Scanning API position accuracy

[andreaziani]

I'm going to realize a indoor positioning application using Cisco Meraki technology.

I've inserted the floor plan in the Meraki dashboard and activated the web server to manage the receive of the HTTP POST scanning API.

In the HTTP POST I obtained the latitude, longitude, x and y arrays and all of them have the same value for all connected devices despite devices are not in the exactly same position.

So my question is: is it possible to obtain the device's location with one only Access Point (only one Meraki MR33) or I need more APs?

[PhilipDAth]

You need each client to be seen by a minimum of 3 APs, ideally 4.  Otherwise all it can report is that the people are in the vicinity of the AP.  The AP's should not be in a straight line either.

Their is a field "unc" which specifies the level of uncertainty of the measurement.  With one AP the unc will be high.

https://documentation.meraki.com/MR/Monitoring_and_Reporting/Scanning_API#Scanning_Data_Elements 

[andreaziani]

Hi, thank you for your fast reply.

I've read the documentation and isn't write the difference in the received data elements having 1 AP instead of 3/4 APs.

Otherwise I've notice that the "unc" value in my survey is quite variable, some clients are detected with unc value close to 0 (with only one AP).

Is it possible to calculate the distance from device to AP with only the unc value and the position?

 "observations": [
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 18.905358527674867,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T15:59:48Z",
        "ssid": null,
        "os": null,
       "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409588,
        "rssi": 28,
        "ipv6": null,
        "manufacturer": "Huawei Technologies"
      },
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 0.41857468626495203,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T16:00:52Z",
        "ssid": null,
        "os": null,
        "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409652,
        "rssi": 56,
        "ipv6": null,
        "manufacturer": "Hon Hai/Foxconn"
      },
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 23.374642923293919,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T16:00:40Z",
        "ssid": null,
        "os": null,
        "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409640,
        "rssi": 28,
        "ipv6": null,
        "manufacturer": "Hon Hai/Foxconn"
      },
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 1.233417960754815,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T16:00:13Z",
        "ssid": null,
        "os": null,
        "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409613,
        "rssi": 47,
        "ipv6": null,
        "manufacturer": "AMPAK Technology"
      },
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 33.423762656612396,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T16:00:23Z",
        "ssid": null,
        "os": null,
        "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409623,
        "rssi": 22,
        "ipv6": null,
        "manufacturer": "Samsung"
      },
      {
        "ipv4": null,
        "location": {
          "lat": 22.322323232323421,
          "lng": 12.117757849558416,
          "unc": 9.2297522781748285,
          "x": [
            8.6949159407678032
          ],
          "y": [
            7.5237199778860475
          ]
        },
        "seenTime": "2018-10-01T15:59:55Z",
        "ssid": null,
        "os": null,
       "clientMac": "XX:XX:XX:XX:XX:XX",
        "seenEpoch": 1538409595,
        "rssi": 37,
        "ipv6": null,
        "manufacturer": "Apple"
      },

P.S. attached the detected results.

[PhilipDAth]

I'm going to guess the sample with a low unc is very very close to the AP, so it doesn't matter exactly where it is with regard to the AP - when you know it is within 1m.

[Manuel_Mora]

using the meraki location APIs and putting the correct design for location (3/4AP),
what is the range of precision we could have in meters?