Operation of the Astronomical Radio Interferometric Earth Surveying (ARIES) in a proof of concept mode is discussed. Accuracy demonstrations over a short baseline, a 180 km baseline, and a 380 km baseline are documented. Use of ARIES in the Sea Slope Experiment of the National Geodetic Survey to study the apparent differences between oceanographic and geodetic leveling determinations of the sea surface along the Pacific Coast is described. Intergration of the NAVSTAR Global Positioning System and a concept called SERIES (Satellite Emission Radio Interferometric Earth Surveying) is briefly reviewed

Claflin, E. S.

Lockhart, T. G.

Macdoran, P. F.

Morabito, D. D.

Niell, A. E.

Ong, K. M.

Resch, G. M.

English

NASA Technical Reports Server

Mobile Radio Interferometric Geodetic Systems N79 21468
P. F. MacDoran, A. E. Niell, K. M. Ong, G. M. Resch, D.D. Morabito, E. S. Claflin, T. G.
Lockhart
Jet Propulsion Laboratory, California Institute of Technology
Pasadena, California 91103
SUMMARY
The mobile VLBI geodetic system called
ARIES for Astronomical Radio Interfero-
metric Earth Surveying is currently
operating in a proof of concept mode that
is adapted to also acquire geophysically
significant data. These geophysical
data are acquired by careful choice of
the transportable antenna's location
using the advice and counsel of the
Caltech Selsmological Laboratory.
Figure I shows the fixed base stations
at Goldstone and Owens Valley and por-
table antenna sites in southern California.
Initially, the ARIES 9m stations began
S-band (2.3 GHz) experiments on a 307 m
baseline near the Goldstone 64m MARS
station (DSS 14) and demonstrated a 3 cm
accuracy relative to a direct line of
sight geodetic survey (Ong, et al 1976).
That first experiment sequence demon-
strated absolute three-dimensional
accuracy (within 3 cm) in a limited
case; that is, if the technique could
not achieve the absolutely correct
vector on 307 m, it certainly would
fail on longer baselines where the
initial goal was 10 cm. Such success
was, of course, only a necessary
condition since over such a short
baseline the factors of troposphere
and ionosphere were self-cancelling
and the system was insensitive to radio
source positional uncertainties, uni-
versal time and polar motion effects.
The next step was to operate on a
longer baseline so the parameters that
were previously self-cancelling or of
low sensitivity could now be sensed,
and the ability to calibrate for their effects
could be demonstrated.
In August 1974, the ARIES station was moved
to JPL in Pasadena, a location logistically
favorable, accessible .to conventional geodetic
systems to check on claimed results and close
to the San Gabriel fault.
The measurement accuracy for the 180 km
JPL/Goldstone (DSS 14) baseline was estimated
in June 1975 at approximately 8 cm. ARIES
then made its measurements available to the
National Geodetic Survey in advance of NGS
geodetic connection of JPL to the TCT, Trans
Continental Transverse, the most accurate
large scale horizontal control network in
the U.S. The results of the comparison of
the ARIES derived baseline length with that
of the NGS agreed within 13 cm, in good
agreement with the 8 cm accuracy estimates
of both techniques.
Prix-, of the 9lh GEOP Conference. An Inifrtittfitnitil Symposium tin ihv AppHi-tuion* of
(1'iWr.trfiifiViK/vniiiiHr.v. Orntherl-5.1978. Dept. of Geodetic Science Kept. No. 280. The
Ohio Suie Univ.. Columbus. Ohio 43210.
While the ARIES accuracy results on 180 km
were gratifying, the conventional geodesy
accuracy estimates of 8 cm may have been
overstated and a more conclusive test situa-
tion was desired. What was needed was as
long a distance as could be found (hopefully
also of geophysical interest) which a laser
distance measuring device could make in a
single direct line of sight. Such a pair
of locations was found, Malibu (MAL), on the
Santa Monica/Malibu fault and Palos Verdes
(PV) Peninsula near the Inglewood/Newport
fault. Both the MAL and PV sites are
abandoned NIKE air defense bases with roads
and their perimeter fences still intact.
By observing on approximately 380 km base-
lines from ARIES 9m station to the 40m
telescope of the Caltech Owens Valley
Radio Observatory (OVRO), the three dimen-
sional position of PV and MAL was derived
relative to the OVRO telescope. By
differencing the components of the posi-
tions of the two sites, the vector was
obtained from Malibu to Palos Verdes, a
42 km path across Santa Monica Bay in
southern California, with an estimated
accuracy of better than 10 cm. In May
1977, the Santa Monica Bay experiment
results were again provided in the blind
to the National Geodetic Survey which then
directly measured both the intersite
distance and azimuth by conventional first-
order horizontal geodetic control methods.
The two techniques differ by 6 + 10 cm in
baseline length and 0.5 + 1.2 arc sec in
azimuth (corresponding to 10 + 20 cm).
The details of the Santa Monica Bay experi-
ments are contained in (Niell, et al, 1979).
The ARIES Santa Monica Bay accuracy
demonstrations were a prerequisite to the
Sea Slope Experiment of the NGS to study
the apparent differences between oceano-
graphic and geodetic leveling determina-
tions of the sea surface along the Pacific
Coast. With joint NGS and NASA OSTA support,
ARIES developed the relative geometric
positions of tide gages at La Jolla and San
Francisco, California where a 65 cm sea slope
to the south was indicated by geodetic
leveling. ARIES acquired data at San
Francisco (SF) in June 1977 and La Jolla (LJ)
in July 1977 spanning a total of 42 days.
Using the 40m telescope at OVRO as the primary
base station, 6 cm or better, three dimen-
sional accuracies were obtained over these
380 to 500 km baselines. A secondary base
station, the 26m Venus antenna at Goldstone,
also participated. Based upon a triangle
baseline vector closure criterion, individual
baseline determinations indicated 6 cm
accuracy with a one part in 10' closure.
Simultaneous S-band (2.3 GHz) and X-band
https://ntrs.nasa.gov/search.jsp?R=19790013297 2020-03-22T00:01:20+00:00Z
(8.4 GHz) observations at SF to OVRO pro-
cessed as separate experiments yielded
identical baseline vector results within
the 2 to 5 cm uncertainty estimates imposed
by signal to noise limits. The San
Francisco/La Jolla experiments also utilized
dual channel water vapor radiometers at
all stations and played an essential role
in calibrations of local vertical relative
positioning. Hydrogen maser frequency
references were made available by the
Goddard Space Flight Center for use at
all stations. The final combination of
ARIES geometric tide gage positional data
with the geoid between La Jolla and San
Francisco remains an analysis task for
the NGS in order to directly compare
with spirit leveling observations, to resolve
the sea slope controversy.
Five measurement sessions have now been
conducted between the JPL Pasadena site and
Goldstone since August 1974 for a total of
eight measurements to Goldstone and five to
OVRO. The precision in the east-west coordi-
nate appears to be approximately 3 cm when
measurements are taken closely in time as in
the Sea Slope experiment previously discussed.
For the JPL/Goldstone baseline, a 12-15 cm
westward movement of JPL site relative to
Goldstone has occurred with most of the
displacement taking place in the last half
of 1975. For 1976 to 1978 relative stability
is indicated using both OVRO and Goldstone
base stations. For all baselines, no vertical
displacements appear significant in the
presence of the 6 to 10 cm system noise
imposed mainly because water vapor radiometer
tropospheric calibrations are not yet consis-
tently available.
A 4m high mobility ARIES station has now
begun initial field demonstrations. Early
experiment results indicate an inadequate
signal to noise margin which limited the
quasar catalog resulting in a biased solution.
Telecommunications upgrades to the 4m antenna
are dual Mark II recording (8 Mb/sec) and a
traveling wave maser first stage receiver
amplifier. With these improvements, the 4m
station will probably out perform the 9m
station while providing a two site per week
site measurement yield compared to the one
site per month yield of the 9m system. At
present the 4m antenna is undergoing side-
by-side tests with the 9m antenna at the JPL
site. Following successful side-by-side
tests, the 4m station will demonstrate its
high mobility and accuracy by repeating
the Malibu/Palos Verdes experiment but this
time to acquire the data at both sites in
one week.
The satellites of the NAVSTAR Global
Positioning System (GPS) offer an important
new geodetic resource making possible a
highly accurate portable radio geodetic
system. A concept called SERIES (Satellite
Emission Radio Interferometric Earth
Surveying) makes use of GPS radio trans-
missions without any satellite modifica-
tions. By employing the technique of
VLBI and its calibration methods, 0.5
to 4 cm three dimensional baseline
accuracy can be achieved over distances
of 3 to 300 km respectively, with only
2 hours of on-site data acquisition.
The use of quasar referenced ARIES Mobile
VLBI to establish a sparse fundamental
control grid will provide a basis for
making SERIES GPS measurements traceable
to the time-invariant quasar directions.
Using four SERIES stations deployed at
previously established ARIES sites, will
allow the GPS satellite apparent posi-
tions to be determined. These apparent
positions then serve as calibrations
for other SERIES stations at unknown
locations to determine their positions
in a manner traceable to the quasars.
Because this proposed radio inter-
ferometric configuration accomplishes
its signal detection by cross-correla-
tion, there is no dependence upon
knowledge of the GPS transmitted wave-
form which might be encrypted. Since
GPS radio signal strengths are 10^
stronger than quasar signals, a great
reduction in telecommunications so-
phistication is possible which will
result in an order of magnitude less
cost for a SERIES GPS station-compared
to a quasar based mobile VLBI system.
The virtually all-weather capability
of SERIES offers cost-effective geodetic
monitoring at less than $1,000 per site.
Details of the SERIES-GPS system will
be published in the Bulletin Geodesique
in early 1979.
REFERENCES
1. Ong, K. M., P. F. MacDoran, J. B. Thomas,
H. F. Fliegel, L. J. Skjerve, D. J.
Spitzmesser, P. D. Batelaan, S. R. Paine,
M. G. Newsted, A Demonstration of a
Transportable Radio Interferometric
Surveying System with 3-cm Accuracy on a
307 m Baseline, Journal of Geophysical
Research, Vol. 81, No. 20, July 10, 1976.
2. Niell, A. E., K. M. Ong, P. F. MacDoran,
G. M. Resch, D. W. Fite, L. J. Skjerve,
D. J. Spitzmesser, D. D. Morabito, L.
Tanida, E. S. Claflin, B. B. Johnson,
M. G. Newsted, A. Banisch and J. F.
Dracup, Comparison of a Radio Inter-
ferometric Differential Baseline
Measurement with Conventional Geodesy,
Tectonophyslcs, 52 (1979), 532.
This paper presents the results of
one phase of research carried out at the
Jet Propulsion Laboratory, California
Institute of Technology, under contract
No. MAS 7-100, sponsored by the National
Aeronautics and Space Administration,
Office of Space and Terrestrial Applica-
tions .
PROJECT ARIES NETWORK
ARIES NETWORK ARIES/CONVENTIONAL GEODESY INTERCOMPARISON
DBASE STATIONS
CARIES SITES
PACIFIC
OCEAN
OWENS
VALLEY
GOLDSTONE a
PEARBLOSSOM
A
MALIBU
 AJPL
>
PALOS VERDES^
LAJOLLA)
ARIES IIUVRO-PVI - IOVRO-MAL) I • 41 573.102 t 0.086 B
NGS- IPV-MAL) • 41 573.844 * 0.06M
ARIES • NGS • 0.058 • 0.105 * AND AGREEMENT WITHIN 0.5 ARC SEC RELATIVE
TO GEODETIC NETWORK LOCATIONS IMPLYING - 6 CM THREE
DIMENSIONAL ACCURACY IS BEING ACHIEVED BY ARIES
ON - 400 KM BASELINES.
•RESULTS AS OF 9/16/77 FROM J. DRACUP, CHIEF
HORIZONTAL CONTROL BRANCH
NATIONAL GEODETIC SURVEY
ARIES GEODETIC SYSTEM
EXTRAGAUCTIC
RANDOM RADIO
SIGNALS
ARIES SEA SLOPE I NETWORK
DIFFERENCE IN
TIME OF ARRIVAL
OWENS
VALLEY
DEDUCED
VECTOR
PACIFIC
OCEAN
•f\ * ' .
v
 ' GOLDSTONI
\
PEARBLOSSOM
v A
'MALIBU A
, JPL
PALOS VERGES *'
100 Km
LA JOLLA
50
ARIES SEA SIOPE I RESUITS
OVRO. PRIME BASE STATION
X. m
OVRO-SF
IJ.OVRO
V. m 2. m
298 106.79 t 0.03 -220 735.63 t O.M -tl 774.66 t 0.05
-»> W>. 77 ± 0.03 -289 057.63 < 0.(M -397 130.42 ' 0.06
I SSF-IJ
-252257.0210.05 509 823. 26 1 0. 06 446 TO. 08 10.08
L E N G T H SF-U • 723 379.23 l 0.03 m
GOLDSTONE (OSS 131 SECONDARY BASE STATION
Sf-U -252257.12*0.04 5W 823.07* 0.05
LENGTH • 723379.19* 0.05m
446 905.17 ' «.<H
— —
ISF-U) - ISF-U>.
m
/10cm \
>., • ( 9 )
" V-9 /geocentric local
OVRO/ARIES (SAN FRANCISCO) BASELINE VEOOR
RELATIVE LOCAL COORDINATES AT S.F..-OVRO ASSUMED FIXED
SOUTH
(cm)
EAST
Icml
VERTICAL
(cm)
LENGTH
1374 25846.31 0
(cm)
10
0
-10
10
0
-10
10
0
-10
10
-10
1977
06106 06108 06/10
S
i i i
I 1 '
' ' ' * fL
- f ' I
" [ "'~ "'
; t ' L
- J .f *
i i i
06/10
X
1
I ;
*
I ;
~ i
RMS
Icml
3.4
2.1
5.2
.1.9
GOIDSTONE (DSS-)4)/ARIES (JPL) BASELINE VEOOR
RELATIVE LOCAL COORDINATES AT JPL; DSS-14 ASSUMED FIXED
SOUTH
(cm)
EAST
(cm)
VERTICAL
(cm)
LENGTH
(179 28570.0)
(cm)
20
10
0
-10
-20
10
0
-10
20
10
0
-10
10
0
-10
: i
T
" [
-
- I
A
1974
I
I I
f I
 ?
l l I
I
; t
Ij M A
1975
j
t
. f
{
1
I j
I
I
I
I
1
A 1
1976
l-_
-
-
J _
I:
i:
-
RMS
Icml
4.9
6.6
4.8
Ti
A
1977
51


Mobile radio interferometric geodetic systems

Mobile radio interferometric geodetic systems

Abstract

Similar works

Full text

Available Versions

NASA Technical Reports Server