gnss-converters-0.3.40: src/Data/RTCM3/SBP/Ephemerides.hs
{-# LANGUAGE NoImplicitPrelude #-}
-- |
-- Module: Data.RTCM3.SBP.Ephemerides
-- Copyright: Copyright (C) 2016 Swift Navigation, Inc.
-- License: LGPL-3
-- Maintainer: Swift Navigation <dev@swiftnav.com>
-- Stability: experimental
-- Portability: portable
--
-- RTCMv3 to SBP Ephemerides Conversions.
module Data.RTCM3.SBP.Ephemerides
( gpsConverter
, glonassConverter
) where
import BasicPrelude
import Control.Lens
import Data.Bits
import Data.Conduit
import Data.RTCM3
import Data.RTCM3.SBP.Time
import Data.RTCM3.SBP.Types
import Data.Word
import SwiftNav.SBP
--------------------------------------------------------------------------------
-- GNSS RTCM observation reconstruction utilities
-- | Produce GPS time from RTCM time (week-number % 1024, tow in seconds, scaled 2^4).
-- Stateful but non-side-effecting. The week number is mod-1024 - add in the base
-- wn from the stored wn masked to 10 bits.
toGpsTimeSec :: MonadStore e m => Word16 -> Word16 -> m GpsTimeSec
toGpsTimeSec wn tow = do
time <- view storeCurrentGpsTime
wn' <- view gpsTime_wn <$> liftIO time
pure GpsTimeSec
{ _gpsTimeSec_tow = 16 * fromIntegral tow
, _gpsTimeSec_wn = wn' `shiftR` 10 `shiftL` 10 + wn
}
-- | Produce GPS time from GLONASS RTCM time.
--
toGlonassTimeSec :: MonadStore e m => Word8 -> m GpsTimeSec
toGlonassTimeSec epoch = do
time <- view storeCurrentGpsTime
t <- liftIO time
let epoch' = fromIntegral epoch * 15 * minuteMillis - 3 * hourMillis + gpsLeapMillis
epoch''
| epoch' < 0 = epoch' + dayMillis
| otherwise = epoch'
dow = fromIntegral (t ^. gpsTime_tow) `div` dayMillis
pure GpsTimeSec
{ _gpsTimeSec_tow = fromIntegral $ (dow * dayMillis + epoch'') `div` 1000
, _gpsTimeSec_wn = t ^. gpsTime_wn
}
-- | Validate IODE/IODC flags. The IODC and IODE flags (least significant bits) should be
-- equal. IODC is Word16 while IODE is Word8, so we shift IODC to drop the most significant bits.
-- We return a 1 if valid, 0 if invalid.
validateIodcIode :: Word16 -> Word8 -> Word8
validateIodcIode iodc iode =
bool 0 1 $ iodc' == iode
where
iodc' = fromIntegral $ iodc `shiftL` 8 `shiftR` 8
-- | Convert between RTCM/GPS URA ("User Range Accuracy") index to a number in meters.
-- See section 2.5.3, "User Range Accuracy", in the GPS signal specification.
-- Indices 1, 3, and 5 are hard-coded according to spec, and 15 is hard-coded according
-- to SBP/Piksi convention.
uriToUra :: Word8 -> Double
uriToUra uri
| uri == 1 = 2.8
| uri == 3 = 5.7
| uri == 5 = 11.3
| uri == 15 = 6144
| uri <= 6 = 2 ** (1 + (fromIntegral uri / 2))
| uri > 6 && uri < 15 = 2 ** (fromIntegral uri - 2)
| otherwise = -1
-- | Lookup Table 4.4 from GLONASS ICD: convert F_T word to accuracy in meters
--
ftToUra :: Word8 -> Double
ftToUra ft
| ft == 0 = 1
| ft == 1 = 2
| ft == 2 = 2.5
| ft == 3 = 4
| ft == 4 = 5
| ft == 5 = 7
| ft == 6 = 10
| ft == 7 = 12
| ft == 8 = 14
| ft == 9 = 16
| ft == 10 = 32
| ft == 11 = 64
| ft == 12 = 128
| ft == 13 = 256
| ft == 14 = 512
| otherwise = -1
-- | Decode SBP 'fitInterval' from RTCM/GPS 'fitIntervalFlag' and IODC.
-- Implementation adapted from libswiftnav/ephemeris.c.
gpsFitInterval :: Bool -> Word16 -> Word32
gpsFitInterval fitInt iodc
| not fitInt = 4 * 60 * 60
| iodc >= 240 && iodc <= 247 = 8 * 60 * 60
| (iodc >= 248 && iodc <= 255) || iodc == 496 = 14 * 60 * 60
| (iodc >= 497 && iodc <= 503) || (iodc >= 1021 && iodc <= 1023) = 26 * 60 * 60
| iodc >= 504 && iodc <= 510 = 50 * 60 * 60
| iodc == 511 || (iodc >= 752 && iodc <= 756) = 74 * 60 * 60
| iodc == 757 = 98 * 60 * 60
| otherwise = 6 * 60 * 60
-- | Convert GLONASS fit interval - Table 4.3 from GLONASS ICD.
--
glonassFitInterval :: Word8 -> Word32
glonassFitInterval fi
| fi == 0 = (60 + 10) * 60
| fi == 1 = (30 + 10) * 60
| fi == 2 = (45 + 10) * 60
| fi == 3 = (60 + 10) * 60
| otherwise = (60 + 10) * 60
-- | Construct an EphemerisCommonContent from an RTCM 1019 message.
--
toGpsEphemerisCommonContent :: MonadStore e m => Msg1019 -> m EphemerisCommonContent
toGpsEphemerisCommonContent m = do
toe <- toGpsTimeSec (m ^. msg1019_ephemeris . gpsEphemeris_wn) (m ^. msg1019_ephemeris . gpsEphemeris_toe)
pure EphemerisCommonContent
{ _ephemerisCommonContent_sid = GnssSignal
{ _gnssSignal_sat = m ^. msg1019_header . gpsEphemerisHeader_sat
, _gnssSignal_code = 0 -- there is an L2P status flag in msg 1019, but I don't think that applies
}
, _ephemerisCommonContent_toe = toe
, _ephemerisCommonContent_ura = uriToUra (m ^. msg1019_ephemeris . gpsEphemeris_svHealth)
, _ephemerisCommonContent_fit_interval = gpsFitInterval (m ^. msg1019_ephemeris . gpsEphemeris_fitInterval) (m ^. msg1019_ephemeris . gpsEphemeris_iodc)
, _ephemerisCommonContent_valid = validateIodcIode (m ^. msg1019_ephemeris . gpsEphemeris_iodc) (m ^. msg1019_ephemeris . gpsEphemeris_iode)
, _ephemerisCommonContent_health_bits = m ^. msg1019_ephemeris . gpsEphemeris_svHealth
}
-- | Construct an EphemerisCommonContent from an RTCM 1020 message.
--
toGlonassEphemerisCommonContent :: MonadStore e m => Msg1020 -> m EphemerisCommonContent
toGlonassEphemerisCommonContent m = do
toe <- toGlonassTimeSec (m ^. msg1020_ephemeris . glonassEphemeris_tb)
pure EphemerisCommonContent
{ _ephemerisCommonContent_sid = GnssSignal
{ _gnssSignal_sat = m ^. msg1020_header . glonassEphemerisHeader_sat
, _gnssSignal_code = 3
}
, _ephemerisCommonContent_toe = toe
, _ephemerisCommonContent_ura = ftToUra (m ^. msg1020_ephemeris . glonassEphemeris_mft)
, _ephemerisCommonContent_fit_interval = glonassFitInterval (m ^. msg1020_ephemeris . glonassEphemeris_p1)
, _ephemerisCommonContent_valid = 1
, _ephemerisCommonContent_health_bits = bool 0 1 $ (m ^. msg1020_ephemeris . glonassEphemeris_mln5) || (m ^. msg1020_ephemeris . glonassEphemeris_mi3)
}
(##) :: (Floating a1, Integral a2) => a1 -> a2 -> a1
(##) p x = (2 ** p) * fromIntegral x
--------------------------------------------------------------------------------
-- RTCM to SBP conversion utilities: RTCM Msgs. 1002 (L1 RTK), 1004 (L1+L2 RTK),
-- 1005 (antenna position), 1006 (antenna position).
-- | Convert an RTCM 1019 GPS ephemeris message into an SBP MsgEphemerisGps.
--
gpsConverter :: MonadStore e m => Msg1019 -> Conduit i m [SBPMsg]
gpsConverter m = do
common <- toGpsEphemerisCommonContent m
toc <- toGpsTimeSec (m ^. msg1019_ephemeris . gpsEphemeris_wn) (m ^. msg1019_ephemeris . gpsEphemeris_toc)
let pi' = 3.1415926535898
m' = MsgEphemerisGps
{ _msgEphemerisGps_common = common
, _msgEphemerisGps_tgd = (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_tgd)
, _msgEphemerisGps_c_rs = (-5) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_rs)
, _msgEphemerisGps_c_rc = (-5) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_rc)
, _msgEphemerisGps_c_uc = (-29) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_uc)
, _msgEphemerisGps_c_us = (-29) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_us)
, _msgEphemerisGps_c_ic = (-29) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_ic)
, _msgEphemerisGps_c_is = (-29) ## (m ^. msg1019_ephemeris . gpsEphemeris_c_is)
, _msgEphemerisGps_dn = pi' * (-43) ## (m ^. msg1019_ephemeris . gpsEphemeris_dn)
, _msgEphemerisGps_m0 = pi' * (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_m0)
, _msgEphemerisGps_ecc = (-33) ## (m ^. msg1019_ephemeris . gpsEphemeris_ecc)
, _msgEphemerisGps_sqrta = (-19) ## (m ^. msg1019_ephemeris . gpsEphemeris_sqrta)
, _msgEphemerisGps_omega0 = pi' * (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_omega0)
, _msgEphemerisGps_omegadot = pi' * (-43) ## (m ^. msg1019_ephemeris . gpsEphemeris_omegadot)
, _msgEphemerisGps_w = pi' * (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_w)
, _msgEphemerisGps_inc = pi' * (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_i0)
, _msgEphemerisGps_inc_dot = pi' * (-43) ## (m ^. msg1019_ephemeris . gpsEphemeris_idot)
, _msgEphemerisGps_af0 = (-31) ## (m ^. msg1019_ephemeris . gpsEphemeris_af0)
, _msgEphemerisGps_af1 = (-43) ## (m ^. msg1019_ephemeris . gpsEphemeris_af1)
, _msgEphemerisGps_af2 = (-55) ## (m ^. msg1019_ephemeris . gpsEphemeris_af2)
, _msgEphemerisGps_iodc = m ^. msg1019_ephemeris . gpsEphemeris_iodc
, _msgEphemerisGps_iode = m ^. msg1019_ephemeris . gpsEphemeris_iode
, _msgEphemerisGps_toc = toc
}
yield [SBPMsgEphemerisGps m' $ toSBP m' 61568]
-- | Convert an RTCM 1020 GLONASS ephemeris message into an SBP MsgEphemerisGlo.
--
glonassConverter :: MonadStore e m => Msg1020 -> Conduit i m [SBPMsg]
glonassConverter m = do
common <- toGlonassEphemerisCommonContent m
let m' = MsgEphemerisGlo
{ _msgEphemerisGlo_common = common
, _msgEphemerisGlo_gamma = (-40) ## (m ^. msg1020_ephemeris . glonassEphemeris_gammaN)
, _msgEphemerisGlo_tau = (-30) ## (m ^. msg1020_ephemeris . glonassEphemeris_tauN)
, _msgEphemerisGlo_d_tau = (-30) ## (m ^. msg1020_ephemeris . glonassEphemeris_mdeltatau)
, _msgEphemerisGlo_pos = (* 1000) . ((-11) ##) <$>
[ m ^. msg1020_ephemeris . glonassEphemeris_xn
, m ^. msg1020_ephemeris . glonassEphemeris_yn
, m ^. msg1020_ephemeris . glonassEphemeris_zn
]
, _msgEphemerisGlo_vel = (* 1000) . ((-20) ##) <$>
[ m ^. msg1020_ephemeris . glonassEphemeris_xndot
, m ^. msg1020_ephemeris . glonassEphemeris_yndot
, m ^. msg1020_ephemeris . glonassEphemeris_zndot
]
, _msgEphemerisGlo_acc = (* 1000) . ((-30) ##) <$>
[ m ^. msg1020_ephemeris . glonassEphemeris_xndotdot
, m ^. msg1020_ephemeris . glonassEphemeris_yndotdot
, m ^. msg1020_ephemeris . glonassEphemeris_zndotdot
]
, _msgEphemerisGlo_fcn = (m ^. msg1020_header . glonassEphemerisHeader_channel) + 1
, _msgEphemerisGlo_iod = ((m ^. msg1020_ephemeris . glonassEphemeris_tb) * 15 * 60) .&. 127
}
yield [SBPMsgEphemerisGlo m' $ toSBP m' 61568]