WEBVTT 00:26.190 --> 00:28.790 Hi , I'm Shawna , the command historian , 00:29.190 --> 00:30.899 and this year marks the 80th 00:30.899 --> 00:33.669 anniversary of the Navy lab , and we 00:33.669 --> 00:35.909 are hosting several events to mark this 00:35.909 --> 00:38.380 special occasion . Today we are here 00:38.380 --> 00:40.950 with Doctor Dan Sternlich , and we're 00:40.950 --> 00:43.117 going to talk about the 2nd revolution 00:43.117 --> 00:46.830 in seabed imaging sonar . Doctor 00:46.830 --> 00:48.886 Sternlich , oh , great , thank you , 00:48.886 --> 00:51.310 Shawna . Um , it was 3 years ago , 00:51.520 --> 00:53.576 wasn't it , that the , the two of us 00:53.639 --> 00:56.020 rolled out the first part of this story , 00:56.400 --> 00:59.159 the first revolution in , in seabed 00:59.159 --> 01:01.849 imaging , uh , where we discussed how 01:02.090 --> 01:05.959 NSWC Panama City invented the side scan 01:05.959 --> 01:08.199 sonar . Well , this , as you said , 01:08.279 --> 01:10.279 this is , this is the second half , 01:10.440 --> 01:12.662 right ? This is the second part of that 01:12.662 --> 01:14.800 story , uh , the , what we call the 01:14.800 --> 01:17.480 second revolution of seabed imaging . 01:17.860 --> 01:21.099 Uh , Panama City's development of the 01:21.300 --> 01:23.900 synthetic aperture sonar , or what we 01:23.900 --> 01:27.260 call SAS for short . But let's first 01:27.260 --> 01:30.059 stop , let's talk about why , why we're 01:30.059 --> 01:32.769 interested in seabed mapping sonars . 01:33.230 --> 01:36.470 Uh , there are many applications . Uh , 01:36.629 --> 01:39.930 there's geology , there is underwater 01:39.930 --> 01:42.510 construction , there's mapping for the 01:42.510 --> 01:45.290 oil and gas industry . Uh , there are 01:45.290 --> 01:48.230 the fisheries sciences . Uh , the , the 01:48.230 --> 01:51.995 geology of the oceans are , are so . So 01:51.995 --> 01:54.051 interesting , actually , the longest 01:54.051 --> 01:56.384 mountain chain in the world is undersea . 01:56.384 --> 01:59.275 It's called the mid-oceanic ridge , and 01:59.275 --> 02:01.834 it stretches for , you know , 40,000 02:01.834 --> 02:03.778 miles . You know , that's , that's 02:03.778 --> 02:06.074 twice the circumference of the Earth . 02:06.345 --> 02:08.623 And we can see this on your image here . 02:08.623 --> 02:11.110 Yes , yes , indeed . And , uh , 02:11.369 --> 02:15.089 undersea cables , crisscross the , uh , 02:15.100 --> 02:17.433 the world . Um , there's basically , uh , 02:17.433 --> 02:21.339 over 500,000 miles of undersea cables . 02:21.699 --> 02:23.910 And these all have to be surveyed in , 02:24.039 --> 02:26.470 and they all have to be maintained . I 02:26.470 --> 02:28.526 mean , 500,000 miles , that's , um , 02:28.669 --> 02:30.649 that's over 20 times . The 02:30.649 --> 02:34.490 circumference of the Earth . Yes , yes . 02:34.889 --> 02:38.229 So , so we need this technology to , 02:38.630 --> 02:42.009 uh , to image and to , and to 02:42.009 --> 02:45.169 understand this 70% of the earth's 02:45.169 --> 02:48.229 surface , which lies beneath our oceans 02:48.570 --> 02:51.149 and beneath our lakes . And this , of 02:51.149 --> 02:53.550 course , led to the , uh , really the 02:53.550 --> 02:57.110 groundbreaking uh invention of the side 02:57.110 --> 03:00.850 scan sonar in the 1950s . Uh , this was , 03:00.949 --> 03:03.770 of course , at , at NSWC Panama City . 03:04.070 --> 03:07.679 Uh , the technology was developed by 03:07.990 --> 03:11.770 Julius Hagemann . And that system , uh , 03:11.800 --> 03:14.250 which was officially designated the 03:14.250 --> 03:17.490 CMAC One , but more informally called 03:17.490 --> 03:20.289 the shadow graph , uh , by , uh , by 03:20.289 --> 03:23.880 most people , uh , would go on to , 03:23.889 --> 03:27.669 um , to transition . Into , um , 03:27.750 --> 03:30.080 um , you know , most of the , uh , NATO 03:30.389 --> 03:33.470 and US uh sonar systems that are used 03:33.470 --> 03:36.710 for airborne surface and EOD mine 03:36.710 --> 03:38.877 countermeasures . It's quite something 03:38.877 --> 03:40.988 like that started here . It's amazing 03:40.988 --> 03:43.449 and to think that , uh , this 03:44.190 --> 03:46.412 technology , which , which was designed 03:46.550 --> 03:49.289 to respond to a capability gap for 03:49.300 --> 03:51.356 finding small man-made objects , for 03:51.356 --> 03:54.205 finding mines . But then have such an 03:54.205 --> 03:56.372 influence throughout the world to , to 03:56.372 --> 03:59.785 help us map and understand that that 03:59.794 --> 04:02.115 that 2/3 of the earth's surface , you 04:02.115 --> 04:04.226 know , that we knew very little about 04:04.226 --> 04:06.595 before . OK . So , so , I mean , you 04:06.595 --> 04:08.317 can see some of the , uh , the 04:08.317 --> 04:10.395 outstanding imagery that we get with 04:10.395 --> 04:12.562 these , these types of systems , which 04:12.562 --> 04:15.035 are all synthetic aperture sonar now in 04:15.035 --> 04:17.114 our fleet that you see on the right 04:17.114 --> 04:19.959 here . So let's talk a little bit about 04:19.959 --> 04:22.160 the , uh , the shadow graph system 04:22.160 --> 04:24.720 itself . Uh , it was an incredible 04:24.720 --> 04:27.220 system . Um , these are some of , uh , 04:27.230 --> 04:29.399 the example images , uh , from that 04:29.399 --> 04:31.760 sonar system . And you can really 04:31.760 --> 04:34.279 discern what kind of sea floor you're 04:34.279 --> 04:36.609 looking at . And even though this , 04:36.720 --> 04:39.459 these were created around the 1960s , 04:39.799 --> 04:42.279 uh , Examples from , you know , 04:42.440 --> 04:45.339 universities and , and , and industry 04:45.519 --> 04:47.630 would not really equal this type of 04:47.630 --> 04:50.709 resolution . Yes , yes , it would be 04:50.709 --> 04:53.320 decades before , um , other systems 04:53.320 --> 04:55.760 would actually produce , uh , this 04:55.760 --> 04:58.920 quality of imagery . And uh that's 04:58.920 --> 05:00.809 because Julius had a uh kind of a 05:00.809 --> 05:03.299 secret sauce . And that was he used 05:03.839 --> 05:06.540 extremely high frequencies . He used um 05:06.959 --> 05:09.440 megahertz of acoustic frequencies . 05:09.790 --> 05:11.457 Those are the , those are the 05:11.457 --> 05:13.234 frequencies that we use like in 05:13.234 --> 05:15.401 ultrasound , right ? Think of the high 05:15.401 --> 05:17.457 resolution image . As you get , uh , 05:17.457 --> 05:20.019 from an ultrasound image . And most 05:20.119 --> 05:22.239 commercial and academic systems , you 05:22.239 --> 05:24.820 know , use tens or hundreds of 05:24.820 --> 05:26.987 kilohertz , you know , up , you know , 05:27.040 --> 05:29.839 for many decades after that . So people 05:29.839 --> 05:32.589 are always astounded at the , um , the 05:32.589 --> 05:35.600 clarity of these images that you got 05:35.600 --> 05:37.890 from the system . Um , and of course , 05:37.929 --> 05:39.929 these were all done on paper at the 05:39.929 --> 05:41.762 time . We did not have the , the 05:41.762 --> 05:43.929 digital storage techniques that we had 05:43.929 --> 05:46.151 back then . So typically a person would 05:46.151 --> 05:48.529 sit at a console that you see on the 05:48.529 --> 05:51.959 right side of this image and , um , and 05:51.959 --> 05:54.070 take a look at the scrolling image as 05:54.070 --> 05:56.429 you , uh , traversed over the sea floor . 05:57.859 --> 06:00.026 So let's , let's pull up and , and put 06:00.026 --> 06:02.137 this all in a little bit of context . 06:02.137 --> 06:04.519 Uh , at around the end of World War II , 06:04.739 --> 06:07.200 uh , the US Navy and , and our allies 06:07.420 --> 06:09.959 had developed some kind of rudimentary , 06:10.339 --> 06:14.260 uh , mine detection sonar systems . Uh , 06:14.440 --> 06:16.384 at the end of World War II , right 06:16.384 --> 06:18.820 actually right about 1950 , it was , uh , 06:18.829 --> 06:21.519 Julius Hagemann and his team . They 06:21.519 --> 06:23.980 were assigned to the task of reviewing 06:24.359 --> 06:27.480 all of the existing technologies , US 06:27.480 --> 06:30.399 technologies , allies , even , even our 06:30.399 --> 06:33.359 former adversaries , and determining , 06:33.559 --> 06:35.726 uh , what . Kind of sonar we would put 06:35.726 --> 06:39.279 on our new class of minesweepers . And 06:39.279 --> 06:42.880 he actually , uh , basically in 06:42.880 --> 06:45.047 this report , they , they come up with 06:45.047 --> 06:47.158 the design that would actually , um , 06:47.158 --> 06:50.160 transition into our Minesweeper fleet . 06:50.279 --> 06:52.501 And that's shown actually on the bottom 06:52.501 --> 06:54.612 of this graph , this , this long line 06:54.880 --> 06:58.079 of , of shipboard sonar systems that 06:58.079 --> 07:00.890 are used to this day . But in that 07:00.890 --> 07:04.329 report , uh , Hagemann mentions that 07:04.329 --> 07:06.549 what the navy really needs for mine 07:06.549 --> 07:10.450 hunting is a sonar capable of creating 07:10.690 --> 07:14.089 picture quality images of the sea floor , 07:14.450 --> 07:17.170 and he would not let this go . So he 07:17.170 --> 07:19.226 thought about this and thought about 07:19.226 --> 07:21.448 this and comes up with the invention of 07:21.448 --> 07:23.726 the side scan sonar , which would then , 07:23.726 --> 07:25.730 of course , transition into many of 07:25.730 --> 07:27.786 these systems that we talked about . 07:28.170 --> 07:30.170 Now there's a little red box in the 07:30.170 --> 07:32.337 middle of this graph , um , and that's 07:32.337 --> 07:34.392 to designate that Panama City didn't 07:34.392 --> 07:37.369 stop working on , you know , the seabed 07:37.369 --> 07:39.690 imaging technologies , uh , at that 07:39.690 --> 07:42.839 time . Uh , we continued the thrust , 07:43.040 --> 07:46.399 and in around 1970 , we actually 07:46.399 --> 07:49.480 started our work on synthetic aperture 07:49.480 --> 07:52.119 sonar . Uh , and the person who really 07:52.119 --> 07:54.380 started that was a scientist here 07:54.799 --> 07:56.880 called David Brown and , and some 07:56.880 --> 07:59.839 groundbreaking reports , and we'll , uh , 07:59.880 --> 08:02.200 we'll talk about Brown's invention in 08:02.200 --> 08:04.422 just a few minutes . But I think it's , 08:04.422 --> 08:07.320 it's very useful to talk about . Uh , 08:07.619 --> 08:09.730 you know , what sides , how side scan 08:09.730 --> 08:11.786 sonar works very briefly in a , in a 08:11.786 --> 08:14.399 side scan sonar imaging geometry . So , 08:14.609 --> 08:16.920 um , side scan sonar , uh , creates 08:17.089 --> 08:19.809 images of the seafloor , uh , one 08:19.809 --> 08:23.059 acoustic ping at a time , one scan line 08:23.059 --> 08:25.179 at a time . Uh , you can see in that 08:25.179 --> 08:28.880 bottom left image that a , a long , um , 08:29.519 --> 08:33.059 strip of seafloor is imaged , uh , by 08:33.059 --> 08:35.226 the sonar system . It's think of it as 08:35.226 --> 08:37.679 one scan line . And then the sonar 08:37.679 --> 08:40.080 moves forward and creates another scan 08:40.080 --> 08:43.320 line , and so on and so on . So , um , 08:43.359 --> 08:45.880 an image is created of the sea floor is 08:45.880 --> 08:48.719 created as the sonar moves through the 08:48.719 --> 08:51.960 water , one line at a time , kind of 08:51.960 --> 08:54.182 like comes out of your printer or a fax 08:54.182 --> 08:57.320 machine . How long does that take for 08:57.320 --> 09:00.239 it to move and create a picture ? Yeah , 09:00.400 --> 09:02.567 that's , that's a very good question . 09:02.567 --> 09:05.179 Uh , sound travels at about 1500 m per 09:05.179 --> 09:07.290 second in the water , so it goes very 09:07.290 --> 09:09.290 quickly . So , we'll typically ping 09:09.290 --> 09:12.770 many times per second . So , um , most 09:12.770 --> 09:14.826 of the time , uh , you know , we can 09:14.826 --> 09:17.140 keep up with the speed of , of whatever 09:17.140 --> 09:19.460 the platform is , as long as we time 09:19.820 --> 09:22.109 the , uh , the signals correctly . So , 09:22.119 --> 09:24.419 a , a tow fish , you know , carrying a 09:24.419 --> 09:26.700 side scan sonar . Um , might be 09:26.700 --> 09:29.469 operating , you know , 5 , 1020 knots . 09:29.940 --> 09:31.829 Uh , but , uh , unmanned undersea 09:31.829 --> 09:33.829 vehicle , you know , they typically 09:33.829 --> 09:37.059 move around 3 to 5 knots . So , um , it 09:37.059 --> 09:39.700 is very important to actually time your 09:39.700 --> 09:41.979 what we call our ping repetition rate , 09:42.380 --> 09:44.491 right , to the , uh , to the movement 09:44.491 --> 09:46.380 of the sonar itself . It's a very 09:46.380 --> 09:48.491 holistic design , right ? You have to 09:48.491 --> 09:50.750 take all of these into account . But I 09:50.750 --> 09:52.694 think that the key point here is , 09:53.229 --> 09:55.340 these images are created , you know , 09:55.340 --> 09:57.830 every ping has a strip of sea floor 09:57.830 --> 09:59.909 associated with it . Uh , one 09:59.909 --> 10:02.076 limitation , if you look at the , um , 10:02.260 --> 10:05.299 uh , kind of the diagram of , of a ping 10:05.299 --> 10:07.909 over to the right , one limitation is , 10:08.260 --> 10:10.940 uh , you can see the words transducucer . 10:11.099 --> 10:13.280 Uh , yeah , that's the actual , you 10:13.280 --> 10:15.391 know , the business part of the sonar 10:15.391 --> 10:17.502 system . Think of it as an underwater 10:17.502 --> 10:20.750 antenna . And the , the size of a pixel 10:20.989 --> 10:23.869 on the sea floor , um , is going to be 10:23.869 --> 10:27.580 dependent on how far away that pixel is , 10:27.659 --> 10:30.530 uh , from the sonar itself . Uh , the , 10:31.059 --> 10:33.710 that is dictated by , um , a , a , a 10:33.710 --> 10:36.099 beam width , uh , uh , angular beam 10:36.099 --> 10:38.266 width coming out of the sonar . And of 10:38.266 --> 10:40.559 course , the longer distances will have 10:40.559 --> 10:42.726 larger pixels , you know , the , the , 10:42.726 --> 10:45.200 that beam will intersect a larger piece 10:45.200 --> 10:48.119 of the sea floor than , than , uh , the , 10:48.200 --> 10:50.179 the terrain , which is closer . So 10:50.340 --> 10:52.840 that's kind of an inherent distortion 10:53.080 --> 10:55.119 that's built into a side scan sonar 10:55.119 --> 10:58.919 image . Uh , now , one way you can Um , 10:59.460 --> 11:02.099 you can resolve that problem is to 11:02.099 --> 11:04.320 create a very long array . The longer 11:04.320 --> 11:07.539 your array , the , uh , the more narrow 11:07.539 --> 11:09.700 that beam is . So you can , you can 11:09.700 --> 11:12.299 actually make these images , uh , finer 11:12.299 --> 11:14.265 in resolution . We still have the 11:14.265 --> 11:17.135 distortion problem though . And , um , 11:17.465 --> 11:19.576 very , very long arrays are extremely 11:19.576 --> 11:22.505 expensive and very hard to manage and 11:22.505 --> 11:24.505 to handle . Think of putting a very 11:24.505 --> 11:26.744 long array on a small unmanned undersea 11:26.744 --> 11:28.965 vehicle , would be very hard to do . 11:29.465 --> 11:31.465 And that's where synthetic aperture 11:31.465 --> 11:34.289 sonar comes in . Uh , so , to put it 11:34.289 --> 11:37.520 very , very generally , uh , synthetic 11:37.520 --> 11:40.840 aperture sonar is , is the creation of 11:40.840 --> 11:43.750 an extremely long 11:44.229 --> 11:46.650 virtual array , virtual array or 11:46.650 --> 11:50.109 synthetic array , and it's created 11:50.369 --> 11:54.359 by integrating or combining , um , 11:54.369 --> 11:57.250 all the pings along the trajectory of 11:57.250 --> 11:59.799 the vehicle itself . So , instead of 11:59.799 --> 12:03.159 being confined to the physical aperture 12:03.400 --> 12:05.456 that you put onto the sonar system , 12:05.520 --> 12:07.760 you are creating this long virtual or 12:07.760 --> 12:10.359 synthetic aperture , which doesn't 12:10.359 --> 12:13.599 exist in space , but it it exists in 12:13.599 --> 12:16.590 time . And yeah , and by doing that , 12:16.880 --> 12:19.599 and by um integrating um all of those 12:19.599 --> 12:23.460 pings , we can create a , a very narrow 12:23.640 --> 12:26.719 strip of , of , of high resolution 12:26.719 --> 12:29.840 seafloor imagery that is constant with 12:29.840 --> 12:31.951 range . It's , it's shown in , in the 12:31.951 --> 12:33.896 middle of , of , uh , that graphic 12:33.896 --> 12:36.840 there . It's constant at range , and 12:36.840 --> 12:39.760 because we can use very low frequencies , 12:40.080 --> 12:42.359 we can actually create this image at 12:42.359 --> 12:45.580 very long ranges too . So as where the 12:45.580 --> 12:47.940 shadow graph system which operated in 12:47.940 --> 12:51.020 the megahertz frequencies could , could 12:51.020 --> 12:53.299 image at maybe ranges up to about 30 12:53.299 --> 12:56.169 yards , uh , with a synthetic aperture 12:56.169 --> 12:58.739 sonar , we can achieve comparable 12:58.739 --> 13:02.340 resolution at hundreds of yards or or 13:02.340 --> 13:05.940 even thousands of yards area 13:05.940 --> 13:08.700 coverage rate ? Yeah , yeah , it's , 13:08.719 --> 13:10.950 it's , it's , it was groundbreaking . 13:11.419 --> 13:13.641 It took a little bit of time to make it 13:13.641 --> 13:17.400 to work . And we had a a number 13:17.400 --> 13:20.000 of challenges , uh , that we had to 13:20.000 --> 13:22.111 overcome in this area , and those are 13:22.111 --> 13:24.750 kind of shown on this graph here . Uh , 13:25.039 --> 13:27.659 one is that , uh , in order to do 13:27.659 --> 13:30.109 synthetic aperture sonar processing , 13:30.400 --> 13:33.479 we have to know the relative position 13:33.479 --> 13:35.701 of the vehicle along the length of this 13:35.701 --> 13:38.150 virtual array . Uh , we have to know 13:38.150 --> 13:40.590 the position within a fraction of an 13:40.590 --> 13:42.989 acoustic wavelength , and that's 13:42.989 --> 13:44.878 basically , uh , think of it as a 13:44.878 --> 13:47.309 fraction of an inch . And this is all 13:47.309 --> 13:51.090 done , uh , without GPS , right ? And 13:51.090 --> 13:53.349 the electromagnetic radiation doesn't 13:53.349 --> 13:56.330 really , uh , propagate well underwater . 13:56.510 --> 13:58.677 So , we had to figure out , you know , 13:58.677 --> 14:00.566 how to overcome that challenge of 14:00.566 --> 14:02.510 knowing where our vehicle was that 14:02.510 --> 14:05.770 precisely . Uh , another challenge 14:06.039 --> 14:08.150 is that there's something we call the 14:08.150 --> 14:11.010 SASS speed limit , and that is , um , 14:11.270 --> 14:13.580 if this is the physical aperture , the 14:13.580 --> 14:16.669 physical array , you can only , you can 14:16.669 --> 14:19.489 only ping , um , every half , 14:20.190 --> 14:22.869 um , a , uh , an element length at a 14:22.869 --> 14:25.150 time , right ? So , here you move a 14:25.150 --> 14:27.849 half , ping , you move a half , ping , 14:28.309 --> 14:30.476 and that can be very slow , right ? So 14:30.476 --> 14:32.642 there's a speed problem that we had to 14:32.642 --> 14:35.940 overcome . Um , another challenge is 14:35.940 --> 14:39.099 the is that the synthetic aperture beam 14:39.099 --> 14:41.900 forming process is , is very highly 14:41.900 --> 14:45.260 complex and can eat up many CPU cycles . 14:45.580 --> 14:47.802 And of course , we're talking about the 14:47.802 --> 14:50.369 1970s , and 1980s , 1990s . That was 14:50.369 --> 14:52.539 very challenging , right , for the uh 14:52.539 --> 14:54.960 computers of that day . And another 14:54.960 --> 14:58.859 challenge is . Um , if you , if you 14:58.859 --> 15:01.599 don't know , um , have a good sense of 15:02.099 --> 15:05.859 the , um , how sound speed varies 15:06.260 --> 15:08.260 through the water space that you're 15:08.260 --> 15:10.679 imaging through , that kind of unknown , 15:10.940 --> 15:13.719 uh , fluctuation in sound speed can , 15:13.780 --> 15:16.770 um , just can interfere with your , 15:16.940 --> 15:20.099 your focusing process . So it's kind of 15:20.099 --> 15:22.570 important to have some kind of sense of , 15:22.580 --> 15:24.913 uh , what that sound speed structure is . 15:25.195 --> 15:27.315 So those were considered , you know , 15:27.515 --> 15:29.682 very big challenges , and there were , 15:29.682 --> 15:31.737 uh , many people who said that , you 15:31.737 --> 15:34.195 know , SASS would , would never be , we 15:34.195 --> 15:36.054 would never be able to make SASS 15:36.054 --> 15:38.332 practical . A lot of obstacles in your , 15:40.015 --> 15:42.348 in the ways , yes , but they were wrong . 15:42.755 --> 15:45.215 Took us a few years . Took us a few 15:45.215 --> 15:47.437 years , but we got there . So let us go 15:47.437 --> 15:51.395 back to 1969 and David Brown 15:51.395 --> 15:54.489 at Panama City . Uh , I , I really 15:54.489 --> 15:56.711 consider this the , the , the launching 15:56.711 --> 15:59.799 point of making SASS practical . 16:00.440 --> 16:02.559 David Brown comes up with this 16:02.559 --> 16:04.960 technique to break that SASS speed 16:04.960 --> 16:07.400 limit , and what he does is he comes up 16:07.400 --> 16:10.195 with the , the algorithm . The 16:10.195 --> 16:12.484 mathematical method to instead of using 16:12.484 --> 16:15.544 just one physical element , to , um , 16:15.554 --> 16:18.375 put in , in line an , an array , a line 16:18.955 --> 16:21.554 of elements , physical elements that we 16:21.554 --> 16:24.335 can put on a vehicle . Um , and he 16:24.335 --> 16:26.934 figures out how to do the as processing . 16:27.510 --> 16:29.621 Uh , with that line of elements , and 16:29.621 --> 16:32.270 what that allows us to do is to move 16:32.270 --> 16:35.429 one half of an array at a time , right ? 16:35.549 --> 16:38.809 So , immensely increasing the speed , 16:39.250 --> 16:41.306 right , that you can , um , that you 16:41.306 --> 16:43.309 can run these operations and , and 16:43.309 --> 16:45.531 create this imagery . So this is huge . 16:45.531 --> 16:47.365 It's , it's called multi-channel 16:47.365 --> 16:50.969 vernier technique , and it really is , 16:51.070 --> 16:53.659 um , what I consider the beginning of , 16:53.940 --> 16:57.570 of making SAS practical . That 16:57.570 --> 17:00.260 launched a a whole research , um , 17:00.330 --> 17:03.650 program in the 1970s and , uh , Shawna , 17:03.729 --> 17:05.785 do you , and it was all done on that 17:05.785 --> 17:07.951 vehicle on the left . Do you recognize 17:07.951 --> 17:10.173 that vehicle ? I know that . That's our 17:10.173 --> 17:12.396 shadow graph . That is our shadow graph 17:12.396 --> 17:14.569 and we did , we did the very early SAS 17:14.569 --> 17:17.410 experiments on the shadow graph vehicle 17:17.410 --> 17:20.194 which I think This is a wonderful tie 17:22.574 --> 17:25.944 back to base actually we do . We can go 17:25.944 --> 17:29.015 look at it at 608 Building 608 , and I , 17:29.094 --> 17:30.983 I encourage , you know , everyone 17:30.983 --> 17:33.205 watching this to go , go take a look at 17:33.205 --> 17:35.427 the system if you can . But this system 17:35.427 --> 17:37.483 right here is , is has two synthetic 17:37.483 --> 17:40.635 apertures , experimental sonars put on 17:40.635 --> 17:42.691 a , a long line on the main body you 17:42.691 --> 17:44.839 can see in the black stripe . And a 17:44.839 --> 17:47.400 smaller lower frequency version um 17:47.400 --> 17:50.800 hanging from the bottom . And that dual 17:50.800 --> 17:53.260 high frequency and low frequency 17:53.369 --> 17:56.859 combination would kind of be canonical 17:57.000 --> 17:58.944 in years to come . It's a , it's a 17:58.944 --> 18:01.056 combination . That we use to this day 18:01.056 --> 18:03.349 where we can use the high frequency to 18:03.349 --> 18:05.750 get um very kind of crisp high 18:05.750 --> 18:08.229 resolution images of the sea floor and 18:08.229 --> 18:10.869 we can use use the low frequency and 18:10.869 --> 18:13.036 the image the resolution is still very 18:13.036 --> 18:15.310 good , but low frequencies penetrate 18:15.310 --> 18:17.430 into the sediment so we can actually 18:17.430 --> 18:19.541 image the subbottom with that is that 18:19.541 --> 18:21.541 what you mean by conical or what is 18:21.541 --> 18:23.708 canonical canonical , you know , being 18:23.708 --> 18:27.000 just kind of , um , a standard , right , 18:27.069 --> 18:30.280 a standard that's used . And um we 18:30.280 --> 18:32.169 actually were able to get the low 18:32.169 --> 18:34.540 frequency uh part working fairly well 18:34.640 --> 18:37.680 and this image on the right is a low 18:37.680 --> 18:40.400 frequency image of buried targets and I 18:40.400 --> 18:43.790 do believe it is the first , um , 18:43.800 --> 18:46.160 existing image of , of SASS being 18:46.160 --> 18:48.216 conducted out in the field . I think 18:48.216 --> 18:51.040 it's kind of historical in 75 . This 18:51.040 --> 18:54.530 was 1975 , yeah . And these are some of 18:54.530 --> 18:56.474 the guys who actually uh made this 18:56.474 --> 18:58.699 happen . Uh , on the , on the left , 18:58.770 --> 19:00.992 you have , uh , Sam Richardson , who is 19:00.992 --> 19:03.489 installing an inertial navigation or an 19:03.489 --> 19:06.209 inertial motion unit in the , uh , in 19:06.209 --> 19:08.376 the fish itself . This was some of the 19:08.376 --> 19:10.410 early attempts to , to get that 19:10.410 --> 19:12.466 position , get that , that very fine 19:12.466 --> 19:14.655 position . Of , of the vehicle . Uh , 19:14.785 --> 19:16.841 it was very expensive . I think that 19:16.841 --> 19:18.744 IMU system , uh , cost a million 19:18.744 --> 19:20.744 dollars . Can you , can you imagine 19:20.744 --> 19:22.800 what the , and this is in 1970 . Can 19:22.800 --> 19:25.194 you imagine how expensive that is . Um , 19:25.425 --> 19:27.592 the cost of those systems and the size 19:27.592 --> 19:29.814 of those systems have come down and now 19:29.814 --> 19:32.036 they're practically off the shelf now . 19:32.150 --> 19:34.150 Uh , but these , on the right , you 19:34.150 --> 19:36.270 have Jim Christoph , uh , who would 19:36.270 --> 19:38.326 lead the SASS program , um , all the 19:38.326 --> 19:40.437 way until , you know , until my early 19:40.437 --> 19:42.603 days working in the field . I , I knew 19:42.603 --> 19:44.800 Jim . Frank Higgins was the , uh , 19:44.910 --> 19:47.219 program manager over to the right , uh , 19:47.239 --> 19:49.810 other folks I , I should mention , um , 19:50.030 --> 19:53.180 Chester Loggins , Ed Pipkin , uh , they 19:53.180 --> 19:56.030 all show up in , uh , much of the early 19:56.030 --> 19:58.689 literature of this day . And around 19:58.689 --> 20:01.930 1980 , let me just go back to that . 20:01.969 --> 20:04.489 And so these are all employees of 20:04.489 --> 20:07.689 NSWCPCD in its prior name . That's , 20:07.770 --> 20:09.881 that's incredible . It is It all came 20:09.881 --> 20:12.010 out of this . It's incredible lab . I 20:12.010 --> 20:13.899 think it was called the , we were 20:13.899 --> 20:16.066 probably , we were probably called the 20:16.066 --> 20:18.288 Mind Defense lab at that time , at that 20:18.288 --> 20:20.288 time , and eventually we became the 20:20.288 --> 20:22.399 coastal System Station , right , so . 20:23.489 --> 20:26.869 And in , in around 1980 , uh , we 20:26.869 --> 20:29.589 decided to tackle this , this issue of , 20:29.910 --> 20:32.709 um , is , is sound , you know , what is , 20:32.819 --> 20:35.109 you know , is , is the sound speed 20:35.109 --> 20:38.670 structure stable enough to , uh , to do 20:38.670 --> 20:42.069 SA processing . So we , we built this , 20:42.150 --> 20:44.780 this large , um , test rail structure . 20:44.939 --> 20:47.810 This , this rail was , was , uh , 20:48.150 --> 20:50.372 designed and developed by Frank Higgins 20:50.372 --> 20:53.550 and , and Lyle Z Adair . And um it was 20:53.550 --> 20:55.606 attached to the Hathaway Bridge . It 20:55.606 --> 20:57.828 was a permanent fixture for some time , 20:57.828 --> 20:59.939 and it would be lowered down into the 20:59.939 --> 21:02.050 water , and you could move the uh the 21:02.050 --> 21:04.106 sonar apparatus through the water on 21:04.106 --> 21:07.839 this rail , and it , it allowed us to 21:07.859 --> 21:10.469 to see , to test our sonar gear and to 21:10.469 --> 21:12.589 test our algorithms , but to see how 21:12.589 --> 21:15.349 stable the uh the sound speed structure 21:15.349 --> 21:17.439 was , was in a tidal environment , 21:17.550 --> 21:19.828 right ? With the tide going in and out . 21:19.828 --> 21:21.939 And we found that it was sufficiently 21:21.939 --> 21:24.589 stable to continue the program and to 21:24.589 --> 21:26.589 build this , this kind of early 21:26.589 --> 21:29.469 generation on the right of a towed dual 21:29.469 --> 21:32.000 frequency synthetic aperture sonar 21:32.000 --> 21:35.479 system . So then we moved to the 21:35.479 --> 21:38.680 1990s , and I , I kind of call this the , 21:38.760 --> 21:41.339 the era of , of influential 21:41.430 --> 21:44.239 demonstrations . And in this , in this 21:44.239 --> 21:46.880 era , we built this , uh , I think of 21:46.880 --> 21:50.060 it as like the battleship of , of 21:50.199 --> 21:52.469 sensor platforms . Um , you can see 21:52.469 --> 21:56.270 it's 30 ft long . It housed a synthetic , 21:56.390 --> 21:58.390 you know , dual frequency synthetic 21:58.390 --> 22:00.668 aperture sonar , which a picture of it , 22:00.668 --> 22:02.723 which you can see close up on on the 22:02.723 --> 22:04.510 top left . But it also had a 22:04.510 --> 22:06.939 forward-look sonar , it had an 22:06.939 --> 22:10.800 electro-optic , uh , sensor on it . And 22:10.810 --> 22:14.569 this tow body itself towed another tow 22:14.569 --> 22:16.689 body which had a magnetometer . It 22:16.689 --> 22:19.410 itself was 10 or 15 ft long . So , you 22:19.410 --> 22:22.250 can imagine , you know , very , very um 22:22.250 --> 22:24.660 complicated to launch and to recover , 22:24.969 --> 22:27.849 but a wonderful platform for testing 22:27.849 --> 22:30.530 out and refining the technology and the 22:30.530 --> 22:34.030 success of this system . Uh , really 22:34.030 --> 22:36.430 convinced the Navy to , uh , invest 22:36.430 --> 22:38.560 more in synthetic aperture sonar and 22:38.560 --> 22:42.319 move it towards transition . And , uh , 22:42.329 --> 22:44.551 again , you know , some of the pioneers 22:44.551 --> 22:46.607 of , of the 1990s , some of them are 22:46.607 --> 22:48.718 shown here , um , I'll think of names 22:48.718 --> 22:51.689 like , uh , of Gary Samuelman , uh John 22:51.689 --> 22:54.810 Lathrop , Jose Fernandez , Carry 22:54.810 --> 22:57.050 Commander , uh , they were all part of 22:57.050 --> 22:59.000 this , uh , this effort to , uh , 22:59.010 --> 23:02.510 refine this synthetic aperture sonar 23:02.510 --> 23:05.560 technology . And so we get to the 23:05.560 --> 23:08.880 2000s , and , um , Panama City is the 23:08.880 --> 23:12.550 first to uh integrate a synthetic 23:12.550 --> 23:14.839 aperture sonar onto an unmanned 23:14.839 --> 23:16.950 undersea vehicle that was done around 23:16.950 --> 23:20.699 uh 2002 . And uh that 23:21.359 --> 23:24.849 success led to a , um , a family of 23:24.849 --> 23:27.280 systems called the Small synthetic 23:27.280 --> 23:29.880 aperture Min , Mindhunter of the , the 23:29.880 --> 23:32.047 different generations that you can see 23:32.047 --> 23:34.260 on the right . And that technology 23:34.260 --> 23:37.079 itself , uh , transitioned into our 23:37.079 --> 23:39.780 surface warfare fleet . So in a very , 23:39.939 --> 23:42.890 a very , very successful , uh , 23:42.900 --> 23:45.339 progression of , of , of developments 23:45.339 --> 23:47.780 in this technology . And I will just 23:47.780 --> 23:49.947 mention , you know , our of course our 23:49.947 --> 23:53.020 collaborators , um , uh , did a lot too , 23:53.060 --> 23:55.060 uh , you can see on the bottom left 23:55.060 --> 23:56.727 there there were , there were 23:56.727 --> 23:58.504 techniques what we that we call 23:58.504 --> 24:00.616 autofocusing to take care of any kind 24:00.616 --> 24:04.069 of residual , um . Uh , errors in the 24:04.069 --> 24:06.125 sound speed structure that we didn't 24:06.125 --> 24:08.291 know about that that way we could just 24:08.291 --> 24:10.236 look , work with the data and in a 24:10.236 --> 24:12.291 sense , make the data work , right ? 24:12.291 --> 24:14.180 Think of it as a , as an early AI 24:14.180 --> 24:16.347 technique to make the data work , um , 24:16.347 --> 24:18.569 and focus the image without even having 24:18.569 --> 24:20.736 to know what the sound speed structure 24:20.736 --> 24:22.680 is . There were advances in motion 24:22.680 --> 24:25.030 estimation and compensation . Uh , we 24:25.030 --> 24:27.890 had , we had advances in , in fast 24:27.890 --> 24:31.459 algorithms to Um , compensate for the 24:31.459 --> 24:33.515 fact that our computers weren't fast 24:33.515 --> 24:35.681 back then , but now our computers have 24:35.681 --> 24:37.848 gotten faster too , right ? So that we 24:37.848 --> 24:40.015 have lots of options on how we do this 24:40.015 --> 24:42.237 fast processing . And then there were , 24:42.237 --> 24:45.439 uh , advances in the , in the sonar 24:45.439 --> 24:47.780 technology and the , uh , components 24:47.780 --> 24:49.891 themselves , you know , that , that , 24:49.891 --> 24:52.058 um , our partners actually developed . 24:52.058 --> 24:54.113 And so , all of this together , um , 24:54.113 --> 24:56.280 got us to the point of where we are in 24:56.280 --> 24:59.119 transitioning this technology . And I 24:59.119 --> 25:01.286 thought here we just look at a , a , a 25:01.286 --> 25:03.640 few sample , um , images that we get 25:03.640 --> 25:05.819 with this , this type of technology . 25:06.199 --> 25:09.680 Um , I show the , the high frequency on 25:09.680 --> 25:12.209 the right . And the exact same survey , 25:12.290 --> 25:14.689 exact same bit of sea floor , uh , on 25:14.689 --> 25:17.430 the left imaged with a low frequency 25:17.589 --> 25:19.890 part of , of that dual-band system . 25:20.089 --> 25:22.311 And believe it or not , that's the same 25:22.311 --> 25:24.760 real estate . Uh , the high frequency , 25:24.770 --> 25:27.048 as you can see , gives you these crisp , 25:27.048 --> 25:29.270 kind of high resolution images of the , 25:29.270 --> 25:32.770 of the um of the interface of the ocean 25:32.770 --> 25:35.660 floor . And the , the lower frequency , 25:35.739 --> 25:37.859 I , we call it mid frequency there 25:37.859 --> 25:39.970 actually penetrates into the bottom , 25:39.970 --> 25:41.920 uh , so you see a , a lattice-like 25:42.089 --> 25:44.010 geological structure surface with 25:44.719 --> 25:46.939 exactly , and , and it's , it's , you 25:46.939 --> 25:48.661 can see that it's really quite 25:48.661 --> 25:50.939 different . But if you train your eyes , 25:50.939 --> 25:53.050 you'll see that there's a pot , there 25:53.050 --> 25:55.161 are a couple of potholes which appear 25:55.161 --> 25:57.272 in both images , and you look at that 25:57.272 --> 25:59.495 and you can convince yourself that that 25:59.495 --> 26:01.772 is the same piece of real estate . Now , 26:01.772 --> 26:03.828 on the insets on the right side is a 26:03.828 --> 26:07.040 field of objects put on the sea floor . 26:07.469 --> 26:09.525 And on the left side is , you know , 26:09.525 --> 26:11.691 the , the low frequency image of those 26:11.691 --> 26:13.829 objects , but you see more of them , 26:14.069 --> 26:16.189 and you see more of them because the 26:16.189 --> 26:18.300 low frequency is penetrating into the 26:18.300 --> 26:20.790 bottom . And so we're able to see 26:20.790 --> 26:22.957 objects which are buried . It's a very 26:22.957 --> 26:26.829 powerful tool for mind hunting . And 26:26.829 --> 26:29.150 then , um , this led to an even lower 26:29.150 --> 26:31.229 frequency synthetic aperture sonar 26:31.229 --> 26:33.089 system , which , uh , completely 26:33.089 --> 26:35.849 penetrated , um , into the sea floor 26:36.510 --> 26:39.949 and create and gave us the ability to 26:39.949 --> 26:42.349 create three dimensional images of 26:42.349 --> 26:46.290 buried objects . And then that even 26:46.290 --> 26:49.459 itself led to tomographic techniques of , 26:49.569 --> 26:52.650 of object imaging , where , uh , once 26:52.650 --> 26:56.250 we detected an object , we could run 26:56.250 --> 26:59.729 around at 360 degrees , get a 360 26:59.729 --> 27:01.869 degree view , um , of this object 27:01.869 --> 27:03.925 laying on the sea floor , and create 27:03.925 --> 27:06.510 these just a Astounding images that you 27:06.510 --> 27:08.939 see here . It's 3D images . If you can 27:08.939 --> 27:11.589 even , you can even see on the right 27:11.589 --> 27:15.339 bottom is a 3D printout of , of one of 27:15.339 --> 27:17.450 the objects . It , it happens to be a 27:17.450 --> 27:20.699 lobster pot isn't , I , I think it's , 27:20.750 --> 27:24.229 it's quite amazing . It's amazing . The 27:24.229 --> 27:27.540 rope and knot . Yeah . And this , this 27:27.540 --> 27:29.939 led to what I , what I like to , to 27:29.939 --> 27:33.010 call the , the age of SAS product lines . 27:33.170 --> 27:36.800 Uh , by around 2010 , 2012 , 27:37.180 --> 27:39.890 um , the US , of course , had its , its 27:39.900 --> 27:41.956 product lines and SASS developing to 27:41.956 --> 27:44.178 the left . But , you know , many of our 27:44.178 --> 27:46.233 coalition partners and , and , and , 27:46.300 --> 27:48.300 and navies and companies around the 27:48.300 --> 27:50.500 world were actually starting to , to 27:50.500 --> 27:52.859 build synthetic aperture sonar systems 27:52.859 --> 27:56.709 too . So it's , it's almost , um , an 27:56.709 --> 27:59.140 off the shelf kind of technology now . 27:59.640 --> 28:01.473 And all these products came from 28:01.473 --> 28:03.529 research led by this lab . Exactly , 28:03.529 --> 28:06.449 exactly . Something to be proud of . 28:06.680 --> 28:09.449 Something to be proud of indeed . And 28:09.449 --> 28:12.219 here just um this uh slide here 28:12.219 --> 28:14.441 emphasizes that , uh , while we've come 28:14.441 --> 28:16.497 a long way and we've transitioned to 28:16.497 --> 28:18.663 this technology , um , there are still 28:18.663 --> 28:22.489 um advances uh uh being made in using 28:22.489 --> 28:24.322 these types of systems . There's 28:24.410 --> 28:27.160 increasing the range , there's , um , 28:27.170 --> 28:29.003 there's creating high resolution 28:29.003 --> 28:32.290 bathymetry . uh , we , we are , we are 28:32.290 --> 28:34.400 still advancing the , um . The 28:34.400 --> 28:36.719 tomographic imaging technology , uh , 28:36.839 --> 28:38.839 making it , um , finer resolution , 28:38.920 --> 28:42.680 making it , um , uh , more 3D as , as 28:42.680 --> 28:44.920 you mentioned before , um , and the 28:44.920 --> 28:47.500 field of automatic target recognition 28:47.599 --> 28:50.079 is , is using many of the advances in , 28:50.119 --> 28:52.286 in artificial intelligence and machine 28:52.286 --> 28:55.790 learning . To allow us to , 28:55.800 --> 28:59.239 uh , use this type of data to really 28:59.239 --> 29:02.280 definitively and quickly determine what 29:02.280 --> 29:04.447 we're looking at on the seabed so that 29:04.479 --> 29:07.449 the robotic vehicle itself can can 29:07.449 --> 29:10.680 perceive the environment and understand 29:10.680 --> 29:13.390 what it's looking at and , and take , 29:13.400 --> 29:17.369 uh , take action . So . So I'll 29:17.369 --> 29:19.410 just say , you know , current and 29:19.410 --> 29:22.969 emerging MCM systems , uh , our 29:22.969 --> 29:26.359 platforms are the , uh , MCM ships , uh , 29:26.369 --> 29:28.425 that you see on the left there , and 29:28.425 --> 29:30.480 then of course our , our and the MCM 29:30.480 --> 29:32.702 ships use the , uh , the shipboard or , 29:32.702 --> 29:34.890 or , um , mine countermeasures sonar , 29:34.969 --> 29:38.510 the SQQ 32 , the littoral combat ship , 29:38.530 --> 29:41.859 uh , variants that we have , uh , use , 29:41.890 --> 29:44.410 um , you know , variants of the , um . 29:45.040 --> 29:48.800 AQS 24 and the AQS 20 sonar systems , 29:48.839 --> 29:51.006 uh , towed in , in , in many different 29:51.006 --> 29:53.189 ways . They are explosive ordnance 29:53.189 --> 29:56.770 disposal , um , uh , contingent , uh , 29:57.079 --> 29:59.760 uses UUV systems , uh , which have 29:59.760 --> 30:01.816 synthetic aperture sonars mounted on 30:01.816 --> 30:04.560 them . And I have to mention that there 30:04.560 --> 30:07.119 are the , the diver and marine mammal 30:07.119 --> 30:10.180 teams too . The , the marine mammals 30:10.180 --> 30:12.500 are maybe the oldest sonar system 30:12.500 --> 30:15.270 around , prehistoric , if you may , yes , 30:15.660 --> 30:17.938 and very sophisticated , and they have , 30:17.938 --> 30:20.300 uh , some very keen capabilities to 30:20.300 --> 30:22.540 find certain types of objects on the 30:22.540 --> 30:25.739 sea floor . It is great and that's 30:25.739 --> 30:28.859 that's a whole topic and , and , and 30:28.859 --> 30:32.489 lecture in itself . It is , it is . 30:32.780 --> 30:35.260 And of course , uh , you know , we are 30:35.260 --> 30:37.939 doing this in in advancing and evolving 30:37.939 --> 30:40.180 these capabilities to support the 30:40.180 --> 30:42.890 Navy's and and the Office of Naval 30:42.890 --> 30:46.599 Researchers uh vision of of expanding 30:46.599 --> 30:49.380 and enhancing our future mine 30:49.380 --> 30:52.969 countermeasures for us . So , you know , 30:53.079 --> 30:54.968 I just want to reflect a little , 30:54.968 --> 30:57.135 little bit . Um , there , there really 30:57.135 --> 31:00.959 is over 50 years of developing 31:00.959 --> 31:03.609 this technology at , at Naval Surface 31:03.609 --> 31:05.831 Warfare Center , Panama City Division . 31:06.189 --> 31:09.069 And , um , you know , we , we , we went 31:09.069 --> 31:11.291 from the early shadow graph systems all 31:11.291 --> 31:14.510 the way to these systems that are , are 31:14.829 --> 31:16.900 now used quite a bit on unmanned 31:16.900 --> 31:19.589 undersea vehicles . And , uh , it 31:19.589 --> 31:21.811 really , it really shows the , uh , the 31:21.811 --> 31:24.449 innovative nature of this laboratory . 31:24.829 --> 31:27.430 Um , and it is a , a tradition , uh , 31:27.640 --> 31:29.862 that , that we're very proud of , and , 31:30.239 --> 31:32.183 and I'm sure we'll continue , uh , 31:32.239 --> 31:34.295 through the decades ahead . We don't 31:34.295 --> 31:36.517 know what our next 80 years is going to 31:36.517 --> 31:38.739 show us . Thank you , Doctor Sterling . 31:38.739 --> 31:40.683 This was a very great presentation 31:40.683 --> 31:42.560 taking us down the path and the 31:42.560 --> 31:46.420 evolution of seabed imaging and sonar , 31:46.719 --> 31:48.830 and I can't wait to see what the next 31:48.830 --> 31:51.319 80 years brings . We have something to 31:51.319 --> 31:53.500 be very proud of . Thank you .