13th International Workshop on Laser RangingWashington DC, USA, 7-11 October 2002

G. BiancoASI/CGS, Matera, Italy

T. OldhamHTSI, Lanham, MD, USA

Status report

Day & night, 1- and 2-color rangingcapability to satellites from 400 km orbit tothe Moon

Single-shot RMS jitter• ≤≤≤≤ 5 mm on LAGEOS (≤≤≤≤ 1 mm NP)

• ≤≤≤≤ 5 mm on Starlette, ERS (≤≤≤≤ 1 mm NP)

• ≤≤≤≤ 15 mm on Etalon, Glonass (≤≤≤≤ 3 mm NP)

• ≤≤≤≤ 15 mm on Moon (≤≤≤≤ 10 mm NP)

MLRO MLRO specificationsspecifications

Astronomical quality telescope, 1” pointingaccuracy, 1.5 m aperture

MLRO performance testMLRO performance test

Performance tested at GGAO during collocation(1998) and at the ASI/CGS (2000)

Full-rate Normal points

Mean(mm) # pass Mean(mm) # NPLAGEOS 4.96 ± 0.51 76 0.30 ± 0.003 2778

Starlette, ERS 4.28 ± 0.51 16 0.41 ± 0.017 75

Etalon, GLONASS 8.72 ± 0.31 51 0.41 ± 0.017 355

Full-rate Normal points

Mean(mm) # pass Mean(mm) # NPLAGEOS 4.96 ± 0.51 76 0.30 ± 0.003 2778

Starlette, ERS 4.28 ± 0.51 16 0.41 ± 0.017 75

Etalon, GLONASS 8.72 ± 0.31 51 0.41 ± 0.017 355

Statistics from GGAO collocation

LAGEOS II LAGEOS II observations from observations from MLROMLRO

-2 -1.5 -1 -0.5 0 0.5 1 1.5 20

100

200

300

400

500

600

700

Residuals (cm)

Num

ber

of o

bser

vatio

ns

Lageos 2 pass on 98/10/15

pass length = 46 min.

number of obs. = 21945

return rate = 80%

rms= 5.08 mm

skewness = 0.17

kurtosis = -0.13

Lageos 2 pass on 98/10/15

pass length = 46 min.

number of obs. = 21945

return rate = 80%

rms= 5.08 mm

skewness = 0.17

kurtosis = -0.13

-20

-15

-10

-5

0

5

10

15

20

7000 7500 8000 8500 9000 9500 10000Time (sec)

MLRO status report

System is producing good quality data

2-color PMT configuration operational

2-color streak camera configurationoperational (several passes tracked)

LLR configuration operational (Moontracked)

System currently undergoing finalacceptance tests

ILRS network performances

LAGEOS II residuals:spectral signature from rotation

(October 15, 1998)

LAGEOS II residuals:spectral signature from rotation

(May 29, 2000)

Observed LAGEOS II down-spinning rate

1998.5 1999 1999.5 2000 2000.5 2001 2001.5 2002 2002.510

15

20

25

30

35

40

45

50

55

60Observed LAGEOS-2 down-spinning rate (exponential fit)

Year

Rot

atio

n P

erio

d (s

)post-fit RMS 88.5 ms

Down-spinning rate: factor of 2 every 1.5 years factor of 10 every 4.9 years Period (s) = 11.1 * e(Year-1998.79)/ 2.1

Shot by shot differential refraction (green-UV)residuals w.r.t. Marini-Murray

AJISAI – dual PMT mode

Streak cameradual pulse(green-UV) fromTOPEX-Poseidon

MLRO lunar observations

MLRO lunar observations

ConclusionsConclusions

Millimeter-level single shot precision

High observational efficiency

Millimeter level signatures detection in the

residuals

Two-color capable (355 & 532 nm)

Moon observed, yet still critical