calpath

Calpath, developed in C++, is a software used for calculating satellite tracks and sensor paths. During the execution, the program will retrieve the necessary inputs from the data folder, calculate the tracks and paths for the upcoming 7 days, and generate a new data file by writing the results into it. The default data folder is ../data.

Additionally, the orbitTools folder which is included serves as a reference to orbitTools developed by Michael F. Henry, and is utilized to calculate satellite tracks based on SGP4 and TLE.

database

Calpath retrieves data from satellites and sensors stored in a SQLite database. By default, the database is located at ../data/sat.db. Below are the table definitions.

satellite

column name	type	description
id	int	primary key
noard_id	string	NOARD ID of satellite
name	string	custom satellite name
hex_color	string	color of satellite, in hex format

sensor

column name	type	description
id	int	primary key
sat_noard_id	string	NOARD ID of satellite
sat_name	string	satellite name
name	string	sensor name
resolution	float	resolution of sensor
width	float	width of sensor
right_side_angle	float	max right side angle, for side pendulum
left_side_angle	float	max left side angle, for side pendulum
observe_angle	float	observe angle of sensor, should not be null if width not provided
hex_color	string	color of sensor, in hex format
init_angle	float	angle to the right is positive, for special sensors

sys_user

column name	type	description
id	int	primary key
user_name	string	user name
password	string	password, encrypted
email	string	email

tle

column name	type	description
id	int	primary key
sat_noard_id	string	NOARD ID of satellite
time	int	timestamp of TLE
line1	string	line1 of TLE
line2	string	line2 of TLE

tle_site

column name	type	description
id	int	primary key
site	string	site name
url	string	site url for updating TLE
description	string	description

output

CalPath will save the results to SQLite databases located in the data folder. By default, this folder is ../data. The satellite track file will be saved as ../data/{NOARD_ID}.sqlite, while the sensor path file will be saved as ../data/{NOARD_ID}/{SENSOR_NAME}.sqlite.

satellite result tables

track_info

column name	type	description
id	int	primary key
sat_noard_id	string	NOARD ID of satellite
sat_name	string	satellite name
start_time	int	calculation start time, in timestamp second

track

column name	type	description
id	int	primary key
time_offset	int	time offset after start_time
x	float	x coordinate
y	float	y coordinate
z	float	z coordinate
vx	float	velocity on x coordinate
vy	float	velocity on y coordinate
vz	float	velocity on z coordinate
lon	float	longitude
lat	float	latitude
alt	float	altitude

sensor result tables

path_info

column name	type	description
id	int	primary key
sat_noard_id	string	NOARD ID of satellite
sat_name	string	satellite name
sen_name	string	sensor name
start_time	int	calculation start time, in timestamp second

sen_path

column name	type	description
id	int	primary key
time_offset	int	time after start_time
lon1	float	longitude of left point
lat1	float	latitude of left point
lon2	float	longitude of right point
lat2	float	latitude of right point

Build and run

Prerequisites

Ensure that you have installed all the necessary prerequisites on your development machine:

• g++
• make
• sqlite-dev

To rebuild and run, execute the command calPath/refresh.sh. The output will be saved in the data folder.