Remote sensing of ground vibration is a key tool in the detection of shallowly buried objects, such as land mines. Millimeter wave systems show promise for replacing laser Doppler vibrometers as the key sensing technology on the grounds of reduced cost and because they provide a larger (10 cm versus 1 mm), more robust sensor footprint. We have developed a double-conversion interferometer operating at 39 GHz that can be built for about $10 000. The system employs quadrature detection in order to provide reliable sensitivity over wavelength-sized changes in target range. Laboratory tests show that it can estimate sinusoidal ground motion from a 1 s time series with an uncertainty of about 5μm.

1.
Dimitri M.
Donskoy
, in
Alternatives for Landmine Detection
, edited by
J.
MacDonald
, Appendix H (
RAND
,
Santa Monica, CA
,
2003
).
2.
M. J.
Sabatier
and
N.
Xiang
,
Proc. SPIE
3710
,
215
(
1999
).
3.
T. Dylan
Mikesell
,
K.
van Wijk
,
J. A.
Scales
, and
J. R.
Peacock
,
Geophys. Res. Lett.
32
,
L01308
(
2005
).
4.
S.
Kim
,
Development of millimeter wave integrated-circuit interferometric sensors for industrial sensing applications
, Ph.D. thesis,
Texas A&M University
,
2004
.
5.
D. J.
Thomson
,
Bell Syst. Tech. J.
I
,
56
(
1977
).
6.
B. D.
Percival
and
A. T.
Walden
,
Spectral Analysis for Physical Applications
(
Cambridge University Press
,
Cambridge, UK
,
1993
).
7.
D.
Slepian
,
Bell Syst. Tech. J.
V
,
57
(
1978
).
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