HRIT/EMWIN Reception

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HRIT/EMWIN Reception

Sources for HRIT/EMWIN systems and components:

Some LRIT receiver manufacturers are offering HRIT/EMWIN receivers.
Ref: https://www.noaasis.noaa.gov/NOAASIS/ml/manulst.html

EMWIN system modifications may provides an alternative to replacing an entire system. Information on the fabrication of Intermediate Frequency (IF) and Radio Frequency (RF) digitizer boards, and use of software radios may be found on line:
Ref: https://www.goes-r.gov/users/hrit-links.html

US Government auction of L-band frequency spectrum (1695 to 1710 MHz) adjacent to GOES-R HRIT/EMWIN transponder frequency is likely to adversely impact the reliability of HRIT/EMWIN signal reception in the US due to cell phone interference.

Cannot accurately quantify the interference, or identify when the spectrum will be occupied.

Preliminary interference analysis will be revisited when the specific service characteristics are better known.
https://satelliteconferences.noaa.gov/2015/doc/presentation/Session%204/4.4e%20Future%20EMWIN%20Implications%20R1_Valles.pptx

US Government is investigating options to improve operations in a shared spectrum environment

RF protection zones granted by the FCC were not offered to non-Federal sites/systems/users.

Users may employ methods for minimizing interference (e.g., blocking source of interference)

HRIT/EMWIN Downlink Characteristics (NESDIS-2)

Coding – BPSK

Convolutional rate ½ code with constraint length 7 concatenated with Reed Solomon (255,223) with Interleave = 4

Square Root Raised Cosine filtering using an Alpha factor of 0.3

The resulting “Necessary Bandwidth” for this signal will be 1.205 MHz

Modem Required: predicted C/No is in the range of 63-67 dB
Maximum Demodulator Required is -

Eb/No is 4.6 dB for a BER of 1x10-8 after decoding

Minimum Antenna System

At 5 degree elevation, the minimum antenna is 1.2 meter.

At 10 degrees or more elevation the minimum size is 1.0 meter

Using a LNA or LNB with a system noise temperature of about 200 K will provide a G/T of 1.0 dB/K or -0.3 dB/K respectively