Fit for Purpose Accuracy

SBAS GPS for Horticultural Farm Management

This project is investigating potential improvements in GNSS positioning accuracy using satellite based augmentation (SBAS) in various farming environments in NZ.

Put simply, SBAS is a system with a network of known land-based control points that provides correction signals to GPS units via satellite. The US equivalent is WAAS, the European equivalent is EGNOS.

The project focuses on testing the SBAS Technology, comparing it with commercial systems currently available (at different levels of accuracy). Through insights gained from growers, the economic benefit SBAS could bring are being assessed.

Vegetable growers view RTK-GPS as the Gold Standard and use it where precise positioning has value. Uncorrected signals are suitable for some applications but sub-metre is preferred. Handheld devices are often tried and generally rejected after disappointment, losing potential benefits of better management if better location data were available.

High accuracy RTK-GPS on both tractor and implement keeps weeders in correct position

Apple growers appear slower to adopt GPS technologies because they identify a gap between very expensive and unwarranted RTK-GPS and cheap inadequate alternatives.  Part of the reason is trouble getting good signals when working in large trees. The SBAS technology offers fit-for-purpose guidance and logging that could change the way growers use positioning technologies to enhance management and profitability.

A number of growers have tried SBAS technologies for both static point location and kinematic guidance. Static location is beneficial for recording points of interest such as diseased plants, weeds and harvest bin location. Kinematic guidance allows growers to track operations such as spraying, ensuring no missed or double ups.

We tested a few systems at the MicroFarm. Rings at RTK-GPS points, blue and white lines are runs using our Arrow100 with SBAS , yellow line is a Bad Elf with SBAS and the green line a smartphone GPS.The project is one of a number being funded under a joint Australia/New Zealand government initiative through the Australian CRC for Spatial Information and LINZ.

The team supporting LandWISE in this project includes

Promoting sustainable production