@signalk/nmea0183-signalk/hooks/BOD.js

A node.js/javascript parser for NMEA0183 sentences. Sentences are parsed to Signal K format.

/**
 * Copyright 2019 Signal K and Fabian Tollenaar <fabian@decipher.industries>.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const debug = require('debug')('signalk-parser-nmea0183/BOD')
const utils = require('@signalk/nmea0183-utilities')

/**
 * $GPBOD,045.,T,023.,M,DEST,START*01
 *
 * Bearing - origin to destination waypoint (BOD)
 *
 * 0) 045.       bearing 045 True from "START" to "DEST"
 * 1) T,           True
 * 2) 023.         bearing 023 Magnetic from "START" to "DEST"
 * 3) M            Magnetic
 * 4) DEST         destination waypoint ID
 * 5) START        origin waypoint ID
 **/

module.exports = function BODHook(input) {
  const { id, sentence, parts, tags } = input
  const upper = (str) => str.trim().toUpperCase()

  debug(`[BODHook] decoding sentence ${id} => ${sentence}`)

  if (
    upper(parts[0]) === '' ||
    upper(parts[1]) === '' ||
    upper(parts[2]) === '' ||
    upper(parts[3]) === '' ||
    upper(parts[4]) === ''
  ) {
    return null
  }

  const bearingOriginToDestination = {}

  bearingOriginToDestination[upper(parts[1]) === 'T' ? 'True' : 'Magnetic'] =
    utils.transform(parts[0], 'deg', 'rad')
  bearingOriginToDestination[upper(parts[3]) === 'T' ? 'True' : 'Magnetic'] =
    utils.transform(parts[2], 'deg', 'rad')
  const destinationWaypointID = parts[4].trim()
  const originWaypointID = parts[5].trim()

  return {
    updates: [
      {
        source: tags.source,
        timestamp: tags.timestamp,
        values: [
          {
            path: 'navigation.courseRhumbline.bearingTrackTrue',
            value: bearingOriginToDestination.True || null,
          },
          {
            path: 'navigation.courseRhumbline.bearingTrackMagnetic',
            value: bearingOriginToDestination.Magnetic || null,
          },
          {
            path: 'navigation.courseRhumbline.nextPoint.ID',
            value: destinationWaypointID,
          },
          {
            path: 'navigation.courseRhumbline.previousPoint.ID',
            value: originWaypointID,
          },
        ],
      },
    ],
  }
}