add starlink-vhf support

SatsDecoder/systems/__init__.py

@@ -14,6 +14,7 @@
 from SatsDecoder.systems.roseycubesat import *
 from SatsDecoder.systems.sharjahsat import *
 from SatsDecoder.systems.sonate2 import *
+from SatsDecoder.systems.starlink_vhf import *
 from SatsDecoder.systems.usp import *
 from SatsDecoder.systems.wtc_simba import *
 
@@ -27,6 +28,7 @@
         'roseycubesat',
         'sharjahsat',
         'sonate2',
+        'starlink_vhf',
         'wtc_simba',
         ):
     m = getattr(sys.modules['SatsDecoder.systems'], i)

SatsDecoder/systems/starlink_vhf.py

@@ -0,0 +1,93 @@
+#  Copyright (c) 2024. Alexander Baskikh
+#
+#  MIT License (MIT), http://opensource.org/licenses/MIT
+#  Full license can be found in the LICENSE-MIT file
+#
+#  SPDX-License-Identifier: MIT
+
+import construct
+
+from SatsDecoder import utils
+from SatsDecoder.systems import common
+
+__all__ = 'StarlinkProtocol',
+
+proto_name = 'starlink-vhf'
+
+
+"""
+https://emitters.space/Starlink.pdf
+"""
+
+
+starlink_beacon = construct.Struct(
+    '_name' / construct.Computed('starlink_beacon'),
+    'name' / construct.Computed('Beacon'),
+
+    # header
+    'msg_num' / construct.Int24ul,
+    'sc_num' / construct.Hex(construct.Int16ul),
+    'ptype' / construct.Hex(construct.Byte),
+    'semi_fixed' / construct.Bytes(7),
+    'Time' / common.UNIXTimestampAdapter(construct.Int32ul),
+
+    # ephemeris
+    'lat' / construct.Float32l,
+    'lon' / construct.Float32l,
+    'alt' / construct.Int32ul,
+    'semi_fixed_tbd' / construct.Bytes(8),
+
+    # telemetry-A
+    'tbd_a' / construct.Bytes(15),
+    'gps_week' / construct.Int16ul,
+    'gps_sec' / common.LinearAdapter(100, construct.Int32ul),
+    'gps_time' / construct.Computed(lambda ctx: utils.gps_to_utc(ctx.gps_week, ctx.gps_sec)),
+
+    # telemetry-B
+    'tbd_b' / construct.Bytes(29),
+)
+
+
+class StarlinkProtocol:
+    columns = 'ptype',
+    c_width = 40,
+
+    tlm_table = {
+        'starlink_beacon': {
+            'table': (
+                ('name', 'Name'),
+                ('msg_num', 'Message Number'),
+                ('sc_num', 'Spacecraft Number'),
+                ('ptype', 'Packet Type'),
+                ('semi_fixed', 'Semi-fixed'),
+                ('Time', 'Time'),
+                ('lat', 'Latitude'),
+                ('lon', 'Longitude'),
+                ('alt', 'Altitude'),
+                ('semi_fixed_tbd', 'Semi-fixed TBD'),
+                ('tbd_a', 'TBD-A'),
+                ('gps_week', 'GPS Week Number'),
+                ('gps_sec', 'GPS Seconds'),
+                ('gps_time', 'GPS Time'),
+                ('tbd_b', 'TBD-B'),
+            ),
+        },
+    }
+
+    def __init__(self, outdir):
+        self.ir = None
+
+    def recognize(self, bb):
+        x = starlink_beacon.parse(bb)
+        if not x:
+            return
+
+        yield 'tlm', 'Starlink #%i' % x.sc_num, '0x%02X' % x.ptype, (x, x)
+
+
+if __name__ == '__main__':
+    a = 'ae803e5109cc0000d0eb4e4b036d765564313d06c262100f4319530600000098a31400043090fc21ba0403000082ca660e060800d408c0ba090318b601e58f2f4b1481d8bce93eb3fcff2b74f6ff674afbff1e10d2dc07'
+    b = bytes.fromhex(a)
+    x = starlink_beacon.parse(b)
+    print(x)
+    print('Starlink #%i' % x.sc_num)

SatsDecoder/utils.py

@@ -5,6 +5,7 @@
 #
 #  SPDX-License-Identifier: MIT
 
+import datetime as dt
 import enum
 import sys
 import tkinter as tk
@@ -341,6 +342,57 @@ def bayer2rgb(data, mode, w, h):
     return np.dstack((r, g, b)).astype(in_dtype)
 
 
+_GPS_BORN = dt.datetime(1980, 1, 6) + dt.timedelta(seconds=19)
+
+def gps_to_utc(week, sec):
+    """
+    https://hpiers.obspm.fr/eop-pc/index.php?index=TAI-UTC_tab&lang=en
+    """
+
+    x = _GPS_BORN + dt.timedelta(weeks=week)
+    # leaked seconds
+    if x < dt.datetime(year=1981, month=7, day=1):
+        sec -= 19
+    elif x < dt.datetime(year=1982, month=7, day=1):
+        sec -= 20
+    elif x < dt.datetime(year=1983, month=7, day=1):
+        sec -= 21
+    elif x < dt.datetime(year=1985, month=7, day=1):
+        sec -= 22
+    elif x < dt.datetime(year=1988, month=1, day=1):
+        sec -= 23
+    elif x < dt.datetime(year=1990, month=1, day=1):
+        sec -= 24
+    elif x < dt.datetime(year=1991, month=1, day=1):
+        sec -= 25
+    elif x < dt.datetime(year=1992, month=7, day=1):
+        sec -= 26
+    elif x < dt.datetime(year=1993, month=7, day=1):
+        sec -= 27
+    elif x < dt.datetime(year=1994, month=7, day=1):
+        sec -= 28
+    elif x < dt.datetime(year=1996, month=1, day=1):
+        sec -= 29
+    elif x < dt.datetime(year=1997, month=7, day=1):
+        sec -= 30
+    elif x < dt.datetime(year=1999, month=1, day=1):
+        sec -= 31
+    elif x < dt.datetime(year=2006, month=1, day=1):
+        sec -= 32
+    elif x < dt.datetime(year=2009, month=1, day=1):
+        sec -= 33
+    elif x < dt.datetime(year=2012, month=7, day=1):
+        sec -= 34
+    elif x < dt.datetime(year=2015, month=7, day=1):
+        sec -= 35
+    elif x < dt.datetime(year=2017, month=1, day=1):
+        sec -= 36
+    else:
+        sec -= 37
+
+    return x + dt.timedelta(seconds=sec)
+
+
 seqs_map = {
     '\x72\x73\x32\x30\x73': 'aHR0cHM6Ly91cGxvYWQud2lraW1lZGlhLm9yZy93aWtpcGVkaWEvY29tbW9u'
                             'cy90aHVtYi80LzRhL0N1YmVTYXRfR2Vvc2Nhbi1FZGVsdmVpc19lbWJsZW0u'