsecond Resolution with VSOP-2: Astrophysics and Technologies', Astronomical Society of the Pacific Conference Series, 402, 448. VLBA Imaging and Polarimetry Survey at 5 GHz, (VIPS); PI: G. Taylor; VLBA BT085; C-band; 16 segments; since 2006.01.03 through 2006.08.12. Reference: \citet{r:vips} \citet{r:astro_vips} Paper: Taylor, G. B., Fassnacht, C. D., Sjouwerman, L. O., Myers, S. T., Ulvestad, J. S., Walker, R. C., Fomalont, E. B., Pearson, T. J., Readhead, A. C. S., Gehrels, N. Michelson, P. F. VLBA Imaging Polarimetry of Active Galactic Nuclei: An Automated Approach, 2005, APJS, 159, 2007 L. Petrov, G. Taylor, Precise absolute astrometry from the VLBA imaging and polarimetry survey at 5 GHz, 2011, Astron. J., 142, 89 Low Luminosity gamma-ray blazars; PI: G. Taylor; VLBA S2078, BT110; C-band; 7 segments; since 2009.11.22 through 2010.07.30. Reference: \citet{r:linford12} Paper: Linford, J.D., Taylor, G.B., Romani, R.W., Helmboldt, J.F., Readhead, A.C.S., Reeves, R., Richards, J.~L., "Contemporaneous VLBA 5 GHz Observations of Large Area Telescope Detected Blazars", Astropys. J., (2012), 744:2, 177. 1FGL Active Galactic Nuclei at parsec scales (1FGL-VLBI); PI: Y. Kovalev; VLBA S3111; X-band; 3 segments; since 2010.12.05 through 2011.01.09. Reference: {} 2FGL Active Galactic Nuclei at Parsec Scales (2FGL-VLBIa); PI: Y. Kovalev; VLBA S4195; X-band; 3 segments; since 2013.05.07 through 2013.06.22. Reference: {} 2FGL AGNs at parsec scales, 2nd survey (2FGL-VLBIb); PI: F. Schinzel; VLBA BS241; X-band; 7 segments; since 2015.02.16 through 2015.07.01. Reference: \citet{r:aofus2} Paper: Schinzel, F.K., Petrov, L., Taylor, G.B., Mahony, E.K., Edwards, P.G., Kovalev, Y.Y., "New Associations of Gamma-Ray Sources from the Fermi Second Source Catalog", (2015), Astrophys. J. Supp. Ser., 217:4, 4. VLBI follow-up of Fermi sources (2FGL-VLBIc); PI: F. Schinzel; VLBA S5272; X-band, 4 segments; since 2013.08.06 through 2013.12.05. Reference: \citet{r:aofus2} Paper: Schinzel, F.K., Petrov, L., Taylor, G.B., Mahony, E.K., Edwards, P.G., Kovalev, Y.Y., "New Associations of Gamma-Ray Sources from the Fermi Second Source Catalog", (2015), Astrophys. J. Supp. Ser., 217:4, 4. 3FGL at parsec scales (3FGL-VLBI); PI: F. Schinzel; VLBA S7104; X-band; 9 segments; since 2016.06.27 through 2016.07.26. Reference: \citet{r:aofus3} Paper: Schinzel, F.K., Petrov, L., Taylor, Edwards, P.G., "Radio Follow-up on All Unassociated Gamma-Ray Sources from the Third Fermi Large Area Telescope Source Catalog", (2017), Astrophys. J. 838, 139. VLBA Survey of unassociated gamma-ray objects in the 7-year Fermi/LAT catalog (VOFUS-1); PI: F. Schinzel; VLBA BS262; C/X bands; 21 segments; since 2018.04.08 through 2018.07.24. Reference: {} VLBA Survey of unassociated gamma-ray objects in the 7-year Fermi/LAT catalog, 2nd survey (VOFUS-2); PI: F. Schinzel; VLBA SB072; C/X bands; 31 segments; since 2018.08.25 through 2019.02.17. Reference: {} The VLBA Galactic Plane Survey (VGaPS); PI: L. Petrov; VLBA BP125; K band; 3 segments; since 2006.02.04 through 2006.10.20. Reference: \citet{r:vgaps} Paper: Petrov, L., Kovalev, Y.Y., Fomalont, E.B., Gordon, D. "The VLBA Galactic Plane Survey --- VGaPS", Astron J, 2011, 142, 35 The EVN Galactic Plane Survey (EGaPS); PI: L. Petrov; EVN EP066; K band; 1 segment; 2009.10.27. Reference: \citet{r:egaps} Paper: Petrov, L., "The EVN Galactic Plane Survey --- EGaPS", MNRAS, 2012, 416, 1097-1105 Asian VLBI Galactic Plane Survey (AGaPS); PI: L. Petrov; EAVN AP001A; K band; 4 segments; since 2018.10.09 through 2019.01.28. Reference: {} VERA Galactic Plane Survey (VEGaPS); PI: L. Petrov; VERA R07030A, R07100A; K band; 2 segments; since 2007.01.30 through 2007.03.21. Reference: {} A search for high-frequency calibrators within 10 degrees of the Galactic center (GC-KVN); PI: L. Petrov; KVN N20LP01; K/Q bands; 14 segments; since 2020.03.05 through 2020.06.16. Reference: {} Searching for candidate radio sources for the GAIA astrometric link (OBRS-1); PI: P. Charlot; EVN+VLBA GC030; 1 segment; 2008.03.07. Reference: \citet{r:obrs1} \citet{r:bourda11} Paper: Petrov, L., The catalogue of positions of optically bright extragalactic radio sources OBRS-1, 2011, Astron. J., 142, 105 Searching for candidate radio sources for the Gaia astrometric link and global VLBI observations of weak sources (OBRS-2); PI: G. Bourda; EVN+VLBA GC034, GB073; 7 segments; since 2010.03.23 through 2012.05.27. Reference: \citet{r:obrs2} \citet{r:bourda11} Paper: Petrov, L., The catalogue of positions of optically bright extragalactic radio sources OBRS-2, 2013, Astron. J., 146, 5 Search for SOuthern Fermi Unassociatied sources (SOFUS); PI: L. Petrov; LBA SOFUS, V592; X-band; 4 segments; 2017.04.07 through 2021.05.08 Reference: {} VLBI Ecliptic band survey with the CVN (VEPS-1); PI: F. Shu CVN VEPS; X band; 18 segments; since 2015.02.13 through 2017.12.14. Reference: \citet{r:veps1} Paper: F. Shu, L. Petrov, W. Jiang, B. Xia, T. Jiang, Y. Cui, K. Takefuji, J. McCallum, J. Lovell, S.-O Yi, L. Hao, W. Yang, H. Zhang, Z. Chen, J. Li, "VLBI ecliptic plane survey VEPS-1", The Astrophysical Journal Supplement Series, 2017, 230:13 (10pp). Bessel Calibrator Search (BeSSel-Cal1); PI: M. Reid; VLBA BR145; X-band; 34 segments; since 2009.11.16 through 2010.08.29. Reference: \citet{r:bessel} Paper: Immer, K., Brunthaler, A., Reid, M. J., Bartkiewicz, A., Choi, Y. K., Menten, K. M., Moscadelli, L., Sanna, A., Wu, Y. W., Xu, Y., Zhang, B., Zheng, X. W., The VLBA Calibrator Search for the BeSSeL Survey, ApJS, vol., 194, 25, 2011 Bessel Calibrator Search follow-on (BeSSel-Cal2); PI: M. Reid; VLBA BR149; X-band; 13 segments; since 2012.08.07 through 2013.08.04. Reference: {} The Bologna Complete Sample of Nearby Radio Sources; PI: G. Giovannini; VLBA BG069, BG094, BG158; 3 segments; since 1997.04.06 through 2000.01.22. Reference: \citet{r:bolsam} Paper: Liuzzo, E., Giovannini, G., Giroletti, M., Taylor, G.B., The Bologna complete sample of nearby radio sources. II. Phase referenced observations of faint nuclear sources", (2009), Astron. & Astrophys., 505:2, 509-520. Densification of the International Celestial Reference Frame; PI: P. Charlot; EVN EC013, EC017; S/X bands; 3 segments; since 2000.05.31 through 2003.10.17 Reference: \citet{r:cha04} Paper: Charlot, P, Fey, A.L., Jacobs, C.S., Ma, C., Sovers, O.J., Baudry, A., "Densification of the International Celestial Reference Frame: Results of EVN Observations", (2004), In European VLBI Network on New Developments in VLBI Science and Technology, 2004, 313--316, astro-ph/0412458. A VLBA Survey of Flat-Spectrum FIRST Sources; PI: J. Ulvestad; VLBA BU007; C band; 1 segment; 1996.12.19 Reference: \citet{r:ulv99} Paper: Ulvestad, J.S., Fomalont, E.B., Kimora, H., A VLBA Survey of Flat-Spectrum FIRST Sources", (1999) American Astronomical Society Meeting Abstracts #194, 50.23. Caltech Jodrell Bank snapshot survey; PI: S. Britzen; VLBA BB119; C band; 3 segments; since 1999.11.21 through 1999.11.26. Reference: \citet{r:bri07} Paper: Britzen, S., Vermeulen, R.C., Taylor, G.B., Campbell, R.M., Pearson, T.J., Readhead, A.C.S., Xu, W., Browne, I.W.A., Henstock, D.R., Wilkinson, P., "A multi-epoch VLBI survey of the kinematics of CJF sources. I. Model-fit parameters and maps", (2007), Astron. & Astrophys., 472:3, 763-771. LBA Calibrator Survey-1 (LCS-1); PI: L. Petrov; LBA V230R, V254, V271AR, V271BR, V271CR; X band; 4 segments; since 2008.02.05 through 2009.12.12 Reference: \citet{r:lcs1} Paper: Petrov, L., Phillips, C., Bertarini, A., Murphy, T., Sadler, E.M, The LBA Calibrator Survey of southern compact extragalactic radio sources --- LCS1, Mon. Not. of Roy. Astron. Soc., 2011, 414(3), 2528-2539 LBA Calibrator Survey--2 (LCS-2); PI: L. Petrov; LBA V271DR, V271ER, V271F, V271G, V271H, V271I, V271J, V271K, V271L, V271M, V271N, V271O, V441, V493; X band; 16 segments; since 2010.03.11 through 2016.06.28. Reference: \citet{r:lcs2} Paper: Petrov, L., de Witt A., Sadler E. M., Phillips, C., Horiuchi S. The Second LBA Calibrator Survey of southern compact extragalactic radio sources -- LCS2, 2019, MNRAS, 485(1), 88-101. VLBA Flux-limited Surveys of VLASS Fields - Pilot Observations (BB409) PI: A. Beasly VLBA BB409; C band; 4 segments; since 2020.05.20 through 2020.07.20 Reference: {} II. Astrometric follow-ups: Regular Geodesy with VLBA (RDV); PI: C. Ma, A. Fey, J. Gipson, D. Gordon; VLBA RDV, RDG, RDW, RDS, RV, CN18, CN19, TC001, BF012, BF090, BP138, BL115, BL122, BL166, BR005, BR025, BW008, BW025, BE010; S/X bands; 205 segments, since 1994.07.08 through 2022.11.28 Reference: \citet{r:rdv} Paper: L. Petrov, D. Gordon, J. Gipson, D. MacMillan, C. Ma, E. Fomalont, R. C. Walker, C. Carabajal, "Precise geodesy with the Very Long Baseline Array", Journal of Geodesy, 2009, vol. 83(9), 859, Investigation of residual systematic errors in dual-band linear combinations of delays caused by the ionosphere PI: L. Petrov; VLBA BP175; C/X-band; 10 segments; since 2013.10.26 through 2013.12.26 Reference: \citet{r:wfcs} Paper: L. Petrov, "The wide-field VLBA calibrator survey -- WFCS", 2021, The Astronomical Journal, 898 (1): 51. S/X Astrometry Program; PI: A. Fey; VLBA BF025; S/X bands; 2 segments; since 1997.01.10 through 1997.01.11. Reference: \citet{r:bf025} Paper: Fey, A.L., Charlot, P., "VLBA Observations of Radio Reference Frame Sources. II. Astrometric Suitability Based on Observed Structure", (1997), Astrophys. J. Supp. Ser., 111:1, 95-142. VLBA Ecliptic Plane Survey (VEPS-V1); PI: F. Shu; VLBA BS250; S/X bands; 4 segments; since 2016.03.22 through 2016.05.19. Reference: \citet{r:veps1} Paper: F. Shu, L. Petrov, W. Jiang, B. Xia, T. Jiang, Y. Cui, K. Takefuji, J. McCallum, J. Lovell, S.-O Yi, L. Hao, W. Yang, H. Zhang, Z. Chen, J. Li, "VLBI ecliptic plane survey VEPS-1", The Astrophysical Journal Supplement Series, 2017, 230:13 (10pp). VLBA Ecliptic Plane Survey 2 (VEPS-2); PI: F. Shu; VLBA BS264; S/X bands; 6 segments; since 2018.03.21 through 2018.06.15. Reference: {} VLBI Ecliptic Plane Survey followup (VEPS-3); PI: L. Petrov; CVN EPA; S/X bands; 2 segments; since 2018.01.24 through 2018.02.10. Reference: {} Probing milliarcsecond optical structure through VLBI observations of Gaia detected AGNs (GAIA-V1); PI: L. Petrov; VLBA BP222, BP236; X/S bands; 38 segments; since 2018.05.15 through 2020.04.19. Reference: {} Revealing milliarcsecond optical structure through VLBI observations of Gaia detected AGNs at Southern Hemisphere (GAIA-L2); PI: L. Petrov; LBA V561; S/X bands; 2 segments; since 2017.06.16 through 2018.03.14. Reference: {} Second epoch VLBA Calibrator survey (VCS-II); PI: D. Gordon; VLBA BG219; S/X bands; 9 segments; since 2014.01.04 through 2015.03.17. Reference: \citet{r:vcs-ii} Paper: Gordon D., C. Jacobs , A. Beasley , A. Peck , R. Gaume , P. Charlot, A. Fey, C. Ma, O. Titov, D. Boboltz, "Second epoch VLBA calibrator survey observations: VCS-II", 2016, Astron. J., 151--154 Third epoch VLBA Calibrator survey (VCS-III); PI: A. Fey; VLBA UF001; S/X bands; 20 segments; since 2017.01.16 through 2017.10.21. Reference: {} Fourth epoch VLBA Calibrator survey (VCS-IV); PI: D. Gordon; VLBA UG002; S/X bands; 24 segments; since 2018.01.18 through 2019.01.21. Reference: {} Fifth epoch VLBA Calibrator survey (VCS-V); PI: D. Gordon; VLBA UG003; S/X bands; 26 segments; since 2019.01.27 through 2020.08.09 Reference: {} SOuthern Astrometry Program (SOAP); PI: L. Petrov; LBA AUA, V561; S/X bands; 24 segments; since 2017.08.22 through 2019.12.04. Reference: {} K- and Q-band VLBI Calibrators near the Galactic Center (GC-VLBA), PI: Y. Pihlstrom; VLBA BP251; K/Q bands; 8 segments; since 2021.03.19 through 2022.05.25. Reference: {} III. High frequency extensions K-band KVN calibrator survey; PI: J. A. Lee; KVN N13JL01, S14TJ05, S14JL01; K-band; 7 segments; since 2013.09.04 through 2014.12.24. Reference: {} K/Q survey (K/Q-Survey); PI: G. Lanyi; VLBA BR079, BL115, BL122, BL151, BL166; X/K/Q bands; 14 segments; since 2002.05.15 through 2011.02.05. Reference: \citet{r:kq_astro} \citet{r:kq_image} Paper: Lanyi, G.~E., Boboltz, D.~A., Charlot, P., Fey, A.~L., Fomalont, E.~B., Geldzahler, B.~J., Gordon, D., Jacobs, C.~S., Ma, C., Naudet, C.~J., Romney, J.~D., Sovers, O.~J., \& Zhang, L.~D., Lanyi,~G.~E., Boboltz,~D.~A., Charlot,~P., et al.\ The Celestial Reference Frame at 24 and 43 GHz. I. Astrometry 2010, Asrtronomical Journal, 139, 1695. Paper: Charlot P., D. A. Boboltz, A. L. Fey, E. B. Fomalont, B. J. Geldzahler, D. Gordon, C. S. Jacobs, G. E. Lanyi, C. Ma, C. J. Naudet, J. D. Romney, O. J. Sovers, L. D. Zhang, The Celestial Reference Frame at 24 and 43 GHz. II. Imaging 2010, Asrtronomical Journal, 139, 1713. Improving the K-band Celestial Reference Frame in the North; PI: A. de Witt; VLBA BJ083; K band; 5 segments; since 2015.07.21 through 2016.06.20 Reference: {} UD001 K-band astrometry; PI: A. de Witt; VLBA UD001; K band; 24 segments; since 2017.01.08 through 2018.07.22 Reference: \citet{r:witt23} Paper: A. de Witt, C. S. Jacobs, D. Gordon, M. Bietenhol, M. Nickola, A. Bertarini, The Celestial Reference Frame at K Band: Imaging. I. The First 28 Epochs, The Astronomical Journal, Volume 165, Number 4, DOI 10.3847/1538-3881/aca012 UD009 K-band astrometry; PI: A. de Witt; VLBA UD001; K band; 35 segments; since 2018.09.09 through 2021.06.12 Reference: \citet{r:witt23} Paper: A. de Witt, C. S. Jacobs, D. Gordon, M. Bietenhol, M. Nickola, A. Bertarini, The Celestial Reference Frame at K Band: Imaging. I. The First 28 Epochs, The Astronomical Journal, Volume 165, Number 4, DOI 10.3847/1538-3881/aca012 UD015 K-band astrometry; PI: A. de Witt; VLBA UD001; K band; 18 segments; since 2021.07.26 through 2023.01.06 Reference: {} Detection of the background position noise due to non-stationary of the Galactic gravitational field (GAJI); PI: L. Petrov; KVN GAJI; K/Q bands; 4 segments; since 2018.09.25 through 2018.12.29. Reference: {} Asian K- and Q-band VLBI Calibrators survey near the Galactic Center PI: L. Petrov; KVN n20lp; K/Q bands; 14 segments; since 2020.03.05 through 2020.06.16 Reference: {}