Glossary of terms

See a term in a post that you don’t understand? It may well be listed here.

There will be things missing from this list. I try and keep it updated but let me know if anything is missing.

APT Automatic Picture Transmission’. Analog broadcasting protocol used by old satellites to send live pictures back to Earth
Arduino A microprocessor board with input and output pins. Programs can be uploaded to the board to control the voltages on the output pins. Can basically control anything in the physical world.
ASAT Anti Satellite’. Any capability to disable a satellite in orbit – usually by a kinetic impact. Varies from ‘no real issue’ to ‘fantastically stupid’ on the consequence scale.
ASIC Application Specific Integrated Circuit’. A processor made specifically for an exact task (like mining Bitcoin)
Bresenham’s line algorithm A method to draw lines on a computer screen or with vector graphics.
Brute Force Attack A program which tries every possible combination in turn until it find the correct one. Always finds the solution, but requires the longest time.
C++ High level programming language on which Arduino is based. I have a base knowledge of this, but tend to use Python where I can.
CPU Central Processing Unit’ – the main processor of a computer
Galvo/galvanometer High speed motor used for deflecting laser beam. Must be used in conjunction with PID controller.
GPS / GLONASS Satellite navigation networks.
GPU Graphics Processing Unit’ – a second processor found in almost all computers. Responsible for handling the graphics.
LRPT Low Rate Picture Transmission’. The digital replacement for APT. Fraught with issues due to interference but used by the Russian METEOR satellites.
NOAA POES National Oceanographic and Atmospheric Association Polar Orbiting Environmental Satellite’. US weather satellites that send back APT images.
NORAD North American Aerospace Defence Command’. I don’t know how they get ‘NORAD’ from that. Anyway, maintains RADAR network to track objects in space.
Orbital Inclination How tilted an orbit is.
Periapsis Point in an orbit at which the orbiting body is closest to the thing which it is orbiting.
PID control Proportional Integral Derivative’. A form of feedbakc mechanism where the position (or state) of something is determined based on it’s current state, previous states and target state.
PWM Pulse Width Modulation’. Switching a signal on and off rapidly so the output appears somewhere between the ‘on’ voltage and zero.
Python Versatile and easy to use programming language.
R Programming language suitable for statistics and data analysis. Not the easiest to use but I’ve been doing a lot of work in R recently to improve my capabilities.
Raspberry Pi Very different to an Arduino. This is an entire computer on a board. It can do basically anything (given enough effort)
Resistor ladder A form of digital to analog convertor. Converts a parallel stream of 1’s and 0’s to a single number.
SDR Software Defined Radio’. A process by which radio signals are processed by software rather than expensive hardware. Has basically allowed anyone to get into amateur radio easily and for very little money.
Semi Major Axis Orbiting objects make an ellipse. The semi major axis is half of the length of the ellipse.
TLE Two Line Element’. Format in which satellite orbital parameters are published.
XSA Cross Sectional Area’. I type this accidentally all the time without saying what it means.