# Presentation: 028569

## EMWIN into LRIT Overview

**Inserts the EMWIN service into LRIT with minimal service latency and minimal bandwidth overhead**
**Complies with CGMS & CCSDS and supports NOAA LRIT VC priority scheme**
**Allows re-use of existing EMWIN S/W or new TCP/IP based EMWIN S/W **
**D6 S/W supports simultaneous RS-232 & TCP/IP interfaces**
**TCP/IP Socket (internal & external) output for newer S/W**
**RS232 to support legacy EMWIN user S/W**

## NOAA LRIT System Architecture 

- NOAA LRIT System Architecture

- GOES

- Transmitter

- T-1

- GMS Input

- NWS Input

- METEOSAT

- Input

- LRIT

- Uplink

- (GE Americom from

- CDA)

- LRIT

- Downlink

**LRIT**

**Preprocessor**

- - Product

-   Rx & Selection

- - Extract Metadata

- - LRIT File Build

- - File Push

**LRIT**

**Communication**

**Processor**

- - File Rx

- - APID, VCID Selection

- & Prioritization

- - Compression

- - Encryption

- - AP & VCDU Build

- - VCDU Push

**LRIT Products**

**Processor**

- POES

- LRIT

- FEP

- - GOES & POES

- Level 1B

-   Product

- - Product Log Files

- - High-Level Product

-   Processing

- Sensor

-   Processing

**LINUX**

**Cluster**

- - GMS

- Processing

- - NMC

- Processing

- - Other Product

-   Processing

**CEMSCS Main**

**Processor**

- 1

**BPSK**

**Modulator**

**BPSK**

**Demodulator**

- Tx Data Verify Path

- 6

**CDA**

- Wallops, VA

**LRIT  User**

**Terminal**

- - Rx, Demodulate

- - Bit & Frame Synch

- - Viterbi, R-S EDAC

- - VCDU Proc

- - Decompress

- - Decrypt

- - Packet Extract

- - File Creation

- - Image Viewer

**IPD**

- Suitland, MD

**Green = Avtec**

**EMWIN RS-232 Input**

** ****COTS**
**EMWIN**
**RS-232**

## CGMS Communication Model

|   |             TX 
(uplink station) |  |  |  |  |  |             RX
 (user station) |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|   | Layers |  | Services | Service Data Unit | Services |  | Layers |   |  |
|   | Application |  | Generation of User Data | ____ | Processing of User Data |  | Application |   |  |
|   | Presentation |  | Insertion of User Data Into Files | User data | Retrieval of User Data from Files |  | Presentation |   |  |
|   | Session |  | Compression Encryption | LRIT file | Decompression Decryption |  | Session |   |  |
|   | Transport |  | Segmentation | LRIT file | File Assembly |  | Transport |   |  |
|   | Network |  | Path Selection | CCSDS version-1 packet | (none) |  | Network |   |  |
|   | Data Link
<VCLC>
<VCA> |  | Muliplexing CommutationSerialization | CCSDS version-1 packet
<VCLC-LRIT MPDU>
 | Demultiplexing Decommutation VCDU Acquisition |  | Data Link
<VCLC>
<VCA> |   |  |
|   | Physical |  | Modulation Transmission | NRZ-L serial bitstream | Demodulation Reception |  | Physical |   |  |
| Communications media space path |  |  |  |  |  |  |  |  |   |

- LRIT
- Insertion

- LRIT
- Extraction

## LRIT Domain 4 Existing Design

## Domain 4 Context

## Communication Processor

- Monitors arrival of LRIT files received from Preprocessor via FTP.
- Implements Session, Transport, Network, and partial Datalink CGMS layers.
- Sends CADUs to Uplink Processor via IPDU interface.
- Uplink Processor implements remainder of Datalink layer as well as physical layer

## Domain 4 Architecture

## Domain 5 Uplink Processor(No changes)

## LRIT Domain 5

** ****Domain 5 Functional Specification**
-  Receive IPDU Encapsulated VCDU + ASM
-  RS Encode, Randomize, Optional Differential Encode (NRZ-M), Optional Convolution Encode
-  Insert Fill VCDUs (VC63) to maintain constant  uplink rate (IOC=146.942 kbps, FOC=293.884 kbps)
- IPDU > LRIT VCDU + Non-LRIT VCDU > CVCDU > Serialize (constant rate)

## Domain 5 Context

## Domain 5 Specification

| Processing Detail | LRIT Specification |
| --- | --- |
| Domain 4 VCDU  | 7136 bits, CCSDS, MSB first  |
| Out-of-Band VCDU  | 7136 bits, CCSDS, MSB first |
| ASM  | Hexadecimal ‘1ACFFC1D’  |
| Reed-Solomon  | (255,223, I=4) not including ASM |
| CADU  | 8192 bits (including ASM & Reed-Solomon)  |
| Randomization  | h(x)=x8 + x7 + x5 + x3 +1; initialized to all 1s  |
| Differential Encoding  | Default is NONE; NRZ-M Optional  |
| Convolution  | (R= 0.5, K=7, NO G2 symbol inversion)  |
| Constant Clock  | Internal Frequency Synthesizer, or External Clock  |

## Domain 5 Architecture

**Out-of-Band**

**WDCA Time Code**

**Transmitter**

**External TX Clock**

**LRIT Clock Out**

**LRIT NRZ-L Data**

**Non-LRIT **
**Serial Stream**
**Data & Clock**

**LRIT **
**VCDUs**

**Network**
**IPDU**
**Receiver**

**CCSDS Vitual Channel**
**Generator**
**(optional)**

**Spooler**
**(VCDU Rate Buffer)**

**Network**
**Socket Server**
**(optional)**

**Encode**
**& Serialize**
- (R/S,
- PN,
- NRZ-L to NRZ-M, Convo. Encode)

**Mux   Event**

**External  Byte Stream**

**Non-LRIT **
**Serial Data**

**COTS Avtec PTP **

**BPSK Modulation **
**( w/ SRRC ISI filter)**

**   ****70 <-> 1691 MHz**
**       ****Up/Down**
**       ****Converter**

**Modulated    LRIT Signal**

**IRIG-B/NASA-36 Time Code Decoder **

**T1 Link**

**Uplink Processor **

**VCDU**
**Events**

**D4 VCDU**

## LRIT Domain 6 Existing Design

## LRIT Domain 6 Context

- Feed/LNB

- BPSK Receiver +
- + Viterbi Decoder

- Frame Sync + CCSDS & LRIT
- Processing

## Domain 6 Software Context

**LRIT File Automation Processor**

## Domain 6 Transfer Application

- DLLs implemented as in-process COM Servers
- Data flow roughly follows layer model
- Log / Error logging object

## EMWIN-LRIT Insertion 

**Carry EMWIN as a bit-stream, but inside a simple file encapsulation**
**Use MPDU + Application Packet (AP)+ LRIT File Headers**
**Use CGMS File Type for mission specific use (128...255). ****Assign EMWIN: LRIT file type 214 (0xD6).**
**Group EMWIN RS-232 bits into fixed length bit-stream segments**
**Insert each EMWIN bit-stream segment after the LRIT File Header**
**1 VCDU per EMWIN bit-stream file**
**D6 groups file segments, extracts & concatenates, then outputs serially**
**Preserves minimum latency & low overhead bandwidth feature of bit-stream**
**LRIT  rate = 17.9 frames / sec ; EMWIN rate @ 9.6 = 1.14 frames/sec**
**D6 Output compatible with RS-232 COTS EMWIN S/W (i.e. RealEmwin)**

## EMWIN Bit-Stream VCDU Format

| VCDU
Primary
Header | VCDU
Data Zone | Reed-Solomon
Check Symbols |
| --- | --- | --- |
| 6 bytes | 886 bytes | 128 bytes |

| MPDU
Header | Packet
Header | LRIT File
Header | NOAA
Header | EMWIN Bit-Stream
Data | Packet
CRC |
| --- | --- | --- | --- | --- | --- |
| 2 bytes | 16 bytes | 16 bytes | 14 bytes | 836 bytes | 2 bytes |

**EMWIN Bit-Stream VCDU Format**

-  **For preservation of bandwidth and minimal latency, received EMWIN Bitstream is segmented into fixed length segments (836 bytes) **
**File creation latency = 836 bytes * input baud rate; file complete prior to queueing**
**Fixed length segments  are encapsulated per CGMS MPDU/AP/LRIT-File Headers, and sequentially output**
**LRIT File Types 128...255 available for mission specific use**

## CGMS CCSDS VCDU Header

| version number | set to 1 specifying version-2 CCSDS |
| --- | --- |
| VCDU-ID | virtual channel data unit identifier as specified by higher layers, consisting of spacecraft identifier and virtual channel identifier, set to 63 for fill VCDUs |
| VCDU counter | sequential count (modulo 16777216) of VCDUs on each virtual channel |
| signaling field/replay flag | set to 0 specifying real-time VCDUs |

| version number | VCDU-ID |  | VCDU
counter | signaling field |  |
| --- | --- | --- | --- | --- | --- |
|  | S/C ID | VC ID |  | replay flag | spare |
| 2 bit | 8 bit | 6 bit | 24 bit | 1 bit | 7 bit |

## D4 Communication Processor Upgrades for New Design

**H/W**
- Allow configuration of two RS-232 ports
- Both ports are installed and active
**S/W**
- New Config file S/W monitors config file and implements VC(Priority), COM port settings (speed, parity, stop/start)
- Create S/W for receiving bit-stream data (strip start/stop bits) over RS-232
- Create S/W for encapsulating bitstream in sequential fixed length files
- S/W uses configuration file to select valid data source port

## LRIT D4 EMWIN Upgrade

## D6 User Terminal Upgrades

- H/W
- Allow configuration of multiple RS-232 ports for multiple output
- S/W
- Create S/W for concatenating EMWIN File Type data
- Output concatenated data as serial stream to sockets
- Allow routing of received bit-stream data to RS-232 port(s)
- Allow routing of received bit-stream data to TCP/IP port(s)

## Domain 6 Transfer Application

- LRIT Session Layer Modified to support EMWIN
- EMWIN Outputs: file / RS-232 / TCP-IP

**LritDataLinkLayer.dll**

- Packets

- OOB Bitstream

**LritSessionLayer.dll**

- LRIT Files

**EMWIN (file / RS-232 / TCP/IP)**