1. R ESOLVING AND P ARAMETER E STIMATION OF N ON -S YNCHRONOUS S AMPLING P ULSE S IGNALS B ASED ON T AYLOR S ERIES E XPANSION Bo Wu National Mobile Communications Research Laboratory Southeast University, Nanjing 210096, P.R. China Email: Wuboyx@gmail.com

2. I NTRODUCTION Overlapped pulse signals detection in white noise has been widely discussed, the well-known matched filter maximizes signal-to-noise ratio in the presence of Gaussian wideband noise. To reduce the effects of masking nearby targets, Many efforts have been made. In general, there are two kinds of approaches, one widely accepted approach is to adopt different kinds of waveforms, Another type of approach is different estimation strategies.

3. I NTRODUCTION Non-synchronous sampling is shown in this figure.

4. A LGORITHM DESCRIPTION : PE Considering the non-synchronous sampling, the receive signal can be represented as By executing Taylor series expansion, we have

5. A LGORITHM DESCRIPTION The performance of parameter estimation with derivative is acceptable, Better performance is achieved by using higher derivatives but more consumption and calculation is needed. Simplified, we have Expressing the above equation in vector form, we get

6. A LGORITHM DESCRIPTION

8. M ODIFIED CLEAN A LGORITHM FOR D ISCRETE P OINT T ARGETS The proposed algorithm tentatively chooses the strongest target signal and estimates the parameter of the chosen target by the presented parameter estimation method based on Taylor series, then recovers the echo using the tentative estimator and subtracts it from original received signal. Without disturbing from the strongest echo, the output from estimator about rest targets' parameter is more reliable and accurate. Canceling the weaker echoes recovered using the above estimator, the strongest echo's parameter can be accurate.

9. M ODIFIED CLEAN A LGORITHM FOR D ISCRETE P OINT T ARGETS

10. C OMPUTATIONAL C OMPLEXITY ANALYSIS the total consumption can be expressed as follows: Multiplication ： Addition ：

11. S IMULATION R ESULTS This figure shows how our algorithm distinguishes the two adjacent targets. The signal amplitude from the stronger target is a little greater than another target.

12. S IMULATION R ESULTS The effect of different iterations on performance is given in this figure.

13. S IMULATION R ESULTS The performance of the algorithms is been raised as the increasing of time interval. Beyond 1.1 time of symbol length, the simulation's statistics are primarily affected by SNR instead of the targets’ distance.

14. C ONCLUSION Non-synchronous sampling inevitably exists because of the low SNR and persistently sampling time. Most of the exiting algorithms fail to separate the overlapped pulse signals in non- synchronous sampling. We propose a Taylor series based parameter estimation method which combines with the CLEAN. Simulation results demonstrate that our proposed algorithm can succeed in distinguishing two adjacent similar- power targets. Simultaneously, the proposed algorithm is effective in eliminating the sidelobe effect of nearby targets.