GPS World

Tag: RTK KEEP

  • ComNav launches GNSS high-precision positioning for lawn mowers

    ComNav launches GNSS high-precision positioning for lawn mowers

    Image: ComNav
    Image: ComNav

    ComNav Technology now provides a GNSS high-precision positioning solution for navigation and positioning of autonomous lawn mowers. Environmentally friendly and intelligent robotic lawn mowers are growing more popular, making the mowing task easier, safer and more convenient.

    R&D background

    It is difficult to develop autonomous lawn mowers because they obtain navigation information by means of visual and acoustic sensors, usually through embedded cables in the working area and detection through eddy current sensors. The shortcomings are obvious: before the mower starts, it must be set up with cables and other equipment. Cable requirements differ in various countries, and cable laying can be complicated, wasting resources and money.

    With these difficulties in mind, ComNav applied its K8 series of GNSS high-precision modules to lawn mowers to break through the application limit. It solved this accuracy problem to make the lawn mower achieve centimeter-level driving according to the setup path in an open field. With ComNav’s other technologies — quantum algorithm and LAI, HighLock, PPP, RTK-KEEP — the law mowers continues to operate under trees, around corners or in other obscured areas.

    Introduction of ComNav’s solution

    With the K8 series module, ComNav facilitates the lawn mower’s fieldwork with position data provided by GPS, GLONASS, Galileo, Beidou, QZSS, IRNSS and SBAS.

    The high-precision positioning system for lawn mowers consists of a base station and a rover station. Three solutions are recommended for the terminal to obtain differential data from the base station.

    Base and rover datalink. A base station acquires differential data through a datalink and provides corrections to the rover. The rover station — comprising the parts installed on the lawn mower, including the GNSS antenna, the GNSS high-precision module, datalink and UHF antenna — enables centimeter-level positioning and navigation.

    Image: ComNav
    Image: ComNav

    Local CORS network. Utilizing existed local CORS, the rover station obtains differential data from the CORS service, enabling the lawn mower to achieve positioning and navigation accuracy on a centimeter level.

    Image: ComNav
    Image: ComNav

    Self-built CORS network. Base stations can be placed anywhere based on requirements. Doing so eliminates the worry about prevailing conditions and makes high-precision positioning and navigation of lawn mowers possible.

    Image: ComNav
    Image: ComNav

    Technology Features

    LAI technology. ComNav’s patented low-power anti-interference (LAI) technology provides a jamming-to-signal ratio of up to 50 dB. Power consumption is only 0.1 W when turned on. By quickly detecting and eliminating interference with simple settings, LAI technology can reduce failure time and ensure safe operation. The technology can generate a spectrum diagram of interference sources, enabling identification of interference types and potential interference sources.

    Quantum algorithm. ComNav’s quantum algorithm has sophisticated technology for detecting and repairing cycle slips. It uses full-constellation and full-frequency tracking capabilities along with multi-frequency combination, model and parameter estimation. Quantum is able to eliminate errors caused by the ionosphere, the troposphere and multipath in seconds. As a result, the initialization time of real-time kinematic (RTK) is greatly shortened and precision and reliability are improved. Meanwhile, the extra-long baseline calculation capability expands the operation range.

    RTK-KEEP technology. By estimating model and parameter values, RTK-KEEP Technology can reduce errors caused by satellite orbit, clock difference, ionosphere and troposphere when the base station’s data is lost. Centimeter-level accuracy can be kept for more than 10 minutes, greatly improving the availability of RTK.

    Benefits of ComNav’s Solution

    ComNav’s solution allows the lawn mower to achieve centimeter-level positioning and reduce mowing repetitions. It helps the lawnmower to operate safely and reliably in the corners, under trees, or in other places where satellite signals are weak or lost. With its strong anti-interference capabilities, the lawn mower can maintain continuous and effective positioning in complex environments, meeting the needs of a variety of applications.

  • Unicore’s position accuracy matters for all farm tasks

    Unicore’s position accuracy matters for all farm tasks

    Photo: Unicore
    Photo: Unicore

    Although GNSS has been applied in agriculture for many years, farmers still encounter challenges caused by GNSS. No matter the farm task — planting, spraying, harvesting or specialized applications such as robotic grass mowing — position accuracy matters.
    Here are the most common issues farmers have and how Unicore’s products help.

    • Under canopy. They are unable to get a fix under heavy foliage canopy because the real-time correction signal is interrupted or “shaded out” by the canopy. Unicore is launching two new modules that will help mitigate this problem.
    • Loss of lock. At times, the receivers lose lock or get large position errors when the ionosphere’s effects are severe. Driven by a full-constellation and full-frequency RTK engine, Unicore’s RTK algorithm takes advantage of triple and quad frequency observables, effectively mitigating ionospheric residuals.
    • Loss of 4G signals. RTK can provide real-time centimeter-level high-precision positioning, which requires real-time base station data. In practical applications, radio or wireless network communication is often interrupted. During the interruption of the base station data, RTK’s positioning accuracy decreases quickly. Unicore’s RTK KEEP technology can maintain the centimeter-level positioning accuracy for more than 10 minutes after the interruption.
    • Lack of CORS stations. It is challenging to provide a stable high accuracy position for an ultra-long baseline. With the mitigation of ionospheric and tropospheric delays, Unicore products’ RTK baseline can be extended to up to 50 kilometers.

    The UM980 is Unicore’s new-generation high-precision RTK positioning module, supporting full constellation and full-frequency. Relying on the strengths of high reliability, precise positioning accuracy and low latency, UM980 is not only well suited for high-precision surveying and mapping, but also a good choice for rover or base station receivers in agriculture.

    The UM982 is a dual-antenna high-precision positioning and heading module. Since its master and slave antennas can simultaneously track all the frequencies of all the GNSS systems, the UM982 performs fast on-chip RTK positioning and dual-antenna heading solutions without the need to initialize the IMU. Featuring great positioning performance and stability, the UM982 is a perfect choice for high-precision agriculture applications, such as drones, autonomous tractors and autonomous lawnmowers.

    Both products will be available in June 2022.