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Export of pypredict updates from central repo
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@jerematt
jerematt authored May 7, 2020
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PyPredict
=======

><b>NOTE</b>: To preserve compatibility with `predict`, pypredict uses __north__ latitude and __west__ longitude for terrestrial coordinates.
Do you want accurate and time-tested satellite tracking and pass prediction in a convenient python wrapper?
You're in the right place.

PyPredict is a C Python extension directly adapted from the ubiquitous [predict](http://www.qsl.net/kd2bd/predict.html) satellite tracking command line application.
Originally written for the commodore 64, predict has a proven pedigree; We just aim to provide a convenient API.
PyPredict is a port of the predict codebase and should yield identical results.

NOTE: pypredict and predict uses __north__ latitude, __west__ longitude for groundstation site coordinates.

If you think you've found an error, please include predict's differing output in the bug report.
If you think you've found an error in pypredict, please include output from predict on same inputs to the bug report.
If you think you've found a bug in predict, please report and we'll coordinate with upstream.

### Installation
Expand All @@ -31,36 +31,48 @@ tle = """0 LEMUR 1
2 40044 097.9584 269.2923 0059425 258.2447 101.2095 14.72707190 30443"""
qth = (37.771034, 122.413815, 7) # lat (N), long (W), alt (meters)
predict.observe(tle, qth) # optional time argument defaults to time.time()
# => {
'decayed': 0,
'elevation': -41.35311129599831,
'name': '0 LEMUR 1',
'norad_id': 40044,
'altitude': 640.7111771881182,
'orbit': 3048,
'longitude': 317.1566472306673,
'sunlit': 0,
'geostationary': 0,
'footprint': 5492.870800739669,
'epoch': 1421197860.582528,
'doppler': -777.9630509272195,
'visibility': 'N',
'azimuth': 104.54206601988983,
'latitude': -10.614365448199932,
'orbital_model': 'SGP4',
'orbital_phase': 208.99510848736426,
'eclipse_depth': 23.38122135548474,
'slant_range': 9338.612365004446,
'has_aos': 1,
'orbital_velocity': 27165.627315567013
}
# => {'altitude': 676.8782276657903,
# 'azimuth': 96.04762045174824,
# 'beta_angle': -27.92735429908726,
# 'decayed': 0,
# 'doppler': 1259.6041017128405,
# 'eci_obs_x': -2438.227652191655,
# 'eci_obs_y': -4420.154476060397,
# 'eci_obs_z': 3885.390601342013,
# 'eci_sun_x': 148633398.020844,
# 'eci_sun_y': -7451536.44122029,
# 'eci_sun_z': -3229999.50056359,
# 'eci_vx': 0.20076213530665032,
# 'eci_vy': -1.3282146055077213,
# 'eci_vz': 7.377067234096598,
# 'eci_x': 6045.827328897242,
# 'eci_y': -3540.5885778261277,
# 'eci_z': -825.4065096776636,
# 'eclipse_depth': -87.61858291647795,
# 'elevation': -43.711904591801726,
# 'epoch': 1521290038.347793,
# 'footprint': 5633.548906707907,
# 'geostationary': 0,
# 'has_aos': 1,
# 'latitude': -6.759563817939698,
# 'longitude': 326.1137007912563,
# 'name': '0 LEMUR 1',
# 'norad_id': 40044,
# 'orbit': 20532,
# 'orbital_model': 'SGP4',
# 'orbital_phase': 145.3256815318047,
# 'orbital_velocity': 26994.138671706416,
# 'slant_range': 9743.943478523843,
# 'sunlit': 1,
# 'visibility': 'D'
# }
```

#### Show upcoming transits of satellite over groundstation

```python
p = predict.transits(tle, qth)
for i in range(1,10):
for _ in xrange(10):
transit = p.next()
print("%f\t%f\t%f" % (transit.start, transit.duration(), transit.peak()['elevation']))
```
Expand All @@ -72,34 +84,47 @@ predict.quick_find(tle.split('\n'), time.time(), (37.7727, 122.407, 25))
predict.quick_predict(tle.split('\n'), time.time(), (37.7727, 122.407, 25))
```

##API
## API
<pre>
<b>observe</b>(<i>tle, qth[, at=None]</i>)
Return an observation of a satellite relative to a groundstation.
<i>qth</i> groundstation coordinates as (lat(N),long(W),alt(m))
If <i>at</i> is not defined, defaults to current time (time.time())
Returns an "observation" or dictionary containing:
<i>norad_id</i> : NORAD id of satellite.
<i>name</i> : name of satellite from first line of TLE.
<i>epoch</i> : time of observation in seconds (unix epoch)
<i>azimuth</i> : azimuth of satellite in degrees relative to groundstation.
<i>elevation</i> : elevation of satellite in degrees relative to groundstation.
<i>slant_range</i> : distance to satellite from groundstation in meters.
<i>sunlit</i> : 1 if satellite is in sunlight, 0 otherwise.
<i>decayed</i>: 1 if satellite has decayed out of orbit, 0 otherwise.
<i>geostationary</i> : 1 if satellite is determined to be geostationary, 0 otherwise.
<i>latitude</i> : sub-satellite latitude.
<i>longitude</i> : sub-satellite longitude.
<i>altitude</i> : altitude of satellite relative to sub-satellite latitude, longitude.
<i>has_aos</i> : 1 if the satellite will eventually be visible from the groundstation
<i>doppler</i> : doppler shift between groundstation and satellite.
<i>orbit</i> : refer to predict documentation
<i>footprint</i> : refer to predict documentation
<i>visibility</i> : refer to predict documentation
<i>orbital_model</i> : refer to predict documentation
<i>orbital_phase</i> : refer to predict documentation
<i>eclipse_depth</i> : refer to predict documentation
<i>orbital_velocity</i> : refer to predict documentation
<i>altitude</i> _ altitude of satellite in meters
<i>azimuth</i> - azimuth of satellite in degrees from perspective of groundstation.
<i>beta_angle</i>
<i>decayed</i> - 1 if satellite has decayed out of orbit, 0 otherwise.
<i>doppler</i> - doppler shift between groundstation and satellite.
<i>eci_obs_x</i>
<i>eci_obs_y</i>
<i>eci_obs_z</i>
<i>eci_sun_x</i>
<i>eci_sun_y</i>
<i>eci_sun_z</i>
<i>eci_vx</i>
<i>eci_vy</i>
<i>eci_vz</i>
<i>eci_x</i>
<i>eci_y</i>
<i>eci_z</i>
<i>eclipse_depth</i>
<i>elevation</i> - elevation of satellite in degrees from perspective of groundstation.
<i>epoch</i> - time of observation in seconds (unix epoch)
<i>footprint</i>
<i>geostationary</i> - 1 if satellite is determined to be geostationary, 0 otherwise.
<i>has_aos</i> - 1 if the satellite will eventually be visible from the groundstation
<i>latitude</i> - north latitude of point on earth directly under satellite.
<i>longitude</i> - west longitude of point on earth directly under satellite.
<i>name</i> - name of satellite from first line of TLE.
<i>norad_id</i> - NORAD id of satellite.
<i>orbit</i>
<i>orbital_phase</i>
<i>orbital_model</i>
<i>orbital_velocity</i>
<i>slant_range</i> - distance to satellite from groundstation in meters.
<i>sunlit</i> - 1 if satellite is in sunlight, 0 otherwise.
<i>visibility</i>
<b>transits</b>(<i>tle, qth[, ending_after=None][, ending_before=None]</i>)
Returns iterator of <b>Transit</b> objects representing passes of tle over qth.
If <i>ending_after</i> is not defined, defaults to current time
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