## Binary Phase-Shift Keying (BPSK)

Binary Phase-Shift Keying (BPSK) is one of the modulation methods of Phase-Shift Keying (PSK), which uses two phases. BPSK signal is descrived as below. $s(t) = A\cos{(2\pi ft+\phi)}$ where $$A$$ is amplitude of carrier wave, $$f$$ is frequency of carrier wave. $$\phi$$ is phase depending on signal, Using this equation, BPSK signal can be shown …

## Two-Line Element Set (TLE): Format Overview

To calculate the position of the object around the earth, for example, satellites and space debris, we need information on the orbital parameters which describes the shape and size of the orbit. Two-Line Element Set is one of the data formats for describing the orbital parameters. In this article, we explain TLE and its format …

## TLE Epoch to Date

TLE Epoch in the form of NNNNN.NNNNNNNN Date in ISO format

## Kalman Filter

What is Kalman Filter? Kalman filter is a method to estimate true state from data including uncertainty. For example, the Kalman filter was used in the rocket of the Apollo program. All sensors have error in their measurement value, so we need to correct them to estimate the true state value. Kalman filter uses odometry …

## EIRP meaning and calculation

EIRP is the power required when the antenna is replaced by an isotropic antenna, and can be calculated from the transmit power, feed line loss, and gain of the transmit antenna. This article explains the meaning of EIRP and how to calculate it. Table of Contents What is EIRP? EIRP stands for Equivalent Isotropically Radiated …

## Earth Centered Inertial Frame (ECI)

Earth Centered Inertial Frame (ECI) is the coordinate system that places the origin at the center of the earth, the x-axis to the vernal equinox, the z-axis to the north pole, and the y-axis as a right-handed system. This coordinate system does not rotate against the Earth’s rotation, thus this system can be regarded as …