Badge guide

Indoor worker location without beacons: how Wi-Fi positioning works

Name: Indoor worker location without beacons: how Wi-Fi positioning works
Brand: ZeroBadge

Indoor worker location without beacons uses Wi-Fi positioning: the badge listens for nearby Wi-Fi networks, without joining them, and the pattern it hears points to a place. GPS is weak inside buildings, so ZeroBadge learns each site's Wi-Fi over the first visits and matches later readings to it. That answers which jobsite a worker is at, not which room.

Last updated October 29, 2026

Wi-Fi positioning works from networks the badge can hear, not networks it joins

Every Wi-Fi router broadcasts an identifier and a signal. A badge that scans can record which routers it hears and how strongly, without connecting to any of them and without the site's Wi-Fi password. The set of routers heard, with their signal strengths, is a pattern that is much the same each time the badge is in that spot.

Public Wi-Fi positioning services work from the same inputs. Google's Geolocation API documentation lists Wi-Fi access point data, such as MAC address and signal strength, and cell tower data as its inputs, and it returns a position with a radius of uncertainty. That is a published example of the general method, not a description of ZeroBadge's internals.

Why each method behaves differently indoors
Method	What it needs	Indoors
GPS	A clear view of satellites	Weak. gps.gov lists indoor or underground use among common causes of error, and says accuracy worsens near buildings, bridges and trees.
Wi-Fi positioning	Wi-Fi networks the badge can hear, whose locations are known or learned	Works where there are networks to hear. No hardware from you.
Cellular continuity	Cellular signal	Coarse. Google's documentation says macro cell towers rarely give a radius below 100 meters, so ZeroBadge labels cellular low confidence.
Stored readings	Nothing at the time	Fills the gap after the badge reconnects, with original timestamps

ZeroBadge learns each site's Wi-Fi over the first visits

A site's Wi-Fi pattern is not known until badges have been there. ZeroBadge learns it: readings taken where the position is already confirmed, for example outdoors on GPS inside the geofence you drew, tie the Wi-Fi networks heard to that jobsite. Later indoor readings are matched against what has been learned. Nothing is installed to make this happen.

What the first days at a new jobsite can look like

SetupThe office draws the jobsite from its address. No Wi-Fi is known yet.
First visit, outdoorsGPS places the badge inside the geofence. Networks heard nearby are noted against the jobsite.
First visit, indoorsGPS gets weak. Readings rely on whatever Wi-Fi is already known, or on cellular continuity marked low confidence, so some indoor time can show as lower confidence or location unverified.
Later visitsMore of the site's Wi-Fi has been seen and confirmed, so indoor readings match it more often and with more confidence.

Every reading stores its method and a confidence level

Confidence tells the office how much weight a reading deserves, and every reading stores the method that produced it. Cellular continuity is always labelled low confidence. A reading that matches well-learned Wi-Fi at a site carries more confidence than one matching little. The labels never make a weak reading look strong.

How readings are labelled and what the office should do with them
Reading	How confident	What it means for the timesheet
GPS fix inside the geofence	Usually the strongest	Time is allocated to the jobsite
Wi-Fi match to a well-learned site	Higher	Time is allocated to the jobsite, including indoors
Wi-Fi match to a site with little history	Lower	Time is allocated, but the reading is shown as lower confidence
Cellular continuity	Low, always labelled	Extends the last confirmed place for a while and is never treated as a precise position
No usable reading	None	Shown as other or location unverified until a reading arrives or a stored reading uploads

Anything shown as lower confidence can be reviewed on the weekly timesheet before the week is approved. A correction keeps an audit trail, so nothing is silently edited. See how geofencing works for time tracking.

When indoor location is weaker, and what to do about it

Indoor readings are weakest where there is little Wi-Fi to hear or where the site is new. That is common on construction, and it is worth planning around rather than discovering at the end of the week.

Weak spots for Wi-Fi positioning on construction work
Situation	Why it is weaker	What to expect and do
A brand-new site	No Wi-Fi has been learned yet	More lower-confidence time at first. Review the exceptions list after the first week.
A building under construction before Wi-Fi exists	Few or no networks to hear inside, and GPS is weak under a roof	Indoor time leans on cellular continuity and stored readings. Expect more time marked low confidence or unverified until neighboring or temporary networks are in range.
Neighboring buildings with Wi-Fi	Their networks can help the badge recognise the area	Nothing to configure. The badge listens to networks it can hear, including ones you do not own.
Sparse Wi-Fi: rural jobs, open lots, large yards	Few networks in range	GPS covers most outdoor work. Indoor stretches are lower confidence.
Basements, mechanical rooms, elevator pits	Weak signal of every kind	Readings are stored on the badge and upload on reconnect with their original timestamps.
A site you rarely visit	Little history to match against	Behaves like a new site each time.

What which jobsite, not which room, means in practice

Accuracy for ZeroBadge means placing a worker at the right jobsite geofence, not at the right room or floor. Inside one drawn site, a badge on the first floor and a badge on the third floor are both simply at that jobsite, and both count as on-site time.

One day at a three-story tenant improvement

6:30 AM to 10:00 AM: Third floor, rough-in. On site: Riverside TI.
10:00 AM to 10:30 AM: Walks to the lobby and the truck. On site: Riverside TI.
10:30 AM to 12:00 PM: Basement mechanical room, no signal. Readings stored, uploaded later. On site: Riverside TI.
Total for the three stretches: 3 hours 30 minutes + 30 minutes + 1 hour 30 minutes = 5 hours 30 minutes on one jobsite
What the office sees: 5 hours 30 minutes at Riverside TI. It does not say third floor, lobby or basement.

If two buildings on a campus need separate time, draw them as two jobsites. The unit of accuracy is the geofence you draw, so size and split sites to match the question you want answered.

If your question is room-level, a fixed system is the better tool. See worker tracking without gateways for when that is worth the installation.

How the office handles lower-confidence time

Lower-confidence time is reviewed, not hidden. The weekly timesheet and the exceptions list show missing clock-outs, late starts, early finishes and time outside approved sites, and the office decides what to confirm before approving the week.

1
Open the exceptions list
It shows the items worth a conversation, not every reading.
2
Ask the foreman
A foreman who was on the site on Tuesday knows where the crew was.
3
Correct if needed
Corrections keep an audit trail with who changed what and why.
4
Approve the week
Approved hours are sent to your payroll provider. ZeroBadge integrates with payroll providers, with CSV, Excel and PDF export.

Frequently asked questions

How does a badge know where a worker is indoors without beacons?

It listens for nearby Wi-Fi networks, without joining them, and matches the pattern to what ZeroBadge has learned about each jobsite. Where there is no known Wi-Fi it falls back to cellular continuity, which is labelled low confidence.

Does the badge need the site's Wi-Fi password?

No. The badge has its own cellular connection for sending readings. It only listens to nearby Wi-Fi networks to estimate position, so it never needs a password or access to your network.

Why is a new jobsite less reliable at first?

Because the Wi-Fi at a new site has not been seen yet. ZeroBadge learns it over the first visits, so early indoor readings lean on GPS at the edges and cellular continuity inside. Expect more lower-confidence time at first and check the exceptions list.

Will it work in a building that has no Wi-Fi yet?

Only partly. Outdoors GPS still works. Indoors, with no Wi-Fi to hear, time relies on cellular continuity and stored readings, which are lower confidence. Hours still count when readings show the badge at the site, but more of them will be marked for review.

Can ZeroBadge tell which floor or room a worker is on?

No. It answers which jobsite a worker is at. Indoor readings place the badge at the site, not on a floor. If you need room-level position, see worker tracking without gateways.

Sources

1.GPS accuracy: typical smartphone accuracy under open sky, and what degrades it (buildings, indoor use) · GPS.gov (U.S. government)
2.Geolocation API requests and responses: Wi-Fi access point and cell tower inputs, accuracy radius, macro cell accuracy · Google Maps Platform