# an electronic device that knows its position

Is there an electronic device that I can use that can tell me its position in 3D space? For instance if I put it in the middle of my desk it can tell it is at (0,0,0). If I move it back on the desk it knows it is at (0,0,-2). If I pick it up it knows it is at (0,4,-2). I am talking about hardware not software. What are some of the possible ways to impliment something like this?

• PS: Imagine something like a GPS system. But I need many of them so something simpler and less expensive and hopefully smaller.
• : PS: Imagine something like a GPS system. But I need many of them so something simpler and less expensive and hopefully smaller.
:

You mean something like this?

http://www.jandspromotions.com/zilog2003/h-4206.htm
• Not exactly. I believe that device only detects the orientation of the device, not its location. I believe the xyz components they talk about are the rotations around the xyz axis'.

What I am thinking is something like this (I don't know if it is possible): Place receivers at each of the six corners of a room. Place a device in the room that transmits to those receivers every x number of miliseconds. This is the device whose location we are trying to determine. You should be able to calculate the relative distance of the transmiter from each receiver based on how long it takes the signal to reach them. For instance say that it reaches one receiver at a certain time. Then a little later it reaches a different receiver. Then it reaches a different receiver a little later, etc... If you know the exact locations or each reciever you should be able to triangulate the position of the transmiter. The main problem is that radio signals travel at the speed of light and so the differences in time it takes to travel to each receiver would be so small that it would be impossible to create a timer that can even distinguish between the times. This is sort of like how GPS works but GPS satelites are so far away that it takes substantially longer for their signal to reach recievers, making it possible to time and calculate the distance to the reciever.

What I am thinking about is a motion-capute suit. One that can have many transmiters that transmit unique identifiers. The positions of those transmiters can be calculated and used to create polygon meshes for 3D character animations.
• I guess the main question I need to ask is if it is possible to accurately calculate the distance between a reciever and a transmiter? If I can do this in one dimension I can make it work in two or three dimensions.

I thought of one other posibility. If I can calculate a ray that passes through the object I am tracking from three different points I can also triangulate the objects position. The point lies at the intersection of the three lines.

Any other ideas?
• Hi,

We have developed a Local Positioning System to locate a device in a known locale using Triangulation. Mabe our solution might address your need.

Cheers
Srikar

: I guess the main question I need to ask is if it is possible to accurately calculate the distance between a reciever and a transmiter? If I can do this in one dimension I can make it work in two or three dimensions.
:
: I thought of one other posibility. If I can calculate a ray that passes through the object I am tracking from three different points I can also triangulate the objects position. The point lies at the intersection of the three lines.
:
: Any other ideas?
:

• : Is there an electronic device that I can use that can tell me its position in 3D space? For instance if I put it in the middle of my desk it can tell it is at (0,0,0). If I move it back on the desk it knows it is at (0,0,-2). If I pick it up it knows it is at (0,4,-2). I am talking about hardware not software. What are some of the possible ways to impliment something like this?
:
Maybe you need a gyroscope like an aircraft uses, once it is calibrated it keeps its orientation. It would take 3 devices.
• This was a fairly old post. It was an idea that I have had in the back of my mind for some time but have not found a sufficient answer yet. I do not think a gyroscope would work but it is an interesting idea. I have seen an article about an electronic gyroscope but I think such a device as well as a mechanical gyroscope would be too bulky for what I envisioned. Also, a gyroscope only tells you your Heading/Pitch/Yaw. It has no way of knowing if you have moved in a certain direction or the distance (unless you are thinking of something I am not). What I am interested in is the position of a point not it's orientation. Also, just knowing the direction something is facing does not mean it is going to move in that direction. Thank you for your interest and help but I do not think I will be finding the answer anytime soon.
• [b][red]This message was edited by GeoHoffman at 2004-9-9 22:36:19[/red][/b][hr]
I just saw your post. I would be very interested in any links to info about it or a more detailed description of how this works.

What I basically would like to do is create a motion capture suit. This can be used to create a 3D model/animation of the person wearing the suit. So I would need to make many "trackable" devices and embed them into the suit. These would need to be fairly small and inexpensive because most character models have a minimum of 1024 polygons (lets say about 350 vertices) for a low resolution model.

I am not really a hardware guy. I am only a software programmer that has some interests in electronics and hardware. I really would just like to know if this is theoretically possible. It could also be a practical and marketable product what with the amount of money game companies shell out to develope their products. It could save many hours of modeling by hand and help create ultra realistic models.

if you have any suggestions my email is: geohoffman49431@aol.com

thanks

• : hi srikar
i am also devicing a position system for indoor use and was wondering if detals of your project could be outlined to me this would be very greatly appriciated and could mean for me from fail to a pass, i am using dsss signal inorder to transmit dat to the receiver but not yet had the chance to implement my model fully....
i look for ward hearing from you.

Hi,
:
: We have developed a Local Positioning System to locate a device in a known locale using Triangulation. Mabe our solution might address your need.
:
:
: Cheers
: Srikar
:
:
: : I guess the main question I need to ask is if it is possible to accurately calculate the distance between a reciever and a transmiter? If I can do this in one dimension I can make it work in two or three dimensions.
: :
: : I thought of one other posibility. If I can calculate a ray that passes through the object I am tracking from three different points I can also triangulate the objects position. The point lies at the intersection of the three lines.
: :
: : Any other ideas?
: :
:
:

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