A tag shows in the wrong room — what to check

Use this page when someone says "it says I'm in the pantry, but I'm at my desk". Each section starts with what you see, explains why it happens, and lists the steps to fix it. Start with the two places that tell you what Omaya is actually doing, because the fix depends on which of the problems below you have.

Most fixes are switches on one panel: System → Configuration, the Indoor Positioning card. They apply to your whole organisation and take effect from the next sweep after you press Save. Change one at a time, then watch for a day, so you know which change helped — or, before you change it, press Try on the last day next to it on the Overview tab to see what it would have done to your own tags yesterday (how a trial works).

The two pages at the top answer most of the question before any setting is touched. The Health tab speaks for the whole floor over the last seven days; Why here? speaks for one device, right now, and its What happened column usually names the stage that held the tag where it is.

Each stage a tag goes through on its way to a room is drawn in How a tag becomes a room; the sections below are the same stages, seen from the symptom end.

Before anything else: is the tag where you think it is?

At Northwind Tower, Mei Ling Tan (Receptionist) reported that the Boardroom was always shown empty during the Monday meeting. The badges were in the attendees' bags, which were in the cloakroom next door. Check where the tag physically is — on the person, in a drawer, on a trolley — before suspecting the positioning.

Start here: what Omaya sees

The floor's Health tab

Space → Venue, open the floor, then the Health tab on the floor plan.

It covers the last 7 days on that floor:

• Rooms that can be shown, Gateways placed, Typical stay in a room and Flickers between rooms.
• A list of advice for this floor, for example a missing gateway height.
• Rooms: every zone, marked has a gateway, by room estimation, or cannot be shown. A room marked cannot be shown will never be reported, whatever you change in settings.
• What placed devices here: which positioning methods made the decisions.
• Settings: whether Room estimation, Floor majority vote, Gateway receive offsets and Presence hysteresis (the panel's Bermuda-style zone stability) are on, with a link to change them.

If Flickers between rooms is high, go to Flicking between two neighbouring rooms. If the room you expected says cannot be shown, go to A room is never detected.

The device's "Why here?" explanation

Monitor → Live Monitor, click the device to open Sensor Detail, then press Why here? at the top.

The page shows:

• Reported location: the floor and room, the Method, the Committed gateway with its signal, and As of, the time of that record.
• What the gateways hear: every gateway that heard the tag recently, with its signal strength, strongest first.
• Which floor the signal favours: the vote of those gateways, floor by floor.
• Why it has not moved: the recent decisions. Each one shows the gateway it stayed on, the gateway that challenged it, the Gap in decibels, the Outcome, and a sentence under What happened.

Method uses the same names as the Health tab's What placed devices here (hold the pointer over it for the internal code). What each means:

Method	What placed the device
Zone estimate	Room estimation
Triangulated	Distances from three or more gateways
Triangulated (offset)	The same, then pulled onto a walkable spot
Fused	The radio map (fingerprint), combined with triangulation
Fingerprint	The radio map on its own
Bounded	A rough box from the gateways' ranges, when triangulation could not settle
Loudest gateway, Presence (anchored)	The loudest gateway: the device is in that gateway's zone
Fixed sensor	A fixed sensor's own placed position
Beacon anchor, Wi-Fi anchor	A badge or phone that scans: the room of the anchors it heard loudest. See Beacon and Wi-Fi anchors
GPS	The tracker's own GPS fix, outdoors. See Indoor and outdoor

The table under Why it has not moved explains gateway decisions, so it only applies to tags the gateways hear. For a Beacon anchor or Wi-Fi anchor device, use Recent placements on Space → Beacon & Wi-Fi Anchors instead.

The sentence under What happened usually names the cause:

What happened says	What it means	Go to
"…was ahead by 3 dB, but a switch needs 6 dB."	The other room was not convincingly louder.	Flicking, and the Speed margins
"…is ahead but has not held the lead long enough yet."	A move is on its way; it is waiting for Hold before writing.	Nothing, unless every move is late: the Speed preset
"The device has not moved recently, so it is held on…"	The tag is still, and a hold is keeping it where it was.	Desk tag
"…has gone quiet, but … must win again before the device is moved…"	The tag's usual gateway stopped hearing it. Omaya waits one more sweep, so a gateway restarting does not throw the tag across the building. If the gateway does not come back, the tag moves on the next sweep.	Check that gateway is online, if it happens often
"Most gateways in the building kept placing the device on…'s floor…"	The floor vote moved it.	Wrong floor
"The floor model judged…" / "…the floor model still places the device on…"	Your organisation has the floor model on, and it moved, or held, the floor.	Wrong floor
"…looked stronger now, but its recent history is weaker…"	A one-off spike from the other gateway was ignored.	Nothing: this is the guard working
"…led on the latest reading but not across the recent window…"	The other gateway won one reading, not the last few.	Nothing, unless it never moves: the Speed preset
"…stopped hearing the device, so the commitment was released…"	The usual gateway went silent and the tag moved to the next one that hears it.	If the tag did not really move, check that gateway is online

Why here? explains the gateway decisions. When Room estimation is on, the room inside the floor is chosen after them, so a device can be committed to the right gateway and still be shown in the neighbouring room; the Flicking section covers that case.

The tag is on the wrong floor

What you see. A person on Level 4 is shown on Level 5, or keeps hopping between floors.

Why. Radio passes through floor slabs and up stairwells. A gateway upstairs can hear a tag downstairs, sometimes as loudly as the gateways on the tag's own floor.

What to do.

1. Open Why here? for the tag and look at Which floor the signal favours and What the gateways hear. If one gateway on the other floor is much louder than everything on the right floor, the problem is that gateway's placement (for example above a stairwell or a thin slab). No setting fully overrides physics.
2. In System → Configuration → Indoor Positioning, open the Floors tab.
3. Turn on Pick the floor by majority vote. Every gateway that hears the tag then votes for its own floor, so one stray gateway upstairs can no longer pull the tag up.
4. Under How separated are your floors?, pick the preset that describes the building: Concrete slabs, Standard or Open plan (mezzanines, atriums). Leave Advanced thresholds alone unless you have measured a reason.
5. Turn on Ignore faint readings from another floor. This drops a reading heard only by one or two gateways, all of them faint, which is usually a tag on the floor above or below.
6. Press Save, and check the tag again after a few minutes.
7. Check each venue's Floor level under Space → Venue. Floors are compared by that number: two venues with the same level, or levels in the wrong order, confuse every floor decision.
8. If tags still land on the wrong floor, turn on Weigh the floor over time on the same tab. It weighs the evidence from sweep to sweep instead of deciding the floor on each reading alone.
9. Look at Where coverage is thin on the Overview tab. If it names two gateways on different floors that hear the same tags about equally, tags near them are a coverage problem: move one of the two, or add a gateway on either floor further from that spot.

Short real trips are real. A tag that goes upstairs for three minutes to drop a key off will be shown upstairs for about that long, once the move has won for the time on the Speed tab. A visit shorter than that time is not recorded at all, by design; with Weigh the floor over time on, tags with a motion sensor can show shorter trips if Change floor sooner while a tag is moving is on too. And a visit to a part of a floor that only a gateway on the other floor hears well cannot be told apart from a tag that never left: the fix there is a gateway on the visited floor near that spot, not a setting.

More: Floors settings.

Flicking between two neighbouring rooms

What you see. A tag that is not moving changes room every few minutes, back and forth between the same two rooms. The trail fills with short visits.

Why. Signal strength wobbles by a few decibels on its own. A tag near a wall is heard almost equally by the gateways on either side, so the louder one keeps changing.

What to do.

1. Check the floor's Health tab: Flickers between rooms tells you how widespread it is, and Settings shows what is already on.
2. In System → Configuration → Indoor Positioning, open the Rooms tab.
3. Turn on Room estimation. It works out the room from every gateway on the floor rather than the single loudest one, and keeps a tag steadier. It needs zones drawn on the floor plan and at least one gateway placed.
4. Turn on Also use triangulation as evidence. With three or more gateways heard, the distance fix counts towards the room, and rooms are held a little longer.
5. If the flicking is around a gateway mounted where two or three rooms meet (a corner, or a shared wall), also turn on …but not beside a gateway on a room corner. A tag right next to such a gateway is then judged without the distance fix, which is what was flipping it between those rooms. Gateways well inside one room are not affected. Better still, if you can, move that gateway a metre or two into one of the rooms: no setting beats a gateway that is clearly in one room.
6. If it still flicks, open the Speed tab and choose a steadier preset: Stable for desks and equipment, Balanced for staff and visitor tags. Steadier presets take longer to show a real move, and visits shorter than the time shown at the top of the tab are not recorded.
7. On venues with four or more gateways, the Stability & records tab's Bermuda-style zone stability can help as well. It has no effect on venues with one to three gateways.
8. Press Save.

More: Rooms settings, Speed settings.

A tag left on a desk wanders, or sticks in the wrong room

What you see. A tag lying still on a desk or a shelf drifts from room to room over the day. Or the opposite: a tag that has been put down stays in a room it is clearly not in.

Why. While a tag lies still, the readings around it still drift slowly as people walk past and doors open. Omaya can hold a still tag where it is, but a hold keeps whatever room was shown when the tag was put down, right or wrong.

What to do if it wanders.

1. Check the tag has a motion sensor. The holds below only work for tags that report movement. Tags without one are not affected.
2. In System → Configuration → Indoor Positioning, open the Speed tab and check Settling hold at rest is not 0. This holds the gateway decision once the tag has been still for that long, adds no delay to arriving, and is still overruled by a gateway 10 dB louder.
3. For a firmer hold, open the Rooms tab and turn on Hold the room while a tag lies still. Once a tag has not moved for 5 minutes, it keeps its room until it is picked up again. This only acts while Room estimation is on.
4. Press Save.

What to do if it sticks in the wrong room.

1. Open Why here?. If What happened says the device has not moved recently and is being held, a hold is doing exactly what it was set to do.
2. Pick the tag up and move it a little. The hold releases as soon as it moves, and the room is worked out again.
3. If this happens often, turn Hold the room while a tag lies still off. You are trading fewer wanders for fewer stuck tags; which matters more depends on how the tags are used.

One kind of tag is always in the wrong place

What you see. Card tags position well, but wristbands (or another model) are consistently placed too far from the gateways, in the next room, or near the middle of the floor.

Why. Each gateway's calibration was measured with one particular tag, the one carried on the calibration walk. A model that transmits louder or quieter is heard that much louder or quieter everywhere, and Omaya reads the difference as distance. Six decibels makes every range 1.7 times too long.

What to do.

1. Open one of the affected tags under Device → Sensor and look at its Tag Power card under Calibration. If it says Not measured, that model has never been compared with the reference tag.
2. Measure the model on the calibration bench: Device → Sensor, the Tag Power button, then Measure. Follow Measuring tag power, step by step.
3. If only one tag of a model is off and the others are fine, its card may show a warning that tags of this model advertise different power. Compare it with a sibling first, as described in Checking one tag against its siblings. Then give that tag its own value in This tag's own offset on its Tag Power card, rather than changing the whole model.

Background: The tag the walk was carried with.

One gateway pulls tags in from next door

What you see. Tags in the room beside one particular gateway keep being shown in that gateway's room. Why here? shows that gateway as louder than the one actually in the tag's room.

Why. Gateways do not all hear equally. The model, the antenna and how it is mounted make some gateways hear a few decibels louder than others, and a louder gateway wins tags that are really nearer a quieter one.

What to do.

1. Check the gateway's placement first: Space → Venue, open the floor, the Gateways tab. A gateway placed on the plan away from where it really hangs makes the problem look like this too. See Placing the gateways.
2. On the same Gateways tab, find Receive offsets (it shows In use or Switched off). Press Suggest from calibration to get suggested offsets from your calibration walk, then Use the suggestions if they look sensible. You can also set one gateway by hand in its Rx field: how much louder (+) or quieter (−) it hears than the others on the floor.
3. If you want the offsets measured properly, with the gateways taken down and compared side by side, ask your Omaya operator. That is done on the operator's calibration bench; see Measuring gateway hearing. Once measured, OAIA can apply each gateway's measured offset for you and checks the next day whether tags bounce between rooms less; see Gateway receive offsets from the Calibration Bench.
4. Offsets do nothing until the switch is on. In System → Configuration → Indoor Positioning, Rooms tab, turn on Allow for gateways that hear louder than others and press Save. This changes how every tag in the organisation is assigned to a room, so turn it on on a quiet day and check the result.

A room is never detected

What you see. Nobody is ever shown in a particular room, even when people are clearly in it.

Why. A room can only be reported if a gateway is in it, or if Room estimation can tell it apart from its neighbours. No setting makes a gateway hear further.

What to do.

1. Open the floor's Health tab and find the room under Rooms.
   • cannot be shown: go on to step 2.
   • by room estimation or has a gateway: the room can be shown, so the problem is one of the sections above. Use Why here? on a tag that was in the room.
2. Check the room is drawn as a zone on the floor plan. A space that is not a zone cannot be reported.
3. Turn on Room estimation (System → Configuration → Indoor Positioning, Rooms tab). Without it, only rooms with their own gateway can ever be shown.
4. If the room still says cannot be shown, it needs a gateway in it or near it. Add one, place it on the plan, and include it in the next calibration walk.

Positions got worse after someone changed something

What you see. A floor that used to position well is now off — everything a little too far from the gateways, or whole rooms swapped — and the only thing that happened was an improvement.

Why. Several settings feed one another, and changing one without the one it depends on makes things worse, not better.

What to check, in this order.

Change that was made	What it does to the floor	Fix
The reference line was redrawn, or the width and height were retyped	Every distance on the floor is rescaled. The Scale tab shows From this line against Image tab says; a difference there is the size of the error.	Re-measure the line between two points you have actually measured.
Gateway heights (H) or Tags travel at were set on a floor that was already walked	The walk's fall-off already contains the height difference, so it is corrected twice.	Walk the floor again.
A gateway was moved or added	Earlier walks on that floor stop counting, so the floor drops from fingerprint to triangulation until it is walked again.	Place the gateway accurately, then walk again.
Someone ran a short or partial walk	A thin radio map can be promoted to fingerprint and outvote good triangulation.	On the Calibrate gateways page, pin the Positioning method to Triangulation, or walk properly.
Receive offsets were applied	Allow for gateways that hear louder than others now changes every room decision.	Turn the switch off and compare on a quiet day.
A setting was switched on	Every switch acts on the whole organisation.	Turn it off again; change one thing at a time.

Pin down when the floor went wrong — a tag's trail under Reports → Sensor Trail shows the day its rooms changed character — and then ask what changed that day. The floor's Health tab lists which positioning switches are on now.

Related

• Floor plans and positioning, for the plan, the gateways, the walk and every positioning setting.
• The calibration bench, for measuring tag power.
• Setting up a site, for the order things depend on each other.