Posts by Justin Bertelsen
Space and Missile Systems Center
Overview The Space and Missile Systems Center (SMC) is a unit of the United States Space Force (USSF). Its purpose is to acquire, vet, and implement affordable and resilient space-based military systems for the United States military. One of SMC’s major directorates is the Military Satellite Communications Directorate which gives the SMC the task of…
Read MoreTrellis Coded Modulation (TCM)
Overview Trellis Coded Modulation (TCM) is the combination of convolutional (or trellis) coding and modulation into one step. A 1/2 convulation code takes one bit and codes it into two bits. Modulation is the process of converting a signal into analog form via a sinusoidal carrier. During TCM both of these processes occur simultaneously. The…
Read MoreIridium
Iridium is a LEO satellite constellation which provides high-quality voice and data connections across the entire planet. The constellation was originally conceived to consist of 77 satellites, hence the name Iridium which is 77 on the periodic table of elements. However, the original launch was completed with a total of 66 cross-linked satellites orbiting at…
Read MoreSignal-to-Noise Ratio (SNR)
Overview Signal-to-Noise Ratio (SNR) is a measure used to directly compare the strength of a signal relative to background noise. [1] SNR is often expressed in decibles using the equation where represents the total signal power and represents the total noise power. [2] Shannon-Hartley Theorem SNR is related to the maximum achievable BER (also referred…
Read MoreQuadrature Amplitude Modulation (QAM)
Quadrature Amplitude Modulation (QAM) is the combination and modulation of two signals which have a 90º phase shift from one another. It is the 90º phase shift which causes the two signals to be in quadrature. The first signal is called the in-phase signal and the other is refered to as the quadrature signal. A…
Read MoreSpace Data Highway
The Space Data Highway (SDH) is a service operated by Airbus that uses the European Data Relay System (EDRS) to provide laser-based communications from LEO and airborne systems to GEO satellites for relay back to ground stations. The SDH uses both the EDRS-A and EDRS-C satellites and is operated by Airbus in Munich, Germany. As…
Read MoreARTES
The European Space Agency’s Advanced Research in Telecommunication Systems (ESA’s ARTES) is a program focused on developing products and services for the satellite communication sector in Europe and Canada. ESA’s Telecommunications and Integrated Applications (TIA) directorate oversees ARTES and provides technological support, facilitates market and industry research, and promotes satcom standards for European agencies. ARTES…
Read MoreU.S. Spaceforce
The United States Space Force (USSF), formerly the Air Force Space Command (AFSC), is the branch of the United States military forces that addresses space warfare for the United States. The United States Space Force officially replaced the AFSC in December 2019 with the signing of the 2020 National Defense Authorization Act (NDAA). As of…
Read MoreScyLight
ScyLight is a program run by the European Space Agency (ESA) with the purpose to address innovative optical communications technologies for satellite communication applications. ScyLight aims to use optical communications to support the developing European market, utilize current technology, and seize market opportunities as they arise. The four main areas of development are “Optical Communication…
Read MoreCoherent Orthogonal Optical Frequency Division Multiplexing (CO-OFDM)
Coherent Orthogonal Optical Frequency Division Multiplexing (CO-OFDM) a type of WDM technology that uses the mathematical principle of orthogonality to send many secure signals in a small waveband. This makes the information received by a CO-OFDM system have no overlap between signals, i.e., no adjacent signal interference. Since CO-OFDM can transmit many different signals at…
Read More