Mobile platform for new astro

SIMPOZIONUL INTERNAŢIONAL «ASTRONOMUL NICOLAE DONICI - 140 DE ANI DE LA NAŞTERE»
8 SEPTEMBRIE 2014, ACADEMIA ROMÂNĂ
MOBILE PLATFORM FOR
NEW ASTRO-GEODETIC
OBSERVATIONS
Octavian BĂDESCU(1), Dan Alin NEDELCU(2), Alexandru CĂLIN(3), Marin PLOPEANU(1), Marcel POPESCU(2), Paul Daniel DUMITRU(1)
(1) Bucharest
Technical University of Civil Engineering (BTUCE), Faculty de Geodesy (FG)
Astronomical Institute of the Romanian Academy (AIRA)
(3) Geogis Proiect s.r.l.
(2)
• Astronomical coordinates (, ) + Geodetic
coordinates (, ) → Astro-Geodetic Vertical
Deviation ()
• Astro-geodetic vertical deviation determination
as independent method for:
ASTRO-GEODETIC
OBSERVATIONS
•
correct the terrestrial geodetic measurements
•
local or regional geoid determination
Ground astrometry with adequate
instruments for precise and accurate
determination of astronomical
latitude, longitude: , .
•
global geoid models validation
Geodetic techniques for precise and
accurate determination of geodetic
latitude and longitude: , .
•
GOCE (ESA, Gravity field and steady-state Ocean
Circulation Explorer)
•
GRACE (NASA, Gravity Recovery & Climate
Experiment)
•
CHAMP (Germany, CHAllenging Minisatellite
Payload)
•
EGM2008 (U.S. National Geospatial-Intelligence
Agency (NGA), Earth Gravitational Model, not
satellite model)
• Methods for vertical deviation determination:
VERTICAL DEVIATION
Angular difference between local vertical
(direction of the gravity vector) and normal to the
ellipsoid, in the same point on the Earth's
topographical surface (Helmert definition, T).
Angular difference between the direction of the
gravity vector (local vertical) and the normal of
the ellipsoid in the one and the same point on the
geoid (Pizetti definition, G)
GEOID-ELLIPSOID
SEPARATION
The distance, along the vertical (or plumb line)
between geoid and ellipsoid (N).
•
Indirect (using N), from terrestrial gravity
measurements (T)
•
Indirect (using N), from GNSS technique combined
with precise geodetic levelling (G)
•
From gravity potential coefficients determined by
satellite measurements (GOCE, GRACE, CHAMP, G)
•
Direct from astro-geodetic observations (T)
• T ≠ G
• Methods for ellipsoid-geoid separation
determination:
•
Direct, from gravity terrestrial measurements
•
Direct, from GNSS technique combined with precise
geodetic levelling
•
From gravity potential coefficients determined by
satellite measurements (GOCE, GRACE, CHAMP)
•
Indirect (using eT from astro-geodetic
determinations)
Vertical deviation
CLASSICAL
DETERMINATION OF
THE VERTICAL
DEVIATION
•
Some stars in certain positions - favorable conditions
•
Ephemerides calculations before observations
•
Angular (astrometric) measurements
•
•
Universal theodolites, passage instruments, astrolabe
•
Heavy, difficult to manipulate, auxiliary devices
Time measurements
•
Mechanical sidereal chronometers or chronograph
•
Less precise methods (“eyes and ears”)
•
Different methods for  and  separate determination
•
Intensive using only of zenithal measurement
(astronomical refraction)
•
Long time observations (inconsistent results, high costs)
•
Trained personnel in the field of astronomy
•
Theoretical aspects (catalogues, reductions: proper
motion, precession, nutation, light aberration, parallax,
refraction)
• Most determinations 1965-1975
ROMANIAN CONTEXT
Over 100 years (1859-1999) of astrogeodetic determination realized by
Topographical Military Directorate &
Military Astronomical Observatory.
•
Official: 146 Laplace points & 118 astrogravimetric points
•
Laplace points: 24 nights, Astro-gravimetric: 15
nights
•
Team: 10 persons (officers and soldiers)
•
Reported precision: 0.30 , 0.45 , 0.50
A (exaggerated optimism…)
• A huge unused number of astro-geodetic
determinations
•
Over 3000 points (in study…)
• Last determinations and tests
•
AIRA: (1998-2000) Astrolabe, CCD (probably one
of the first attempts in the world)
•
BTUCE-FG: (2000-2002, 2012, 2014)
Electronically Total Stations (ETS), Improved
methods and algorithms
Fundamental geodetic point of the
national geodetic network “Dealul
Piscului” (West Meridian Pilaster)
•
Built in 1895
•
First  determination – 1895
•
First  determination – 1900
LEICA
TC 2002
LEICA
TC
2002
Astro-geodetic determination of the
vertical deviation at AIRA (1998-2000) by
using:
DANJON
ASTROLABE
Electronic
chronometer
RUHLA (UTC)
DANJON
Astrolabe
CCD camera
CCD camera
a)
Un-transportable Danjon astrolabe
and CCD observations
b)
Transportable high precision unmotorized geodetic ETS and visual
observations
•
Renaissance of the astro-geodetic determination thanks to
CCD development
•
The latest technical solutions
INTERNATIONAL
CONTEXT
Astro-geodetic determination of the
vertical deviation abandoned with
few exceptions (Germany, Swiss,
Croatia). Until 5-10 years ago …
DIADEM - Digital Astronomical Deflection
Measuring System, Swiss Federal Institute of
Technology, Zurich, Geodesy and Geodynamics
Laboratory
Transportable Zenith Camera TZK2-D, Institut für
Erdmessung, Hannover, Germany
Reported accuracy of vertical deflection measurements: 0".02 to 0".3 for both
components
• The Geoid Slope Validation Survey of 2014 (GSVS14)
commenced in June 2013 when a field crew from the
National Geodetic Survey set approximately 200
official survey benchmarks. Survey observations
commenced in May 2014 and will include leveling,
GPS, gravity, and astrometric observations (DIADEM).
•
AGEO PROJECT
Astro-geodetic
platform for high
accuracy geoid
determination
Coordinating organization:
•
•
•
Partner organizations:
•
P1: Geogis Proiect s.r.l.
•
P2: Astronomical Institute of the Romanian Academy
Short description of the project
•
•
•
Geoid determination and/or validation by astro-geodetic
measurements
Project goal
•
Programme Research-Development-Innovation
for Space Technology and Advanced Research STAR
CO: Technical University of Civil Engineering Bucharest,
Faculty of Geodesy (http://www.utcb.ro/)
Design, perform and test of a mobile platform for astrogeodetic measurement capable to provide real time vertical
deviation at a satisfactory precision and low cost by
astronomical and geodetic measurements. Techniques &
algorithms.
Estimated results
•
Efficiency, precision and accuracy increasing of the astrogeodetic determination → cm level or better accuracy for
geoid determination → method standardization
Mobile platform for astro-geodetic measurement
First solution for image system …
… artisanal, plastic, EO objective, laboratory tests, first daylight image.
Second solution for image system…
… industrial 2D project, bronze, EO objective,
laboratory calibration tests, conclusions.
Third, fourth, fifth solution for image system …
… industrial 3D project, Duramid®, own optics, laboratory and
terrain calibration tests, conclusions.
Time system solution…
… GPS time receiver ±5x10-6 s
projected & realized by AIRA
Test area
All benchmark points for astro-geodetic network realization ( 100
recognized candidates points/1000 km)
Definitive benchmark for astro-geodetic network realization – 25+4/5
special points/night recognized
Algorithms tests
MTD-Military Astronomical Observatory
BTUCE-Faculty of Geodesy
BTUCE Hydro Technical
Laboratories (HTL)
AIRA
First stars images