WEBVTT - How LORAN Worked 0:00:04.160 --> 0:00:07.160 Get in touch with technology with tech Stuff from how 0:00:07.240 --> 0:00:13.880 stuff Works dot com. Hey there, and welcome to tech Stuff. 0:00:13.880 --> 0:00:17.320 I'm your host, Jonathan Strickland. I'm an executive producer at 0:00:17.360 --> 0:00:20.960 How Stuff Works and All Love All Things Tech. And 0:00:21.079 --> 0:00:25.120 in my recent episode profile of alfred Ley Loomis, if 0:00:25.160 --> 0:00:28.200 you haven't listened to that one it published last weeks ago, 0:00:28.280 --> 0:00:32.040 check that out. I mentioned that Loomis was instrumental in 0:00:32.120 --> 0:00:36.800 developing a technology called Lauren l O R A N. 0:00:36.800 --> 0:00:39.559 And today I'm going to talk about that technology in 0:00:39.680 --> 0:00:43.879 deeper detail and how it uses mathematics and radio signals 0:00:44.080 --> 0:00:47.400 to help ships navigate far off the coast, or rather 0:00:47.760 --> 0:00:50.240 how it used to do that, as the system has 0:00:50.240 --> 0:00:53.080 since been phased out, but more on that later. I 0:00:53.120 --> 0:00:55.480 do think that Lauren is pretty cool, and it does 0:00:55.520 --> 0:00:57.520 give me a chance to talk about mathematics a little 0:00:57.560 --> 0:01:00.480 bit now, as we'll discuss in this episode. I won't 0:01:00.520 --> 0:01:06.800 go into incredible detail mathematically speaking, because it involves things 0:01:06.800 --> 0:01:10.000 like hyperbolas, which are way easier to talk about with 0:01:10.040 --> 0:01:13.080 the use of visual aids. However, first I should give 0:01:13.160 --> 0:01:16.880 some background on laur Anne. In the nineteen forties, there 0:01:16.959 --> 0:01:21.240 was no such thing as the Global Positioning System or GPS. 0:01:21.360 --> 0:01:24.600 You could not turn on a computing device and activate 0:01:24.640 --> 0:01:26.959 a helpful little app to see where you were on 0:01:27.000 --> 0:01:30.039 the globe. No one had invented a rocket capable of 0:01:30.080 --> 0:01:33.360 reaching orbit, let alone put a satellite out in space 0:01:33.400 --> 0:01:36.360 at that point. Yet there was a need for reliable 0:01:36.440 --> 0:01:40.600 navigation systems for ships and later on for aircraft. This 0:01:40.680 --> 0:01:44.040 need was made more urgent when the Second World War began. 0:01:44.319 --> 0:01:47.360 So you had different systems that were already in place, 0:01:47.880 --> 0:01:51.640 but many of them relied upon the elements things like 0:01:51.760 --> 0:01:55.400 seeing where the sun was and making measurements using something 0:01:55.440 --> 0:01:58.760 like a sextant. You had ships even leading up into 0:01:58.760 --> 0:02:01.760 World War Two that we're dependent upon these kind of systems, 0:02:02.080 --> 0:02:06.040 and for commercial ships that didn't have the benefit of 0:02:06.160 --> 0:02:10.919 military technology, this lasted even longer, and that was not 0:02:11.160 --> 0:02:15.800 ideal by n It seemed the question wasn't if the 0:02:15.880 --> 0:02:18.519 United States was going to be pulled into the Second 0:02:18.639 --> 0:02:22.639 World War, but rather when. Because of this impending threat, 0:02:22.680 --> 0:02:27.320 several important people urged President Franklin Roosevelt to form a 0:02:27.400 --> 0:02:31.320 Special Scientific Council to head research and development projects in 0:02:31.360 --> 0:02:35.359 science and technology that could be useful during wartime. Among 0:02:35.400 --> 0:02:39.240 these people were Vanavar Bush, who served as scientific advisor 0:02:39.360 --> 0:02:43.480 to the President. James Knant, who was president of Harvard 0:02:43.520 --> 0:02:46.240 at the time, and Carl Compton, who was president of 0:02:46.440 --> 0:02:50.120 m I. T. Roosevelt approved the plan, and the National 0:02:50.240 --> 0:02:54.639 Defense Research Council, or in d r C was born. 0:02:55.240 --> 0:03:00.840 The council looked at different technologies for detecting aircraft, often ships, 0:03:00.840 --> 0:03:04.680 and decided that microwaves were the most promising. Lead Carl 0:03:04.760 --> 0:03:07.840 Compton reached out to Alfred Lee Loomis to head up 0:03:07.880 --> 0:03:11.920 a special committee called the Microwave Committee to look into 0:03:11.960 --> 0:03:15.160 the matter. Loomis and his team determined that microwaves could 0:03:15.160 --> 0:03:18.079 be ideal for a detecting aircraft, but that the US 0:03:18.120 --> 0:03:21.680 had no technology capable of emitting microwaves in the frequency 0:03:21.760 --> 0:03:25.880 range they desired and enough power to work properly. Meanwhile, 0:03:26.200 --> 0:03:30.360 in Great Britain, scientists had developed a magnetron capable of 0:03:30.400 --> 0:03:34.680 creating powerful microwaves in those frequencies. Great Britain sent a 0:03:34.720 --> 0:03:37.120 group of scientists to the United States to try and 0:03:37.160 --> 0:03:41.040 develop a radar system that could take advantage of this technology. 0:03:41.080 --> 0:03:44.440 Sir Henry Tizard and his team brought over a cavity 0:03:44.520 --> 0:03:48.960 magnetron and Loomis invited the UK scientists to meet with 0:03:49.120 --> 0:03:53.600 the Microwave Committee. The committee convinced Compton to set aside 0:03:53.880 --> 0:03:57.000 a space at m I T for research and development 0:03:57.000 --> 0:04:00.960 with microwaves, and the m I T Radiation Laboratory or 0:04:01.120 --> 0:04:04.960 rad Lab was born. Now, the reason they chose the 0:04:05.000 --> 0:04:09.360 name Radiation Laboratory was pretty interesting. It was all a 0:04:09.400 --> 0:04:14.160 matter of deception of misdirection. The lab did not want 0:04:14.200 --> 0:04:18.240 anyone associated with the Access powers to find out what 0:04:18.279 --> 0:04:22.120 they were working on, so the Allies could maintain an 0:04:22.160 --> 0:04:25.480 advantage during the war, especially when it came to navigation 0:04:25.480 --> 0:04:29.040 and detection of aircraft and other vessels. So to that 0:04:29.240 --> 0:04:34.320 end they chose the name Radiation Laboratory for a siwhat 0:04:34.320 --> 0:04:37.920 paradoxical reason, or at least in retrospect, it seems paradoxical. 0:04:38.600 --> 0:04:41.440 It made it sound as though the lab was investigating 0:04:41.760 --> 0:04:45.920 nuclear science, as in things like nuclear power and potentially 0:04:45.920 --> 0:04:49.960 a nuclear bomb. Not At the time, the prevailing feeling 0:04:50.080 --> 0:04:53.680 was that nuclear science was such a young discipline that 0:04:53.720 --> 0:04:56.240 would take too long to make any advances in the 0:04:56.279 --> 0:04:59.320 field that could possibly have an effect during the war, 0:04:59.800 --> 0:05:02.359 and and so they chose to disguise their efforts to 0:05:02.400 --> 0:05:06.240 advance radar technology by claiming to be a nuclear science lab, 0:05:06.560 --> 0:05:08.919 which I think is pretty wild, especially when you consider 0:05:09.240 --> 0:05:12.279 that the actual end of World War Two would be 0:05:12.440 --> 0:05:15.480 in large part due to the development of nuclear weapons. 0:05:15.880 --> 0:05:20.240 The lab made significant contributions to science and technology, with 0:05:20.440 --> 0:05:25.880 numerous practical applications. Among them was the Long Range Navigation 0:05:25.920 --> 0:05:29.200 System or LAUREN. Now, the story of LAUREN really gets 0:05:29.240 --> 0:05:33.200 going on October first, nineteen forty, when the Army Signal 0:05:33.320 --> 0:05:36.760 Technical Committee met to create requirements for what it called 0:05:37.040 --> 0:05:41.960 a precision navigational equipment for guiding airplanes. The committee was 0:05:42.000 --> 0:05:44.840 asking for a means to provide navigational assistance from a 0:05:44.880 --> 0:05:48.480 distance of five hundred miles, a flight ceiling of thirty 0:05:48.480 --> 0:05:52.279 five thousand feet, and inaccuracy of within one thousand feet 0:05:52.360 --> 0:05:55.320 at two hundred miles out. In other words, a planes 0:05:55.400 --> 0:05:58.240 navigator should be able to determine the planes position within 0:05:58.360 --> 0:06:01.400 one thousand feet of its act tool position while still 0:06:01.400 --> 0:06:04.120 two hundred miles out from the radio transmitters that are 0:06:04.160 --> 0:06:07.640 beaming signals to the plane. Alfred Lee Loomis had a 0:06:07.680 --> 0:06:12.760 proposal to meet these requirements. He thought that this would 0:06:12.760 --> 0:06:16.560 originally be used for ships, not for aircraft because it 0:06:16.600 --> 0:06:20.600 would require building special receivers, and at the time, there 0:06:20.760 --> 0:06:23.640 wasn't really a practical way of building a receiver small 0:06:23.760 --> 0:06:27.000 enough to fit on an aircraft, which already had a 0:06:27.080 --> 0:06:29.960 pretty strict limit on how much weight and how much 0:06:30.000 --> 0:06:33.159 space was available in them. Loomis had a clever idea 0:06:33.200 --> 0:06:39.159 that involved pairs of radio transmitting stations sending out synchronized signals. 0:06:39.200 --> 0:06:42.240 A receiver aboard a ship would pick up these signals, 0:06:42.279 --> 0:06:45.880 and by measuring the delay between the two signals, you 0:06:45.920 --> 0:06:49.360 could figure out your basic distance from the two transmitters. 0:06:49.400 --> 0:06:53.400 With a second pair of transmitters or a third transmitting tower, 0:06:53.760 --> 0:06:56.640 you could figure out your actual position. And it all 0:06:56.760 --> 0:07:00.520 had to do with the formulas for hyperbolas, which is 0:07:00.520 --> 0:07:05.159 why laura and is also known as a hyperbolic navigation system. Now, 0:07:05.160 --> 0:07:07.800 I know all the mathematicians out there already have a 0:07:07.800 --> 0:07:10.680 firm grasp of what a hyperbola is, but for some 0:07:10.760 --> 0:07:14.760 of us we might need some instruction or refresher It's 0:07:14.800 --> 0:07:18.080 been more than twenty years since I took a mathematics course, 0:07:18.400 --> 0:07:21.520 and I needed a little reminder for myself. So here 0:07:21.520 --> 0:07:26.520 we go. Hyperbola is a symmetrical open curve that represents 0:07:26.560 --> 0:07:30.160 this set of points in a plane whose distances to 0:07:30.400 --> 0:07:34.080 two fixed points called folk i in that same plane 0:07:34.320 --> 0:07:38.600 have a constant difference. So by a symmetrical open curve 0:07:38.640 --> 0:07:41.520 we mean you have two curved lines called branches or 0:07:41.640 --> 0:07:45.640 connected components. They are symmetrical, so they are mirror images 0:07:45.800 --> 0:07:48.600 of each other, with the open side of the curves 0:07:48.720 --> 0:07:52.120 facing outward from each other. They look kind of like 0:07:52.240 --> 0:07:56.320 infinite bows. As the arms extend out from the center 0:07:56.360 --> 0:07:59.480 of the hyperbola, which is called the vert vertex the 0:07:59.560 --> 0:08:03.400 verticey ease of the hyperbola, they become less curved. So 0:08:03.440 --> 0:08:06.200 the further out the lines go, the more straight they appear. 0:08:06.840 --> 0:08:10.160 The two fixed points or foci, are each on the 0:08:10.240 --> 0:08:14.480 inside of one of those curves or branches. Now remember 0:08:14.520 --> 0:08:17.360 the branches represent a set of points. If you were 0:08:17.400 --> 0:08:21.200 to select any of those points along one of the curves, 0:08:21.560 --> 0:08:24.080 you can measure the distance between that point and the 0:08:24.120 --> 0:08:27.200 two foci. The point will be closer to its own 0:08:27.280 --> 0:08:30.400 focus than the focus of the other curve, and you 0:08:30.440 --> 0:08:33.800 subtract one distance from the other and you take the 0:08:33.800 --> 0:08:36.360 absolute value, meaning you make it a positive value. So 0:08:36.679 --> 0:08:38.640 if it would have been negative, you change it to 0:08:38.679 --> 0:08:42.880 a positive You will then find the constant for that hyperbola. 0:08:43.440 --> 0:08:45.760 If you were to pick any other point on that 0:08:45.920 --> 0:08:49.120 same curve and repeat this process where you measure the 0:08:49.160 --> 0:08:52.080 distance between that point and the FOLCA and it's foci 0:08:52.520 --> 0:08:54.640 and that point and the folk I of the other curve, 0:08:54.880 --> 0:08:57.920 and then subtract the two, you would still arrive at 0:08:57.960 --> 0:09:01.600 that same value. That woman, you take the absolute value. 0:09:02.040 --> 0:09:04.520 The folk I are in a position relative to the curves, 0:09:04.559 --> 0:09:07.080 so that the difference between the distance of any point 0:09:07.120 --> 0:09:09.640 on the curves and the folk I will always be 0:09:09.840 --> 0:09:13.760 the same. The curves thus represent a selection of possible 0:09:13.880 --> 0:09:19.040 locations from the perspective of the folk I. Now that's 0:09:19.080 --> 0:09:22.800 the secret behind Lauren. But how well I'll tell you. 0:09:23.160 --> 0:09:34.880 But first let's take a quick break to thank our sponsor. Okay, 0:09:34.920 --> 0:09:39.480 So imagine you've got a coastline, and along this coastline 0:09:39.760 --> 0:09:43.200 you have transmitting towers that are paired together so that 0:09:43.280 --> 0:09:47.720 they send out a pulse of signals in perfect synchronization. 0:09:48.360 --> 0:09:50.880 If you were on a boat out at sea equa 0:09:51.040 --> 0:09:54.559 distant from the two towers, you would receive both sets 0:09:54.559 --> 0:09:58.200 of signals at exactly the same time. But let's say 0:09:58.280 --> 0:10:01.240 you're a little closer to Tower A than you are 0:10:01.520 --> 0:10:04.880 from Tower B. What happens then, Well, Tower A and 0:10:04.920 --> 0:10:08.520 Tower B send out their signals at exactly the same time. 0:10:08.559 --> 0:10:12.240 It is synchronized, so you would receive Tower a's signals 0:10:12.320 --> 0:10:16.920 a little bit earlier than you would receive Tower b's signals. 0:10:17.160 --> 0:10:20.080 That's because the signals from Tower B have to travel 0:10:20.280 --> 0:10:23.720 further than the signals from Tower A, and the signals 0:10:23.760 --> 0:10:26.600 are traveling at a constant rate of speed. So what 0:10:26.800 --> 0:10:30.880 speed is that, Well, it's the speed of light, because 0:10:31.520 --> 0:10:35.840 radio waves are electromagnetic radiation, as is light now in 0:10:35.880 --> 0:10:39.280 our atmosphere, because light does travel at different speeds through 0:10:39.320 --> 0:10:42.240 different media. In the vacuum of space, it's one speed. 0:10:42.280 --> 0:10:47.440 But in our atmosphere light travels at two thousand seven 0:10:47.920 --> 0:10:50.760 kilometers per second. I'm really going to focus on kilometers 0:10:50.760 --> 0:10:52.800 for this. It makes it easier in the long run. 0:10:52.960 --> 0:10:55.640 So it's not like there would be a long delay 0:10:55.760 --> 0:10:58.720 between the two incoming signals. I mean that that speed. 0:10:59.240 --> 0:11:02.079 Unless you are really far away, you wouldn't be able 0:11:02.440 --> 0:11:04.800 to have a massive delay between the two. And if 0:11:04.800 --> 0:11:06.319 you were really far away, you wouldn't be able to 0:11:06.320 --> 0:11:09.480 pick up the signals in the first place. So, uh, 0:11:09.520 --> 0:11:12.880 we're talking about a delay that's measurable in micro seconds, 0:11:13.320 --> 0:11:16.240 but with a Loran receiver that's long enough to do 0:11:16.280 --> 0:11:21.120 some serious calculations. Now, the two towers that are transmitting 0:11:21.520 --> 0:11:25.160 represent the foci of a hyperbola. So you're on this 0:11:25.240 --> 0:11:27.960 boat and your receiver picks up that you're getting the 0:11:28.000 --> 0:11:31.400 signals from Tower A let's say about two hundred micro 0:11:31.520 --> 0:11:34.520 seconds before you get the signals from tower B, so 0:11:34.600 --> 0:11:37.600 you are closer to Tower A by a factor of 0:11:37.600 --> 0:11:40.439 two hundred micro seconds. You also happen to know how 0:11:40.480 --> 0:11:44.560 far apart Tower A and Tower B R because that's 0:11:44.600 --> 0:11:46.280 part of the whole system. You have to know the 0:11:46.320 --> 0:11:50.160 location of the transmitting towers and their distance relative to 0:11:50.200 --> 0:11:52.880 each other. Otherwise you don't have enough information to make 0:11:52.960 --> 0:11:57.080 any important determinations, and that information is freely available to 0:11:57.080 --> 0:12:01.000 anyone who's part of the Louran system. So you know 0:12:01.120 --> 0:12:04.560 the physical distance that separates these two folk i from 0:12:04.559 --> 0:12:08.000 each other along the coast. Using those pieces of information, 0:12:08.200 --> 0:12:11.200 you can actually plot the hyperbola curves. So let's say 0:12:11.240 --> 0:12:14.599 the two towers are four kilometers apart. The speed of 0:12:14.640 --> 0:12:18.760 the radio waves is point to nine nine seven nine 0:12:18.760 --> 0:12:22.440 two kilometers per micro second, and the difference between the 0:12:22.520 --> 0:12:26.400 two sets of pulses was two hundred microseconds. We can 0:12:26.440 --> 0:12:30.440 calculate the constant of this hyperbola by using the equation 0:12:30.880 --> 0:12:35.680 distance equals rate times time. The rate is the rate 0:12:35.760 --> 0:12:39.199 of the radio waves that's point to nine nine seven 0:12:39.280 --> 0:12:42.760 nine two kilometers per microsecond, and the amount of time 0:12:42.800 --> 0:12:46.360 that passes is two dred microseconds. That gives us fifty 0:12:46.480 --> 0:12:49.880 nine point nine five eight four kilometers. So let's just 0:12:49.960 --> 0:12:52.840 round it up. We're gonna call it sixty kilometers. That's 0:12:52.880 --> 0:12:56.800 your constant. Any point along the hyperbola will have a 0:12:56.840 --> 0:13:00.840 difference in distances from the two folk i of about 0:13:01.120 --> 0:13:04.280 sixty kilometers. Now, that still doesn't tell you where you 0:13:04.320 --> 0:13:06.840 are in relation to anything else. It just tells you 0:13:06.880 --> 0:13:12.480 the relationship between the difference in distances between the two transmitters. However, 0:13:13.040 --> 0:13:17.000 knowing the constant gives you enough information to suss out 0:13:17.040 --> 0:13:20.280 the rest of the equation for the hyperbola. The equation 0:13:20.320 --> 0:13:23.080 for an east west hyperbola. So if you were to 0:13:23.080 --> 0:13:26.320 plot this on the old X Y axis, you know, 0:13:26.440 --> 0:13:29.040 a good old grid, then this would be the ones 0:13:29.080 --> 0:13:32.199 that would face left and right, a north south hyperbola 0:13:32.280 --> 0:13:35.360 would face up and down along the y axis as 0:13:35.360 --> 0:13:38.680 opposed to left and right along the X axis. So 0:13:38.920 --> 0:13:41.599 when you plot and east west hyperbola on an x 0:13:41.720 --> 0:13:46.400 y axis, the equation for a hyperbola is X squared 0:13:46.800 --> 0:13:51.520 divided by A squared minus Y squared divided by B 0:13:51.720 --> 0:13:57.920 squared equals one. That's your your hyperbola equation. Now, if 0:13:57.960 --> 0:14:00.440 this were an up down a north south hype perbola, 0:14:00.760 --> 0:14:03.760 you would actually have Y squared over A squared minus 0:14:03.960 --> 0:14:07.000 X squared over B squared equals one. Just a little 0:14:07.160 --> 0:14:09.680 bit of mathematics for you. The A, by the way, 0:14:09.960 --> 0:14:14.439 represents the vertices. The that would be the the center 0:14:14.600 --> 0:14:19.040 of the hyperbola. That that point where it has the 0:14:19.120 --> 0:14:22.000 curve where it curves around the very center of that 0:14:22.080 --> 0:14:25.120 is the the of Both of those curves are the vertices, 0:14:25.720 --> 0:14:29.600 and the B represents the covertices. Describing that as a 0:14:29.640 --> 0:14:32.720 little more tricky without visual aids. So just go with 0:14:32.760 --> 0:14:36.600 me on this if you want to really understand what 0:14:36.640 --> 0:14:39.640 this is. There's a video I highly recommend. I found 0:14:39.640 --> 0:14:42.720 it extremely useful. The video that you can find is 0:14:42.760 --> 0:14:45.720 on YouTube. I have no connection to the person who 0:14:45.720 --> 0:14:48.280 makes this video or the company that makes this video. 0:14:48.440 --> 0:14:50.520 I just found it very useful. The title of the 0:14:50.600 --> 0:14:54.720 video is applying hyperbola as navigation, and it's by think 0:14:54.800 --> 0:14:58.280 Well VIDs, and you can see this applied specifically for 0:14:58.360 --> 0:15:01.000 the purposes of navigation. That even use an example very 0:15:01.000 --> 0:15:03.640 similar to what I'm talking about, although he uses miles 0:15:03.760 --> 0:15:07.120 rather than kilometers. Uh. If you check that out, you'll 0:15:07.120 --> 0:15:09.640 be able to see this in action, and it'll be 0:15:09.720 --> 0:15:13.440 much easier for you to visualize since I'm working just 0:15:13.520 --> 0:15:16.720 from an audio format here. The point being that once 0:15:16.760 --> 0:15:19.640 you figure out the equation for the hyperbola, you can 0:15:19.640 --> 0:15:23.200 plot out all those points on a map that have 0:15:23.480 --> 0:15:28.880 this this constant this constant difference of of distances between 0:15:28.880 --> 0:15:31.680 the two folki. So you get that curved line that 0:15:31.800 --> 0:15:35.520 represents all of those physical points on the map. We 0:15:35.680 --> 0:15:40.440 call this the Loran line of position. By itself, that 0:15:40.480 --> 0:15:44.240 information isn't that useful because you don't know exactly where 0:15:44.360 --> 0:15:47.640 along that line your position is. You just know that 0:15:47.680 --> 0:15:50.360 it has to be one of those points. Based on 0:15:50.400 --> 0:15:54.720 the math, you could be anywhere along that curve. Well, 0:15:54.760 --> 0:15:57.120 if you're on a boat, you would presumably be anywhere 0:15:57.120 --> 0:16:00.680 out over the ocean, because if the curve extends out 0:16:00.720 --> 0:16:04.080 over the land, you probably aren't there if you're in 0:16:04.120 --> 0:16:06.720 a boat. If you are there, then you don't really 0:16:06.760 --> 0:16:09.200 need to worry about your position so much, because chances 0:16:09.200 --> 0:16:12.800 are it's not really changing. Boats don't move well on land. 0:16:13.400 --> 0:16:16.800 What you need now is either a third tower that's 0:16:16.840 --> 0:16:21.640 pulsing the same synchronized signal, or, as the original design 0:16:21.640 --> 0:16:25.880 of Laurent intended, a second pair of transmitting towers. So 0:16:25.920 --> 0:16:28.760 with a third tower, let's remember our first two towers 0:16:28.760 --> 0:16:31.440 were Towers A and B. Uh this would be Tower C. 0:16:32.000 --> 0:16:35.040 You would run the same calculations with regard to the 0:16:35.080 --> 0:16:38.960 ship and Tower A. That will produce a second hyperbola, 0:16:39.280 --> 0:16:42.320 one in which the curve of that second hyperbola will 0:16:42.360 --> 0:16:46.320 intersect with the curve from the first hyperbola. If you 0:16:46.360 --> 0:16:48.800 were using a second pair of towers, we'll call these 0:16:48.800 --> 0:16:51.440 towers D and E, you would repeat the process you 0:16:51.480 --> 0:16:54.040 did for Towers A and B, measuring the difference in 0:16:54.080 --> 0:16:56.480 time it takes towers Tower D signal to get to 0:16:56.480 --> 0:16:58.800 you compared to Tower E signal. That would let you 0:16:58.840 --> 0:17:01.440 plot out a second hyper bluff, and you would still 0:17:01.480 --> 0:17:04.480 see a second set of points representing your possible location. 0:17:04.960 --> 0:17:08.679 More importantly, they would intersect with your first set of points, 0:17:08.720 --> 0:17:12.280 and it's at that intersection where the two lines cross 0:17:12.920 --> 0:17:16.560 that your location would have to be. That's the only 0:17:16.600 --> 0:17:21.120 place your ship could be, because the mathematics would tell 0:17:21.160 --> 0:17:24.320 you that you have to exist along both of these 0:17:24.320 --> 0:17:29.199 curved lines simultaneously, and they only intersect at one point. 0:17:29.240 --> 0:17:32.879 That point is your location. So by using a Loran 0:17:33.000 --> 0:17:37.080 receiver and taking in transmissions from different towers and applying 0:17:37.080 --> 0:17:39.720 a little math, you can figure out exactly where you 0:17:39.720 --> 0:17:42.560 are out in the ocean, even if land isn't in 0:17:42.680 --> 0:17:45.640 sight and the sky is overcast. By sending out these 0:17:45.680 --> 0:17:48.720 pulses with identify irs, you'll know where you are in 0:17:48.800 --> 0:17:52.119 relation to where you're headed and can make course corrections 0:17:52.160 --> 0:17:54.640 and take the measures to pilot your ships safely toward 0:17:54.680 --> 0:17:58.920 its destination. This is particularly useful during wart wartime, when 0:17:59.359 --> 0:18:02.119 you might have to worry about enemy ships patrolling certain 0:18:02.160 --> 0:18:05.200 areas of the seas and being able to navigate around them. Now, 0:18:05.240 --> 0:18:08.800 the theory behind Lauren was solid. The math works. The 0:18:08.880 --> 0:18:12.320 trick then was to make it a practical technology. Knowing 0:18:12.359 --> 0:18:14.600 that the theory was sound was one thing, but to 0:18:14.680 --> 0:18:17.120 put it into practice to actually build stuff that could 0:18:17.240 --> 0:18:19.800 use it. That was another and that presented a bit 0:18:19.800 --> 0:18:22.080 of a challenge. If the committee could find a way 0:18:22.080 --> 0:18:26.160 to synchronize transmissions from radio towers hundreds of miles apart, 0:18:26.600 --> 0:18:30.560 the scheme would work. But that synchronization was absolutely critical 0:18:30.720 --> 0:18:33.440 because without it, the difference in time between the two 0:18:33.480 --> 0:18:37.000 signals would be meaningless. The receiver would have no way 0:18:37.000 --> 0:18:40.520 of knowing the relationship between time and distance if the 0:18:40.520 --> 0:18:43.719 two sets of signals weren't sent out at exactly the 0:18:43.760 --> 0:18:47.440 same time. The team requested about four hundred thousand dollars 0:18:47.440 --> 0:18:51.879 worth of equipment on December uh well in December, in 0:18:52.040 --> 0:18:54.679 order to carry out an experimental run to determine if 0:18:54.680 --> 0:18:59.080 the mathematically attractive solution was actually feasible in the real world. 0:18:59.400 --> 0:19:02.520 And if we just that four hundred thousand dollars for inflation, 0:19:02.960 --> 0:19:06.040 that would be about seven point two million dollars worth 0:19:06.080 --> 0:19:09.640 of stuff in today's money. The team looked for suitable 0:19:09.640 --> 0:19:12.919 spots to construct the transmission towers, and at first they 0:19:13.160 --> 0:19:16.280 they considered some mountain peaks along the coast, but then 0:19:16.320 --> 0:19:20.560 they found two former Coastguard lifeboat stations that had fallen 0:19:20.600 --> 0:19:25.000 into disuse. One was outside Montauk Point, Long Island and 0:19:25.040 --> 0:19:28.520 the other off of Fenwick Island, Delaware. The two locations 0:19:28.520 --> 0:19:31.479 were two d nine nautical miles apart from one another, 0:19:31.760 --> 0:19:34.480 and they weren't too far from the headquarters for the project, 0:19:34.600 --> 0:19:37.640 which was in the Bell Telephone Laboratories in New York. 0:19:38.160 --> 0:19:42.960 The earliest tests concentrated not on synchronization, which was an 0:19:42.960 --> 0:19:46.240 area that Alfred Lee Loomis was particularly intrigued by as 0:19:46.240 --> 0:19:49.720 he had a fascination with timekeeping, but rather in how 0:19:49.800 --> 0:19:53.479 far they could broadcast the radio signals. They tried several 0:19:53.520 --> 0:19:56.960 different wavelengths to see which ones could perform best under 0:19:57.000 --> 0:20:00.639 different situations, and they discovered that longer wave length radio 0:20:00.680 --> 0:20:04.359 waves seemed to travel further at night, and shorter ones 0:20:04.480 --> 0:20:07.680 seemed to travel further during daylight hours, and that kind 0:20:07.680 --> 0:20:10.000 of suggested to them that maybe they should compromise and 0:20:10.040 --> 0:20:13.080 go with a medium wave length signal that would perform 0:20:13.160 --> 0:20:17.479 the best under most circumstances. They also did not test 0:20:17.520 --> 0:20:20.720 it with a ship at sea at first. Rather, they 0:20:20.760 --> 0:20:24.080 created a Loran receiver and they mounted it aboard a 0:20:24.200 --> 0:20:28.800 humble station wagon that traveled as far away as Springfield, Missouri. 0:20:29.160 --> 0:20:31.639 Now I have to say more about the development of 0:20:31.720 --> 0:20:34.480 Lauren in just a second, but first let's take another 0:20:34.560 --> 0:20:44.960 quick break to thank our sponsor. As work continued on 0:20:45.000 --> 0:20:47.080 the lor End project, the group began to work on 0:20:47.080 --> 0:20:51.359 a way to synchronize signals, because without synchronization, these equations 0:20:51.400 --> 0:20:54.400 are not going to create an accurate hyperbola. The solution 0:20:54.520 --> 0:20:58.639 was called a two trace indicator technique. A trace is 0:20:58.680 --> 0:21:02.040 a type of log or record of events. A common 0:21:02.080 --> 0:21:05.040 reference time acts as the anchor point for the traces, 0:21:05.280 --> 0:21:07.960 which can then be analyzed against each other to determine 0:21:08.000 --> 0:21:11.960 how close to synchronicity the two transmitters are and adjustments 0:21:11.960 --> 0:21:16.560 can be made. Eventually, they created a time keeping algorithm 0:21:16.600 --> 0:21:19.600 that was accurate enough that were in a wrist watch, 0:21:20.000 --> 0:21:22.480 you could go for a full decade without losing a 0:21:22.560 --> 0:21:27.840 minute on it. By January ninety two, the project was 0:21:27.880 --> 0:21:30.359 able to create a system that had an average error 0:21:30.400 --> 0:21:32.720 in the line of position of about two and a 0:21:32.800 --> 0:21:36.359 half miles or around four kilometers, which sounds like an 0:21:36.400 --> 0:21:38.879 awful lot, but when you're thinking about the distances that 0:21:38.960 --> 0:21:42.960 these various craft were traveling, it was actually pretty good. 0:21:43.359 --> 0:21:46.640 The remaining challenge was one that was solved relatively easily, 0:21:46.920 --> 0:21:50.080 The problem was the receivers would pick up two signals 0:21:50.119 --> 0:21:54.679 of different amplitudes, meaning different strength of signal, and the 0:21:54.720 --> 0:21:57.359 difference in amplitudes made it more difficult to measure the 0:21:57.440 --> 0:22:01.000 time difference between the signals accurately. So to fix this, 0:22:01.280 --> 0:22:05.120 the team built in differential gain control to help boost 0:22:05.160 --> 0:22:07.960 a low signal or dampen a powerful one, so that 0:22:08.000 --> 0:22:11.919 the calculations could be made more easily. Successful tests with 0:22:12.000 --> 0:22:15.520 ships and blimps convinced the U. S. Army and Navy 0:22:15.600 --> 0:22:18.840 to fund the construction of transmission stations for a larger 0:22:18.880 --> 0:22:23.280 tests in the Northwest Atlantic in nineteen two. Work continued 0:22:23.320 --> 0:22:27.280 in America, Canada, and Greenland to build out transmission stations. 0:22:27.600 --> 0:22:31.040 The project was a success, and work soon extended to 0:22:31.080 --> 0:22:33.480 other parts of the coast, as well as over in 0:22:33.560 --> 0:22:37.000 the UK. The application proved to be a sound one. 0:22:37.520 --> 0:22:41.000 Advancements in receiver technology allowed aircraft to use the same 0:22:41.040 --> 0:22:44.480 system a little bit later, which became incredibly useful during 0:22:44.520 --> 0:22:47.800 the war. Planes and ships could meet at rendezvous points 0:22:47.800 --> 0:22:50.400 that previously have been would have been impossible to achieve. 0:22:50.920 --> 0:22:54.480 Uh they were able to pair together different navigation systems, 0:22:54.760 --> 0:22:58.239 some of them were more accurate at closer ranges, and 0:22:58.320 --> 0:23:00.919 Lauren was more accurate at long range, so using the 0:23:01.000 --> 0:23:03.639 two together was really helpful. By the end of n 0:23:04.880 --> 0:23:08.560 more than three thousand naval ships and thirty thousand planes 0:23:08.640 --> 0:23:12.359 had Laura end technology aboard. After the war, the system 0:23:12.400 --> 0:23:15.400 was recognized as being so useful as to be instrumental 0:23:15.520 --> 0:23:18.800 in the shipping industry moving forward, and the US Coast 0:23:18.840 --> 0:23:22.520 Guard even produced a short film to convince shipping companies 0:23:22.720 --> 0:23:27.200 to adopt Lauren technologies for the purposes of navigation. Lauren 0:23:27.359 --> 0:23:31.479 stations were manned by military personnel, primarily the Coastguard. Now 0:23:31.480 --> 0:23:35.199 according to the Coastguard blog site, an assignment to a 0:23:35.359 --> 0:23:39.160 lur End station could be pretty lonesome. The crews tended 0:23:39.200 --> 0:23:42.479 to range in size between eight and twenty five people, 0:23:43.160 --> 0:23:45.800 and typically the person put in charge was a junior 0:23:45.880 --> 0:23:49.120 officer who had maybe served a tour of duty aboard 0:23:49.200 --> 0:23:52.560 a ship and now was put in charge of an office, 0:23:53.040 --> 0:23:57.119 and frequently this would be the highest military officer rank 0:23:57.359 --> 0:24:00.000 in the area, not meaning that the rank was particular 0:24:00.000 --> 0:24:04.080 really high, but rather that these stations were in pretty 0:24:04.200 --> 0:24:07.760 remote spaces, sometimes so much so that the only communication 0:24:07.840 --> 0:24:11.080