Calculate expected RTK GPS accuracy based on baseline distance from base to rover. Returns horizontal and vertical accuracy estimates, baseline length status, and field setup recommendations.
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Shop Express Tools →RTK GPS is the standard precision positioning tool for construction layout, earthwork control, and as-built surveys. The base station broadcasts correction data to the rover over a radio link (typical range 5–10 km) or via cellular NTRIP connection (up to 50+ km via network). Accuracy degrades with baseline length — this calculator estimates expected accuracy based on the 1ppm degradation model.
RTK (Real-Time Kinematic) GPS uses a base station at a known location to broadcast correction data to a rover. The rover receives corrections via radio link, Bluetooth, or cellular/NTRIP and computes a fixed position solution with centimeter-level accuracy. Typical RTK accuracy is ±1 cm horizontal and ±2 cm vertical (fixed solution), compared to ±1–5 m for single-point GPS.
For single-base RTK with radio link, reliable range is typically 0–10 km depending on terrain, radio power, and obstructions. Beyond 10 km, ionospheric errors begin to degrade accuracy and fix reliability. Network RTK (NTRIP/VRS) uses a network of permanent reference stations and can achieve similar accuracy over much longer baselines — typically up to 30–50 km.
Typical RTK GPS accuracy in fixed solution: horizontal ±8mm + 1ppm (parts per million) of baseline length, vertical ±15mm + 1ppm. At 5 km baseline: horizontal ≈ ±13mm, vertical ≈ ±20mm. At 10 km: horizontal ≈ ±18mm, vertical ≈ ±25mm. Actual accuracy depends on satellite geometry (PDOP), multipath conditions, and base station occupation quality.
A fixed RTK solution (the integer ambiguities are resolved) gives centimeter accuracy. A float solution hasn't resolved integers and is typically ±10–50 cm — similar to DGPS. Always wait for a fixed solution before taking survey-grade shots. Most controllers show solution type as 'Fixed,' 'Float,' or 'SBAS.' Only Fixed solutions meet survey-grade requirements.
Set the GPS antenna over the control point with a tribrach and optical plummet. Measure the antenna height (from ground mark to antenna reference point) carefully — antenna height errors directly translate to vertical errors in all rover shots. Enter the control point coordinates into the controller, start logging, and wait for the rover to initialize. Log base data for static post-processing if required.
Pole height in meters (most GPS controllers use meters)
Distance from base to rover