A cloud-native, crash-free alternative to RTKLIB
RTKLIB is powerful open-source software, but desktop compilation, GUI crashes on large files, and manual ephemeris downloads slow teams down. PosFlow unifies the entire geodetic pipeline into one web workspace.
Before you process it, find out whether the data holds up. Free, no account.
Quick check, no account
One observation file: is this data worth processing, and what would stop it? You get a verdict, the score and up to three findings. The full report, the download and the next step need a free account.
One file up to 100 MB (20 MB gzipped), ten checks per day. The file is deleted as soon as the result is ready.
No file to hand? Check a public reference station's daily observation instead.
Why surveyors seek an RTKLIB alternative
RTKLIB (RTKPOST, CONVBIN, RTKPLOT) has been the go-to open-source GNSS tool for years. However, compiling it on modern operating systems (especially macOS ARM64 and modern Linux) is notoriously error-prone, the Windows GUI frequently crashes on 24-hour multi-frequency RINEX files, and finding matching precise orbits from CDDIS requires manual scripting.
PosFlow vs RTKLIB capabilities
- Zero installation: Runs directly in any web browser on macOS, Windows, Linux, and tablets
- Automated ephemeris retrieval: Sub-second pairing with IGS, CODE, and GFZ precise orbits and clocks
- Robust large-file processing: Server-grade processing without desktop RAM limits or GUI freeze-ups
- Unified multi-vendor converter: Replaces CONVBIN with native support for u-blox, Septentrio, Trimble, Leica, Topcon, and NovAtel
- Multi-engine quality check: Comprehensive 0–100 scoring replacing manual text parsing and fragmented plots
- Dual-engine precise positioning: Scientific-grade PPP and PPK with automated antenna models and cross-validation
- Team collaboration & shareable links: Instant cloud deliverables, PDF summaries, and CSV/Excel exports
Preserving scientific transparency
Like RTKLIB, PosFlow uses transparent, traceable geodetic algorithms. All coordinate solutions provide formal covariance matrices, residual plots, and reproducible processing parameters.
Common questions
Can PosFlow process kinematic rover data against a base station like RTKPOST?
Yes. Apex PPK accepts rover and base station RINEX files to compute kinematic trajectories and static baseline vectors with customizable elevation masks and antenna models.
Does PosFlow support raw binary conversion like CONVBIN?
Yes. Flux converts raw binary logs from u-blox (.ubx), Septentrio (.sbf), Trimble (.t02/.dat), and other manufacturers into clean RINEX 2, 3, or 4.
Can I use PosFlow for free?
Yes. The Free plan includes 25 credits per month — 5 Fast Mode analyses, or 25 conversions — with up to 100 MB per file, no credit card required.
What won't produce a result
Worth checking before you upload, so a run doesn't cost you credits to tell you what your data was missing.
Base and rover observation files that were not recorded over the same time window
Base and rover logs with an overlapping observation span. A baseline can only be solved for the period both receivers were logging at once.
Only one receiver's log, with no second station to differentiate against
Both a rover log and a base station log. A single-receiver file has no second point to form a baseline against.
A base station whose coordinates are unknown
At least an approximate known position for the base. Without one, the solved baseline vector has no reference frame to be reported in.