GNSS COMPASS

Product Name: SC120 GNSS Compass – High-Performance Marine GNSS Compass

Product Overview
The SC120 GNSS Compass is a professional-grade, all-in-one heading sensor that provides 0.2° RMS heading accuracy and 0.3° RMS pitch/roll accuracy for critical marine navigation systems. Leveraging multi-constellation GNSS (GPS, BeiDou, Galileo, GLONASS) and advanced carrier-phase decoding, this GNSS compass delivers stable, interference-free true heading for radar, autopilots, ECDIS, AIS, and sonar.

Why Choose the SC120 as Your Primary GNSS Compass?

Ultra-high accuracy: 0.2° heading (0.1° resolution optional)

Multi-constellation: GPS/BDS/Galileo/GLONASS for faster fix and redundancy

Inertial backup: Built-in gyro and INS provide 1-minute heading output during satellite signal loss

Dynamic performance: 90°/s turn rate and 20Hz heading updates

Low maintenance: No gyro compass spinning parts, virtually zero upkeep

Flexible connectivity: Multiple NMEA0183 ports (IEC61162-1 & -2) plus AD-10 and BAM/INS outputs

 

Applications for SC120 Marine GNSS Compass

Radar & ECDIS – Stabilized true motion and overlay

Autopilot systems – High-precision heading for course keeping

AIS & Doppler sonar – Accurate ship's heading for target tracking

Fish finders & plotters – Stable vessel orientation for bottom mapping

Dynamic positioning (DP) – Redundant heading source for DP1 vessels

 

Equipment List:

Product model	Antenna unit	Data processing and display unit (Junction box for short)
SC120	SC1201	SC1200

 

1. Q: What is the real-world heading accuracy of the SC120 GNSS compass?
A: The SC120 GNSS compass delivers 0.2° RMS heading accuracy under normal operating conditions. This high precision is achieved through pre-type carrier phase decoding technology and multi-constellation support (GPS/Galileo/BeiDou/GLONASS). For applications requiring even higher resolution, 0.01° heading resolution is available through your dealer.

2. Q: Does the SC120 GNSS compass work if satellite signals are lost?
A: Yes. The SC120 features a built-in high-precision inertial navigation module (INS) and gyro compensation system. If satellite navigation signals become weak or are temporarily lost, the system can maintain heading output for up to 1 minute without interruption. This ensures your autopilot, radar, and other connected systems continue operating seamlessly during short signal outages (e.g., under bridges or near tall structures).

3. Q: How fast does the SC120 marine GNSS compass update heading data?
A: The SC120 provides a heading update rate of up to 20 times per second (20Hz). This high-speed output, combined with a maximum continuous turning rate of 90° per second, makes the SC120 ideal for fast-moving vessels and dynamic applications such as high-speed craft, Doppler sonar, and radar stabilization.

4. Q: What NMEA sentences does the SC120 GNSS compass output?
A: The SC120 outputs a comprehensive set of NMEA0183 sentences through multiple IEC61162-1 and IEC61162-2 ports. Key outputs include: HDT (True Heading), RMC, ROT (Rate of Turn), THS, HCR, as well as ALC, ALF, ARC, HBT. Additional sentences like GBS, GGA, GLL, GNS, GRS, GSA, GST, GSV, HDG, VTG, and ZDA are also available. Proprietary SHR output is available upon request.

5. Q: Is the SC120 GNSS compass waterproof and suitable for exposed mounting?
A: Yes. The SC120 antenna unit has an IP56 protection rating, meaning it is protected against high-pressure water jets from any direction (e.g., deck washing, heavy rain, sea spray) and is dust-protected. It can be mounted in exposed locations on the vessel. The junction box has an IP20 rating and should be installed in a protected, dry environment.

6. Q: What constellations does the SC120 multi-GNSS compass support?
A: The SC120 supports GPS, Galileo, and BeiDou as standard. GLONASS support is available as an option. Using multiple constellations simultaneously provides faster position fixing, better satellite availability in challenging environments (harbors, narrow channels), and improved heading stability.

7. Q: How does the SC120 GNSS compass compare to a traditional gyro compass?
A: Compared to a traditional gyro compass, the SC120 GNSS compass offers several advantages:

Virtually no maintenance – No spinning parts to wear out

Instant start-up – No 2-4 hour settling time required

Lower cost – Significantly less expensive to purchase and install

No periodic overhauls – Gyro compasses require bearing replacements every few years

True heading from satellites – No latitude-dependent speed error

Built-in attitude – Provides pitch and roll data (0.3° RMS accuracy)

9. Q: Can the SC120 GNSS compass be connected to multiple onboard systems simultaneously?
A: Yes. The SC120 provides 4 NMEA0183 ports total (2 x IEC61162-2 and 2 x IEC61162-1), plus 2 dedicated AD-10 ports for heading output, and 2 BAM/INS ports. This allows you to simultaneously output heading data to your autopilot, radar, ECDIS, AIS, sonar, and other navigation equipment without needing an external multiplexer.

10. Q: What is the typical installation location for the SC120 antenna unit?
A: For optimal performance, the SC120 antenna unit should be mounted:

In a location with a clear, unobstructed view of the sky (360° horizon)

High on the vessel (e.g., on top of a mast, radar arch, or pilot house roof)

Away from other transmitting antennas (VHF, satellite communications, radar) to avoid interference

With the vessel's centerline properly aligned (or offset programmed)

The IP56 rating allows exposed mounting, but avoid areas subject to physical impact

 

Technical parameters：

1. General

1.1 Receiving frequency	GPS/GALILEO/BEIDOU/GLONASS (optional)
1.2 Heading accuracy
SC120	0.2°RMS
1.3 Heading resolution	0.1°,0.01°(0.01° requires contact your dealer)
1.4 Rate of Turn	90°/s
1.5 Position fixing time	less than 2min
1.6 Attitude accuracy	Pitch/Roll: 0.3°RMS
1.7 Power supply	DC11-36V

 

2. Interface

2.1 Number of port
IEC61162(NMEA0183)	IEC61162-2: 2 port, IEC61162-1: 2 port
AD-10	2 port, for heading output
BAM/INS	2 port
2.2 Data port/Alert port
Input	ACN, HBT
Output	ALC, ALF, ARC, HBT, HDT, RMC, ROT, THS, HCR GBS*, GGA*, GLL*, GNS*, GRS*, GSA*, GST*, GSV*, HDG*, VTG*, ZDA*,
2.3 Output proprietary sentences	SHR*

Note: output the sentence with * requires contact your dealer.

 

3.Environmental conditions

3.1 Ambient temperature
Antenna unit	-25 ℃ to 70 ℃
Junction box	-15 ℃ to +55 ℃
3.2 Relative humidity	95% or less at +40 ℃
3.3 IP protection
Antenna unit	IP56(Exposed)
Junction box	IP20(Protected)
3.4 Vibration	IEC 60945 Ed.4

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