GPS Troubleshooting Guide for Topcon Grader and Dozer Systems

Troubleshooting Guide for Grader and Dozer GPS Systems

Introduction This guide provides detailed troubleshooting steps for common issues encountered with GPS systems in Grader and Dozer applications. Each section will help you diagnose problems, understand their causes, and implement the correct solutions to ensure optimal operation and precision.

1. GPS Bar at the Bottom of the Screen Turns Red

Cause: This happens when you have lost initialization due to issues with GPS or Radio.

Solution:

• Identify the Problem: Select the red bar at the bottom of the screen and then select GPS info.
• Follow these steps based on the status at the top of the Fix tab:
  • Waiting for Satellites: Ensure the GPS antenna has a clear view of the sky. Check connections between the antenna and rover box. If only a red flash is present, restart the control box. If the issue persists, it may be a hardware issue.
  • No Radio Link or Waiting for Radio Link: Ensure the base station is operational and check all cable connections. Make sure the rover box is set to the correct radio frequency and that settings are configured properly.
  • Initialising or Waiting to Initialise: If the status does not change after a few minutes, reset the RTK calculation and check satellite geometry. Ensure a good ‘spread’ of satellites across the sky. Adjust the Mask angle to 13 degrees to improve accuracy.

2. GPS Bar at the Bottom of the Screen Turns Orange

Cause: Low Precision – GPS will still be initialized, but the RMS values are out of tolerance.

Solution:

• Adjust tolerances in the machine builder file under Control-Machine Setup.
• You can also try lowering your elevation mask to track satellites closer to the horizon.

3. Slope Bar at the Bottom of the Screen Turns Red

Cause: ‘Slope Sensor not connected’ – This indicates that 3DMC is not receiving data from one or more sensors.

Solution:

• Check all cabling and connections for corrosion or damage.
• Physically inspect the sensors for any signs of damage. If no physical damage is evident, sensors may have failed internally.

4. Passes Do Not Match

Cause: This can occur when one or more sensors are not providing the correct reading, usually due to an error in the calibration. Blade wear can also be a contributing factor.

Solution:

• Proper calibration of the sensors is crucial. Follow the on-screen instructions for calibration and adjust for blade wear if necessary.

5. Blade Not Matching Grade Fast Enough

Solution: Adjust the gains to control the speed at which the blade matches the grade. The default setting is 45; increase to speed up or decrease to slow down the blade’s movement.

6. Bench Check

Procedure:

• Position the cutting edge directly over the benchmark and measure the height difference.
• Use this measurement to adjust the GPS antenna height and ensure the machine is grading correctly.

Definitions:

• GPS: The Global Positioning System is the American-based constellation of 24 satellites.
• GLONASS: The Global Navigation Satellite System is the Russian-based constellation of satellites.
• RTK: Real-Time Kinematic, a technique used in GPS to enhance the precision of position data.
• PDOP: Positional Dilution of Precision, linked directly to the geometry of the satellites.

This troubleshooting guide is designed to help operators and technicians quickly resolve issues with GPS systems in Grader and Dozer equipment, ensuring minimal downtime and maintaining high precision in operations.