Fractional time delay estimation algorithm based
on the maximum correntropy criterion and the Lagrange FDF
Yu Ling
a,b
, Qiu Tian-shuang
a,
n
, Luan Shengyang
a
a
Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024, China
b
School of Electronic & Information Engineering, Liaoning University of Technology, Jinzhou 112021, China
article info
Article history:
Received 25 August 2014
Received in revised form
14 December 2014
Accepted 15 December 2014
Available online 24 December 2014
Keywords:
Fractional time delay estimation
Correntropy
Maximum correntropy criterion
Lagrange FDF
abstract
In this paper, a novel algorithm for fractional time delay estimation is proposed. It is based
on the maximum correntropy criterion and the Lagrange fractional delay filter (FDF). The
instantaneous correntropy is introduced to measure the similarity between received
signals and estimated ones in the proposed algorithm. It leads to an effective performance
under both Gaussian and impulsive noises. The performances, including the convergence
of the algorithm and the variance of the tim e delay estimation, are theoretically analyzed.
Simulations demonstrate that the time delay estimation precision of the proposed
algorithm is higher than that utilizing the mixed modulated Lagrange explicit time delay
estimation (MMLETDE) especially under low generalized signal-to-noise ratio (GSNR).
& 2014 Elsevier B.V. All rights reserved.
1. Introduction
Fractional time delay estimation (referred to as FDE), also
known as subsample time delay estimation, is widely
utilized in high precision location (such as the radar [1,2],
the medical auxili ary diagnosti c [3], the satellit e navigation
[4] and the fault location [5]) and the time delay compensa-
tion (such as the digital pre-dis to rtion [6,7],sensorscalibra-
tion [8] and the beam forming [9]).
W ell-known fractional time delay estimation algorithms
include the interpolation algorithm [1 0], the Hilbert transform
based algorith m [11], the e xplicit adaptation of time delay
(ETDE) algorithm [12], etc. The interpolation algorithm inter-
polates some appro ximate values based on a fitting function
between the estimated adjacent integral time delays to
estimate the fractional time delay . Although it has low
calculation complexity, the accuracy of the interpolation
algorithm is not sufficient for high precision applications.
The Hilbert transform based algorithm is fast since it consists
of only one scalar multiplication, but it is only applicable to
the time delay estimation for narrowband signals. As a classic
iterativ e FDE method, the ETDE algorithm r eplaces the FIR
coefficients with a truncated sinc function to obtain an explicit
time delay estimation expression in the iterativ e adaptiv e
process. But the truncated sinc fractional filter has been
prov ed to be a poor fractional delay filter (FDF) due t o its
consider ab le pass-b and ripp le [13]. The mixed modulated
Lagrange ETDE (referred to as MMLETDE) [14] is another
improved FDE algorithm. It replaces the truncated sinc frac-
tional filter of ETDE with the Lagrange FDF and has better FDE
precision. However, both algorithms rely heavily on Gaussian
noise assumption, which could not alway s be satisfied.
In this paper, a novel algorithm for fractional time delay
estimation based on the maximum correntropy criterion
and the Lagrange FDF is proposed, which is referred to as
MCCL. It has better accuracy under both Gaussian and
impulsive noises, especially when the GSNR is low.
2. Mixed modulated Lagrange ETDE algorithm
Suppose the tunable finite impulse response delayer
(TFD) is maximally flat at ω¼ω
0
, where ω is the normal-
ized angular frequency. The coefficients of TFD can be
recognized as the Lagrange interpolation coefficients [15].
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/sigpro
Signal Processing
http://dx.doi.org/10.1016/j.sigpro.2014.12.018
0165-1684/ & 2014 Elsevier B.V. All rights reserved.
n
Corresponding author. Tel.: þ86 411 84709573;
fax: þ86 411 84709573.
E-mail address: qiutsh@dlut.edu.cn (Q. Tian-shuang).
Signal Processing 111 (2015) 222–229