GeoAstra BLE-GNSS User Manual 目录 / Contents

GeoAstra BLE-GNSS User Manual

Subtitle: For Columbus BLE GNSS receivers
Platform: Apple iPhone / iPad (iOS)
Example receiver: Columbus EX-1 RTK GNSS (screenshots in this manual primarily use this model)
Brand: GeoAstra
Developer / Publisher: GPSWebShop (Canada) Inc.
Version: Refer to the version shown in the App under About

Contents

  1. Introduction: Why this App is needed
  2. Compatible devices
  3. Before you start
  4. Chapter 1: Scan and connect a compatible GNSS receiver
  5. Chapter 2: Configuration
  6. Chapter 3: Dashboard
  7. Chapter 4: Share NMEA with other iOS apps
  8. Chapter 5: RTK Base
  9. Chapter 6: RTK Rover
  10. Chapter 7: EX-1 vs P-70
  11. Chapter 8: Projects
  12. Chapter 9: Collect Data
  13. Chapter 10: My Data
  14. Appendix A: Glossary
  15. Appendix B: FAQ
  16. Appendix C: QField quick setup (example)
  17. Appendix D: Video demos

Knowledge-card index

If you are new to surveying, open these short explanations first, then return to the steps:

Topic Jump to
Orthometric height (MSL) vs ellipsoidal height (h) 2.1.5
hAcc / vAcc (receiver-side accuracy) 3.5
NTRIP Caster / your own CORS 5.2
What is GeoJSON? 10.3
Export decimal places 10.3
NTRIP Server auto-reconnect 5.6

Introduction: Why this App is needed

The reality on iOS

On Android and some other platforms, many external GNSS receivers can feed coordinates into system Location Services for all apps.
iOS is different: Apple does not allow an external GNSS receiver to replace or inject into system Location Services the way the built-in GPS does. Therefore:

In short: to make an external GNSS usable on iPhone, you usually need a bridge app.

What this App solves

GeoAstra BLE-GNSS is that bridge. For Columbus BLE GNSS receivers on iOS it provides:

  1. Reliable Bluetooth connection with automatic reconnect on unexpected link loss, plus live positioning (Dashboard)
  2. Core RTK features (Rover / Base, depending on model)
  3. Local data capture (Collect Point, Record Track)
  4. Project management, browse / export / Stakeout
  5. NMEA Server: forward receiver NMEA over local TCP/UDP to other iOS apps that support NMEA over TCP/UDP (for example QField, ArcGIS Survey123, ArcGIS QuickCapture; see Chapter 4)

Important:
Positions shown in this App come from the connected Columbus receiver, not from the iPhone’s built-in GPS. The GNSS receiver log also shows the receiver’s raw NMEA, not phone GPS.

One sentence for beginners

Think of this App as:

“Connect a Bluetooth GNSS to your iPhone so you can survey points and tracks yourself, and share coordinates with other professional mapping apps.”

Compatible devices

Built-in compatible models currently include:

Device Plain-language notes
Columbus EX-1 RTK GNSS RTK Rover / Base; Survey-in and fixed coordinates can be written to the receiver; example model in this manual
Columbus P-70 Ultra RTK GNSS RTK Rover / Base; Survey-in is Receiver Managed; Output Rate can be set in-app and saved to the device (1 / 5 / 10 / 20 Hz)
Columbus P-9 Race GNSS High-precision GNSS (sports / general positioning); Output Rate can be set in-app and saved (1 / 5 / 10 / 25 Hz); no in-app NTRIP Rover/Base
Columbus P-7 Pro GNSS High-precision GNSS; no in-app NTRIP Rover/Base; this App does not provide Output Rate write control

EX-1 / P-70 Bluetooth names:
Names with NTRIP appear in the scan list, for example:

Overview of the five bottom tabs (Dashboard / Projects / Collect Data / My Data / Discover)

Overview of the five bottom tabs (Dashboard / Projects / Collect Data / My Data / Discover).

Before you start

  1. Hardware: A compatible Columbus receiver (this manual uses EX-1), charged, with a clear sky view outdoors.
  2. Phone: iPhone / iPad with GeoAstra BLE-GNSS installed and Bluetooth permission allowed.
  3. Network (RTK only): Cellular or Wi‑Fi when the Rover connects to an NTRIP caster or the Base uploads to a caster.
  4. Other apps (optional): If you use QField, ArcGIS Survey123, ArcGIS QuickCapture, or similar TCP NMEA apps, install them and note the local NMEA Server address (often 127.0.0.1:9000 TCP).
  5. CORS / NTRIP (RTK only): RTK Rover usually needs a CORS / NTRIP subscription; RTK Base that broadcasts online usually needs an NTRIP Caster account (free commercial-grade signup at https://geoastra.com/ via Sign-up; product page: landing-ntrip-caster).
System Bluetooth permission dialog on first launch (if still reproducible)

System Bluetooth permission dialog on first launch (if still reproducible).

Chapter 1: Scan and connect a compatible GNSS receiver

1.1 Two entry points

Entry Path Purpose
Discover Bottom tab Discover Scan nearby not-yet-saved compatible devices and connect
Device List Device list on the Dashboard root Manage saved devices; Bluetooth Scan can jump to Discover
  1. Power on the receiver and wait for Bluetooth advertising.
  2. Open the App → bottom Discover.
  3. Keep the phone close; scanning lasts about 15 seconds.
  4. In Nearby Devices, tap your device (for example EX-1 shows as EX-1 NTRIP BLE).
  5. Wait for connection; on success the App opens that device’s Dashboard and registers it in Device List.

Connection timeout: about 20 seconds. On failure, tap Try Again or cancel and retry.

Discover scanning with EX-1 NTRIP BLE in Nearby Devices

Discover scanning with EX-1 NTRIP BLE in Nearby Devices.

Connecting… overlay

Connecting… overlay.

Rover Dashboard after a successful connection (live coordinates / Fix preferred)

Rover Dashboard after a successful connection (live coordinates / Fix preferred).

1.3 Reconnect a saved device

  1. Open Dashboard (device list).
  2. Find the device and turn on the connect switch / button.
  3. The App runs a targeted scan (about 30 seconds) and connects automatically when found.

1.4 Automatic reconnect (unexpected Bluetooth loss)

If the receiver drops Bluetooth unexpectedly (for example you walk out of range or the receiver powers off briefly), the App can automatically try to reconnect while you stay on that device’s Dashboard.

Topic Behavior
When it runs Only after an unexpected disconnect—not after you turn off the connect switch yourself, and not during short EX-1 / P-70 configuration transactions
Which device The device you are viewing on Dashboard (or the last successfully connected device)
What you see Orange status such as Reconnecting… attempt 1/5 in progress or waiting for attempt 2/5; the connect switch stays On but is disabled until reconnect finishes or you tap Cancel; the map shows BLE link lost — … instead of “BLE connected”
Attempts Up to 5 tries over about 2 minutes (direct reconnect first, then short burst scans)
After success BLE link and streaming resume; NTRIP Client / Server turn back on if they were active before the drop
After failure Auto-reconnect stops quietly (no notification); turn the connect switch off/on or use Discover to connect manually
Collect Data Does not auto-resume Record Track or Collect Point—use the orange interrupted banner and Finalize / Discard, or reconnect and Resume as in 9.6
Setting Dashboard top-right … → Connection → Auto-reconnect (default On)

Background note: While the App is in the background, only the first phase of reconnect runs (about 30 seconds). Bring the App to the foreground to continue the full sequence.

1.5 Chapter summary

Chapter 2: Configuration

Configuration is usually done after the device is saved. Common entries:

Device List … menu showing RTK Settings, NMEA Server Settings, Rename, Delete

Device List … menu showing RTK Settings, NMEA Server Settings, Rename, Delete.

2.1 RTK settings

Screen name: RTK Settings

2.1.1 Key terms

Term Plain meaning
RTK Improves accuracy using a Rover + Base differential corrections; often centimeter-level (depends on environment and link)
Rover The unit you carry in the field; receives RTCM corrections from a caster
Base Fixed on known or surveyed coordinates; sends RTCM to a caster
NTRIP Common internet protocol for carrying RTCM (a “network pipe” for corrections)
NTRIP Caster Internet relay: Base uploads corrections; Rover downloads them (see Chapter 5)
CORS Continuously Operating Reference Station network; many CORS services deliver RTK via NTRIP

2.1.2 GNSS Mode

2.1.3 RTK Role

Capability notes:

2.1.4 Rover: NTRIP Client (Rover connects to a caster)

Why you usually need a CORS / NTRIP subscription first

An RTK Rover is not “centimeter-ready” by itself—it must continuously receive RTCM corrections from a reference. Those usually come from:

Before configuring Rover, get from your CORS / NTRIP provider (or their portal):

Without a valid correction source, even with a good antenna and sky view you typically stay at single-point / DGPS quality and rarely reach stable RTK Fixed.

Use Clear NTRIP Client Setting to reset the fields.

EX-1 RTK Settings with Role=Rover and NTRIP Client filled (password may be masked)

EX-1 RTK Settings with Role=Rover and NTRIP Client filled (password may be masked).

2.1.5 Base: position & NTRIP Server (Base upload)

Base coordinate source (EX-1):

  1. Enter Fixed Position
    • Enter latitude and longitude
    • Height may be MSL (orthometric) or ellipsoidal h (the App converts the other on save; see knowledge card below)
  2. Survey In Current Position
    • Minimum observation time (seconds), default about 30
    • Required accuracy (mm), default about 1000 mm
    • Optionally start Survey-in automatically after connect

Base coordinate source (P-70):

P-70 uses a Receiver Managed Survey-in / Base workflow:
Survey-in parameters and progress are managed mainly inside the receiver; the App starts/monitors in Receiver Managed mode instead of EX-1-style Duration / Accuracy mm fields.
You can still enter fixed coordinates, or let the receiver finish Survey-in; follow Receiver-managed in RTK Settings and Dashboard status.

Knowledge card: MSL height vs ellipsoidal height h

Why does a Base still need an NTRIP Caster?

Radio-only Base coverage is limited. Configure the Base as an NTRIP Server (uploader) and send RTCM to an internet NTRIP Caster:

GeoAstra NTRIP Caster signup:

  1. Open https://geoastra.com/ → Sign-up (or Login; Apple / Google / Microsoft or a local account)
  2. Product / plans: https://geoastra.com/landing-ntrip-caster
  3. Signup docs: NTRIP Caster Sign-up / Login

After first login, mount point and Base / Rover credentials are usually generated. Enter Host / Port / Mount Point / User / Password in this App’s NTRIP Server / Client settings (case-sensitive; follow Dashboard values).

Unexpected loss: After a Base upload has connected successfully, the App can automatically reconnect to the caster if the link drops unexpectedly (see 5.6). You can turn this off under Connection settings.

2.1.6 Writing settings into EX-1 (important)

For EX-1:

Button Meaning
Apply to EX-1 Temporarily Temporary Bluetooth apply (e.g. CFG-TMODE3); may be lost after power-off
Save to EX-1 Permanently After temporary apply and verification, write to receiver BBR/Flash

Note: Changing only caster account/password (network-side) usually does not require permanent save to the receiver.
Permanent save mainly applies to receiver mode / fixed coordinates.

EX-1 Base settings (Fixed Position or Survey-in visible)

EX-1 Base settings (Fixed Position or Survey-in visible).

Apply Temporarily / Save Permanently buttons

Apply Temporarily / Save Permanently buttons.

P-70 Base settings (Receiver-managed option visible)

P-70 Base settings (Receiver-managed option visible).

2.2 NMEA Server settings

Screen name: NMEA Server Settings

2.2.1 What it does

After the receiver sends NMEA to this App over Bluetooth, the App can open a small local server / output so other apps on the same iPhone/iPad (QField, Survey123, QuickCapture, etc.) can fetch that NMEA via TCP or UDP.

This is not an internet cloud caster—it is local port sharing.

2.2.2 Server Type

Option Meaning
None Disable network output
NMEA Server Enable local NMEA output (recommended default)

Newly registered devices usually default to NMEA Server (TCP, 127.0.0.1, port 9000).

2.2.3 Protocol and ports

Protocol Typical use Default port (auto-updates when switching if still on the old default)
TCP Other local apps connect in (most common: QField / Survey123 / QuickCapture) 9000
UDP This App sends UDP packets to a target address 11111

TCP concept: this App listens; other apps connect to 127.0.0.1:9000.
Only one device may use the same protocol/port at a time; conflicts show Replace / Cancel.

NMEA Server Settings: Type=NMEA Server, TCP, 127.0.0.1:9000

NMEA Server Settings: Type=NMEA Server, TCP, 127.0.0.1:9000.

2.3 Output Rate (P-70 / P-9)

Some models can change the receiver NMEA / position output rate on the Dashboard and save it to the device (persists across power cycles, per model flow):

Model Rates Notes
P-70 Ultra 1 / 5 / 10 / 20 Hz Choose on Dashboard → Apply; persist with Save … to Device (labels follow the App)
P-9 Race 1 / 5 / 10 / 25 Hz Same idea: set in-app and save to device
EX-1 / P-7 — This App does not provide that Output Rate UI

About EX-1: Output rate cannot be changed in this App; it is set by factory defaults or other configuration tools.
Tip: Higher rates suit fast motion and denser sampling, but use more battery, Bluetooth bandwidth, and storage. Daily point survey is usually fine at 1 Hz. Top rates may show a performance warning in the UI.
Relation to Collect Data: This is the receiver output rate. For a denser logged track, raise Output Rate here first, then choose Raw Update Rate under Collect Data → Record Track (9.5). 1 Hz and other Collect Data choices are logging thinning on the App side and are independent of Output Rate.

P-70 Dashboard Output Rate and Save to Device

P-70 Dashboard Output Rate and Save to Device.

Chapter 3: Dashboard

After a successful connection you see that device’s Dashboard (Rover or Base layout depends on role).

3.1 What you see

Typical content:

EX-1 Rover Dashboard overview (Status expanded, Apple Maps visible, Fix preferred)

EX-1 Rover Dashboard overview (Status expanded, Apple Maps visible, Fix preferred).

3.2 Connection switch and automatic reconnect

At the top of each device Dashboard:

During auto-reconnect the map placeholder reads BLE link lost — Reconnecting… (with attempt progress), not “BLE connected — waiting for GNSS data”.

3.3 Rename Device

Rename from the device menu to change the display name (Bluetooth advertised name is unchanged). Useful for labels like “East site EX-1” or “Warehouse spare”.

3.4 Delete Device

Removes the saved entry from Device List.
If connected, disconnect first, then delete.

3.5 Logs and diagnostics

Name Purpose
GNSS Log Console / GNSS Receiver Log Raw NMEA from the receiver over Bluetooth (can pause)
NTRIP Log Console NTRIP connection / data logs (wording differs for Rover vs Base)
Diagnostics No separate “Diagnostic Log” menu; related info for P-70 etc. appears under GNSS Status
GNSS Receiver Log with scrolling NMEA lines

GNSS Receiver Log with scrolling NMEA lines.

NTRIP Log (more representative when Rover is connected to a caster)

NTRIP Log (more representative when Rover is connected to a caster).

3.6 How to read GNSS Status (for beginners)

Field Meaning
Fix Solution type, e.g. GPS Fix, DGPS, RTK Float, RTK Fixed (usually ideal)
Satellites Satellites used in the solution; more is often better (geometry also matters)
HDOP / VDOP Horizontal / vertical dilution; smaller is better for geometry—not a meter error by itself
hAcc / vAcc Estimated horizontal / vertical accuracy in meters; smaller is better. This App prefers receiver-reported estimates (below)
Altitude Usually MSL-related in this App; see 2.1.5 knowledge card for vs ellipsoidal height

Knowledge card: why hAcc / vAcc beat “HDOP × factor”
Many simple apps estimate meters from HDOP × a rule of thumb—that is only geometric rough guessing.
This App prefers receiver-reported hAcc / vAcc (meters):

3.7 Multi-device: Device List

Device List can store multiple receivers. The list … menu also provides:

Action Notes
Import Devices Import a device config package (creates new entries; does not overwrite by identity)
Export Devices Export device configs; optionally exclude passwords (default) or include passwords
Delete All Devices Clears the list (irreversible; confirm)
Compatible GNSS List Registered compatible models and notes
Device List with at least one EX-1

Device List with at least one EX-1.

Device List … menu: Import / Export / Delete All

Device List … menu: Import / Export / Delete All.

Chapter 4: Share NMEA with other iOS apps

4.1 Typical scenario

You want iOS apps that support TCP NMEA to use the Columbus external GNSS instead of the iPhone GPS.

Common examples:

Industry trend: On iOS, external GNSS rarely injects into system location, so “consume NMEA over TCP/UDP inside the app” is becoming the common industrial pattern. More surveying / GIS / field apps are expected to add the same support. If the peer app can connect to 127.0.0.1 (or its documented address) and port, it can work with this App’s NMEA Server.

Setup example: Below and Appendix C use QField; Survey123 / QuickCapture usually follow the same idea (TCP address + port in positioning / external GNSS settings).

  1. Connect the receiver in this App; confirm NMEA and a live fix.
  2. Open NMEA Server Settings:
    • Server Type = NMEA Server
    • Protocol = TCP
    • Host = 127.0.0.1
    • Port = 9000 (or your chosen port)
  3. Turn on NMEA Server on the Dashboard (if shown).
  4. In QField / Survey123 / QuickCapture (or another TCP NMEA app), set external GNSS / NMEA input to:
    • Host 127.0.0.1
    • Same port as above
  5. On this App’s Dashboard, confirm a client is connected (TCP shows client status when available).

4.3 Notes

Dashboard with NMEA Server on and TCP client connected (if available)

Dashboard with NMEA Server on and TCP client connected (if available).

See Appendix C (QField Positioning / TCP settings)

See Appendix C (QField Positioning / TCP settings).

Chapter 5: RTK Base

5.1 When to use Base

Use Base when you provide your own correction source or upload Base corrections to an NTRIP caster.

5.2 How an NTRIP Caster turns your Base into “your own CORS”

An NTRIP Caster is an internet correction relay:

  1. Your RTK Base (via this App’s NTRIP Server) uploads RTCM to a Mount Point;
  2. Your RTK Rover (or other users’ Rovers) as NTRIP Clients download corrections from the same caster;
  3. No radio required for that hop, not limited to short range—one Base can serve many Rovers. That is “turning your Base into your own CORS / reference service.”

If you do not have a caster yet, Sign-up for a free commercial-grade account at https://geoastra.com/ (see landing-ntrip-caster); then copy mount-point credentials from the Dashboard into this App’s NTRIP Server settings.

5.3 EX-1 Base quick flow (concept)

  1. Fix the unit, stabilize the antenna, clear sky.
  2. RTK Settings → RTK GNSS → Role = Base.
  3. Choose coordinate source:
    • Known precise coordinates → Enter Fixed Position
    • Unknown / average in place → Survey In
  4. Configure NTRIP Server (Host / Port / Mount Point / credentials).
  5. On EX-1: Apply Temporarily when needed; after verification Save Permanently.
  6. Return to Dashboard (Base view); confirm Survey-in / fixed status and NTRIP upload.

5.4 P-70 Base notes

P-70 Base uses Receiver Managed Survey-in: choose Receiver-managed in RTK Settings; the receiver drives Survey-in / lock while this App handles connection, NTRIP upload, and status. Fixed coordinates can also be entered and saved to the device (follow in-app labels).

5.5 What you see during Survey-in

Dashboard may show Base accuracy, elapsed time, and Stop Survey-in (model/mode dependent).
Only after criteria are met should the Base coordinates be used as a differential reference (follow receiver and configuration).

EX-1 Base Dashboard (Survey-in in progress or fixed)

EX-1 Base Dashboard (Survey-in in progress or fixed).

5.6 NTRIP Server auto-reconnect after unexpected loss

After the Base NTRIP Server has connected to the caster and started uploading RTCM, if the caster, phone network, or TCP link drops unexpectedly, this App (iOS / Android, EX-1 / P-70) can automatically try to reconnect and resume uploading.

Topic Behavior
When it runs Only after a successful first connection, then an unexpected loss—for example caster closed the session, network changed, upload write failed, or the App returned to the foreground and found the session dead
When it does not run You manually turn off the Dashboard NTRIP toggle; initial caster connection failures (bad credentials, mount point, incomplete settings); receiver is no longer in Base mode
What is retried TCP / NTRIP session only—no new Survey-in or receiver Base coordinate rewrite; pending RTCM is discarded while waiting (the receiver keeps producing new data; upload resumes after reconnect)
Protocol Same as the first connect: NTRIP v2 POST first, then NTRIP v1 SOURCE fallback if rejected
Backoff About 5 s → 15 s → 1 min → 5 min (then every 5 min)
Time window Retries for 3 hours from the unexpected loss; then stops, shows gave-up status, and notifies you to check the Base device and network
BLE loss If phone–receiver Bluetooth also drops, NTRIP reconnect pauses the clock; resumes after BLE is back (works with 1.4)
Foreground When the App becomes active again, it checks immediately and retries if the window is still open
UI Dashboard NTRIP toggle stays On; status may show Reconnecting to caster… (attempt 2) or next try in 45s, etc.
Notifications Local notifications on unexpected loss, restored upload, and 3-hour give-up (if the OS allows notifications)
Logs NTRIP Log Console records each scheduled attempt and outcome
Setting Dashboard … → Connection → NTRIP Server auto-reconnect (default On); independent from Bluetooth Auto-reconnect

How this differs from Bluetooth auto-reconnect:

How to stop: Turn off the Dashboard NTRIP toggle, or disable NTRIP Server auto-reconnect under Connection.

Chapter 6: RTK Rover

6.1 When to use Rover

Field survey, stakeout, and RTK fixed solutions: the Rover pulls RTCM from a caster.

Prepare CORS / NTRIP first: the Rover does not generate centimeter corrections itself—it must get RTCM from a CORS network or your own Base+Caster. Ask your provider for account, mount point, and port (see 2.1.4).

6.2 EX-1 / P-70 Rover quick flow

  1. RTK Settings → RTK GNSS → Role = Rover.
  2. Fill NTRIP Client (Host / Port / Mount Point / credentials from your CORS or NTRIP provider).
  3. Connect the device; turn on NTRIP on the Dashboard.
  4. Wait for Fix to reach RTK Float or ideally RTK Fixed.
  5. Then collect or stake out.

6.3 Can I survey yet?

Status Guidance
No Fix Check antenna, sky view, Bluetooth
GPS Fix / DGPS Navigation-grade; wait for RTK for high-precision work
RTK Float Differentials present; usually better than single point, may still drift
RTK Fixed Typically used for centimeter points / stakeout (still environment-limited)
Rover Dashboard showing RTK Fixed with NTRIP connected

Rover Dashboard showing RTK Fixed with NTRIP connected.

Chapter 7: EX-1 vs P-70

Both support RTK Rover / Base, but Survey-in, permanent save, and Output Rate differ:

Item EX-1 P-70 Ultra
BLE name (discoverable) EX-1 NTRIP BLE P-70 Ultra NTRIP BLE
RTK Rover / Base Supported Supported
Survey-in App Duration / Accuracy (mm) fields, etc. Receiver Managed (Receiver-managed option)
Fixed coordinates Supported; Apply / Save to receiver Supported; can save to P-70
Permanent write Apply Temporarily / Save Permanently (UBX BBR/Flash) Save … to Device (P-70 flow; follow UI labels)
In-app Output Rate No (factory / other tools) Yes: 1 / 5 / 10 / 20 Hz, savable
hAcc / vAcc source u-blox UBX HPPOSLLH, etc.

Most screenshots and step-by-step examples use EX-1; for P-70 follow this table plus Receiver-managed in RTK Settings.

Chapter 8: Projects

8.1 What is a Project?

One Project = one local database file containing:

Only one Active project at a time.
Collect Data and My Data both read/write the Active project.

8.2 Common actions

Action Notes
New Create an empty project
Tap a list item Make it the Active project
Rename Rename
Delete Delete the project and all its data (irreversible)
Import Project Import a previously exported .gpkg as a new project (does not auto-activate)
Export Project Export a full GeoPackage for backup / archive
Projects page with an Active mark and at least one non-default project

Projects page with an Active mark and at least one non-default project.

Export Project prepare / share UI

Export Project prepare / share UI.

8.3 Tips

Chapter 9: Collect Data

9.1 When is it available?

All of the following must be true:

  1. An Active Project is selected
  2. Dashboard role is Rover (not Base)

Normal collection (live GNSS, Start Tracking / Start Observation) also requires:

  1. The receiver is connected

Exception — interrupted recovery: If a Collect Point or Record Track session was interrupted by a receiver disconnect in the same Active Project, Collect Data stays available without a connection so you can Finalize or Discard the saved data. If you switch to a different project, Collect Data is grayed out until you return to the project where the interruption occurred.

Otherwise Collect Data may be grayed out; tapping explains why. OK can jump to Dashboard to connect.

9.2 Status banner during collection

While a track or point collection is in progress, a banner appears at the top of the App:

Banner Meaning
Track Recording (red) A track is being recorded
Point Collection (blue) A point observation is in progress
Track Interrupted (orange) Track recording stopped because the receiver disconnected
Point Interrupted (orange) Point collection stopped because the receiver disconnected

Tap the banner to return to Collect Data. During an interruption, this opens the recovery screen (see 9.6).

9.3 Two modes

Top switch:

The page also shows Live GNSS Position and a map.

Collect Data in Collect Point mode with live coordinates

Collect Data in Collect Point mode with live coordinates.

9.4 Collect Point

  1. Enter name (optional; empty becomes something like Point <timestamp>) and notes.
  2. Set Occupation: 1–30 seconds, default 5.
  3. Tap Start … Observation.
  4. Wait: the App averages valid epochs and shows valid / rejected counts.
  5. Preview, then Save Point, or Retake / Cancel Observation.

Tip: For high-precision points, observe under RTK Fixed and keep the pole still.

Observation in progress with progress and valid/rejected counts

Observation in progress with progress and valid/rejected counts.

Observation finished, ready to Save Point

Observation finished, ready to Save Point.

9.5 Record Track

  1. Enter name and notes.
  2. Choose Frequency (default 1 Hz). Options include:
    • Raw Update Rate — log every valid position from the current receiver stream with no time thinning; does not change the receiver Output Rate. For denser tracks, raise Output Rate on the Dashboard first. Selecting Raw shows an orange note about battery use and project size.
    • 1 Hz / 0.5 Hz — thin by GNSS epoch time (not the phone’s receive time); an occasional +1 s gap is normal.
    • Every 5 seconds … every hour — same GNSS-time interval logic.
  3. Choose Fix Level (minimum quality):
    • Any fix
    • DGPS+
    • RTK Fixed
  4. Start Tracking → Pause / Resume / Stop.
  5. The UI shows Recorded samples (written to the track), Rejected samples (filtered out), distance, etc.

Output Rate vs Frequency

What still counts as Rejected: fix below Fix Level, non-increasing GNSS time, or implausible jump (>150 m/s vs the previous point). With Raw + Any fix and a stable fix, Rejected should stay near zero.

If Bluetooth drops during recording, see 9.6 Interruption handling.

Record Track setup with Frequency = Raw Update Rate and orange note visible

Record Track setup: Frequency = Raw Update Rate, orange note visible.

Record Track in progress (Raw mode), high Recorded and low Rejected

Record Track in progress (Raw example): Recorded samples should dominate; Rejected should stay low.

9.6 Interruption handling (receiver disconnect)

When Record Track or Collect Point is active and the receiver disconnects before you save, the App keeps the data collected so far on the device.

How to open recovery

Orange Track Interrupted banner at top of the App

Orange interrupted banner at the top (tap to open recovery).

Recovery screen

Interrupted collection recovery screen with Finalize and Discard

Recovery screen: Finalize or Discard without reconnecting the receiver.

Project scope

Notes

Chapter 10: My Data

My Data browses and manages Points and Tracks in the Active project.

My Data list with Points and Tracks

My Data list with Points and Tracks.

10.1 List page

Menu item Purpose
Import Stakeout Targets Import stakeout targets from CSV / KML / GeoJSON
Select to Export Multi-select then export
Select to Delete Multi-select then delete

10.2 Import Stakeout Targets

  1. … → Import Stakeout Targets
  2. Read the instructions → Import → pick a file
  3. Targets appear in Points (usually as imported points)
Import Stakeout Targets screen

Import Stakeout Targets screen.

10.3 Select to Export / Select to Delete

  1. Enter selection mode (title becomes Select to Export / Select to Delete).
  2. Check points and/or tracks; Select All is available.
  3. Confirm Export or Delete at the bottom (delete asks again).
  4. Cancel exits selection mode.

After export, iOS Share Sheet opens—see 10.6.

Point export formats

When only points are selected: CSV, GeoJSON, KML.

Format Good for Why exchange well
CSV Excel / Numbers / custom tables Universal tabular; easy edits, QC, GIS import
KML Google Earth and many GIS / field apps Very common landmark exchange format
GeoJSON Web GIS, QGIS, cloud / developer pipelines Open, structured, easy for software (see knowledge card)

Track export formats

When only tracks are selected: GPX, GeoJSON, KML, CSV.

Format Good for Why exchange well
GPX Track replay, outdoor / navigation apps, many GIS imports De-facto track interchange format
KML Google Earth, path visualization for non-specialists Easy to present and share routes
CSV Tabular time / coordinate / accuracy analysis Research post-processing and scripts
GeoJSON Modern web / GIS stacks shared with points Points and lines in one JSON ecosystem

Mixed selection: When points + tracks are both selected, usually GeoJSON / KML are available (CSV cannot mix points + lines). For a full project backup use Export Project (GeoPackage) under Projects.

Export numeric precision

When exporting survey points, tracks, and stakeout results to CSV, GeoJSON, KML, or GPX, numeric fields are formatted to fixed decimal places at export time only (half-up rounding), for easier exchange with Excel, QGIS, and other tools. In-project GeoPackage storage and Show Data keep full precision; for an unrounded full backup use Export Project.

Field type Decimals Example
Latitude / longitude 8 43.89334745, -79.30840036
Altitude (m) 3 202.717
HDOP / PDOP / VDOP 2 0.50
hAcc / vAcc, residuals, distances (m) 3 0.047
Heading (°) 2 127.45
Speed (knots) 3 0.125
Sample interval / average rate (Hz) 6 1.000000
Fix quality, satellites, counts integers unchanged

Applies to track points, survey points, stakeout target / staked coordinates and residual fields, and GeoJSON properties. GeoJSON coordinates[2] matches GPX <ele> (3 decimals). Missing altitude: no third coordinate / no <ele> (same as before).

Exported CSV share preview with fixed-decimal coordinates and accuracy columns

Exported CSV share preview: 8-decimal lat/lon and fixed precision on altitude / hAcc.

Knowledge card: What is GeoJSON?
GeoJSON describes geographic features as JSON text: points, lines, and polygons as coordinates + properties.
Field crews may know CSV / DWG / Shapefile better; in web maps, cloud GIS, mobile, and open-source GIS (e.g. QGIS), GeoJSON is extremely common.
Think of it as a machine-friendly “shipping box” for coordinates—less spreadsheet-friendly than CSV, but often smoother for programmatic and cross-platform exchange.

Select to Export with items checked and Export at the bottom

Select to Export with items checked and Export at the bottom.

10.4 Points detail

Open a point → title Points.

Stakeout notes

Points detail with GNSS Quality and Start Stakeout

Points detail with GNSS Quality and Start Stakeout.

Stakeout navigation (EX-1, RTK Fixed preferred)

Stakeout navigation (EX-1, RTK Fixed preferred).

10.5 Tracks detail

Open a track → title Tracks.

Show Data (spreadsheet-style)

Example columns: #, Time, Lat, Lon, Alt, Fix, HAcc.
Tap a row → Track Point detail; first line reads:

Point of <track name>

(This is a track sample, not an independent survey Point, and has no Stakeout.)

Tracks detail with Playback

Tracks detail with Playback.

Show Data table with multiple rows

Show Data table with multiple rows.

Track Point detail with Point of … on the first line

Track Point detail with Point of … on the first line.

10.6 iOS Share Sheet

After many exports (points, tracks, multi-select, project export, device config export, etc.), the App opens the iOS Share Sheet instead of locking files inside the App only.

You can:

This is the standard iOS way to hand off results: after fieldwork, share CSV / KML / GPX / GeoJSON / GeoPackage without a cable.

iOS Share Sheet example

iOS Share Sheet example.

Appendix A: Glossary

Term Meaning
GNSS Global Navigation Satellite Systems (GPS, BeiDou, GLONASS, Galileo, etc.)
NMEA Standard text sentences from receivers (e.g. GGA, RMC) used by many apps for position
RTCM Differential correction format required by RTK Rovers
NTRIP Protocol to carry RTCM over the internet
NTRIP Caster Relay: Base uploads, Rover downloads; can turn a private Base into “your own CORS”
CORS Continuously Operating Reference Station network; often delivers RTK via NTRIP
RTK Fixed / Float Fixed vs floating solution; Fixed is usually more stable and accurate
hAcc / vAcc Receiver horizontal / vertical accuracy estimates (m); EX-1=UBX, P-70=HPPOSLLH, P-9=proprietary
Ellipsoidal h / MSL height Height above ellipsoid vs mean sea level / geoid; differ by geoid undulation
Occupation Stay on a point for several seconds and average
Stakeout Navigate to known target coordinates and mark the location
GeoPackage (.gpkg) Project database / full project exchange format used by this App
GeoJSON Open JSON format for points/lines/polygons; common in modern web / GIS
GPX Common XML format for tracks and waypoints
KML Common visualization / landmark format (e.g. Google Earth)
CSV Comma-separated tables; easy in Excel and most software
Share Sheet iOS system share panel: Files, cloud drives, Mail, AirDrop, other apps

Appendix B: FAQ

Q1: Why is Collect Data grayed out?
A: You need an Active project and a connected Rover for normal collection. Base role cannot collect. Exception: if a point or track collection was interrupted in another project, switch back to that project—or if you have no interrupted collection and no connection, connect a Rover on Dashboard.

Q7: The receiver disconnected while I was recording. Do I have to reconnect to save?
A: No. Open Collect Data or tap the orange interrupted banner in the same project, then tap Finalize to save (same as Stop / Save Point) or Discard to delete. To continue recording the same track, reconnect the same receiver and use Resume on the connected Collect Data page.

Q8: What does “Reconnecting… attempt 1/5 in progress” mean?
A: The App is automatically trying to restore an unexpected Bluetooth drop (see 1.4). In progress means the current try is active; waiting for attempt 2/5 means the next try is scheduled. Tap Cancel or turn Auto-reconnect off under Dashboard … → Connection to stop. This is separate from saving interrupted Collect Data (Q7).

Q11: What does “Reconnecting to caster…” mean?
A: The Base NTRIP upload session is automatically reconnecting after an unexpected caster/network drop (see 5.6). This is not the same as Bluetooth Reconnecting… attempt 1/5 (Q8). To stop: turn off the Dashboard NTRIP toggle, or disable NTRIP Server auto-reconnect under Connection. Initial caster connection failures (wrong account, mount point, etc.) are not auto-retried—fix NTRIP Server settings in RTK Settings first.

Q9: How do Raw Update Rate and Dashboard Output Rate relate? Is a high Rejected count normal?
A: Output Rate sets how fast the receiver sends fixes; Raw only controls whether the App thins what it logs (it does not change Output Rate). For a denser track: raise Output Rate on the Dashboard (e.g. P-70 at 20 Hz), then choose Raw Update Rate in Collect Data (9.5). Rejected counts epochs that failed Fix Level, had non-increasing GNSS time, or failed the jump filter (>150 m/s). With Raw + Any fix and a stable fix, Rejected should stay near zero. Points skipped by a 1 Hz (etc.) interval gate are not Rejected.

Q10: Why do exported CSV / GPX coordinates show only a few decimal places?
A: CSV / GeoJSON / KML / GPX exports format numbers at export time (8 decimals for lat/lon, 3 for altitude and meter fields, 2 for DOP, half-up rounding) for interchange. Project storage and Show Data keep full precision; use Export Project for an unrounded backup. See 10.3 Export numeric precision.

Q2: Why don’t I see my EX-1 in the list?
A: Confirm power and Bluetooth permission; check whether it is filtered as already saved; the list should show a name such as EX-1 NTRIP BLE.

Q3: QField / Survey123 / QuickCapture cannot connect to NMEA?
A: Confirm this App’s NMEA Server is TCP, 127.0.0.1, matching port, and enabled; both apps running; port not taken by another device. The peer app must support TCP NMEA external GNSS. See Appendix C (QField example).

Q4: RTK stays Float and never Fixed?
A: Check CORS/NTRIP credentials and mount point, network, baseline length, and sky obstruction. Without a valid correction source you cannot fix.

Q5: Can deleted projects / points / tracks be recovered?
A: Usually no. Export important data first and save via Share Sheet to cloud or a computer.

Q6: Where do I enter Survey-in Duration on P-70?
A: P-70 uses Receiver Managed Survey-in; parameters are managed on the receiver, not with EX-1-style Duration/Accuracy fields in the App.

Appendix C: QField quick setup (example)

This section uses QField as the example for consuming this App’s TCP NMEA.
Survey123, QuickCapture, and other TCP NMEA iOS apps usually follow the same idea: choose TCP in positioning / external GNSS settings and enter the local host and port. Adapt menu names to each app.

C.1 Prepare this App first

  1. Columbus receiver connected; Dashboard shows a live fix.
  2. NMEA Server Settings: Type = NMEA Server, Protocol = TCP, Host = 127.0.0.1, Port = 9000 (or your custom port).
  3. Turn on NMEA Server on the Dashboard.
This App Dashboard with NMEA Server enabled

This App Dashboard with NMEA Server enabled.

C.2 Add a TCP positioning device in QField

  1. Open QField (keep this App running).
  2. Go to Settings → Positioning.
  3. Tap Add; choose connection type TCP (on iOS, TCP/UDP is typical—not direct Bluetooth to the receiver).
  4. Address 127.0.0.1, port matching this App (default 9000), then save.
  5. Set it as the current Positioning device and Connect.
  6. Optionally enable location / accuracy indicators; return to the map and confirm the position comes from the external GNSS.
QField Positioning list / Add entry

QField Positioning list / Add entry.

QField TCP settings 127.0.0.1:9000

QField TCP settings 127.0.0.1:9000.

QField connected to external GNSS with accuracy / coordinates shown

QField connected to external GNSS with accuracy / coordinates shown.

C.3 QField tips

Official positioning docs: QField — GPS, GNSS and NTRIP.

Appendix D: Video demos

Demo videos are hosted on the public S3 bucket geoastra-media (prefix demo_videos/). Click a link to play in the browser (Content-Type: video/mp4).

Base URL: https://geoastra-media.s3.us-east-1.amazonaws.com/demo_videos/

# Demo Description Play
1 Scan Scan and connect to a nearby BLE GNSS receiver Play video
2 Device List: Export, Delete All & Import Export device configs, delete all devices, and import Play video
3 RTK Rover Configuration Configure RTK Rover / NTRIP Client settings Play video
4 RTK Base Survey-in Configuration Configure RTK Base and run Survey-in Play video
5 NTRIP & NMEA Log Consoles View NTRIP and GNSS/NMEA receiver log consoles Play video
6 Project Management Create, switch, rename, import, and export projects Play video
7 Data Point Collection Collect a survey point with occupation averaging Play video
8 Track Recording Record a continuous GNSS track Play video
9 Track Playback Play back a recorded track on the map Play video
10 Stakeout Navigate to a target point and mark it as staked Play video
11 Data Point Export Export collected points (e.g. CSV / KML / GeoJSON) Play video
12 Export Track Export a recorded track Play video

This manual is based on current App features and behavior to help GNSS beginners understand why a bridge app is needed and how to connect, run RTK, collect data, and share results. Screenshots are hosted on S3; demos are in Appendix D.