[Smwg] Response to AI 2017-0512-47 (Provide Service Catalog input on statements of service performance)
Barkley, Erik J (3970)
erik.j.barkley at jpl.nasa.gov
Thu Oct 26 21:26:27 UTC 2017
Hugh,
At the the San Antonio meetings I took an action item to provide service catalog inputs with regard to statements of service.
Below are a couple of examples that I had in mind when we discussed this at the San Antonio meetings. It strikes me that for missions that are investigating whether or not to use a particular service provider the kind of characteristics below are going to be very useful in determining whether or not the service provider is of interest for the particular Mission. The first table provides the kind of service performance parameters I was thinking about for command service, and the second table provides an example of performance parameters for the telemetry service.
In going through the draft service catalog material to date, it struck me that it is more akin to stating a service catalog per se rather than specifying how a service catalog is stated. I think that ultimately to be of use in guiding CCSDS member agencies the best practice needs to state the overall template to follow and then requirements in each section as to what shall be provided (descriptions, service characteristics/parameters at a minimum), what should be provided (things that are very desirable for a mission to know about) and things that may be provided (nice to have but not critical in determining mission supportability). For what it's worth, I have provided a few more comments on the service catalog example that are kind of in line with this thinking, which I have uploaded to the CWE (new structure).
Although I won't be at the meetings I do hope that perhaps this can serve as a useful part of discussion at the upcoming meetings.
Best regards,
-Erik
---Command Service Table Example----
Parameter
Value
Frequency Bands Supported
Near-Earth S, X
Deep space S[1], X
EIRP and Transmitting Power
S-Band:
34m BWG
99 dBW at 20 kW
34m HEF
79 dBW at 250 W
70m
106 dBW at 20 kW
X-band:
34m BWG/HEF
110 dBW at 20 kW
70m
116 dBW at 20 kW
Refer to Table 5-1
Polarizations Supported
RCP
LCP
No RCP/LCP simultaneity
Modulation Types
BPSK on subcarrier for uplink rate ≤ 4 kbps
BPSK directly on carrier for uplink rate 4 kbps to 256 kbps[2]
Modulation Formats
NRZ: L, M, S
Bi-phase L or Manchester, M, S
Modulation Index Range
Sinewave subcarrier: 0.1 – 1.52 radians
Squarewave subcarrier: 0.1 – 1.40 radians
No subcarrier: 0.1 – 1.57 radians
Carrier/Subcarrier Waveform
Residual carrier: sine wave
Subcarrier: 8 or 16 kHz
Uplink Acquisition Types
CCSDS Physical Link Operations Procedure-2 (PLOP-2)
Uplink Data Rate
Maximum 256 kbps
Minimum 7.8 bps
Channel Coding
Provided by mission user
Data from MOC to DSN
Stream of CLTUs over a TCP/IP interface
or
File of CLTUs
Data from DSN To Spacecraft
CLTU per CCSDS TC Space Link Protocol (ref. CCSDS 232.0-B-1)
Data Unit Size
Maximum CLTU size: 32,752 bits
Minimum: 16 bits
A series of CLTUs can be contiguously radiated.
Data Retention Period
No data retention other than buffer staging for radiation
Data Delivery Methods from MOC to DSN
CCSDS Space Link Extension (SLE) Forward CLTU (ref. CCSDS 912.1-B-2), on-line delivery mode
CCSDS SLE Enhanced Forward CLTU (ref. CCSDS 912.11-O-1), on-line delivery mode (being implemented, available in 2017)
AMMOS Space Command Message File (SCMF) Interface, on-line or off-line delivery mode
Radiation Latency
≤ 125 milliseconds per CLTU
Service Operating Mode
Automated
Service Availability
Nominal 95%
Mission critical event 98%
Data Quality†
Bit error rate: 10-7
CLTU error rate: 10-4
Accountability Reporting
SLE command radiation status report
Ground Communication Interface Methods
Refer to Section 3.8
DSN Interface Specifications
DSN documents 810-005; 810-007[3]; 820-013 0163-Telecomm, 0191-Telecomm, 0197-Telecomm, 0198-Telecomm
-----Telemetry Service Table Example---
Parameter
Value
Frequency Bands Supported
Near-Earth S, X, Ka[4]
Deep space S, X, Ka
G/T @ 45 Degree Elevation, diplexed (refer to Table 5.1)
S-Band
G/T (dB)
34m BWG
40.8
34m HEF
39.4
70m
49.8
X-Band
G/T (dB)
34m BWG
54.2
34m HEF
53.2
70m
61.5
Ka-Band
G/T (dB)
34m BWG (deep space, 32 GHz)
61.1
34m BWG (near Earth, 26 GHz)
58.2
Polarizations Supported
RCP
LCP
RCP/LCP simultaneity at some stations for S-, X-and deep space Ka-band.
Modulation Types
PSK on residual carrier (with or without subcarrier)
BPSK on suppressed carrier (no ranging)
QPSK, OQPSK* (no ranging)
Modulation Formats
NRZ: L, M, S;
Bi-phase L or Manchester, M, S
Carrier/Subcarrier Waveform
Residual carrier: sine or square wave
Downlink Data Rate
(Information and redundancy)
Maximum: 150 Mbps for near Earth Ka-band
10 Mbps for other frequencies
Minimum: 10 bps (> 40 bps recommended for timely acquisition)
Downlink Symbol Rate
Maximum: 300 Msps for near Earth Ka-band (with ½ code)
20 Msps for other frequencies (with ½ code)
Minimum: 20 sps (with ½ code)
Forward Error Correction
Convolutional codes: (k=7, r=1/2), without punctured code option
Reed-Solomon (RS) interleave = 1 to 8
Reed-Solomon (RS) without convolutional code
Reed-Solomon (outer) concatenated with convolutional (inner) code
Turbo codes: 1/2, 1/3, and 1/4 (1.6 Mbps max); not available for near-Earth Ka-band
Turbo code: 1/6 (1 Mbps max); not available for near-Earth Ka-band
Low Density Parity Code (LDPC): ½, 2/3, 4/5, 7/8 (10 Msps, max); not available for near-Earth Ka-band.[5]
Data Format, from Spacecraft to the DSN
CCSDS TM Synchronization and Channel Coding (ref. CCSDS 131.0-B-1)
Transfer frame format conforming to CCSDS TM Space Data Link Protocol (ref. CCSDS 132.0-B-1)
VCDUs conforming to CCSDS AOS Space Data Link Protocol (ref. CCSDS 732.0-B-2)
Data Format, from DSN to MOC
Stream of frames or VCDUs
Data Unit Size (information bits only)
TM frame or VDCU: 8920 bits (nominal), 1760 bits (safing and critical events), 16 kbits (maximum)
Maximum Number Of Virtual Channels Supported
64 (16 virtual channels can be processed at a given time)
Data Retention Period at the DSN
Nominal 14 days after acquisition[6].
Data Delivery Methods from the DSN to the MOC
CCSDS Space Link Extension (SLE) RAF/RCF (ref. CCSDS 911.1-B-2 and 911.2-B-2)
On-line timely
On-line complete
Off-line
Data Delivery Latency (DSN to MOC)
Engineering telemetry: Typically on-line timely (seconds) and on-line complete (hours)
Science telemetry: Typically off-line (hours to 24 hours).
Note: Latency commitment limited by bandwidth from DSN to project MOS
Service Operating Mode
Automated
Service Availability
Nominal: 95%
Mission critical event: 98%
Data Quality†
Frame rejection rate: 10-4 to 10-5 typical
Time Tagging Accuracy
10-50 microseconds in Earth Receive Time (ERT) relative to UTC, depending on downlink data rate
Accountability Reporting
SLE RAF/RCF status report
Frame accountability report
0199-Telecomm, 0206-Telecomm-SLE
Ground Communication Interface Methods
Refer to Section 3.8
________________________________
[1] S-band uplink at Madrid excludes the use of 2110-2120 MHz frequency band, per agreement between NASA and Secretaria de Estado de Telecomunicaciones para la Sociedad de la Informacion (SETSI), January 2001.
[2] It is recommended to use large CLTU size (32 kb) for high command data rate (e.g., 256 kbps) to minimize the transaction rate.
[3] DSN Mission Interface Design Handbook, Document No. 810-007, Rev. E, Jet Propulsion Laboratory, Pasadena, California.
[4] Near-Earth Ka-band can be concurrently received with S-band, but not X-band
[5] LDPC code will be available in 2018, with a firm commitment on code rate ½ to support Human Space Flight mission. Availability of other code rates (2/3, 4/5, 7/8) may extend beyond 2018.
[6] Longer retention period due to mission-specific need could be negotiated, subject to data volume constraint.
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