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 Hackeando Satélites da NASA em casa! 
Open Satellite Project
- Telecomunicações espaciais geralmente seguem uma especificação.
- Conteúdo limitado de páginas na internet falando sobre Processamento Digital de Sinais. 
- Software Defined Radios são acessíveis . 
- As imagens dos satélites metereologicos mostram a imensidão do nosso planeta. 

Como um SDR funciona?
Open Source SDRs
- Faixa de Frequência: 24 MHz - 1768 MHz
- Resolução de ADC: 8 Bits
- Samples: 3.2 MSPS IQ
- Frequência: 24 MHz - 1768 MHz
- Resolução: 12 Bits
- Samples: 10 MSPS R2  e 8 MSPS Mini
- Open Source Firmware
- Frequência: 1 MHz - 6 GHz
- Resolução: 8 Bits ADC / 10 bits DAC
- Samples: 20 MSPS IQ
- Half-Duplex Transceiver 
- Open Source Hardware & Software
LimeSDR Mini
- Frequência: 10 MHz - 3.5 GHz
- Resolução: 12 Bits ADC & DAC
- Samples: 30.72 MSPS IQ
- Full-Duplex Tranceiver
- Open Source Firmware & Hardware

Satélites de Orbita Baixa
- Polarização RHCP
- Frequência de ~137MHz
- Baixa Resolução (1-4 km)
- Antena QFH ou V-Dipole
- Filtro Passa-Banda

Roscosmos Meteor M-N2 
- Resolução: 10-bit @ 1km por pixel.
- Modulação: Quadrature Phase Shift Keying
- Canais: Infrared, Near-Infrared e Visible Light.
- Correção de Erro: Viterbi 2/7 & Reed-Solomon
Visible Light
 Canais LRPT do Meteor M-N2
NOAA-N Prime APT Signal
- Resolução: 4km por pixel.
- Não tem correção de erros.

Geostationary Operational Environmental Satellite
Hardware de Recepção
- Antena Parabólica de 1.9 m 
- Dois Amplificadores (SPF5189)
- Filtro Passa-Faixa (Bandpass)
- SDR*
Wave Guide Feed (Canantena)
Remember the "old" wardrive times?
Low Noise Amplifier
(LNA4ALL ou SPF5189)
Bandpass Filter
- 1675 MHz Center Frequency
- 150 MHz Bandwidth
- Low Insertion Loss
- 1690 MHz Center Frequency
- 30 MHz Bandwidth
- Chebyshev ~3dB Ripple
- Low Insertion Loss

One LNA4ALL and Lorch Filter
Recepção e Demodulação
L-Band FFT do GOES-16 
Binary Phase Shift Keying
GNU Radio Companion
BPSK Receiver Constellation
- Usually wireless systems use convolution coded outputs
- Convolution Coded generates parity. The transmitter sends
   only parity data.
- The reverse algorithm to convolution code is Viterbi
- There are few standard parameters for viterbi
- GOES satellites use k=7 , G1 = 0x4F, G2 = 0x6D
- GOES uses Standard CCSDS Sync Word ( 0x1ACFFC1D )
- Easiest way to sync frames: Generate a Encoded Sync Word
   and search for correlation
Syncing using correlation
Viterbi Output
Data Randomization
- Usually wireless transmissions randomize the data send
- First Reason: Avoid sync word collision
- Second Reason: Avoid Line Polarization and Symbol
- Pseudo-Random Sequence: 1 + x^3 + x^5 + x^7 +x^8
Reed-Solomon Error Correction
- 223 bytes of data for 32 bytes of parity
- Can correct any 16 bytes over the 223 bytes
- Does not change original bitstream, so if SNR is good no need
   for correction
- GOES has 4 RS Blocks (255 bytes each) interleaved by 1 byte.
- Parity is on the end of the packet
LRIT Admin Message #011
Distribution: East and West
Subject: LRIT contact information
The LRIT Systems team, in an effort to be more responsive
to the user community, would like for users to have
contact information. In the event that a user notices any
long term trends or anomalies in the LRIT data stream, or
has suggestions or comments. We ask that contact be made
via email to

If more immediate matters arise, that the user deems as 
urgent, we advise the use of the following operational 
facility phone number: 301-817-3880.

Emails &

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