scholarly journals A fast and accurate chirp rate estimation algorithm based on the fractional Fourier transform

2017 ◽  
Author(s):  
Ahmet Serbes ◽  
Omair Aldimashki
Keyword(s):  
Fourier Transform ◽  
Fractional Fourier Transform ◽  
Estimation Algorithm ◽  
Chirp Rate ◽  
Rate Estimation

scholarly journals Nyquist Zone Index and Chirp Rate Estimation of LFM Signal Intercepted by Nyquist Folding Receiver Based on Random Sample Consensus and Fractional Fourier Transform

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1477 ◽  
Author(s):  
Xinqun Liu ◽  
Tao Li ◽  
Xiaolei Fan ◽  
Zengping Chen
Keyword(s):  
Fourier Transform ◽  
Random Sample ◽  
Fractional Fourier Transform ◽  
Estimation Method ◽  
Ultra Wideband ◽  
Estimation Methods ◽  
Radar Signal ◽  
Chirp Rate ◽  
Time Frequency ◽  
Random Sample Consensus

The Nyquist folding receiver (NYFR) can achieve a high-probability interception of an ultra-wideband (UWB) signal with fewer devices, while the output of the NYFR is converted into a hybrid modulated signal of the local oscillator (LO) and the received signal, which requires the matching parameter estimation methods. The linear frequency modulation (LFM) signal is a typical low probability of intercept (LPI) radar signal. In this paper, an estimation method of both the Nyquist Zone (NZ) index and the chirp rate for the LFM signal intercepted by NYFR was proposed. First, according to the time-frequency characteristics of the LFM signal, the accurate NZ and the rough chirp rate was estimated based on least squares (LS) and random sample consensus (RANSAC). Then, the information of the LO was removed from the hybrid modulated signal by the known NZ, and the precise chirp rate was obtained by using the fractional Fourier transform (FrFT). Moreover, a fast search method of FrFT optimal order was presented, which could obviously reduce the computational complexity. The simulation demonstrated that the proposed method could precisely estimate the parameters of the hybrid modulated output signal of the NYFR.

Comments on discrete chirp-Fourier transform and its application to chirp rate estimation [with reply]

2002 ◽  
Vol 50 (12) ◽  
pp. 3115-3116 ◽  
Author(s):  
Xin Guo ◽  
Hong-Bo Sun ◽  
Sheng-Li Wang ◽  
Guo-Sui Liu
Keyword(s):  
Fourier Transform ◽  
Chirp Rate ◽  
Rate Estimation

scholarly journals High Order Chirp Rate Shift Keying Modulation Using the Fractional Fourier Transform

2017 ◽  
Vol 2 (4) ◽  
pp. 1 ◽  
Author(s):  
Seema Sud
Keyword(s):  
Fourier Transform ◽  
Fractional Fourier Transform ◽  
Wigner Distribution ◽  
High Order ◽  
Modulation Scheme ◽  
Chirp Rate ◽  
Bandwidth Utilization ◽  
Time Frequency ◽  
Rate Shift ◽  
Shift Keying

In this paper, we discuss an improved demodulation scheme using the Fractional Fourier Transform (FrFT) for a modulation scheme employing chirp rate shift keying (CrSK). CrSK in conjunction with the FrFT enable very high order, e.g. more than 32-ary modulation schemes to be achievable with good bit error rate (BER) performance, even in the absence of coding, thereby overcoming limitations of traditional schemes including phase shift keying (PSK) or QAM (quadrature amplitude modulation). By using an FrFT-based demodulator, we expand our demodulation degrees of freedom from a single (e.g. frequency) axis to an entire time-frequency domain, called the Wigner Distribution (WD). We show how the proposed demodulation scheme using the FrFT improves over past approaches by more than 7 dB, enabling us to achieve close to 4-ary performance with a 32-ary modulation scheme. This enables future systems to operate at 5 bits/s/Hz bandwidth efficiency, enhancing bandwidth utilization for future generation, high data rate, applications, such as internet.

Fetal heart rate estimation using fractional Fourier transform and wavelet analysis

2021 ◽  
Author(s):  
Abel Jaba Deva Krupa ◽  
Samiappan Dhanalakshmi ◽  
N.L. Sanjana ◽  
Naveen Manivannan ◽  
R. Kumar ◽  
...  
Keyword(s):  
Heart Rate ◽  
Fourier Transform ◽  
Wavelet Analysis ◽  
Fetal Heart Rate ◽  
Fractional Fourier Transform ◽  
Fetal Heart ◽  
Rate Estimation ◽  
Heart Rate Estimation

scholarly journals Fractional Fourier Transform for Ultrasonic Chirplet Signal Decomposition

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Yufeng Lu ◽  
Alireza Kasaeifard ◽  
Erdal Oruklu ◽  
Jafar Saniie
Keyword(s):  
Experimental Data ◽  
Pattern Recognition ◽  
Fourier Transform ◽  
Parameter Estimation ◽  
Fractional Fourier Transform ◽  
Signal Decomposition ◽  
Chirp Rate ◽  
Rate Parameter ◽  
Ultrasonic Signals ◽  
The Relationship

A fractional fourier transform (FrFT) based chirplet signal decomposition (FrFT-CSD) algorithm is proposed to analyze ultrasonic signals for NDE applications. Particularly, this method is utilized to isolate dominant chirplet echoes for successive steps in signal decomposition and parameter estimation. FrFT rotates the signal with an optimal transform order. The search of optimal transform order is conducted by determining the highest kurtosis value of the signal in the transformed domain. A simulation study reveals the relationship among the kurtosis, the transform order of FrFT, and the chirp rate parameter in the simulated ultrasonic echoes. Benchmark and ultrasonic experimental data are used to evaluate the FrFT-CSD algorithm. Signal processing results show that FrFT-CSD not only reconstructs signal successfully, but also characterizes echoes and estimates echo parameters accurately. This study has a broad range of applications of importance in signal detection, estimation, and pattern recognition.

scholarly journals Ship Velocity Estimation in Airborne Along-Track Interferometric SAR Imagery Based on the Fractional Fourier Transform

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Chao Chen ◽  
Yan Li ◽  
Kuihua Huang ◽  
Yonghong Long ◽  
Linlin Zhang ◽  
...  
Keyword(s):  
Fourier Transform ◽  
Fractional Fourier Transform ◽  
Velocity Estimation ◽  
Moving Target ◽  
Chirp Rate ◽  
Target Imaging ◽  
Moving Target Imaging ◽  
Sar Imagery ◽  
Interferometric Sar ◽  
Along Track

Synthetic aperture radar (SAR) was originally exploited to image stationary scenes. However, it is important to derive target information of velocity for many applications. The fractional Fourier transform (FrFT) is a generalization of the classical Fourier transform and is well-known as a useful tool to estimate the chirp rate of linear frequency-modulated (LFM) signals. Motion compensation is critical to moving target imaging. It is difficult for us to obtain the actual motion parameters in real scenarios. Based on the moving target echo model in airborne along-track interferometric SAR (ATI-SAR) and expression of the ATI phase, a method is proposed to estimate the ship velocity by combining the ATI phase with FrFT. First, we use the FrFT to evaluate the chirp rate of the moving target echo. Then, we construct an equation to estimate the ship velocity using the chirp rate estimation, peak response time, and ATI phase. Finally, the simulation experiments are used to validate the effectiveness of the proposed method.

Performance Analysis of LFM Signal Parameter Estimation through FrFT Transform

2012 ◽  
Vol 195-196 ◽  
pp. 80-83
Author(s):  
Ze Zhong Wang ◽  
Yu Huang ◽  
Feng Liu
Keyword(s):  
Fourier Transform ◽  
Parameter Estimation ◽  
Fractional Fourier Transform ◽  
Frequency Estimation ◽  
Parameters Estimation ◽  
Chirp Rate ◽  
Signal Parameter ◽  
Central Frequency ◽  
Simulation Results ◽  
Radar Signals

The fractional Fourier transform (FrFT) used to process linearly frequency modulated (LFM) signals is applied in the differentiation and parameters estimation of LFM radar signals. The performance of the LFM signals detection and parameters estimation through FrFT are studied when the signal-noise ratio (SNR) is low. The situation is set and the demonstration routine through simulations is made so that the performance on the chirp rate estimation and the central frequency estimation of LFM signals through FrFT is tested, the time used to obtain parameter estimation results through computer simulations is compared. The simulation results demonstrate that the method through FrFT could be used to differentiate LFM radar signals and to estimate parameters of LFM radar signals when the SNR is low.

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