CDM — Conjunction Data Message¶

Parses CCSDS Conjunction Data Messages containing state vectors, covariance matrices, and collision probability for two-object close approaches.

CDM ¶

CDM(originator: str, message_id: str, tca: Epoch, miss_distance: float, object1: CDMObject, object2: CDMObject)

A CCSDS Conjunction Data Message (CDM).

CDM messages describe a conjunction between two space objects, containing state vectors, covariance matrices, and collision probability data.

Can be created programmatically or parsed from KVN/XML/JSON.

Parameters:

Name	Type	Description	Default
`originator`	`str`	Originator of the message	required
`message_id`	`str`	Unique message identifier	required
`tca`	`Epoch`	Time of Closest Approach	required
`miss_distance`	`float`	Miss distance in meters	required
`object1`	`CDMObject`	First conjunction object	required
`object2`	`CDMObject`	Second conjunction object	required

Example

from brahe.ccsds import CDM, CDMObject, CDMStateVector, CDMRTNCovariance
import numpy as np

sv1 = CDMStateVector([7000e3, 0.0, 0.0], [0.0, 7500.0, 0.0])
cov1 = CDMRTNCovariance(np.eye(6).tolist())
obj1 = CDMObject("12345", "SATCAT", "SAT A", "2020-001A",
                  "NONE", "CALCULATED", "YES", "EME2000", sv1, cov1)

sv2 = CDMStateVector([7001e3, 0.0, 0.0], [0.0, -7500.0, 0.0])
cov2 = CDMRTNCovariance(np.eye(6).tolist())
obj2 = CDMObject("67890", "SATCAT", "SAT B", "2021-002B",
                  "NONE", "CALCULATED", "NO", "EME2000", sv2, cov2)

tca = Epoch.from_datetime(2024, 1, 15, 12, 0, 0.0, 0.0, TimeSystem.UTC)
cdm = CDM(originator="TEST_ORG", message_id="MSG001",
          tca=tca, miss_distance=715.0, object1=obj1, object2=obj2)
print(cdm.miss_distance)

Initialize instance.

collision_probability `property` ¶

collision_probability: Any

Optional[float]: Collision probability

collision_probability_method `property` ¶

collision_probability_method: Any

Optional[str]: Collision probability method

creation_date `property` ¶

creation_date: Tuple[int, ...]

Epoch: Creation date of the message

format_version `property` ¶

format_version: Any

float: CDM format version (e.g. 1.0, 2.0)

message_for `property` ¶

message_for: Any

Optional[str]: Spacecraft name(s) CDM applies to

message_id `property` ¶

message_id: Any

str: Unique message identifier

miss_distance `property` ¶

miss_distance: Any

float: Miss distance in meters

object1_covariance `property` ¶

object1_covariance: Any

numpy.ndarray: Object 1 RTN covariance matrix (6x6) in m², m²/s, m²/s²

object1_designator `property` ¶

object1_designator: Any

str: Object 1 designator (catalog ID)

object1_international_designator `property` ¶

object1_international_designator: Any

str: Object 1 international designator

object1_name `property` ¶

object1_name: Any

str: Object 1 name

object1_ref_frame `property` ¶

object1_ref_frame: Any

str: Object 1 reference frame

object1_state `property` ¶

object1_state: ndarray

numpy.ndarray: Object 1 state vector [x, y, z, vx, vy, vz] in m and m/s

object2_covariance `property` ¶

object2_covariance: Any

numpy.ndarray: Object 2 RTN covariance matrix (6x6) in m², m²/s, m²/s²

object2_designator `property` ¶

object2_designator: Any

str: Object 2 designator (catalog ID)

object2_international_designator `property` ¶

object2_international_designator: Any

str: Object 2 international designator

object2_name `property` ¶

object2_name: Any

str: Object 2 name

object2_ref_frame `property` ¶

object2_ref_frame: Any

str: Object 2 reference frame

object2_state `property` ¶

object2_state: ndarray

numpy.ndarray: Object 2 state vector [x, y, z, vx, vy, vz] in m and m/s

originator `property` ¶

originator: Any

str: Originator of the message

relative_speed `property` ¶

relative_speed: Any

Optional[float]: Relative speed in m/s

tca `property` ¶

tca: Any

Epoch: Time of Closest Approach

from_file `staticmethod` ¶

from_file(path: str) -> CDM

Parse a CDM from a file, auto-detecting the format.

Parameters:

Name	Type	Description	Default
`path`	`str`	Path to the CDM file	required

Returns:

Name	Type	Description
`CDM`	`CDM`	Parsed CDM message

from_str `staticmethod` ¶

from_str(content: str) -> CDM

Parse a CDM from a string, auto-detecting the format.

Parameters:

Name	Type	Description	Default
`content`	`str`	String content of the CDM message	required

Returns:

Name	Type	Description
`CDM`	`CDM`	Parsed CDM message

to_file `method descriptor` ¶

to_file(path: str, format: str) -> Any

Write the CDM to a file in the specified format.

Parameters:

Name	Type	Description	Default
`path`	`str`	Output file path	required
`format`	`str`	Output format - "KVN", "XML", or "JSON"	required

to_json_string `method descriptor` ¶

to_json_string(uppercase_keys: bool = False) -> str

Write the CDM to JSON with explicit key case control.

Parameters:

Name	Type	Description	Default
`uppercase_keys`	`bool`	If True, use uppercase CCSDS keywords. Default: False.	`False`

Returns:

Name	Type	Description
`str`	`str`	Serialized JSON string

to_string `method descriptor` ¶

to_string(format: str) -> str

Write the CDM to a string in the specified format.

Parameters:

Name	Type	Description	Default
`format`	`str`	Output format - "KVN", "XML", or "JSON"	required

Returns:

Name	Type	Description
`str`	`str`	Serialized CDM string

CDMObject ¶

CDMObject(designator: str, catalog_name: str, name: str, international_designator: str, ephemeris_name: str, covariance_method: str, maneuverable: str, ref_frame: str, state_vector: CDMStateVector, rtn_covariance: CDMRTNCovariance)

One object in a CDM (metadata + state vector + covariance).

Combines object identity, reference frame, state at TCA, and RTN covariance.

Parameters:

Name	Type	Description	Default
`designator`	`str`	Catalog ID (e.g. "12345")	required
`catalog_name`	`str`	Catalog source (e.g. "SATCAT")	required
`name`	`str`	Object name (e.g. "SATELLITE A")	required
`international_designator`	`str`	COSPAR ID (e.g. "2020-001A")	required
`ephemeris_name`	`str`	Ephemeris source (e.g. "NONE")	required
`covariance_method`	`str`	"CALCULATED" or "DEFAULT"	required
`maneuverable`	`str`	"YES", "NO", "N/A", or "UNKNOWN"	required
`ref_frame`	`str`	Reference frame (e.g. "EME2000")	required
`state_vector`	`CDMStateVector`	State at TCA	required
`rtn_covariance`	`CDMRTNCovariance`	RTN covariance matrix	required

Example

from brahe.ccsds import CDMObject, CDMStateVector, CDMRTNCovariance
import numpy as np

sv = CDMStateVector([7000e3, 0.0, 0.0], [0.0, 7500.0, 0.0])
cov = CDMRTNCovariance(np.eye(6).tolist())
obj = CDMObject(
    designator="12345",
    catalog_name="SATCAT",
    name="SAT A",
    international_designator="2020-001A",
    ephemeris_name="NONE",
    covariance_method="CALCULATED",
    maneuverable="YES",
    ref_frame="EME2000",
    state_vector=sv,
    rtn_covariance=cov,
)

Initialize instance.

catalog_name `property` ¶

catalog_name: Any

str: Catalog source

covariance `property` ¶

covariance: Any

numpy.ndarray: RTN covariance matrix (6x6)

covariance_method `property` ¶

covariance_method: Any

str: Covariance method (CALCULATED or DEFAULT)

designator `property` ¶

designator: Any

str: Catalog ID

ephemeris_name `property` ¶

ephemeris_name: Any

str: Ephemeris name

international_designator `property` ¶

international_designator: Any

str: COSPAR international designator

maneuverable `property` ¶

maneuverable: Any

str: Maneuverable flag (YES, NO, N/A, UNKNOWN)

name `property` ¶

name: Any

str: Object name

ref_frame `property` ¶

ref_frame: Any

str: Reference frame

state `property` ¶

state: ndarray

numpy.ndarray: State vector [x, y, z, vx, vy, vz] in m and m/s

CDMStateVector ¶

CDMStateVector(position: list[float], velocity: list[float])

A CDM state vector with position and velocity at TCA.

Parameters:

Name	Type	Description	Default
`position`	`list[float]`	Position [x, y, z] in meters	required
`velocity`	`list[float]`	Velocity [vx, vy, vz] in m/s	required

Example

from brahe.ccsds import CDMStateVector
sv = CDMStateVector(
    position=[7000e3, 0.0, 0.0],
    velocity=[0.0, 7500.0, 0.0],
)
print(sv.position)

Initialize instance.

position `property` ¶

position: Any

numpy.ndarray: Position [x, y, z] in meters

velocity `property` ¶

velocity: Any

numpy.ndarray: Velocity [vx, vy, vz] in m/s

CDMRTNCovariance ¶

CDMRTNCovariance(matrix: list[list[float]])

A CDM RTN covariance matrix (6x6 position/velocity).

Parameters:

Name	Type	Description	Default
`matrix`	`list[list[float]]`	6x6 symmetric covariance matrix in RTN frame. Units: position-position m², position-velocity m²/s, velocity-velocity m²/s²	required

Example

import numpy as np
from brahe.ccsds import CDMRTNCovariance
cov = CDMRTNCovariance(matrix=np.eye(6).tolist())
print(cov.matrix[0][0])

Initialize instance.

matrix `property` ¶

matrix: ndarray

numpy.ndarray: 6x6 RTN covariance matrix

CDM — Conjunction Data Message¶

CDM ¶

collision_probability property ¶

collision_probability_method property ¶

creation_date property ¶

format_version property ¶

message_for property ¶

message_id property ¶

miss_distance property ¶

object1_covariance property ¶

object1_designator property ¶

object1_international_designator property ¶

object1_name property ¶

object1_ref_frame property ¶

object1_state property ¶

object2_covariance property ¶

object2_designator property ¶

object2_international_designator property ¶

object2_name property ¶

object2_ref_frame property ¶

object2_state property ¶

originator property ¶

relative_speed property ¶

tca property ¶

from_file staticmethod ¶

from_str staticmethod ¶

to_file method descriptor ¶

to_json_string method descriptor ¶

to_string method descriptor ¶

CDMObject ¶

catalog_name property ¶

covariance property ¶

covariance_method property ¶

designator property ¶

ephemeris_name property ¶

international_designator property ¶

maneuverable property ¶

name property ¶

ref_frame property ¶

state property ¶

CDMStateVector ¶

position property ¶

velocity property ¶

CDMRTNCovariance ¶

matrix property ¶

See Also¶

collision_probability `property` ¶

collision_probability_method `property` ¶

creation_date `property` ¶

format_version `property` ¶

message_for `property` ¶

message_id `property` ¶

miss_distance `property` ¶

object1_covariance `property` ¶

object1_designator `property` ¶

object1_international_designator `property` ¶

object1_name `property` ¶

object1_ref_frame `property` ¶

object1_state `property` ¶

object2_covariance `property` ¶

object2_designator `property` ¶

object2_international_designator `property` ¶

object2_name `property` ¶

object2_ref_frame `property` ¶

object2_state `property` ¶

originator `property` ¶

relative_speed `property` ¶

tca `property` ¶

from_file `staticmethod` ¶

from_str `staticmethod` ¶

to_file `method descriptor` ¶

to_json_string `method descriptor` ¶

to_string `method descriptor` ¶

catalog_name `property` ¶

covariance `property` ¶

covariance_method `property` ¶

designator `property` ¶

ephemeris_name `property` ¶

international_designator `property` ¶

maneuverable `property` ¶

name `property` ¶

ref_frame `property` ¶

state `property` ¶

position `property` ¶

velocity `property` ¶

matrix `property` ¶