Startup founder here, not technical by background, so apologies if this is muddled. We’re building small autonomous carts that move parts around inside a warehouse. 12 carts in the pilot. Customers keep asking “where are the carts right now” and our engineers say indoor location is hard.
Two questions. What do people actually use to locate robots indoors to within, say, half a metre? GPS obviously doesn’t work. And once we have positions, can a Hermetry dashboard show them on our warehouse floor plan, live? We already send battery and job status from each cart to Hermetry.
BLE positioning gets you 2-3 m on a good day. For half a metre you’re looking at UWB.
How often do you need the position? Once a second per cart is very different from once a minute, both for the radio and for what you store.
Once a second would be nice for the live view, but we could live with every 2-3 s.
We track tractors and handheld scanners in large sheds, so I’ve been through both parts.
Positioning: UWB two-way ranging. Fix 4-8 anchors on walls and columns (more in aisles with racking), put a tag on each cart (Qorvo DWM1001/DWM3000 modules are the usual starting point). The tag ranges to the anchors and computes x, y in metres in your own coordinate frame. 10-30 cm accuracy in line of sight. Racks of metal parts will cost you some of that.
The dashboard part is easier than people think. A Map card has an Image (floor plan) mode: you give it the floor plan picture and its width/height in pixels, and then the latitude and longitude columns hold y and x in pixels from the top-left corner. So convert metres to pixels on the cart (or in the gateway) and send them as two keys:
{"pos_x_px": 812, "pos_y_px": 377, "batt_pct": 74, "job": "B12"}
In the card set Latitude column to pos_y_px and Longitude column to pos_x_px, colour markers from a status column (idle, busy, fault), and add tooltip fields for battery and job. Routes can be drawn and replayed too if you want “where did cart 7 go this morning”.
Megan’s question matters for limits. One message per cart per second is 86,400 a day each, so put all the cart’s values in the same message. The default per-device limit is 10 messages a second, so you’re fine there, but look at your monthly message quota before you go to 50 carts. Map cards
Our engineers ordered a DWM3000 dev kit and 6 anchors for the pilot aisle. The floor plan view works already with fake coordinates. We went with one message every 2 s per cart after doing the quota maths you hinted at. Thanks Owen.
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