Skip to content 
Introduction
Modern agriculture is embracing automation—from autonomous tractors to precision seeding—but measuring ground speed reliably at very low velocities (below 0.5 m/s) remains a challenge. That’s where low-speed millimeter-wave radar sensors—such as TGSS (True Ground Speed Sensors)—play a vital role.
With over 20 years of experience in mmWave Doppler radar, we have witnessed the rise of agricultural radar solutions designed specifically for low-speed applications. We explain why these 24 GHz tractor Doppler radars, particularly Zilai’s radar sensor, are crucial for future farming.
What Makes Low-Speed Radar Sensors So Compelling?
1.1 Proven TGSS Heritage
True Ground Speed Sensors (TGSS) have been used in agriculture for over 30 years to measure tractor ground speed without wheel slip. These sensors operate at the 24 GHz ISM band, using Doppler beams and planar or horn antennas. They provide accurate non-contact speed measurement, essential for precise seeding, fertilizer spreading, and traction control systems.
1.2 All-Weather and Low-Velocity Capability
Radar works in dust, darkness, mist, and glare—conditions common in field environments. Low-velocity radar sensors detect speeds as low as 0.1 m/s (0.36 km/h) with high fidelity, with error under ±1 km/h—making them ideal for slow tractor operations and safety protocols.
1.3 Multi-Target and Material Monitoring
Beyond measuring tractor speed, similar 24 GHz Doppler radars sense material flow rates in seed conveyors or fertilizer spreaders—radar can track particulate motion in dusty, non-transparent ducts where optical sensors fail.
1.4 Robust Standards and Field-ready Design
TGSS modules are built to meet harsh agricultural standards (SAE J1455 / EP455), feature corrosion-resistant housings, vibration isolation mounts, and plug‑and‑play connectors—ensuring long-term farm use with low maintenance.
Spotlight: Zilai’s 24 GHz Tractor Ground Speed Radar Sensor
Leveraging TGSS-inspired architecture, Zilai presents a dedicated 24 GHz tractor Doppler radar sensor optimized for low-speed ground measurement:
Key Features:
K‑band RFCMOS RF design in continuous-wave (CW) Doppler mode, delivering stable low-velocity detection.
Supports RS 485, CAN, and pulse output interfaces, ensuring flexibility through RS485 communication, CAN-bus speed data, or pulse-style output compatible with legacy speed sensors.
Speed detection from 0.1 m/s (0.36 km/h) to 70 km/h, with error below ±1 km/h—well-suited for seeding, plowing, and tractor operations at low ground speed.
Technical Parameters:
| Parameter | Typical Value |
|---|---|
| Frequency | 24.075 – 24.175 GHz |
| Output Power (EIRP) | ~18–20 dBm |
| Beamwidth (H/V) | ~15° |
| Power Supply | 9–16 V DC |
| Current Draw | ~77 mA at 12 V |
| Operating Temp | –45 °C to +85 °C |
| Min Speed Detection | 0.36 km/h (≈ 0.1 m/s) |
| Typical Speed Range | 0.36–70 km/h |
| Mounting Design | Compact, rugged dimensions |
Its compact, rugged form enables easy installation under tractors without civil work. Supporting CAN and pulse output makes it suitable for both legacy tractors and newer smart-ag machinery.
Key Applications of Low-Speed mmWave Radar in Agriculture
3.1 Precision Seeding and Fertilization Control
Accurate ground-speed measurement is vital for precision application systems. Combining tractor speed (from the radar) with seed or fertilizer flow rate ensures consistent field coverage—reducing waste and improving yield.
3.2 Autonomous Farm Vehicle Control
Autonomous or assisted vehicles often must move slowly to operate safely among workers and obstacles. Zilai’s radar sensor provides stable ground-speed feedback for closed-loop speed control—supporting safe, precise traversal.
3.3 Slip Detection and Traction Management
Wheel slip can skew ground-speed estimates. A radar-based low-speed speed radar sensor avoids wheel slippage and provides true speed measurement, improving traction control and field efficiency.
3.4 Livestock or Worker Proximity Detection
At ultra-low speeds, radar modules can sense movement of humans or animals near the tractor—triggering warning systems or slowing the vehicle automatically to enhance safety.
Technology Insights & Design Best Practices
4.1 Doppler Measurement with Beam Geometry
The radar determines speed by measuring Doppler shift. The compact antenna pattern (~15° beamwidth) ensures accurate detection while minimizing ground interference. At low speeds, precision requires high frequency stability and good clutter rejection.
4.2 Installation Considerations
Correct mounting angle and height (typically 0.3–1 m above ground) are critical; error in angle translates directly into speed measurement error.
4.3 Output Interfaces for Flexibility
Supporting pulse output, RS485, and CAN communication covers a wide range of vehicle systems—from older tractors using pulse counters to modern ECU systems requiring CAN bus signals.
How to Engage Users: Messaging That Resonates
5.1 Focus on Real Tractor Needs
Use language tailored to farmers and OEMs, e.g., “Track ground speed at walking pace,” “No wheel slip, direct ground speed,” “Maintain seeding precision even on slopes.”
5.2 Highlight Return‑on‑Investment
Quantify benefits: improved seeding consistency, reduced chemical waste, fewer expensive machine interventions due to speed error. Emphasize how true speed data can reduce calibration and maintenance time.
5.3 Feature Simplification and Reliability
Convey installation ease: “Plug into tractor CAN bus or pulse input,” “No calibration needed after mounting,” “Low power draw under 1 W.” Stress resilience: range of –45 °C to +85 °C, IP65-like durability.
5.4 Use Visual Storytelling
Include diagrams showing radar mounted under chassis, beam footprint relative to ground, interface wiring options, and table of specs. Example bullet points:
Lowest speed detection: 0.1 m/s
Speed range: 0.36–70 km/h
Interfaces: RS485, CAN, Pulse
Doppler CW K‑band radar sensor
Compact size, rugged build for farming use
Conclusion
Low-speed millimeter-wave radar sensors, like TGSS and Zilai’s 24 GHz tractor-mounted modules, offer precise, non-contact ground-speed measurement even at walking pace. With multi-interface connectivity (RS485, CAN, pulse), robust weather resistance, and minimal speed error (<±1 km/h), they are tailor-made for modern agricultural applications.
By addressing real challenges—wheel slip, low-speed tracking, dusty field conditions—these low-velocity Doppler radar sensors deliver direct value in precision farming. Their compact size, ease of installation, and interface flexibility make them a go-to solution for tractor OEMs and farm automation.
