Fix date extraction

src/components/Home.vue

@@ -162,6 +162,7 @@ export default {
                     console.log('unable to load trajectory')
                 }
             }
+            this.state.metadata = { startTime: this.dataExtractor.extractStartTime(this.state.messages.GPS) }
             Vue.delete(this.state.messages, 'AHR2')
             Vue.delete(this.state.messages, 'POS')
             Vue.delete(this.state.messages, 'GPS')

src/tools/dataflashDataExtractor.js

@@ -1,4 +1,5 @@
 import { ParamSeeker } from '../tools/paramseeker'
+import extractStartTime from './datetools'
 
 window.radians = function (a) {
     return 0.0174533 * a
@@ -452,4 +453,8 @@ export class DataflashDataExtractor {
         }
         return ret
     }
+
+    static extractStartTime (messages) {
+        return extractStartTime(messages)
+    }
 }

src/tools/datetools.js

@@ -0,0 +1,31 @@
+
+function leapSecondsGPS (year, month) {
+    return leapSecondsTAI(year, month) - 19
+}
+
+function leapSecondsTAI (year, month) {
+    const yyyymm = year * 100 + month
+    if (yyyymm >= 201701) return 37
+    if (yyyymm >= 201507) return 36
+    if (yyyymm >= 201207) return 35
+    if (yyyymm >= 200901) return 34
+    if (yyyymm >= 200601) return 33
+    if (yyyymm >= 199901) return 32
+    if (yyyymm >= 199707) return 31
+    if (yyyymm >= 199601) return 30
+
+    return 0
+}
+
+export default function extractStartTime (msgs) {
+    for (const i in msgs.time_boot_ms) {
+        if (msgs.GWk[i] > 1000) { // lousy validation
+            const weeks = msgs.GWk[i]
+            const ms = msgs.GMS[i]
+            let d = new Date((315964800.0 + ((60 * 60 * 24 * 7) * weeks) + ms / 1000.0) * 1000.0)
+            // adjusting for leap seconds
+            d = new Date(d.getTime() - leapSecondsGPS(d.getUTCFullYear(), d.getUTCMonth() + 1) * 1000)
+            return d
+        }
+    }
+}

src/tools/mavlinkDataExtractor.js

@@ -313,4 +313,8 @@ export class MavlinkDataExtractor {
         }
         return texts
     }
+
+    static extractStartTime (messages) {
+        return undefined
+    }
 }