GPSlogger Kalman vs VMGPolar

GPSlogger is a GPS track recorder and mainly a sailing / windsurfing / winging performance analyzer for iPhone, iPad and Apple Watch. The app uses Kalman filtering on GPS and altimeter data to improve accuracy. Recording is unlimited. Imported GPX, FIT or VKX tracks are limited to the first 30 minutes; a one-time in-app purchase unlocks unlimited track length. Record tracks using Apple Watch with GPS, or iPhone/iPad with GPS. WeatherKit stores wind conditions at the point of recording (cellular or wifi coverage provided), viewable in a Weather view and widget. Core Location and MapKit are used to acquire and display GPS location data. On Apple Watch, HealthKit is used to acquire heart rate data and export it into the Health app together with the workout activity. RECORDING FEATURES • Creates one extra track with Kalman filtering for latitude/longitude coordinates and elevation. • Stores wind conditions into the GPX file if available at time of recording. • Stores water temperature into the GPX file if available on Apple Watch. • Works on iOS, iPadOS and watchOS. • Tracks can be pushed from the Apple Watch, imported using the built-in File Importer, or opened from the Files app, Email, or iMessage. • Export using the standard File Exporter. • Export GPX 1.0, 1.1 or Garmin FIT. • Records accelerometer and gyroscope data. • 2Hz sampling with motion-sensor-assisted interpolation. • Captures acceleration (longitudinal/lateral), user direction and rotation rate. ANALYSIS FEATURES • Import GPX, Garmin FIT or Vakaros VKX format, including trim and heel data. • Calculates a polar plot. • Calculates VMG (Velocity Made Good) on iOS and iPadOS. • Finds maximum-speed segments over 2s, 10m, 100m, 1000m and 1852m. • Configurable to show the top 1, 5 or 25 non-overlapping speed segments. • Toggle the data graph between speed, altitude, course, heart rate (if available), GPS accuracy cumulative upwind distance and more if available . • Select a segment with markers to calculate distance, time and average speed. • Direct selection of speed segments in a sortable table. • Finds tacks, jibes and crashes, with direct selection in a sortable table. • Lets you crop samples, decimate by 5, and detect and fix glitches. • Supports importing multiple tracks (iOS and iPadOS only), overlaid on the same chart. • Import filter for tracks, with a sortable table. • Weather for your local and favorite locations. • Weather widget so you never miss upcoming wind conditions — interactive, toggling between local and favorite location. WATCHOS EXTRA FEATURES • Heart rate on watchOS uses linear interpolation between updates, so every GPS sample point gets a valid value in the GPX log. • The workout also appears in the iOS Fitness app together with the track log (HealthKit). • A watch widget toggles between showing total distance and current local wind speed.

Sailing wind and boat speed calculator. Enter 3 values to calculate the rest, then save the data into a log that can be exported later. The input fields are highlighted, with the least intensive highlight marking the next field to become a calculated value when a new input is entered. BSP = Boat Speed TWS = True Wind Speed TWA = True Wind Angle AWS = Apparent Wind Speed AWA = Apparent Wind Angle VMG = Velocity Made Good (calculated only) Save and export data to build and validate polar graphs.