Introduction
In the high-precision positioning field, Real-Time Kinematic (RTK) carrier phase difference technology is the core foundation for achieving centimeter to millimeter-level positioning accuracy. However, RTK systems rely on stable, low-latency, highly reliable data links between base stations and rovers to transmit raw GNSS observation data or differential correction values. Traditional data transmission radios and public network communications face challenges in remote areas without network coverage or scenarios with complex electromagnetic environments. LoRa technology, with its long range, strong anti-interference capability and low power consumption, has emerged as a highly attractive solution for RTK data links.
This guide provides an in-depth analysis of how to select appropriate LoRa modules from Chengdu Ebyte Electronic Technology Co., Ltd.'s product portfolio to build reliable RTK data transmission links, based on official product specifications and field deployment verification data.
1. Technical Requirements for RTK Data Transmission Links
Before selecting LoRa modules, it is critical to clarify the core performance requirements of RTK data chains:
| Requirement Category | Specific Indicators | Business Impact |
|---|---|---|
| Throughput & Latency | Sustained bandwidth to support 500B-2KB/s data transmission, end-to-end latency < 500ms | Ensures real-time positioning solution convergence and continuous high-precision output |
| Reliability | Packet loss rate < 1%, strong resistance to co-channel interference and multipath fading | Prevents positioning accuracy degradation or solution failure caused by data loss/corruption |
| Range & Penetration | Support for 3-20km communication distance, with ability to overcome terrain, vegetation and light building obstruction | Adapts to field surveying, agricultural navigation, drone inspection and other outdoor scenarios |
| Power Consumption | Low power design for battery-powered portable rovers and solar-powered base stations | Extends device operation time in field environments without mains power |
2. Core Selection Dimensions for Ebyte LoRa Modules
For RTK applications, evaluate Ebyte LoRa modules from the following dimensions:
2.1 Interface Form
UART (TTL): Most universal interface, directly connects to main control MCUs or GNSS module serial ports, ideal for embedded integration into RTK rovers/base stations
RS232/RS485: Suitable for industrial scenarios with existing standard interfaces or requiring long-distance wired extension
2.2 Transmit Power
| Power Level | Typical Scenario | Power Consumption Tradeoff |
|---|---|---|
| 20-22dBm | Short-range (≤5km) portable devices | Low power consumption, suitable for battery-powered rovers |
| 27-33dBm | Medium-range (5-15km) general applications | Balances range and power consumption, the most widely used configuration |
| 37dBm | Ultra-long-range (≥15km) or harsh environment scenarios | Maximum link budget, requires verification of local radio regulatory compliance |
2.3 Air Data Rate
LoRa air rates range from 0.3kbps to 62.5kbps. For RTK applications, mid-to-high rate gears (9.6kbps, 19.2kbps, 37.5kbps) are recommended to balance communication distance and real-time performance. Lower rates increase range but introduce unacceptable latency for dynamic positioning scenarios.
2.4 Key Functional Features
| Feature | RTK Application Value |
|---|---|
| FEC Forward Error Correction | Actively corrects transmission errors, significantly reduces packet loss rate in complex electromagnetic environments |
| Fixed-point Transmission | Enables one-to-one or one-to-many directional communication, avoids unnecessary network interference |
| LBT (Listen Before Talk) | Intelligent channel avoidance in crowded spectrum, improves communication success rate |
| WOR (Wake On Radio) | Allows rovers to periodically sleep, greatly reduces average power consumption for portable devices |
2.5 Operating Frequency Band
400MHz band (e.g. 433MHz): Global license-free ISM band, excellent diffraction capability, the most commonly used frequency band for RTK data links
900MHz band (e.g. 868MHz, 915MHz): Widely used in overseas markets, higher rate potential, but slightly inferior penetration capability compared to 400MHz band
3. Recommended Ebyte LoRa Module Models for RTK Data Links
Based on Ebyte's product manual specifications and field validation, the following models are particularly suitable for building RTK data chains:
3.1 High-Performance Embedded UART Module Series (First Choice)
Compact size with simple interfaces, can be directly embedded into RTK rover or base station equipment.
Recommended Models:
| Model | Core Advantages | Key Parameters | Application Scenario |
|---|---|---|---|
| E22-400T33S / E22-900T33S | Next-generation SX1262 chip solution, supports up to 62.5kbps air rate, integrates fixed-point transmission, LBT, WOR functions | 33dBm transmit power, 16km ideal range, UART interface | General-purpose embedded RTK devices, balances performance and power consumption |
| EWM32M-xxxT20S | Ultra-small size, low cost, explicitly supports FEC forward error correction | 20dBm transmit power, 5km ideal range, UART interface | Low-power portable RTK rovers, cost-sensitive mass deployment scenarios |
| E220-xxxTxxx | Stable performance, supports up to 62.5kbps rate, flexible networking modes | 30dBm transmit power, 10km ideal range, UART interface | Mid-range embedded applications requiring reliable data transmission |
3.2 Industrial Grade Data Transmission Unit (DTU) Series
Rugged housing with rich interfaces (RS232/RS485), integrated power and antenna interfaces, ideal for fixed base station external data links or integration into large equipment.
Recommended Models:
| Model | Core Advantages | Key Parameters | Application Scenario |
|---|---|---|---|
| E90-DTU(400SL30) / (400SL33) | Industrial-grade aluminum alloy housing, military-grade LoRa modulation, software FEC algorithm | 30/33dBm transmit power, 10/16km ideal range, RS232/RS485 interfaces | Fixed RTK base stations, industrial environment deployment |
| E90-DTU(400SL37) | Ultra-high 37dBm (5W) transmit power, provides extreme link budget | 37dBm transmit power, ultra-long range capability | Harsh environment or ultra-long range RTK applications (subject to regulatory approval) |
3.3 Ultra-Long Range High-Power Professional Series
For large-area surveying or special terrain applications:
E22-XXXT37S: 37dBm (5W) maximum power, 4.5-15V wide voltage supply, 25km ideal communication range, supports 0.3k~62.5kbps adjustable rate, designed for extreme environment deployments.
4. Implementation Configuration and Networking Recommendations
4.1 Parameter Configuration Optimization
Air Rate: Avoid minimum rate configurations (e.g. 2.4kbps). Calculate required bandwidth based on RTK packet size and update rate, select 9.6kbps, 19.2kbps or higher rates to ensure low latency.
Operating Mode: Configure fixed-point transmission mode, set identical network ID for base station and rovers, assign unique addresses to achieve stable one-to-one or one-to-many communication.
Feature Enablement: Mandatorily enable FEC (if supported) and LBT functions to maximize link reliability.
Power Setting: Configure maximum transmit power within regulatory and power consumption constraints.
4.2 Antenna Selection
Use high-gain omnidirectional antennas matched to the module's operating frequency (e.g. 433MHz).
Mount base station antennas in elevated, open positions without obstructions.
Ensure antenna connectors (SMA, IPEX, etc.) are compatible with the module interface.
4.3 Networking Topologies
| Topology | Configuration Method | Application Scenario |
|---|---|---|
| Point-to-Point (1 Base + 1 Rover) | Direct communication using fixed-point mode | Single-rover surveying and mapping applications |
| Point-to-Multipoint (1 Base + N Rovers) | Base station uses broadcast mode (address set to 0xFFFF) to send differential data; rovers use fixed-point mode for return data | Multi-rover scenarios such as precision agriculture and construction management |
| Relay Extension | Deploy intermediate relay stations to automatically forward data using LoRa relay function | Scenarios with obstructions or communication distance exceeding direct link capability |
5. Summary and Selection Flowchart
Ebyte's comprehensive LoRa product portfolio provides diverse options for RTK data links. Their products' anti-interference, reliability and range characteristics, when combined with reasonable selection and configuration, can effectively meet the stringent requirements of RTK applications.
Simplified Selection Process:
Form Factor Decision: Choose UART modules (e.g. E22-400T33S) for embedded designs; select DTUs (e.g. E90-DTU(400SL30)) for external or industrial integration.
Power & Range Matching: Use 20-30dBm models for conventional scenarios; consider 33-37dBm high-power models (e.g. E22-XXXT37S) for ultra-long range or complex obstruction environments.
Feature Validation: Prioritize models with explicit FEC support (e.g. EWM32M series), and ensure required functions such as fixed-point transmission and LBT are available.
Configuration Optimization: Set appropriate air rate based on data volume, correctly configure addresses and network ID, enable FEC and LBT functions.
By combining high-precision GNSS technology with robust LoRa data links, Ebyte modules enable developers to build highly autonomous, stable and reliable professional RTK positioning systems Not restricted by public network coverage, which can be widely applied in precision agriculture, engineering surveying, drone inspection, autonomous driving and other fields.
