Beacon Central Points: Exact Distance Calculations | Marvelmind

0:01 Hello, colleagues. We have been asked one more time about the precise distances between the beacons and where these distances are measured from. So, even though we believe we have covered this topic already, it's worth addressing it again. I will be talking about a couple of points now. First of all, different types of beacons, because really, the answer depends on the type of beacons that you have. Then TX versus RX—so transmitting ultrasound and receiving ultrasound. The point is not exactly the same, and some of the beacons support automatic table of distance building, so you don't have to measure the distance.

1:00 You can simply ask the system to do it automatically for you, and it will be done. So let's do it one by one. Now, first of all, the question is correct. And when we are talking about two-centimeter precision, it's very important to measure from a particular point. What is the center of the beacon? From where is two centimeters? Or from where is the exact central point of the beacon? You want to measure the direct distance to another stationary beacon, or if we are talking about the system in general, where is the system measuring the location from the stationary beacon to the mobile beacon? So the question is not so complex, but nevertheless, it requires clear understanding. First: different types of beacons. That's correct.

1:59 Because for different types of beacons, the central point is different. Let's take the most typical beacon: Beacon HW v4.9. In Beacon HW v4.9, you have five transducers. They are both receiving and transmitting. So this is why, effectively, this is like a star. When you are close to the sun, it's not a point anymore. On a large distance, this is a point, and it doesn't matter. But when you're close, it does matter that the exact point is a bit spread. It's not a single point; it's somewhere in the middle. But for simplicity, when you have to measure something, the center is the center of...

2:59 RX4, about one centimeter below the top. That's the recommended single point when you want to measure the location of Beacon HW v4.9. If you want to go a bit deeper, then you need to understand: if you have a beacon and the beacon is covering this territory, then what I just mentioned—this central point—would be pretty much correct. But at the same time, when the system builds the table of distances, then this beacon, or this sensor, wouldn't work when the distance is measured towards the stationary beacon in that direction. This sensor will be used. So it means that there is automatically a one-centimeter error if you assume this is the center, but in fact, the system will measure...

3:57 The distance from this point. If you are using the embedded functionality of Beacon HW v4.9—the ability to self-build the table of distances—so it means that for the stationary beacons in that direction, this will be used. But for the stationary beacon neighboring from that direction, this will be used. And you see there is already quite a distance between them. This wire, this is kind of okay in the middle, but not necessarily a precise answer in all conditions. Remember this, keep this in mind when you need to calculate something precisely, and maybe even adjust manually by one centimeter to add or to subtract when required. But for Beacon HW v4.9, as a rule of thumb, the center one centimeter below the top would be...

4:56 Their most safe choice for the center of the beacon. This is for Beacon HW v4.9. For Super-Beacons, the story is slightly different. Yes, Super-Beacons have the same structure in terms of transmitting ultrasonic transducers, but for receiving, this is a receiving point. Super-Beacon is not receiving by these ultrasonic sensors. The beacon is receiving by this point, and this point is very precise and very exact. But at the same time, as you see, there is a shift. And it's answering the second question or the second point already. The center for the transmission would be still one centimeter below this RX4 in general. Although those comments that I gave...

5:54 For self-building are still valid, but that's for when the beacon is transmitting ultrasound. When the beacon is receiving, there's no ambiguity, and the point is very precise and very simple: it's the center of the microphone. So one millimeter less below this top, in the middle. So if you want to be super precise and you know that this beacon is used for receiving, then your center is known. For transmission, the same rule as I applied for Beacon HW v4.9. For Industrial Super-Beacons, the logic is the same. So TX is spread a bit more than in this case, but it's spread. And RX is the microphone. So you need to understand whether you are asking about the transmission...

6:53 Or reception, and in which mode the beacon will be operating. And if necessary, you would be able to manually adjust the distances by adding or subtracting the measured distances. But remember that, like in regular Super-Beacons, in Industrial Super-Beacons, the receiving point and transmitting points are kind of shifted—slightly and slightly different. For Industrial RX, the distance is also very straightforward and very simple: it's one millimeter below the surface at the center of the receiving microphone. So use this point when you are calculating the precise position and the precise distance...

7:50 Between the beacons. Then, about building automatically versus not automatically: some of the beacons, like Beacon HW v4.9, are capable to measure the distances automatically. So you don't have to measure it manually at all. You can basically put those beacons on the walls, ask the system to talk and build the system, and in five to ten seconds, the table of distances would be populated by the distance between the stationary beacons. It works perfectly well in good conditions. When the conditions are not good—for example, distances are large and placement of the beacons is not optimal—you can choose between manual or taking partial data.

8:53 For example, the distance from beacon 1 to beacon 2, and from beacon 2 from beacon 1, is measured. The distance is measured; the table is populated. But the distances do not match for whatever reason—as mentioned, because of propagation, because of distances, because of something else. But you can estimate which one is right. Because, for example, if this is 10 and another one is 20, and you know it's certainly not 10, then 20 is the right calculation. Use it. And you can apply out of this pair only one distance to the pair. So you're still not using manual, but you apply one of the measured distances to the pair because usually the system is calculating from one to two and from two to one. If they are matching very, very close, then the table of distances is wide automatically, and it's a confirmation for you that the system measures the distances successfully, and you can just...

9:52 Take what is measured—that's the best way and the most recommended way. But sometimes when I have a complex and distances and noisy environment, you may have only one distance out of two. Use it. Still, you can use it if you cannot measure the distance automatically for whatever reason—because of distance, because of noise, because of something—use the manual calculations from the points I already mentioned. So once again, for Beacon HW v4.9, it's possible to use automatic building the table of distance and automatic positioning in Non-Inverse Architecture. For Super-Beacons, it's possible to build the same in Inverse Architecture, Non-Inverse Architecture, and Multi-Frequency Non-Inverse Architecture, which is why, you know, Super-Beacons are easier to operate in many cases. Now I already mentioned in the previous...

10:52 In some of the previous videos, remember that their microphones have nearly 180 degrees diagram in this direction, in vertical direction, but not 180. So this is why particularly when you have a large distance, you place on the same wall or on the same wall beacons, then on the large distance, these microphones may not hear well those beacons. We already mentioned this. In this case, you would need to measure like this towards that beacon and to like this towards that beacon and then put it, or to use manually—that's always an option. So hopefully this explanation will give even more details about the precise positioning of the dots, and if still not clear, send us a mail, ask questions. We'll be happy to answer them. One more time, thank you.