Abstract

The Septentrio AsteRx SBi3 Pro+ is a ruggedized GNSS/INS receiver designed for professional surveying and geospatial data collection. Equipped with the GNSS+ technology suite (AIM+, APME+, LOCK+, FUSE+, IONO+, RAIM+), it effectively handles complex electromagnetic environments, multipath interference, and signal blockage. Combined with an IP68-rated enclosure and a wide operating temperature range, it ensures stable and continuous operation in various field and industrial conditions.

Q&A

Why choose a GNSS/INS integrated receiver for geodetic surveying?

Traditional GNSS receivers perform well in static or low-speed surveys. However, in dynamic surveying, vehicle/airborne mobile mapping, and environments with brief signal obstructions, positioning continuity and accuracy can degrade. The AsteRx SBi3 Pro+, by integrating a high-performance IMU, provides enhanced RTK positioning accuracy and attitude information when GNSS signals are available; it seamlessly switches to inertial dead reckoning during signal outages, ensuring trajectory continuity.

What are the advantages of the AsteRx SBi3 Pro+ in geodetic control network surveys?

Its core advantages are high accuracy, high reliability, and high efficiency. The RTK-INS mode delivers positioning accuracy of 0.6 cm + 0.5 ppm horizontally and 1 cm + 1 ppm vertically, meeting requirements for high-grade national control point establishment. The dual-antenna configuration enhances heading accuracy to 0.15°, especially suitable for establishing directional benchmarks. AIM+ and APME+ technologies suppress potential radio interference and multipath effects from nearby buildings or vehicles at survey points, ensuring observation data quality. Under baseline conditions <40 km, its typical RTK initialization time is <7 seconds. Combined with a high position output rate of up to 100 Hz, it significantly improves survey efficiency, particularly for rapid static surveys and dynamic base station applications.

How is measurement accuracy ensured in complex terrain or urban canyons?

Challenges in complex environments primarily stem from satellite signal obstruction, multipath reflection, and electromagnetic interference. The AsteRx SBi3 Pro+’s GNSS+ technology suite specifically addresses these issues: LOCK+ technology ensures stable satellite tracking in vibrating vehicle environments; APME+ significantly suppresses reflected signals from the ground and buildings; IONO+ mitigates the impact of ionospheric activity on long-baseline measurements; the FUSE+ deep fusion algorithm utilizes the IMU to maintain high-accuracy state estimation when signals are poor. Furthermore, its RAIM+ integrity monitoring function provides surveyors with data reliability indicators, preventing the use of position results containing gross errors.

How does this receiver integrate with existing surveying systems and post-processing software?

The AsteRx SBi3 Pro+ is designed for high openness and easy integration. It simultaneously outputs fused position/attitude and synchronized raw GNSS observations (2 Hz) and raw IMU data (200 Hz). It supports industry-standard data formats such as Septentrio Binary Format (SBF), RTCM 3.x (including MSM), NMEA 0183, and CMR+, enabling seamless integration with most survey controllers, data collection software, and post-processing platforms (e.g., Trimble, Leica systems). Via network or serial interfaces, it can be directly configured as a rover, base station, or for raw data logging, facilitating post-processed Precise Point Positioning (PPP) or tightly coupled post-processing.

High-Precision GNSS/INS Technology Empowering Modern Geodetic Surveying

From traditional static control network establishment to new surveying methods like airborne LiDAR and mobile mapping vehicles, surveying tasks demand higher positioning accuracy, dynamic performance, and reliability. The AsteRx SBi3 Pro+ deeply integrates a multi-constellation, multi-frequency GNSS receiver with a tactical-grade IMU. It not only provides centimeter-level positioning capability under all weather conditions but also endows the survey platform with precise 3D attitude awareness, achieving a leap from “point positioning” to “full-state perception.” This provides a richer, more reliable spatial data foundation for smart cities, infrastructure construction, geological hazard monitoring, and other fields.

Why does geodetic surveying require centimeter-level GNSS/INS positioning?

Geodetic surveying requires centimeter-level GNSS/INS positioning, with the core objective of meeting the demands for accuracy, continuity, and reliability in its research and applications. GNSS (Global Navigation Satellite System) can provide long-term centimeter-level absolute positioning references, but its signals are susceptible to obstruction and interference. In contrast, INS (Inertial Navigation System) autonomously delivers continuous high-frequency attitude and position calculations, compensating for the shortcomings of GNSS. Through deep integration, GNSS corrects the accumulated errors of INS, while INS maintains high-precision output during GNSS signal interruptions. This ensures continuous, stable, and reliable high-precision spatial data acquisition in various complex dynamic environments (such as crustal movement monitoring, aerial surveying and mapping, and precision engineering surveys). It serves as an indispensable technological foundation for modern geodetic surveying in studying geophysical phenomena and supporting major engineering construction projects.

Core Advantages of the Septentrio AsteRx SBi3 Pro+ GNSS/INS Receiver

The AsteRx SBi3 Pro+ is a ready-to-use, ruggedized GNSS/INS receiver integrating a 544-channel, full-band GNSS engine with a high-performance inertial measurement unit. It is designed for professional surveying applications requiring high precision, high dynamics, and high reliability. Its dual-antenna option and full attitude output capability make it an ideal choice for mobile mapping, directional surveying, and precision engineering monitoring.

Full-System, Full-Frequency GNSS and Deep INS Fusion

Featuring a rugged chassis design (102 × 36 × 118 mm), the AsteRx SBi3 Pro+ offers powerful hardware and data openness:

-544 hardware channels, simultaneously tracking all major constellations: GPS (L1 C/A, L1C, L2C, L2 P, L5), GLONASS (L1 C/A, L2C/A), BeiDou (B1I, B2I, B3I), Galileo (E1, E5a, E5b, E5 AltBOC), QZSS, and SBAS (EGNOS, WAAS, etc.).

-FUSE+ Deep Fusion Technology: Optimally fuses RTK positioning results with high-performance IMU data, outputting smooth, stable, and highly accurate position, velocity, and 3D attitude.

-Flexible Antenna Configuration: Supports single or dual-antenna setup. In dual-antenna mode, RTK heading accuracy reaches 0.15°, providing precise heading without vehicle movement. In single-antenna mode, RTK heading accuracy is 0.2°. Pitch/roll accuracy in RTK mode can reach 0.02°.

-Fully Open Raw Data: Provides synchronized raw GNSS observation data and raw IMU data streams (IMU data up to 200 Hz), facilitating deeper data fusion by users with other sensors (e.g., sonar, LiDAR).

GNSS+ Technology Ensures Survey-Grade Performance in Complex Environments

Septentrio’s unique proprietary technology suite ensures reliable data even in challenging conditions:

-AIM+: Leading anti-jamming and anti-spoofing technology protects data security and accuracy in areas with strong electromagnetic interference like airports and power plants.

-APME+: Advanced Posteriori Multipath Estimation technology significantly reduces the impact of reflected signals near survey poles or in vehicle environments.

-LOCK+: Maintains stable satellite signal tracking during bumpy vehicle motion, reducing cycle slips.

-IONO+: For long-baseline RTK or regional reference network applications, effectively mitigates ionospheric scintillation effects, improving ambiguity resolution success rate and reliability.

-RAIM+: Receiver Autonomous Integrity Monitoring provides key quality control indicators for automated surveying workflows.

These technologies work together to achieve continuous, reliable RTK-INS positioning accuracy:

-Horizontal Accuracy: 0.6 cm + 0.5 ppm

-Vertical Accuracy: 1 cm + 1 ppm

-RTK Initialization Time: < 7 seconds

Integration Advantages of the AsteRx SBi3 Pro+ in Geodetic Surveying Platforms

Rugged Design for Field Operations

Housed in an IP68 waterproof/dustproof metal case (102×36×118 mm, 490 g). Operating temperature range is -30°C to +65°C. Tested to MIL-STD-810G standards for vibration, shock, and humidity, it withstands harsh field environments and vehicular vibration.

Rich Interfaces Support Flexible Networking

Provides 3 high-speed RS232 serial ports, a 10/100 Mbps Ethernet port (supporting PoE), a USB device port, 2 event marker interfaces, and built-in 16 GB storage. Supports TCP/IP, UDP, NTRIP Client, FTP, and other network protocols, facilitating connection to survey instrument buses, remote configuration, and data download.

Open Data Accelerates Workflow Integration

Beyond standard NMEA and RTCM position outputs, the fully open SBF format includes all raw observations, IMU data, fused navigation solutions, and comes with a complete parsing library. This allows deep integration into custom post-processing algorithms, tightly coupled PPP, or high-precision spatio-temporal synchronization with LiDAR/cameras, meeting research and high-end application needs.

AsteRx SBi3 Pro+: The Core for Building Next-Generation High-Precision Surveying Systems

High-Precision Attitude Awareness Enables Intelligent Surveying

Provides precise pole or sensor tilt angles for tilt compensation systems, enabling high-accuracy coordinate calculation without leveling. On airborne or vehicle-mounted mobile platforms, it supplies precise Position and Orientation (POS) data for LiDAR and cameras, forming the basis for generating high-accuracy point clouds and orthophotos.

Anti-Interference and Integrity Ensure Data Reliability

When surveying in complex interference areas like urban construction zones, near power lines, or mines, AIM+ and RAIM+ technologies effectively protect the system from interference and alert surveyors to potential data risks, ensuring result quality complies with specifications.

Seamless Inertial Dead Reckoning Overcomes Signal Challenges

During continuous terrain data collection in areas with intermittent GNSS signals like forests, urban canyons, or underground garage entrances, the inertial dead reckoning function maintains positioning accuracy for short periods, ensuring point clouds or trajectories remain unbroken, enhancing data completeness.