Digital Signal Processing Reference
In-Depth Information
The emulation also considered different amplitude ratio, SNR, and the signal
frequency of the frequency estimation .Among them,200s f = MHz, N = 128,50 times
independent test results as shown in Table 2.
3
Angle Measurement
If signal spatial spectrum can be got, signal Direction-of-Arrival (DOA) can be also
got. Therefore, spatial spectrum estimation technology has differentiation capability
of spatial signal, it can break through and more improve differentiation capability of
signal coming from different direction within a beam forming width. Linear array and
circular array are the two commonest types in adaptive antenna arrays. Based on the
linear array this thesis has analyzed application area and performance of several
spatial spectrum estimation algorithms. Simulation and analysis have been performed
on these algorithms application in linear array .In this thesis The applications of the
classical MUSIC algorithm, the extract MUSIC algorithm, based on beam forming
space MUSIC algorithm and based on concerned dispel MUSIC algorithm in linear
array have been separately discussed
。
it can be concluded the MUSIC algorithm has
more better differentiation capability, estimation precision and stability
[5]
.
3.1
Angle Measurement Algorithm
MUSIC algorithm has good performance under ideal conditions became so bad, but
the performance of the algorithm in the coherence of the source. This is because when
the signal source is coherent, the rank of the data covariance matrix of the array
receiver is reduced to 1, and obviously this will lead to the signal subspace dimension
is less than the number of signal sources. That signal subspace "proliferation" to the
noise subspace, which will lead to some coherent source boot vector and noise sub-
space is not completely orthogonal, thus unable to accurately estimate the direction of
the signal source.
Correctly estimated the core issue of the direction of the signal in the case of
coherent signal source is to be effectively restored the rank of the signal covariance
matrix through a series of processing or transformation, to correctly estimate the
direction of the signal source.
The spatial smoothing algorithm principle for the case of a narrowband uniform
linear array, the L array element data is
N
xt a st nt
()
=
( ) ()
θ
+
()
l
=
1, 2
,
M
(3)
1
1
i
i
1
i
=
1
e
ωτ
−
j
=−
M is the number of array
elements, N is the number of sources. Wherein, d is the spacing of the uniform linear
array, c is the velocity of signal propagation.In addition, for the uniform linear array
a
()
θ
=
τ
( ) n
l d c
θ
In formula(3),
0
li
l
i
li
i
β
=
2
π
d
λ
sin
θ
i
=
1, 2,
,
N
.
i
i
