P. Sarti, C. Abbondanza, S. Montaguti, M. Negusini, L. Vittuari

Presentazione sul tema: "P. Sarti, C. Abbondanza, S. Montaguti, M. Negusini, L. Vittuari"— Transcript della presentazione:

1 P. Sarti, C. Abbondanza, S. Montaguti, M. Negusini, L. Vittuari
Tecniche terrestri di rilievo applicate alle antenne VLBI per lo studio delle deformazioni gravitazionali P. Sarti, C. Abbondanza, S. Montaguti, M. Negusini, L. Vittuari

2 Summary Space geodetic instrument reference point:
Definition (conventional, stochastic, electronic) Stability Local ties and eccentricity vectors Investigation on gravitational deformations affecting Medicina’s VLBI telescope: Terrestrial measurements: Topography Laser scanning Finite Element Model An elevation-dependent signal path correction model: Combination of deformations Signal path variation

3 Reference point: conventional definition
Fixed axis Moving axis O Telescope Invariant Point Antenna Reference Point (ARP)

4 Reference point: electronic definition
frequency dependent elevation dependent

5 Reference point: stochastic definition
RP is realized using observations performed by space techniques RP is realized with terrestrial surveying Direct method Indirect method Hybrid method

6 GPS survey approach

7

8

9 j-th horizontal circle j-th horizontal plane j-th “horizontal” sphere

10 i-th “vertical” sphere
i-th vertical circle i-th vertical plane i-th “vertical” sphere

11 Medicina: visione globale
della rete locale N 20m

12 Medicina: posizione degli strumenti geodetici spaziali GPS VLBI

13 Medicina: dettaglio dei segnali rilevati sul radiotelescopio

14

15

16 P1 (mm) P3 G7 GPS ARP VLBI IP X -1.87 3.17 -1.51 2.08 Y 1.57 -2.85 0.01 -0.81 2.09 Z 0.57 -2.38 -0.53 2.48 -0.13 mod 2.51 4.16 3.22 3.01 2.95 -6.32 6.45 -3.51 9.69 4.73 -0.32 0.68 -4.32 -0.77 0.89 -3.14 0.84 1.83 -0.42 7.94 7.06 6.54 5.86 9.73

17 (U IPE -U IPF)  1 cm U IPF=17.6933±0.0007 (m)
U IP0= ± (m) U IPF= ± (m) U IPE= ± (m) (U IPE -U IPF)  1 cm

18 Focal length Receiver Vertex e Df O

19 Clark and Thomsen 1988

20 Elevation 90 deg

21 Elevation 75 deg

22 Elevation 60 deg

23 Elevation 45 deg

24 Elevation 30 deg

25 Elevation 15 deg

26 g

27 g

28 g

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31 Displacement of the receiver
g

32 Displacement of the receiver
g

33 Displacement of the receiver
g

34 Displacement of the receiver
g

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44 g

45 Displacement of the vertex
g

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