attotime/time_scale/
gpst.rs

1//! Implementation of the time broadcast by the Global Positioning System (GPS).
2
3use crate::{
4    Date, Duration, FromTimeScale, IntoTimeScale, Month, TerrestrialTime, TimePoint,
5    UniformDateTimeScale,
6    time_scale::{AbsoluteTimeScale, TimeScale},
7};
8
9pub type GpsTime = TimePoint<Gpst>;
10
11/// Time scale representing the Global Positioning System Time (GPST). GPST has no leap seconds
12/// and increases monotonically at a constant rate. It is distributed as part of the GPS broadcast
13/// messages, making it useful in a variety of high-accuracy situations.
14#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
15pub struct Gpst;
16
17impl TimeScale for Gpst {
18    const NAME: &'static str = "Global Positioning System Time";
19
20    const ABBREVIATION: &'static str = "GPST";
21}
22
23impl AbsoluteTimeScale for Gpst {
24    const EPOCH: Date = match Date::from_historic_date(1980, Month::January, 6) {
25        Ok(epoch) => epoch,
26        Err(_) => unreachable!(),
27    };
28}
29
30impl UniformDateTimeScale for Gpst {}
31
32impl<Scale: ?Sized> TimePoint<Scale> {
33    pub fn from_gpst(time_point: GpsTime) -> Self
34    where
35        Self: FromTimeScale<Gpst>,
36    {
37        Self::from_time_scale(time_point)
38    }
39
40    pub fn into_gpst(self) -> GpsTime
41    where
42        Self: IntoTimeScale<Gpst>,
43    {
44        self.into_time_scale()
45    }
46}
47
48impl TerrestrialTime for Gpst {
49    const TAI_OFFSET: Duration = Duration::seconds(-19);
50}
51
52/// Compares with a known timestamp as obtained from Vallado and McClain's "Fundamentals of
53/// Astrodynamics".
54#[test]
55fn known_timestamps() {
56    use crate::TaiTime;
57    let tai = TaiTime::from_historic_datetime(2004, Month::May, 14, 16, 43, 32).unwrap();
58    let gpst = GpsTime::from_historic_datetime(2004, Month::May, 14, 16, 43, 13).unwrap();
59    assert_eq!(tai, gpst.into_tai());
60}
attotime/time_scale/gpst.rs

attotime/time_scale/
gpst.rs
