GPS Reliability and Precision

GPS reliability and precision are critical aspects of modern navigation systems. The Global Positioning System (GPS) allows vehicles to receive timing signals from multiple satellites and calculate their position. GOETTING KG integrates GPS data with odometric information from wheel encoders. This provides precise commands to vehicle steering systems.

GPS reliability and precision GPS reliability and precision

The basic GPS system has a precision of approximately ± 16 feet, which is insufficient for vehicle guidance. Goetting KG uses several measures to increase the performance of a GPS-based guidance system to a precision of ± 0.4″ (1 cm).

OPERATIONAL TECHNOLOGIES

  • GPS reliability and precision
  • GPS reliability and precision are enhanced by DGPS (Differential GPS). A fixed-location GPS receiver on-site evaluates the precision of the GPS signals and calculates correction signals. These are then radioed to the vehicle system.
  • PDGPS (Precision DGPS) increases the vehicle receiver’s precision using carrier phase evaluation algorithms. This further improves GPS reliability and precision.
  • Sensor Fusion: GOETTING uses odometric information from the vehicle’s wheel decoders. This increases quality and bridges brief interruptions and errors of the GPS signal. This ensures consistent GPS reliability and precision.

ADVANTAGES AND CHALLENGES

  • GPS reliability and precision are essential. No field installations are needed (a DGPS reference station is required if no sufficient public reference signal is available). Changes of site or vehicle path are handled by self-learning or changes to a virtual computer map.
  • Performance of this guidance system is not affected by adverse light conditions. It works at night, under fog, airborne dust, lint, fluid spraying, bright daylight, and welding. It also handles debris, spills, snow, ice, standing water, fluids, and ground irregularities. Goetting’s sensor fusion technology resolves temporary GPS data interference from sun activity.
  • The precision of the guidance system (± 0.4″) is enough to stack and pick up ISO shipping containers automatically. This is possible if the vehicle or crane offers precision controls. Customers achieved overall vehicle precision of up to ± 0.75″.
  • All GPS antennas need an unobstructed line of sight to the sky, with a 170° opening angle (5° elevation). Indoor operation is not possible. High buildings, container stacks, and overhead cranes can pose challenges. CTS and Goetting offer site surveys to determine GPS antenna mounting positions.
  • The US government operates the satellites in the system. They could temporarily decline this service for reasons like national security.

For more information about Goetting GPS Guidance systems, download the brochure here.