A continuous track can still drift. See how IMU measurements, Kalman filtering and wheel speed shape a position estimate, with a GT-01 tunnel example.
GNSS Handbook
GNSS Handbook
The Kalmix GNSS Handbook explains how satellite positioning actually works, from first principles to the protocol layer. It covers the GNSS pseudorange equation and receiver clock bias, signal bands and constellations, the RTCM correction protocol that RTK depends on, and the coordinate-system pitfalls that can put a perfect fix off the map. Written for engineers integrating GNSS into robotics, AGV, agriculture, and field-automation hardware.
14 articles
Engineering series
GNSS / RTK resources
Overview
Kalmix GNSS Handbook is a free engineering series covering GNSS fundamentals, satellite ranging, pseudorange, satellite geometry, L1/L2/L5 signal bands, constellations, RTCM correction protocols, and geographic coordinate systems including WGS84 datum issues for developers building RTK-based machines.
RTK gives a position now. PPK uses recorded GNSS observations to build and check the final trajectory, with particular value in weak segments, mobile mapping, and UAV flights.
OSR and SSR change what a GNSS receiver receives. PPP, PPP-AR and PPP-RTK show how correction content affects convergence, coverage and receiver support.
Network RTK turns one physical baseline into a regional service through CORS, multi-station modeling, virtual bases, shared grids, and quality control.
Carrier phase RTK reaches centimeters by reducing shared errors, resolving integer ambiguity, and checking whether a Fixed solution remains trustworthy.
RTK GPS adds correction data to ordinary GNSS for centimeter positioning, but the receiver, correction source, antenna, and workflow all matter.
GNSS error budgets start in space, pass through the atmosphere, and end at the antenna, marking which residuals a receiver can model and which require RTK.
How GNSS receivers turn satellite timing into pseudorange measurements, solve four unknowns with four satellites, and output position, velocity, and time.
Frequency support, antenna bandwidth, firmware, and corrections explain why two GNSS receivers can see the same sky but use different satellites.
RTCM is the correction stream behind RTK fixes; reliable deployment depends on frame sync, MSM choices, base coordinates, MT1230, and correction age.
A perfect GNSS or RTK fix can still appear shifted when your receiver, correction service, map layer, and software use different coordinate frames.
NTRIP delivers RTK correction streams over the internet, but reliable fixes still depend on caster access, mountpoints, RTCM payloads, and correction age.
Learn which NMEA 0183 sentences reveal position and RTK state, how checksum validation works, and where receiver output stops being trustworthy.
What kind of sensor GNSS is, why its accuracy is stated as a probability, and which conditions must match before two accuracy claims can be compared.