Parse and encode Two-Line Element sets.
TLE is the legacy fixed-width format for satellite orbital elements, designed for 80-column punch cards in the 1960s. Despite its age, it remains the most widely used format for distributing orbital data.
Parsing
The parser is liberal in what it accepts:
- Trailing whitespace and extra characters are trimmed
- Leading dots in floats (
.123→0.123) - Spaces in numeric fields
Checksum validation is performed and reported but does not prevent parsing.
Examples
{:ok, elements} = Orbis.Format.TLE.parse(line1, line2)
{line1, line2} = Orbis.Format.TLE.encode(elements)Summary
Functions
Encode an %Orbis.Elements{} struct as TLE-format strings.
Parse a two-line element set into an %Orbis.Elements{} struct.
Functions
@spec encode(Orbis.Elements.t()) :: {String.t(), String.t()}
Encode an %Orbis.Elements{} struct as TLE-format strings.
Returns {line1, line2} — two 69-character strings with valid checksums.
Round-trips are character-exact for standard TLEs.
Examples
iex> l1 = "1 25544U 98067A 18184.80969102 .00001614 00000-0 31745-4 0 9993"
iex> l2 = "2 25544 51.6414 295.8524 0003435 262.6267 204.2868 15.54005638121106"
iex> {:ok, el} = Orbis.Format.TLE.parse(l1, l2)
iex> {gen_l1, gen_l2} = Orbis.Format.TLE.encode(el)
iex> gen_l1 == l1
true
iex> gen_l2 == l2
true@spec parse(String.t(), String.t()) :: {:ok, Orbis.Elements.t()} | {:error, String.t()}
Parse a two-line element set into an %Orbis.Elements{} struct.
Returns {:ok, elements} or {:error, reason}.
Logs a warning if checksums are invalid but still parses.
Examples
iex> {:ok, el} = Orbis.Format.TLE.parse(
...> "1 25544U 98067A 18184.80969102 .00001614 00000-0 31745-4 0 9993",
...> "2 25544 51.6414 295.8524 0003435 262.6267 204.2868 15.54005638121106"
...> )
iex> el.catalog_number
"25544"
iex> el.inclination_deg
51.6414