docs/schema: server-side GNSS lever-arm correction#680
Open
dirkwa wants to merge 3 commits into
Open
Conversation
Document the data-model contract for server-corrected navigation.position when GPS antenna offsets are configured. Adds sensors.<id>.sourceRef so sensor metadata can be linked to its data stream; describes navigation.position as the Common Coordinate Reference Point (CCRP) at center-of-vessel on the centerline (body coordinates (length/2, 0) measured from the bow) when correction is active; documents the meta.gpsOffsetCorrection entry that preserves the raw value and the correction provenance. Motivated by SignalK/signalk-server#2399, which adds the multi-GPS configuration UI and the in-server lever-arm corrector.
Rename the linkage field on the sensor object to $source per the $-prefix reference convention, the correction meta to gnssOffsetCorrection with $sensor referencing the sensor instance, and the surrounding prose from GPS to GNSS. Matches the server implementation in SignalK/signalk-server#2399.
dirkwa
changed the title
Update the spec to match the server implementation: correction is an opt-in server option (replace or both modes) rather than always-on, and is not signalled in-band. Drop the meta.gnssOffsetCorrection description - position deltas are high volume so no per-delta marker is added; the 'both' mode keeps the raw antenna value as a separate <id>.ccrp source instead. Document the notifications.navigation.gnss.headingUnavailable notification raised when correction is active but heading is missing.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Summary
Document the data-model contract for server-corrected
navigation.positionwhen GNSS antenna offsets are configured.sensors.<id>.$source(new, optional) links a sensor instance to the source of its data stream — needed when multiple sensors of the same class are present (e.g. multi-GNSS). Named per the$-prefix reference convention established by$sourcein deltas.navigation.positiondescription expanded to define the Common Coordinate Reference Point (CCRP) as center-of-vessel on the centerline (body coordinates(design.length.value.overall / 2, 0)measured from the bow), matching the NMEA 2000 / radar / AIS industry convention.meta.gnssOffsetCorrectionentry that travels with correctednavigation.positiondeltas so history-recording consumers can preserve both the corrected value and the raw antenna measurement (with full provenance:$sensorreferencing the sensor instance, fromBow, fromCenter, lengthOverall, headingTrue, rawValue).mdbook/src/data_model.mdexplaining the lever-arm correction model end-to-end.Motivation
This is the specification side of SignalK/signalk-server#2399, which adds the multi-GNSS configuration UI and the in-server lever-arm corrector. Source priorities mean the active position source can flip between antennas with different offsets, which is fragile to correct client-side; the server has the active-source resolution and the heading, so it applies the correction in-process and emits the raw value plus correction provenance in
metafor downstream history.