Quickstart Guide

The TX2 is a compact all-band GNSS RTK rover designed to optimize your on-site workflow. Simply open your preferred GIS app on any mobile device, pair the TX2 as a BLE device, and access NTRIP corrections using the internet/cellular connection. With its MFi certification, users can now pair the TX2 with Apple's iOS devices! This entire kit ships in a hard-sided case, including additional accessories, and a sticker.

Parts List

The SparkPNT TX2 comes shipped inside a hard-sided carrying case with a few accessories to users get started. Below, is an overview of all the parts included with your purchase:

All the parts included in the carrying case.

1. Carrying Case
2. SparkPNT TX2
3. USB-C Cable
4. USB-C Charger (65W)
5. Thread Adapter (1/4" to 5/8")

note

Any available replacement parts are linked in the list above. Additionally, international adapter sockets can be purchased separately for the power adapter, if required.

Device Overview

info

Tilt compensation is not supported by this device.

Power

To power the device on or off, hold the power button down for more than 3 seconds. When the device powers on, it will beep once; whereas, the device will beep three times when it powers down.

Power button on the front of the device.

info

The center of the power button also serves at the NRP (north reference point) for the device.

Battery

The TX2 features a 49Whr battery and supports PD charging, up to 10W.

Users can access the USB-C port, under the rubber cover, on the back of the device.

• Battery Charging - The TX2 supports PD charging up to 10W; this allows a fully discharged TX2 to be charged to 100% in a few hours. Users can access the USB-C port, under the rubber cover on the back of the device.
  tip

  Don't forget to fully close the rubber cover. The enclosure's IP67 ingress rating (waterproof to 1 meter, for up to 30 minutes), is only valid when the USB cover is closed.

• Battery Capacity - The TX2 includes a 7.2V 6.8Ahr (48.96Whr) battery. This should allow the device to run continuously for more than 50 hours, even in the worst-case conditions.

Connectivity

In order to get corrections or configure the device, users should pair the device with their phone. Double-tap the Power button (press twice, within 1 second) to connect to your device.

BLE

To provide RTK corrections from an NTRIP caster (or server), view the device's position in real-time, and manage datapoints, it is best to utilize a 3rd party app on a mobile device. Users can then, pair the SparkPNT TX2 to their mobile device with a BLE connection.

For a Bluetooth connection, follow these steps:

1. Power the device on.
   • Hold the Power button for more than 3 seconds. It will beep once, indicating it has turned on.
2. Once the device has powered up; double-tap the Power button (press twice, within 1 second).
   • The device will beep twice indicating it is waiting for incoming connections.
3. On your mobile device, connect to BLE device named SparkPNT TX2.

   

   Pairing from an Android device.

   

   Pairing from an iOS device.

4. Once pair, you be able to access the device in your favorite GIS app.

WiFi

To change the configuration settings of the device, it is easiest to connect to the device's WiFi access point and pull-up the configuration webpage. Once connected, users can access the configuration webpage from a browser using the https://rtk.local URL address.

To get into browser configuration, follow these steps:

1. Power the device on.

   • Hold the Power button for more than 3 seconds. It will beep once, indicating it has turned on.

2. Once the device has powered up; double-tap the Power button (press twice, within 1 second).

   • The device will beep twice indicating it is waiting for incoming connections.

3. On your mobile device, connect to WiFi network named RTK Config. Upon connecting, your phone may warn you that the WiFi network is not connected to the internet. This is normal; stay connected and open a browser.

   

   Connecting from an Android device.

   

   Connecting from an iOS device.

   warning

   If you have problems, try disabling mobile/cellular data on your mobile device. The device or browser might be using the cellular connection for its internet access; however, we want to disable this setting to ensure that your mobile device remains on the WiFi access point for the browser.

4. Once the browser is opened, you should be automatically re-directed to the configuration webpage. If not, open a browser (Chrome is preferred) and type http://rtk.local into the address bar.

   https://rtk.local/

   http://rtk.local/

   

   Browser with rtk.local webpage.

Status Indicators

There are three LED status indicators on the TX2.

The LED status indicators on the SparkPNT TX2.

• The GNSS icon () indicates the GNSS solution status.
  • A yellow LED will blink once per second when a GNSS fix is achieved.
  • A green LED will illuminate solid when RTK Fix is achieved.
• The Connection icon () indicates the WiFi or BLE connection status.
  • The LED blinks once per second while waiting for a connection.
  • The LED will turn solid, once it is connected to a phone, laptop, WiFi network, etc.
• There is a small battery LED next to the cover of the USB port, on the back of the device.
  • The LED is green when external power is supplied.
  • When the device is on:
    • The LED will be solid red indicating more than 50% battery capacity remains.
    • The LED will blink red once per second, if less than 50% of the battery capacity remains.

Initial Setup

Users simply need to attach their TX2 to a surveying post or mount point using the 5/8"-11 TPI threaded insert on the bottom of the TX2. This kit also includes a 1/4" adapter for additional mounting options.

The 5/8"-11 TPI threaded insert on the base of the SparkPNT TX2.

Orientation and Alignment

For the most accurate positioning, users should align their device as vertically straight as possible. Additionally, the user interface's power button (front of the device) should be facing north as defined by the device's north reference point.

The antenna reference point and north reference point of the SparkFun TX2.

When marking positions, users can also provide the pole height and distance between the ARP and APC in the RTK Everywhere firmware. This will allow users to accurately mark their positions based on the bottom of the surveying pole.

Placement and Surroundings

This section provides general placement considerations for precision GNSS surveying. Below, are some useful examples of ideal locations for surveying.

• Ideal locations
  • Open fields
  • Hilltops
• Poor locations
  • Canyons and valleys
  • Cities or dense urban areas
  • Dense foilage

Obstructions and Multipath

For precision GNSS surveying, the receiver works best with a wide-open, unobstructed view of the sky.

A wide-open, unobstructed view of the sky offers increased accuracy and precision.

Obstructions can create multiple paths for signals. This introduces timing errors into the solutions provided by the GNSS receiver reducing its precision and accuracy.

The increased signal paths, introduce timing errors into the solutions provided by the GNSS receiver.

info

By default, the TX2 ignores any signals from satellites positioned below, 15° above its horizon (see image). This mitigates any multi-path errors from any obstacles on the horizon; such as buildings, trees, cars, etc.

The TX2 ignores any signals from the horizon (<15°) and only accepts signals from above (green).

Obstructions can also reduce the performance of the GNSS receiver and the precision of its solutions.

Obstructions reduce the distribution and number of satellites used in solutions.

Dilution of Precision

The geometric arrangement of satellites, significantly influences the precision of GNSS solutions. A well-distributed arrangement of satellites allows for more accurate positioning by minimizing errors related to signal distortion and multipath effects. When satellites are positioned at wide angles relative to each other, the geometric dilution of precision improves, enhancing precision of the positioning solutions. Conversely, when satellites cluster closely together in the sky, it can lead to degradation in the geometric dilution of precision and less reliable positioning solutions. Therefore, optimal satellite geometry is crucial for achieving high-precision GNSS solutions.

A wide-open, unobstructed view of the sky offers increased accuracy and precision.

RF Inteference Sources

Nearby electronics can interfere with the reception of the GNSS signals. It is recommended that users limit the use of wireless electronics that produce RF noise. Especially those that operate near the frequencies of GNSS signal bands.

GNSS frequency bands (Source: Novatel)

Rover

In Rover mode, the TX2 will receive L1, L2, and L5 GNSS signals from the four constellations (GPS, GLONASS, Galileo, and BeiDou) and output the devices' position with accuracies around 700mm. The device will calculate the position based on the combination of GNSS and any correction signals (primarily SBAS, if available). Similar to a standard-grade GNSS receiver, the TX2 will output industry standard NMEA sentences at 2Hz and can broadcast them to any paired Bluetooth® device. The end user will need to parse the NMEA sentences using commonly available mobile apps, GIS products, or embedded devices (there are many open source libraries).

Rover with RTK

In Rover with RTK mode, the TX2 will receive GNSS signals and combine them with RTCM correction data to achieve accuracy of approximately 8mm horizontal positional accuracy and 15mm vertical accuracy. The RTCM correction data is most easily obtained over a cellular connection to the Internet using a free app on your phone (see SW Maps or Lefebure NTRIP) and sent over Bluetooth®. Additionally, corrections can be obtained over WiFi, or ESP-NOW. Correction data can come from 2nd unit setup as a base station, from a free local base station, or from a paid service. See the Quick Start guide and the NTRIP Client for more information.

The device connectivity for RTK corrections from an NTRIP network.

Rover with PPP-RTK

In Rover with PPP-RTK, the TX2 will receive GNSS signals and combine them with correction data provided over an IP connection (usually a cell phone hotspot). The corrections are State Space Representation (SSR) based and are also known as PPP-RTK. These corrections are obtained from ublox's PointPerfect network. Time to RTK Fix can take up to 300 seconds and has 14 to 60mm horizontal positional accuracy.

Base Station

In Base Station mode the device is mounted to a fixed position (like a tripod or roof) and will initiate a survey. After 60 to 120 seconds the survey will complete and the TX2 will begin transmitting RTCM correction data over the built in 2.4GHz radio (if ESP-NOW is enabled). A base is often used in conjunction with a second TX2 unit (or RTK Facet, RTK Surveyor, Express, Express Plus, etc) set to Rover to obtain the 8mm accuracy. Said differently, the Base sits still and sends correction data to the Rover so that the Rover can output a really accurate position. The relative accuracy of this mode is 8mm base-to-rover but has higher (up to a meter) of absolute inaccuracy. See how to set up a permanent base to decrease the absolute inaccuracy.

Base Station with NTRIP

In Base Station with NTRIP the device will enter Base Station mode. If WiFi is available, and the NTRIP Server(s) is enabled, its corrections will be broadcast to up to four NTRIP casters and made available to any rover that also has internet access and is within 10-20km.

The device connectivity for RTK corrections from an base station.