User's Manual

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MSAN
-
008
K-Band FMCW Transceiver DF Modules
Application Note
V1.0
1
ST Electronic
s (Satcom & Sensor Systems) Pte Ltd
1 Ang Mo Kio Electronics Park Road, #06-02, ST Engineering Hub, Singapore 567710
Tel: [phone] Fax: [phone] Email: [e-mail]
Website: www.agilsense.com ( Regn. No.: 199103901W )
Moving Object
Due to the existence of doppler frequnency in the
if
f and
if
f , the frequency associated to range is given
by:
2



ifif
R
ff
f
Hence, object’s distance is given by:
k
fc
R
R



2
Where
k
T
B

T: frequency sweeping period of sensor
B
: frequency sweeping bandwidth.
From the graph, the doppler frequency
d
f can be obtained by the following:
2



ifif
d
ff
f
The relationship between doppler frequency and velocity is given by:
0
2 f
cf
v
d



Where
v: velocity of the moving object
0
f : frequency of transmitted signal
c: speed of light in freee space, 3*10
8
m/s
Note: based on the phase of two channels’ output, moving direction of object can be identified.