Wi-Fi CSI Indoor Localization

Why three nodes

• One link cannot triangulate. It says the channel changed, not where. Nine links from three directions turn that into a position.
• The nodes see different rooms. Two below the dividing wall, one above. A single node in one room is blind to the other.
• A dead link stops being fatal. One of the nine is wall-blocked and contributes almost nothing. With one link that would be the whole system.

Data collection Results Measurements

All 40 routes Hide routes Interactive: click any waypoint to isolate its routes

ESP32 node Router Survey waypoint Route leaving the selected point Route arriving at it

1 - 10

1. 1a → b
2. 2a → h
3. 3b → a
4. 4b → g
5. 5b → e
6. 6e → b
7. 7e → f
8. 8h → a
9. 9h → g
10. 10g → h

11 - 20

1. 11g → b
2. 12g → f
3. 13g → c
4. 14f → e
5. 15f → g
6. 16c → i
7. 17c → j
8. 18c → k
9. 19c → d
10. 20c → g

21 - 30

1. 21i → j
2. 22i → c
3. 23j → i
4. 24j → c
5. 25j → k
6. 26j → d
7. 27k → c
8. 28k → j
9. 29k → d
10. 30d → c

31 - 40

1. 31d → k
2. 32d → j
3. 33i → x
4. 34c → x
5. 35d → x
6. 36j → x
7. 37x → d
8. 38x → f
9. 39x → c
10. 40x → j

Surveyed positions (metres, origin at the lower-left corner)

ESP32 node .21	(2.2, 0.5) · lower room, left
ESP32 node .20	(4.9, 1.7) · lower room, right
ESP32 node .24	(5.6, 5.5) · upper room, doubles as waypoint x
Router	(2.7, 7.1) · upper room, far corner
Doorway between halves	1.4 m opening, waypoint c at (3.4, 4.6)