Improving Ship Detection in Clutter-Edge and Multi-Target Scenarios for High-Frequency Radar

Round 1

Reviewer 1 Report

L37-39: true, but this depends on frequency, bandwidth and operational range. Please specify.

L45-47: CODAR was developed by NOAA, true, but it is now know as SeaSonde and commercialised by a private company. Please update

L57-59: true but not only that. COmpact DF systems strongly rely on the measured antenna beam pattern, which is strongly dependent on the antenna near-field and need to be accounted for. please expand on this and discuss further.

L58-59: quote:...'In addition, echoes 58 from small ships are often masked by those from other large ships.' True BUT: detection threshold depends on the ship cross-section: the lower the HFR frequency the bigger the ships to detect. Cite and discuss the relevant bibliograhy dealing with this (for instance: Emery et al.)

L69:'detection of small targets.' again, it depends by a number of factors, including frequency, integration tmes, cross section,.... Expand and discuss

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

I have read the manuscript by Yang et al. entitled "Improving ship detection in clutter-edge and multi-target scenarios for high-frequency radar." This work is an in-depth assessment of several competing methods for target detection using high frequency (HF) backscatter information. The topic is of interest to a wide range of marine scientist, coastal zone managers, and security professionals. This is because coastal HF radar installations have become common and are continuing to proliferate in support of ocean surface current mapping applications. If those same systems can provide dual-use capabilities for vessel tracking support, then marine domain awareness (MDA) can be increased in many places around the world.

 

The manuscript is well written and documented, although it is very dense with acronyms that become difficult to sort out. As mentioned, the topic is important. For these reasons, I recommend the manuscript for publication with only minor corrections.

 

The authors provide an extensive list of references for the relatively contained field of target detection by coastal HF radar systems. They also provide a detailed description of the several different detection algorithms used commonly plus a detailed derivation of their proposal algorithm. The key to the proposed algorithm as highlighted by the authors and as deduced from my own experience is the use of temporal information or, more specifically, time continuity information. This is done by analyzing the results in a time-frequency (TF) image, which goes a long way toward filtering out random peaks in the backscatter spectra that are not associated with realistic vessel tracks. Highlighting this approach is, on its own, important and worthy of publication.

 

MINOR COMMENTS:

 

Line 13: "missing target" should be "missing targets,"

 

Line 73: "environments, smallest" should be "environments, the smallest"

 

Line 73: "and greatest" should be "and the greatest"

 

Line 74: "target in clutter" should be "target in the clutter"

 

Line 79: "situation." should be "situations."

 

Line 82-83: "are another type of" should be "are other types of"

 

Line 142: "successfully, but" should be "successfully,"

 

Line 170: rewrite to read: "The remaining sections of this paper are organized as follows."

 

Line 171: "in TF domain" should be "in the TF domain"

 

Line 287: Please explain more fully what is "type SD" (I can't find the abbreviation in the manuscript). Is this a phased array or compact antenna system?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.