Gea and Gemini are monitoring systems based on GNSS receivers.

They are designed to monitor large structures (bridges, dams, high-rise buildings) as well as landslides and subsidences.


Our GNSS monitoring systems are based on a combination of M-rovers that are placed in the zone to be monitored, R-rovers that are placed outside the monitored zone and used as reference points, and a PC running the software. The PC can also be a remote server.

Rovers are based on dedicated hardware; a GNSS receiver plus power supply and communication. The PC running our software gathers data from the deployed rovers.


GEA rover differs from GEMINI in terms of performance and cost.

GEA is suited for low phenomena such as landslides or subsidence and can reach a precision of 1 mm over 7 days of continuous monitoring.

GEMINI is suited for higher-rate monitoring (up to 50 Hz) and therefore is best suited to structural monitoring. Its precision can go below 1 mm over 7 days of continuous monitoring.


GEA and GEMINI improves the precision of GNSS system, but how do they work?

The principle is to correct the GNNS error sources, that are:

Ionospheric Delay: The Ionospheric layer contains ions particles which delay the satellites signals and affect the position accuracy. The Ionospheric delay varies with solar activity, time of year, season, time of the day and location. Ionospheric models are used to reduce ionospheric delay errors.

Tropospheric Delay: Variations in tropospheric delay are caused by the changes to the humidity levels, temperature and atmospheric pressure in the troposphere. Tropospheric models are used to estimate the amount of error caused by tropospheric delay.

Multipath: It occurs when a GNSS signal is reflected off an object, such as the wall of a building, to the GNSS antenna. Because the reflected signal travels farther to reach the antenna, the reflected signal arrives at the receiver slightly delayed. This delayed signal can cause the receiver to incorrect calculate the position.

Orbit Errors GNSS satellites travel in very precise, well known orbits. However, the orbits do vary a small amount. Also, like the satellite clocks, a small variation in the orbit results in a significant error in the calculated position.

Receiver Noise It refers to the position error caused by the GNSS receiver hardware and software.


Update rate Up to 50 Hz
GNSS signal single or Dual L1/L2
Accuracy Sub-Millimetric
Baseline < 100 Km
NTRIP Protocol Supported
Global Reference Station Protocol Supported
Communication by High speed LAN
Update rate Up to 5 Hz
GNSS signal single frequency L1
Accuracy Millimetric
Baseline < 5 Km
Communication by LoRa Mesh
Low-priced Solution

How does it work?

Gea and Gemini work based on the data analysis coming from two or more baselines created by GNSS receivers. A base station is identified and located outside the monitoring zone, one or more monitoring stations are installed on the structure in question. Stations communicate with each other through radio or wired connections. A PC Server collects all the data from the stations and analyzes the baselines.

Software can send email or SMS alarms based on previous defined trigger events.

How is the accuracy of the GNSS system increased?

This is a standard question and since we are using a GNSS receiver with 5 m precision (in the worst case), how is it possible to achieve 1 mm precision?

Precision is increased on the server side with specific algorithms which work on the mitigation of the following source of errors:

  • Multipath Errors → Reflected GNSS signals which reach the antenna by two or more paths.
  • Ionospheric and Tropospheric Delays → Due to the signal propagation path.
  • Orbital Errors → Slight shifts of the orbits due to gravitational forces.
  • High frequency receiver Errors → Noise introduced by electronics.

What are the advantages of using a GNSS monitoring system instead of a simple RTK station?

  • GNSS errors mitigation and precision (1 cm with RTK → submillimetric with GNSS sw)
  • Data integrity control
  • Alerts
  • Multiple node handling

You can have GNSS-MONITORING configured according your needs

  • 2.4Ghz comunication radio module.

    Thanks to the SoftAP function you can download data and configure your GNSS-MONITORING directly from your device (mobile, tablet, notebook), moreover you can create a network of completly wireless Lunitek devices.

  • HSPA comunication radio module.

    Insert a standard sim card inside you GNSS-MONITORING and you can reach it remotely using a VPN.

  • GNSS-MONITORING is available with standard input impendance (40KΩ) or with high input impendance option (1.8MΩ)
  • GNSS-MONITORING is available with 3, 6 or 9 input channels. Inputs are located on military connectors.
  • You can have GNSS-MONITORING with auxiliary low speed analog/digital inputs.

    Thanks to this option you can integrate sensor data with external environmental information (temperature, humidity) or you can be notified when the containing vault is open. Relay output to control alarms comes as an option.

  • GNSS-MONITORING is compatible with many third part sensors through the MCO option.

    This option allows the instrument to fully interface with the sensors which needs for example the mass centering.

  • You can have your GNSS-MONITORING with a professional protective case.
  • GEA Entry level, equipped with single frequency GNSS receiver, long range low power consumption radio module and backup battery.
  • GEMINI High precision (submillimetric) high rate, dual frequency high accuracy receiver, can be either connected via WiFi or LAN cable, baselines can be as long as 100 km.