31 2 Vol. 31, No. 2 2013 5 PROGRESS IN ASTRONOMY May., 2013 doi: 10.3969/j.issn.1000-8349.2013.02.08 VLBI 1,2 1 ( 1. 200030 2. 100049 ) VLBI VLBI VLBI VLBI VLBI VLBI P228.6 A 1 (VLBI) 20 60 (ITRF) (EOP) VLBI VLBI EOP VLBI VLBI [1] VLBI (IVS) VLBI 2012-11-23 2013-01-23 (11178024,10973030)
242 31 VLBI2010 [2] 1 mm EOP VLBI VLBI [3 5] VLBI2010 24 h [6 11] VLBI VLBI 2 2.1 VLBI VLBI VLBI GPS GPS ( ) [12] VLBI 10 m VLBI 65 m [13,14] (reference point) (axis offset) VLBI 25 m (Az El)
2 VLBI 243 VLBI 2.2 VLBI T T [6] [6,7] ( I) [10] ( II) Az El X Y Az El 1 (1) O i jk O (i, j, k) GPS ITRF (2) F ( ) a 3 1 2 ( ) F 12a (3) ( ) a e e S 1 ( ) e 2 f( ) 3 a f = a e S e f 3 1 I x x 0 0 b y z = y 0 z 0 + R 1(β)R 2 (α)r 3 (A + φ)r 2 (γ) f 0 + R 1(E)R 1 (E 0 ) a 0, (1) (1) a b E 0 T S e f 3 e e e f (2) R i, i = 1, 2, 3 1 2 3
244 31 (3) A E O i jk ( ) ( ) (4) f (5) γ a e (6) α β φ F 12a O i jk (7) (x 0, y 0, z 0 ) T F O i jk (8) (x, y, z) T T O i jk (1) (x, y, z) T A E (x 0, y 0, z 0 ) T f α β φ γ T S e f 3 II OT = OF + R a (A)(OS OF) + R a (A)R e (E)ST, (2) (1) OT T O i jk (2) OF F O i jk (3) A E (4) R a (A) R e (E) a e A E r = (l, m, n) T θ ( ) R r (θ) R r (θ) = R 3 ( λ)r 2 (φ π/2)r 3 (θ)r 2 (π/2 φ)r 3 (λ) = 1 0 0 l 2 lm ln cos θ 0 1 0 + (1 cos θ) lm m 2 mn 0 0 1 ln mn n 2 + sin θ 0 n m n 0 l m l 0, (3) (λ, φ) (l, m, n) (5) OS A = 0 E = 0 S O i jk (6) ST T A = 0 E = 0 O i jk S S i jk a e S i jk I S e f 3 (2) OF OS a e ST OS e ST A = 0 E = 0 [10] a = 1, e = 1 ; (4) (OS OF) a = 0, (OS OF) e = 0. (5) a e 1 a e OF f = OS OF a e A = 0 E = 0 cos 1 (a e)
2 VLBI 245 2.3 I II I II (S i jk) T I α β φ γ II a e v = (v 1 v 2 v 3 ) T = R 2 ( γ)e γ = π/2 cos 1 (a e) ; (6) α = tan 1 (v 3 / v 2 1 + v2 2 ) ; (7) u = v a β = tan 1 (u 3 / u 2 1 + u2 2 ) ; (8) w = R 2 ( α)v φ = cos 1 (w 3 / w 2 1 + w2 2 ), w 2 0 φ = cos 1 (w 3 / w 2 1 + w2 2 ), w 2 < 0. (9) (1) F 12a O i jk R 1 (β)r 2 (α)r 3 (A + φ) A α β φ 3 A φ R 3 (A+φ) R 1 (β) R 2 (α) [6] 1 (2) OS = f (a e) + OF, (10) OF OS (2) 25 m F 15 m f [4] X Y 50 m f OF OS ( ) (2) OT = OF + R a (A) f (a e) + R a (A)R e (E)ST, (11) f OF OS
246 31 (4) a e (3) (2) (11) (4) (5) (10) f (a e) a f (a e) e 0 f a e 25 m VLBI 3 VLBI True ( (1) (2) (11)) O(X) True Est C(X) O C = BdEst + v, (12) B Est dest v (12) dest Est + dest 4 VLBI 60 10 82 8 0 360 (A, E) e σ 0 = 5 mm 5% Est = (1 5%)True 1 10 6 50 3.1 (1) (2) (11) Est True χ 2 α β φ (1) 3 (2) ( ) OF OS (4) (5) (11) 5 10
2 VLBI 247 Est True (4) Est True (5) Est True f α β φ γ( ) (1) (11) a e (6) (9) (11) (1) 3.2 (11) 3.2.1 2 10 50 30 320 15 2 3 ( ) 2 2 3
248 31 3 VLBI 3.2.2 σ 0 5 mm 5 mm 50 mm 4 VLBI 4 3.2.3 VLBI
2 VLBI 249 (A, E) C(X) O(X) O C 35 5 80 10% ε = 10 cm O(X) psig(i) psig (2 std) (13) std 8 mm 4 mm 5 (13) 10% 2% 88% 5 5 3.2.4
250 31 35 5 80 ( 6 ) 6 7 3.2.5 15
2 VLBI 251 7 70% 130% 4 VLBI VLBI VLBI2010 VLBI ( ) VLBI [1] Eschelbach C, Haas R. Proceeding for the 16th Working Meeting on European VLBI for Geodesy and Astromomy, 2003, 203: 109 [2] Petrachenko B, Niell A, Behrend D, et al. IVS Annual Report 2008, NASA/TP-2009-214183, 2009: 13 [3] Dawson J, Sarti P, Johnston G, et al. Journal of Geodesy, 2006, 81: 433 [4],,., 2010, 35: 1387 [5],,., 2010, 35: 76 [6] Lösler M. Journal of Applied Geodesy, 2008, 2: 233 [7] Lösler M. Journal of Surveying Engineering, 2009, 135: 131 [8] Neidhardt A, Lösler M, Eschelbach C, et al. IVS 2010 General Meeting Proceedings, NASA/CP-2010-215864, 2010: 133 [9] Schmeing B, Behrend D, Gipson J, et al. IVS 2010 General Meeting Proceedings, NASA/CP-2010-215864, 2010: 138 [10] Kallio U, Poutanen M. IVS 2010 General Meeting Proceedings, NASA/CP-2010-215864, 2010: 360 [11] Lösler M, Hennes M. Proceeding of the FIG2008 Measuring the changes, 2008 [12] Johnston G, Dawson J. Geoscience Australia record, 2004, 19: 27 [13] Sarti P, Sillard P, Vittuari L. J Geodesy, 2004, 78: 210 [14] Sarti P, Abbondanza C, Petrov L, et al. J Geodesy, 2011, 85: 1
252 31 Analysis of the Monitoring Model of VLBI Antenna Reference Point ZHANG Jin-wei 1,2, LI Jin-ling 1 (1. Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China) Abstract: The monitoring of the reference point and axis offset of VLBI antenna with high precision is of importance to modeling the spatial variation of delay observations as the changing of antenna orientation, the improvement of determination precision of astrometric and geodetic parameters such as station and source coordinates and so on. The nowadays ordinary monitoring method of VLBI antenna is mainly based on some special restrictions to the rotation mode of antenna, which would occupy the effective time of operation of the telescope, the efficiency of the monitoring and the precision of determined parameters are limited. By parameterizing the rotation of VLBI antenna and modeling the coordinates of targets fixed on VLBI antenna in the local control network, it is expected to perform automatic monitoring of antenna parameters without any interruption of normal observation operations of the telescope. Some insights and analysis are presented concerning the establishment of monitoring model, the settings of parameters and the selection of constraints to observation equations, which are verified via simulation analysis to be rational and effective. The effects of the number of targets, the number of antenna orientations, the precision of target positioning observations and the selection of target positioning observations on the determination precision of antenna parameters are also analyzed, and some preliminary conclusions are given for reference for readers. Key words: VLBI; reference point; axis offset; monitoring model; simulation analysis