Ccsds based file delivery protocol

1. CCSDS based File Delivery Protocol (CFDP)
for future SSRs
Srinidhi M.S. – Namrata Kar – Aritra Sarkar

2. • Study of CFDP features
• Feasibility for CFDP in future SSRs (pruning to a CFDP
like Protocol for upcoming ISRO Missions)
• Implementation of CFDP in software platform (basic RtOS
with File Management)
• Hardware (FPGA + IP Core) porting of developed RtOS
and customizing for Project Requirements
Aim and Scope

3. Project Phases
PHASE
I
PHASE
II
PHASE
III
Study CFDP
Project Specifications
Optimal Design
H/W Platform
S/W Platform
CFDP Implementation

4. • ‘FTP for Space’
• Proposed by ESA (1998)
• Was made CCSDS standard in 2002
• Space File Transfer Requirement as articulated by NASA,
ESA, BNSC, CNES, JAXA
• Current Blue Book Standard: CCSDS 727.0-B-4 (2007)
CFDP: Overview

5. • 1st used on space mission operation by NASA (JHU/APL +
JPL developed ‘CFDP Lite’) in Messenger Mission to
Mercury in 2004-15
• NASA’s Deep Impact Probe Mission
• James Webb Space Telescope (JWST)
• SSR to SpaceWire Link in NASA’s Lunar Reconnaissance
Orbiter (LRO)
CFDP: Success Stories

6. • Highly specialized protocol designed to overcome space
communication operation challenges
• Reliability despite long data propagation delays and frequent,
lengthy interruptions in connectivity
• Forward error correction coding that minimizes data loss in
communication across deep space
• Files can be transmitted with a unidirectional link, a half-duplex
link, or a full-duplex link, with near-Earth and deep space delays
CFDP: Features

7. • Class 1 (Best Effort – similar to UDP)
• Class 2 (Reliable – similar to TCP)
• Class 3 & 4 (for Waypoint communications)
• Acknowledgement Types: None, Immediate, Periodic,
Asynchronous (automatic retransmission if ACK fails)
• Configuration of Link Entity: a set of parameters which define
the behavior (e.g. timers, fault handlers, file segment size,…).
• These are modifiable in-flight, allowing integration in
heterogenous networks, or evolving travel times (e.g.
interplanetary mission)
CFDP: Features

8. • Encapsulation protocol for each Link for multi-hop capabilities
(e.g. Rover-Orbiter-Ground; Satellite-Ground-PayloadTeam)
• CFDP allows an instrument to record an observation in a file and
transmit the file to Earth without having to consider whether or
not physical transmission is possible at that time thus can
simplify flight and ground software management.
CFDP: Features

9. Protocol Implementations
CFDP Entity
Onboard
Storage
Data
Users
Mission
Management

10. • Spacecraft mass memory accessed with ‘file’ structure and
associated ‘metadata’
• File Operations: Open/Close, Read/Write(with offset or seek),
Get/Set file size, Rename, Append, Create, Delete file/directory
• Files are segmented at source into the maximum underlying
transmission unit (packet) and reconstituted at the destination
• Files are protected by a checksum
• Meta data: Meta data is used to convey the file name and file
size to the destination and to setup the file transfer by conveying
requests between CFDP user applications
CFDP based Data Storage

11. • PDU: The individual, bounded, self-identifying items of CFDP
data transmitted between CFDP entities
• File Data PDUs convey the contents of the files being
delivered
• File Directive PDUs convey only metadata and other non-file
information that advances the operation of the protocol.
• PDU Formats:
• Fixed-format data
• Length, Value (LV) format
• Type, Length, Value (TLV) format
• Variable-length file data
Protocol Data Units

12. PDU Example
Header Fields

13. Storage Architecture
CFDP
Entity
File based
Commands
Memory
Mapper
Mass
Memory
Memory
Interface
ProcessorFPGA
ProcessorSRAM
SSR
Software

14. • Protocol Class 1
• Processor LEON 3 – UT699
• FPGA ProASIC3E
• TMTC MIL-STD-1553B UT63T143
• Project Linkage CARTOSAT3, RISAT-2A
• Programming Platform ADA’2015
• Program Memory NOR Flash
• Mass Memory NAND Flash
• Power 5V DC
TDP Specifications

15. Software Platform

16. Hardware Design
LEON3
UT699 µP
32 bit
UART
JTAG
1553B
UTMC
Transceiver
MIL-STD-1553B
NOR Flash
(Code)
128MB
NOR Flash
(Data)
128MB
SRAM
(µp Mem)
16MB
EEPROM
(BootOTP)
ProASIC3E
FPGA
MIL-STD-1553B
IPCore
Power
Circuits
SPI
SPW LVDS Tx/Rx

17. • Funding: Non-funded
• Progress:
• Study of CFDP features
• Requirement gathering for generating CFDP
implementation Specification (based on future SSRs)
• Hardware platform schematic initiated
• Software platform tool familiarization
Status

18. Thank You
Q & A