Troubleshooting

Fixes for common problems — no GPS, poor accuracy, receivers that won't connect, RTK stuck at float, NTRIP errors, terrain, offline maps, capture and import.

On this page

Find the message or symptom you're seeing below. If nothing here helps, report a problem from inside the app. It sends your connection and fix state along with your note.

Location and accuracy

"Waiting for GPS…"

The app needs a position and hasn't had one yet.

  • Go outside with a clear view of the sky, and give it a moment. The phone's GPS is much slower and less accurate indoors.
  • If you're using a receiver, check it's connected and has a fix. See Receiver won't connect.

"Location access is off"

OpenSurvey3D doesn't have permission to use your location. Tap Open Settings and allow location access while using the app. Or connect a GNSS receiver instead. See Install and permissions.

Accuracy is much worse than expected

  • Phone GPS alone is good to a few metres horizontally, and its heights can be 5–15 m off. That's normal. For centimetres you need an RTK receiver. See Phone GPS vs a receiver.
  • With a receiver, check the accuracy pill. Only RTK FIXED is survey grade. RTK FLOAT is shown in the alert colour: its estimate can look small and still not be real.
  • The pill reads RECONNECTING. The receiver dropped. Positions have fallen back to the phone's GPS until it reconnects.
  • Coordinates are consistently 1–2 m off published NAD83 values. Your correction service may be ITRF-based. The app treats NAD83 as WGS 84 and can't detect this. See Known limitations.
  • Elevations are off by about the pole height. Check the pole height in the Precision sheet. See Antenna height.

Receivers

Receiver won't connect

The Precision sheet shows the receiver's state:

State What it means
Connecting… The app is opening the connection.
Waiting for receiver A Bluetooth receiver was chosen but isn't available yet. Check it's switched on and paired in iOS Settings → Bluetooth.
Connected · no fix yet The link works, but the receiver hasn't reported a position yet. Give it a clear sky.
Reconnecting… (attempt n) The connection dropped and the app is retrying.
Connection failed The app gave up. A reason appears with it, for example Receiver stopped sending data.
  • Bluetooth: only the Emlid Reach RX, RX2 and RS4 and the Bad Elf Flex and Flex Mini can stream to the app over Bluetooth. A Reach RS2 or RS2+ can't stream to third-party iOS apps over Bluetooth, so connect it over its Wi-Fi hotspot instead. See Connect a Bluetooth receiver.
  • Wi-Fi: join the receiver's hotspot, check the host and port, and allow Local Network access for OpenSurvey3D when iOS asks. The app can't reach the receiver without it. See Connect a Wi-Fi receiver.

The source shows "External accessory via iOS Location Services"

Your receiver is paired with the phone, but the app isn't connected to it. iOS is passing its position along without a fix type or accuracy, and the Precision sheet says Relayed by iOS — connect the receiver above to record fix type and accuracy. Connect the receiver in the Precision sheet so every position records its fix type and quality.

RTK stuck at float, or "no corrections"

  • "no corrections" in the expanded accuracy pill means the receiver isn't getting any. It won't reach a fixed solution until that changes.
  • Correction age turns orange above 10 seconds. Old corrections mean the solution is extrapolating. The QA report flags fixes on corrections more than 30 s old.
  • Connect the receiver before corrections. Corrections are forwarded into it, so Connect corrections stays greyed out until the receiver is connected and a mountpoint is filled in.
  • "This connection can't carry corrections to the receiver…": the Bluetooth corrections channel didn't open. Positions still stream. Power-cycle the receiver and reconnect.
  • Bad Elf Flex: you can instead run NTRIP in the Bad Elf Flex app in the background. Use one path, not both.
  • A distant base or a poor sky view can keep a solution at float. See NTRIP corrections.

NTRIP errors

Message Fix
Unauthorized — check NTRIP username/password. Re-enter your caster login.
Mountpoint not found — caster returned its sourcetable. Check the mountpoint name. The mountpoint is misspelled or doesn't exist. Use Browse mountpoints… to pick from the caster's list.
Unrecognized caster response Check the host and port are an NTRIP caster's.
Reconnecting to caster… (attempt n) The connection dropped. The app retries on its own.

Data and saving

A save is blocked by the accuracy gate

The project's accuracy gate is set to Block. The alert names the problem, for example 0.083 m — outside this project's 0.050 m threshold, or a fix type below the project's floor. Nothing is lost: the measurement stays in hand. Wait for a better solution and measure again, or change the setting under Tools → Accuracy gate. Positions placed by hand are never blocked. See Accuracy gate.

"Database recovered"

The survey database couldn't be opened, so the app started a new one. The damaged file wasn't deleted: it was set aside in the app's data folder as opensurvey-damaged-<date>.sqlite. Photos and scans on disk are kept. Report a problem straight away, before collecting much new data, so the old database can be looked at.

"Couldn't import"

The message says what went wrong. The common ones:

  • Projected coordinates without a zone: set the zone under Tools → Coordinate system, then import again.
  • No importable features: check the column names.
  • No .shp in a ZIP: zip the shapefile's .shp, .shx, .dbf and .prj together.

See Import.

Point file (PNEZD) is greyed out

A PNEZD file needs a projected coordinate system. Set one under Tools → Coordinate system.

A report is waiting to send

Settings → Report a problem shows, for example, 1 waiting to send. The report was saved without a connection. It sends by itself the next time the app opens or comes to the foreground with a signal.

Maps and 3D

The map is blank, with a Retry banner

The basemap couldn't load, usually because there's no connection. Tap Retry once you have a signal. To work without a signal, download the area beforehand under Tools → Offline maps. See Offline maps.

An offline map isn't showing

  • Offline areas have to be downloaded before you lose the signal. Check Tools → Offline maps. An area that shows Resume download didn't finish.
  • If you see "Zoom in or lower the detail level — this area is too large to download politely", choose a smaller area or a lower detail level.
  • Clear map tile cache in Settings doesn't remove downloaded offline areas.

"Terrain failed" or "No connection" in 3D

  • No connection: Terrain needs a one-time download. Build the site model once while online, under Tools → 3D site model, then it works offline.
  • Terrain failed: the banner gives the reason. Tap Retry.

See 3D site model.

Capture

LiDAR or photo capture is unavailable

Point-cloud capture needs a device with LiDAR (iPhone Pro or iPad Pro). Photo capture needs a device that supports Object Capture. On other devices the mode is disabled and shows the reason. See 3D capture overview.

"Collect an asset first"

Photos, videos and 3D scans attach to a surveyed asset. Collect a point on the Survey tab, then capture against it.

"Camera not available"

The device has no camera to use. Choose Library to attach an existing photo instead.

"Export as LAS" refuses

A LAS file needs the scan's position fix, compass heading and anchor height. Without all three it can't be placed on the ground, so the app says which is missing. Share the PLY instead. It's honest about being in a local frame.