FIX: Ensure that HRV data is synchronized with other FIT data.

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/postrunner/HRV_Analyzer.rb b/lib/postrunner/HRV_Analyzer.rb
index 664f7c9..116561b 100644
--- a/lib/postrunner/HRV_Analyzer.rb
+++ b/lib/postrunner/HRV_Analyzer.rb
@@ -170,6 +170,16 @@ module PostRunner
           predictor.insert(dt)
         end
       end
+
+      # The accumulated R-R intervals tend to be slightly larger than the
+      # total timer time measured by the device. It's unclear why this is the
+      # case, but I assume it's an accumulated measuring error. We calculate a
+      # correction factor and time-warp all timestamps so the total time
+      # aligns with the other data of the FIT file. We also correct the R-R
+      # intervals times accordingly.
+      time_warp_factor = @fit_file.total_timer_time / @timestamps.last
+      @timestamps.map! { |t| t * time_warp_factor }
+      @rr_intervals.map! { |t| t ? t * time_warp_factor : nil }
     end
 
   end