def test_properties():
t0 = time.Time(datetime(2000, 1, 1, 1, 1, 1), scale="utc", fmt="datetime")
assert t0.year == 2000
assert t0.month == 1
assert t0.day == 1
assert t0.hour == 1
assert t0.minute == 1
assert t0.second == 1
assert t0.sec_of_day == 3661
assert t0.yydddsssss == "00:001:03661"
assert t0.doy == 1
t1 = time.Time(
[datetime(2000, 1, 1, 1, 1, 1),
datetime(2001, 1, 1, 1, 1, 1)],
scale="utc",
fmt="datetime")
assert (t1.year == np.array([2000, 2001])).all()
assert (t1.month == np.array([1, 1])).all()
assert (t1.day == np.array([1, 1])).all()
assert (t1.hour == np.array([1, 1])).all()
assert (t1.minute == np.array([1, 1])).all()
assert (t1.second == np.array([1, 1])).all()
assert (t1.sec_of_day == np.array([3661, 3661])).all()
assert (t1.yydddsssss == np.array(["00:001:03661", "01:001:03661"])).all()
assert (t1.doy == np.array([1, 1])).all()
def t_dt_utc_a2():
"""Time, format datetime, scale utc, array entry"""
return time.Time(
[datetime(2015, 6, i + 1) for i in range(0, 2)],
val2=[timedelta(hours=23, minutes=59, seconds=i) for i in range(0, 2)],
scale="utc",
fmt="datetime",
)
def t_around_leapsecond():
"""Epochs just before and after leap second on June 30th 2015"""
return time.Time(
[
datetime(2015, 6, 30) + timedelta(hours=23, minutes=59, seconds=i)
for i in range(55, 65)
],
scale="utc",
fmt="datetime",
)
def test_is_tests():
t = time.Time(datetime(2000, 1, 1, 1, 1, 1), scale="utc", fmt="datetime")
dt = time.TimeDelta(30, scale="utc", fmt="seconds")
assert time.Time.is_time(t) == True
assert time.Time.is_time(dt) == False
assert time.Time.is_time(8) == False
assert time.Time.is_timedelta(t) == False
assert time.Time.is_timedelta(dt) == True
assert time.Time.is_timedelta(9) == False
def test_slice(t):
scales = time.TimeArray._scales()
formats = time.TimeArray._formats()
for scale in scales.keys():
converted_t = getattr(t, scale)
for fmt in formats:
try:
t_fmt = getattr(converted_t, fmt)
print(f"Creating time time.Time({t_fmt}, {scale}, {fmt})")
new_time_from_fmt = time.Time(t_fmt, scale=scale, fmt=fmt)
except ValueError as err:
# some formats are only available for certain scales
assert converted_t.scale != "gps" and "gps" in fmt
print(
f"{fmt} is not a valid format for {converted_t.scale}. As expected."
)
continue
assert len(converted_t[0:2]) == 2
print(f"t.{scale}[0:2] == 2 OK")
assert len(new_time_from_fmt[0:2]) == 2
print(f"t.{scale}.{fmt}[0:2] == 2 OK")
def apply_rates(coefficients, truncation_level, rundate):
"""Apply rates to coefficients for the gravitational field
See IERS Conventions [4], equation (6.4).
Args:
coefficients: Dict containing tables of coefficients.
truncation_level: Level of degree and order where coeffs are truncated.
rundate: Start time of integration.
Returns:
None. Coefficients are changed in place.
"""
ref_date = time.Time(datetime(2000, 1, 1, 0, 0), fmt="datetime", scale="utc")
years = (rundate.mjd - ref_date.mjd) / 365.25
if truncation_level >= 2:
# Note that the C20- value is the tide free value on page 89 in [4],
# not the zero tide value in Table 6.2.
coefficients["C"][2, 0] = -0.484_165_31e-3 + 11.6e-12 * years
if truncation_level >= 3:
coefficients["C"][3, 0] += 4.9e-12 * years
if truncation_level >= 4:
coefficients["C"][4, 0] += 4.7e-12 * years
def t_jd_gps():
"""Time, format julian date, scale gps"""
return time.Time(2457448.5, scale="gps", fmt="jd")
def t_dt_utc_s2():
"""Time, format datetime, scale utc, single entry"""
return time.Time(datetime(2015, 6, 30),
val2=timedelta(hours=23, minutes=59, seconds=20),
scale="utc",
fmt="datetime")
def t_dt_utc_sa():
"""Time, format datetime, scale utc, array entry with single value"""
return time.Time(
[datetime(2015, 6, 30) + timedelta(hours=23, minutes=59, seconds=20)],
scale="utc",
fmt="datetime")
def test_empty_object():
time.Time([], scale="utc", fmt="datetime")
def get_gravity_coefficients(gravity_field, truncation_level, rundate):
"""Get coefficients for a gravity field
The coefficient files come with normalized gravity coefficients.
The coefficients are returned in a dict with keys `C` and `S`,
each containing a table of coefficients `C[i, j]` and `S[i, j]`.
Args:
gravity_field: Name of gravity field.
truncation_level: Level of degree and order where coeffs are truncated.
rundate: Start time of integration.
Returns:
A dictionary containing C and S coefficients.
"""
log.info(f"Reading gravity field {gravity_field} up to degree and order {truncation_level}")
try:
gravity_parser = parsers.parse_key(
"gravity_coefficients", file_vars=dict(gravity_field=gravity_field), num_degrees=truncation_level
)
except FileNotFoundError:
log.fatal(f"Unknown gravity field {gravity_field}, exiting!")
gravity_coefficients = gravity_parser.as_dict()
GM = gravity_parser.meta["earth_gravity_constant"]
r = gravity_parser.meta["radius"]
gr = dict()
gr["C"] = np.zeros((truncation_level + 1, truncation_level + 1))
gr["S"] = np.zeros((truncation_level + 1, truncation_level + 1))
rundate = time.Time(rundate, fmt="datetime", scale="utc")
if gravity_coefficients["gfc"].shape == ():
gr["C"][gravity_coefficients["gfc"]["degree"], gravity_coefficients["gfc"]["order"]] = gravity_coefficients[
"gfc"
]["C"]
gr["S"][gravity_coefficients["gfc"]["degree"], gravity_coefficients["gfc"]["order"]] = gravity_coefficients[
"gfc"
]["S"]
else:
for l in gravity_coefficients["gfc"]:
gr["C"][l["degree"], l["order"]] = l["C"]
gr["S"][l["degree"], l["order"]] = l["S"]
if not "gfct" in gravity_coefficients:
if gravity_field == "EGM2008":
# Rates not contained in gravity file, apply rates from IERS
apply_rates(gr, truncation_level, rundate)
return gr, GM, r
for l in gravity_coefficients["gfct"]:
# TODO: Not sure what the xxxx in t0[yyyymmdd.xxxx] actually means (see e.g. EIGEN-6S4)
# Maybe hours and minutes, but in that case the minutes should have been between 0..59.
# They are not.
# It doesn't seem to matter for the orbit determination process,
# so I set hours = 0 for now
t0 = time.Time(
datetime(int(l["t0"][0:4]), int(l["t0"][4:6]), int(l["t0"][6:8]), int(l["t0"][9:11]), 0),
scale="utc",
fmt="datetime",
)
t1 = time.Time(
datetime(int(l["t1"][0:4]), int(l["t1"][4:6]), int(l["t1"][6:8]), int(l["t1"][9:11]), 0),
scale="utc",
fmt="datetime",
)
if t0 <= rundate < t1:
gr["C"][l["degree"], l["order"]] += l["C"]
gr["S"][l["degree"], l["order"]] += l["S"]
for l in gravity_coefficients["trnd"]:
t0 = time.Time(
datetime(int(l["t0"][0:4]), int(l["t0"][4:6]), int(l["t0"][6:8]), int(l["t0"][9:11]), 0),
scale="utc",
fmt="datetime",
)
t1 = time.Time(
datetime(int(l["t1"][0:4]), int(l["t1"][4:6]), int(l["t1"][6:8]), int(l["t1"][9:11]), 0),
scale="utc",
fmt="datetime",
)
if t0 <= rundate < t1:
years = (rundate.mjd - t0.mjd) / 365.25
gr["C"][l["degree"], l["order"]] += l["C"] * years
gr["S"][l["degree"], l["order"]] += l["S"] * years
for l in gravity_coefficients["asin"]:
t0 = time.Time(
datetime(int(l["t0"][0:4]), int(l["t0"][4:6]), int(l["t0"][6:8]), int(l["t0"][9:11]), 0),
scale="utc",
fmt="datetime",
)
t1 = time.Time(
datetime(int(l["t1"][0:4]), int(l["t1"][4:6]), int(l["t1"][6:8]), int(l["t1"][9:11]), 0),
scale="utc",
fmt="datetime",
)
if t0 <= rundate < t1:
years = (rundate.mjd - t0.mjd) / 365.25
gr["C"][l["degree"], l["order"]] += l["C"] * math.sin(2 * math.pi * years / l["period"])
gr["S"][l["degree"], l["order"]] += l["S"] * math.sin(2 * math.pi * years / l["period"])
for l in gravity_coefficients["acos"]:
t0 = time.Time(
datetime(int(l["t0"][0:4]), int(l["t0"][4:6]), int(l["t0"][6:8]), int(l["t0"][9:11]), 0),
scale="utc",
fmt="datetime",
)
t1 = time.Time(
datetime(int(l["t1"][0:4]), int(l["t1"][4:6]), int(l["t1"][6:8]), int(l["t1"][9:11]), 0),
scale="utc",
fmt="datetime",
)
if t0 <= rundate < t1:
years = (rundate.mjd - t0.mjd) / 365.25
gr["C"][l["degree"], l["order"]] += l["C"] * math.cos(2 * math.pi * years / l["period"])
gr["S"][l["degree"], l["order"]] += l["S"] * math.cos(2 * math.pi * years / l["period"])
return gr, GM, r
