Bad Elf Flex

The Bad Elf Flex is a professional-grade multi-frequency GNSS receiver designed for GIS data collection, asset mapping, and field survey. It tracks GPS, GLONASS, Galileo, and BeiDou on multiple frequencies and supports RTK corrections for centimeter-level accuracy. The Flex connects to your iOS or Android device via Bluetooth and is configured through the Bad Elf GPS app (called "Bad Elf GNSS" on some platforms). It features a rugged, weather-resistant housing and a built-in rechargeable battery.

Requirements

• Bad Elf Flex GNSS receiver, fully charged

• Bad Elf GPS app (iOS) or Bad Elf GNSS app (Android) installed on your phone or tablet

• Internet connection on your phone (cellular data recommended for field use)

• RTKdata.com account with active RTK credentials (username and password from your RTK dashboard)

• Survey pole or bipod with a 5/8"-11 thread mount (optional but recommended)

• Clear sky visibility — avoid indoor testing

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Step-by-step setup

1

Power on and pair at OS level

The Bad Elf Flex requires Bluetooth pairing at the operating system level before opening the app. This is different from some receivers that pair through the app directly.

1. Press and hold the power button on the Bad Elf Flex until the LED turns on.

2. The Flex enters Bluetooth pairing mode automatically on first boot. On subsequent boots, it reconnects to the last paired device.

3. On your phone, open Settings → Bluetooth and pair with the device named Bad Elf Flex [serial number].

4. Wait for the pairing to complete and show "Connected" in your phone's Bluetooth settings.

5. Only after OS-level pairing is confirmed, open the Bad Elf GPS app. The Flex should appear as connected in the app's device list.

If you skip the OS-level Bluetooth pairing and try to connect through the app first, the Flex will not be detected. Always pair in your phone's Bluetooth settings first.

2

Navigate to NTRIP settings

1. In the Bad Elf GPS app, tap on your connected Flex device.

2. Tap Settings (gear icon).

3. Scroll to Corrections or RTK Corrections section.

4. Tap NTRIP to open the NTRIP client configuration.

3

Enter RTKdata.com NTRIP settings

Fill in the fields. Select the tab for your region:

North America

• Host (domain): rtk.rtkdata.com

• Host (IP fallback): 13.56.117.10

• Port: 2101

• Username / Password: From RTK Credentials in the internal dashboard (not website login)

• Mountpoint (ALL CAPS): AUTO (recommended) — or AUTO_WGS84, AUTO_ITRF2020, AUTO_ITRF2014

Europe

Australia

Also configure:

• Send GGA: Enabled

Tap Save or Done to store the configuration.

Only these four mountpoints are valid. Always use ALL CAPS.

4

Connect to NTRIP

1. Return to the main device screen.

2. Toggle the NTRIP connection to On (or tap Connect).

3. The app displays correction stream status — look for "Receiving corrections" or similar confirmation.

5

Verify RTK Fix

1. Check the solution status indicator in the app. It will show the progression: Autonomous → DGPS/Float → RTK Fix.

2. Once you see RTK Fix, the receiver is delivering centimeter-level positions.

What to expect

• LED indicators: Green = power on and tracking satellites. Blue blinking = Bluetooth connected. The app provides more detailed status than the LEDs.

• Convergence time: 30–60 seconds to Float, 60–120 seconds to Fix under open sky.

• Accuracy at Fix: 1–3 cm horizontal, 2–5 cm vertical.

• Battery life: Approximately 8–10 hours with Bluetooth and NTRIP corrections active.

Vertical reference (heights)

Heights from RTKdata.com are ellipsoidal, not orthometric (mean sea level). If your project requires orthometric (MSL) heights, apply a geoid transformation in your GIS software.

Troubleshooting

Problem	Cause	Fix
App does not see the Flex	Bluetooth not paired at OS level	Pair the Flex in your phone's Bluetooth settings first, then open the app. This is the most common issue.
"Connection refused" or timeout	Wrong host or port	Verify the caster host spelling and that port is 2101. Check for typos.
"Authentication failed"	Incorrect credentials	Use the credentials from your RTKdata.com RTK dashboard, not your website login email/password.
Corrections received but stuck on Float	Poor sky conditions or GGA not sent	Make sure Send GGA is enabled. Move to open sky away from buildings.
Mountpoint not found	Lowercase or wrong mountpoint name	Type AUTO in all capital letters. Do not select from a list — type it manually.
App crashes on iOS after update	App version incompatibility	Update both iOS and the Bad Elf GPS app to the latest versions. Restart your phone.

Tips and tricks

• Update firmware first. Before heading to the field, check for firmware updates in the Bad Elf app. Newer firmware often improves RTK performance and connectivity stability.

• Always pair at the OS level before opening the app. This is the number one support issue with the Flex on both iOS and Android.

• The Flex works with third-party apps too. Apps like ArcGIS Field Maps, Collector, and other GIS tools can read the Flex's corrected position via Bluetooth GPS.

• Use the app's NMEA log feature to record raw NMEA sentences for quality assurance or post-processing review.

• For best results, mount the Flex on a pole at least 1 meter above ground to reduce multipath interference from the ground surface.

• If you work in multiple regions, create separate NTRIP profiles for each RTKdata server (EU, NA, AUS) and switch as needed.

• Keep your phone within 5–10 meters of the Flex to maintain a stable Bluetooth connection.