Archive for the ‘Radar’ Category

Search status

Friday, February 16th, 2007

Since January 28, the San Francisco police, the Coast Guard and Jim’s friends and family have conducted an extensive search to find him and his sailboat, Tenacious, off the California coast. I want to summarize the status of that search here, so that the broad volunteer community that’s done so much knows where we stand.

The Coast Guard’s air and surface search covered 132,000 square miles in the days immediately following Jim’s disappearance. This search was thorough: Planes, boats and helicopters covered much of the region repeatedly. Radio broadcast alerts were made for a week, and all marinas and harbors were canvassed repeatedly. It found no trace of Tenacious or Jim.

During the Coast Guard search and in the days that followed it, Jim’s friends and family assembled satellite imagery, collected wind and current data and arranged for more air and surface searches over the ocean and coast from Oregon and into Mexico. We have walked stretches of coastline and have postered marinas with details on the missing boat. The story has drawn attention from around the world.

Based on our knowledge of the boat and weather conditions, we do not believe that Tenacious could have outsailed our search, whether it was under power, adrift, sailing under autopilot, or even sailing at best possible speed. We have covered an enormous area.

In the last several days, the Friends of Jim group has reviewed all the data with Coast Guard officials. The fact is that we have no evidence as to what has happened to Tenacious or to Jim Gray. Neither we nor the Coast Guard can come up with a surface search plan that is likely to find either Tenacious or Jim, given everything that has been done already.

Accordingly, the Friends of Jim group is suspending its active effort to find Tenacious that has been centered here at the blog. For both the Coast Guard and the Friends of Jim, “suspension” means that the active search has been discontinued due to exhausting all present leads and the lack of new information. Of course, should we or the Coast Guard receive any new information, we will investigate it.

Understandably, Jim’s family is determined to continue to seek answers, but they deserve to be able to pursue them privately. The family deeply appreciates everything the Coast Guard and Friends of Jim have done.

Jim’s wife Donna asked me to add this statement of thanks from her on behalf of the family:

On behalf of our entire family, I would like to thank every individual and organization who helped, and is continuing to help, in a long and difficult search. As the search takes on a new direction, I want you to know that your faith, hard work and boundless creativity sustain us during this unbearable time.

Jim is very lucky to have you as friends and colleagues, and we are very lucky and grateful to have your support.

Below, in the previous post to the blog, we have posted recent photos of Jim, photos of Tenacious at anchor and under sail, and an email address where you can send any information that could help us with our search. Coast Guard and San Francisco Police contact numbers are also listed.

  • The e-mail address is
  • The Coast Guard contact number is (415) 399-3547.
  • The San Francisco police department contact number is (415) 553-1071.

Thank you, one and all, for this amazing effort to find our Jim.

Contact information and photos

Friday, February 16th, 2007

Anyone with information about Tenacious or Jim Gray should contact:

  • The San Francisco Police Department at (415) 553-1071.
  • The US Coast Guard at (415) 399-3547.
  • Our search email address,

Jim was last seen on January 28, 2007. Here are several photographs of him and of his 40-foot C&C sailboat, Tenacious, sail number 31869.

Jim Gray

Jim Gray



RADARSAT Image Analysis

Sunday, February 11th, 2007

RADARSAT possible target

We have updated with a list of possible targets from the RADARSAT images taken January 31st and February 3rd.  RADARSAT images are 12.5 m per pixel, so the boat should be about 1 pixel. Maybe not the best images, but we thought it was worth a try.

Maria Nieto-Santisteban & Jeff Valenti

Finding good examples for multispectral search

Sunday, February 11th, 2007


In order to test the multispectral search idea, I was wondering if some of you could help out. In order to have the instrument people figure out if there is even a chance of detecting a boat of the size of Tenacious I am wondering if somebody could help in locating some good examples featuring all the conditions listed below:

– Location of a known boat at a known time and GPS coordinates (sailing races that have been featured on GE or Google Maps, Maud Fontenoy recent trip, others….)
– Said location is within the coverage of either Landsat 5/7 or Envisat ( check , <– Internet Explorer only)

– Said Landsat5/7 or Envisat coverage has no cloud on the location of said boat.

As one can see the cloud coverage is pretty important:

Other possible imagery: Multispectral, Hyperspectral, Astronauts acquired

Friday, February 9th, 2007


This is a request for help to the remote sensing community and this is a long shot. I have been talking to some people over the past week about using some lower spatial resolution imagery with higher spectral resolution to see if we could somehow find Jim’s boat. While hyperspectral imagery seems available for a restricted set of conditions (too small of a swath for EO-1), there is multispectral imagery available with resolution between 30 meters to 260 meters.

* 30 meter resolution: In the EROS database of the USGS, there are multispectral views of the scene of interest at about the time that is interesting to our current search. While the resolution is not great (30 m Landsat 7 with ETM+), it seems one can still see boats, I summarized this finding here:

I would be expecting some data fusion process to happen eventually between the current set (ER-2, Radarsat, DG/Ikonos,…) and this new set. The other interesting side of this story would be to increase the search area to the whole coast of California.

However, I am not a remote sensing person, hence I do not have access to EROS imagery nor do I have access to processing capabilities at this time. Can somebody in the audience help ?

* The 260 meter resolution can be found on Envisat, a new european satellite:

and I found nine shots that could help our effort. The resolution is 260 meters but the resolution (S/N) is pretty high.

Again, does anybody know how to get a hold of this imagery for this effort fast, and can somebody process it ?

Finally, there is another possibility for taking a picture over the pacific ocean with a pixel resolution of about 30 meters per pixel: Astronauts Acquired Photographs taken from the International Space Station.

While we can get high resolution shots from Digital Globe, it may be worthwhile to have a much lower resolution but a larger field of view for certain areas especially if there is only one foreign object to detect. I am not quite sure about how to make a request for this type of imagery though.

Some Results from Analysis of ER-2 Data

Monday, February 5th, 2007


here there is a sample of some interesting objects we found in ER-2 data doing semi automatic detection

Candidate_Name       ,Filename    ,Date      ,UTC     , Longitude,Latitude,   X,   Y, Pk, N59438221_121552_35980,59438221.tif,2007-02-02,18:17:34,-121.55193,35.98013,2114,3125, 97, 659438221_121543_35974,59438221.tif,2007-02-02,18:17:34,-121.54253,35.97372,2435,2568, 97, 959438222_121580_35985,59438222.tif,2007-02-02,18:18:04,-121.58027,35.98466,1606,1497,193, 8


Possible candidates from ER-2 

The whole sample in


It would be great if we could collect coordinates in a common way and do cross-matches between images from different data sources or data analysis.


Jeff Valenti and Maria Nieto-Santisteban

RADARSAT-1 imagery news from Melanie Engram.

Friday, February 2nd, 2007

Pasting in an email I just got from Melanie. I should say that Jim’s craft has a radar reflector on the mast, and that algorithmic processing, rather than visual inspection, may well prove useful here.

Melanie writes:

The Canadians have tasked the RADARSAT-1 SAR satellite with two more imaging events: for 3-Feb and 4-Feb., scheduled specifically for Jim’s search. These are the next two orbits that cover the area and the incidence angles are much better for ship detection. The MDA Corporation will make the data available to the same distribution list as last time, at no charge.

2007-Feb-03 02:21; Standard 7 beam mode
Planned in Freeze, OBR (just outside of PASS visibility)
Playback 03-Feb 11:07 UTC – Saturday morning

2007-Feb-04 14:07; Fine 4 beam mode
For planning in Friday Freeze, Realtime Prince Albert

Please let Jim’s family and friends know that the generous response from the Canadians, who own and manage RADARSAT-1, is unprecedented in my experience. I hope it lends some comfort to know that Jim’s search has elicited a large, high-tech response from the international SAR community. When I say “Canadians” I mean: MDA Geospatial Services, the Canadian Space Agency (CSA), and the Canadian Data Processing Facility (CDPF).

Please thank Jim’s wife for her description of Jim’s boat. I also found photos of Jim’s boat on a USCG page, showing reflector, mast, hull, angles that might reflect, etc.:

This is still a small boat and a lot of time has passed, but MDA says the SAR imagery will be available about 15:00-17:00utc Saturday and about 18:00-20:00utc for those who want it (same distribution method as last time).

Thanks to the ASF team in Alaska, and to MDA and the CSA, for the tremendous efforts on this.

Customs radar plane

Thursday, February 1st, 2007

I spoke to the duty officer at Customs Late this morning. They have a Cessna Citation in San Diego with targeting radar and a FLIR. The plane with a crew experienced with finding small boats should be in the air now searching between point Morro and San Diego.

Thanks to Robert Yoha of the California Department of Conservation for the heads up on the availability of this important asset.

MDA contributes radarset to search

Thursday, February 1st, 2007

From Jim Frew:

MDA Geospatial Services has agreed to donate the imagery from today’s RADARSAT pass off northern California to the search, thereby short-circuiting the Coast Guard’s normal channels for obtaining it. Thanks to Joseph Cerna at MDA.

I will pass along the link to the FTP site as soon as I receive it.

Any of us who know anybody who can find boats in radar images, now’s the time to pull them out of your hat.

Attached is an image of some of the ships that were known to be in the area when the image was acquired. Thanks to Melanie Engram of the Alaska SAR Facility.

Thanks to Gary Darling for getting this started.