820-013
Deep Space Network (DSN)
External Interface Specification
JPL D-16765
--------------------------------------------------------------------------------
Revision E: February 29, 2008
--------------------------------------------------------------------------------
Document Owner:
Signature of file in DSMS Library
______________________________ ________
Dong Shin Date
DSN Tracking System Engineer
Approved by:
Signature of file in DSMS Library
______________________________ ________
Jeane Stipanuk Date
Interface Engineer and Release Authority
Approved by:
Signature of file in DSMS Library
______________________________ ________
Timothy Pham Date
Chief DSN System Engineer
Concurred by:
Review not requested
______________________________ ________
Jeff Berner Date
DDOSO Development and Operations Chief Engineer
Review not requested
______________________________ ________
Dong Shin Date
DSN Tracking System Engineer
Review not requested
______________________________ ________
Chuck Naudet Date
Supervisor, Deep Space Tracking Systems
Review not requested
______________________________ ________
David Berry Date
RMDC Subsystem Engineer
Review not requested
______________________________ ________
Dana Flora-Adams Date
TDDS SW CDE
Review not requested
______________________________ ________
Scott Bryant Date
Ranging CDE
Review not requested
______________________________ ________
Jim Border Date
DOR System engineer
Review not requested
______________________________ ________
Tomas J. Martin-Mur Date
MGSS PEM, Navigation and Mission Design
Review not requested
______________________________ ________
Richard D. Benson Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Eugene Burke Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Daniel F Finnerty Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Dwight P. Holmes Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Andrew Kwok Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Peter T. Poon Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Stefan Waldher Jr. Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Byron G. Yetter Date
Telecommunications and Mission System Engineer
Review not requested
______________________________ ________
Ana Guerrero Date
Manager, DDOSO Tracking, Telemetry, Command End-to-End Data Office
Review not requested
______________________________ ________
Susan Kurtik Date
DDOSO Mission Support Manager
===========================================================================
Rev. Check if Issue Date Affected Sections Change Summary
Minor Rev.
-- 06/15/1983 All This is a new document.
1 12/15/1998 All Reformatted. Contains revisions to match
the implementation. Uplink and downlink
doppler phase have been added. Provides
Y2K clarification for the use of
two-digit year.
2 01/15/1999 1.1.1, Appendix A Adds missing text to clarify the
calculation for frequency bias.
3 06/15/2000 1.1.1, Table 3-3b. Deleted Table 3-3b, Item Number 10 values
that are not available and will not be
provided.
Deleted Tables 3-6a and Table 3-6b.
Delete all "PRA" since it no longer exists.
Table 3-3b, items 9 and 10, delete DSN or GSTDN.
D 12/29/2006 All Re-formatted per 820-013, D-16765.
Deletion of OPS-6-8 format
Updated section 2 and Figure 2-1.
Updated section 3 and added Figure 3-1.
Updated Doppler observable formula and added
definition of VLBI Observables, and sequential
ranging in Appendix A.
E X 02/29/2008 Section 1 Minor changes to update footer tags, change
'DSMS' to 'DSN', edit Section 1 sequence
===========================================================================
Section ................................................................... Page
Section 1 Introduction ............................................. 1-1
1.1 Purpose and Scope ........................................ 1-1
1.2 Effectivity .............................................. 1-1
1.3 Revision and Control ..................................... 1-1
1.4 Relationship to Other Documents .......................... 1-1
1.5 Notation and Conventions ................................. 1-2
1.5.1 Notation ................................................. 1-2
1.5.2 Conventions .............................................. 1-2
1.6 References ............................................... 1-3
1.7 Abbreviations ............................................ 1-4
Section 2 Functional Overview ...................................... 2-1
Section 3 Detailed Interface Description ........................... 3-1
3.1 ODF Physical Layout ...................................... 3-1
3.2 File Format .............................................. 3-3
3.2.1 Header ................................................... 3-3
3.2.2 File Label Group ......................................... 3-4
3.2.3 Identifier Group ......................................... 3-6
3.2.4 Orbit Data Group ......................................... 3-7
3.2.5 Ramp group Data .......................................... 3-16
3.2.6 Clock Offsets Group Data ................................. 3-17
3.2.7 End-of-File Group ........................................ 3-17
3.3 Dependencies ............................................. 3-17
Appendix A ODF observables .......................................... A-1
A.1 VLBI Observables ......................................... A-1
A.2 Doppler Observables ...................................... A-1
A.3 Range Observables ........................................ A-2
Figure .................................................................... Page
Figure 2-1. Data Flow for Orbit Data File Interface ....................... 2-1
Figure 3-1. ODF Physical Layout ............................................ 3-2
Table ..................................................................... Page
Table 3-1. Header Format .................................................. 3-4
Table 3-2. File Label Group Data Format .................................... 3-4
Table 3-3. Identifier Group Data Format ................................... 3-6
Table 3-4a. Orbit Data Group Data Format, Common portion .................. 3-8
(Data Types 1, 2, 3, and 4) ............................................... 3-10
(Data Types 5 and 6) ...................................................... 3-11
(Data Types 41, 51, 52, 53, 54, 55, 56, 57, and 58)........................ 3-15
Table 3-5. Ramp Group Data Format ........................................ 3-16
Table 3-6. Clock Offsets Group Data Format ............................... 3-17
This module specifies the Orbit Data File (ODF) format of the radio metric data from the Deep Space Network (DSN). The contents and formats of the ODF are herein defined.
Revision E provides editorial updates only and supersedes Revision D.
The 'Revision D' module update includes: Re-formatted per 820-013, D-16765, deletion of OPS-6-8 format, updated section 2 and Figure 2-1, updated section 3 and added Figure 3-1, updated Doppler observable formula and added definition of VLBI Observables and sequential ranging in Appendix A.
The 'Change 3' update to this module deletes items that are not available and will not be provided. Other updates to clean-up things that do not exist or are no longer applicable.
The 'Change 2' update to this module adds missing text to clarify the calculation for frequency bias in Appendix A.
The 'Change 1' module update corrects the interface specification to be consistent with revisions approved on 15 August 1996 by the Multi-Mission Ground Support Office (MGSO), and implemented in the Radio Metric Data Conditioning (RMDC) software. Uplink and downlink Doppler phase data have been added to the ODF since the original DSN release
Revisions or changes to the information herein presented may be initiated according to the procedure specified in the Introduction to Document 820- 013.
820-013, TRK-2-18 ODF is generated by the RMDC of the TTC (Telemetry, Tracking, and Command) system element. The ODF is converted from 820-013, TRK-2-34 data which is generated by the TDDS (Tracking Data Delivery Subsystem) of the TTC system element.
The definitions provided here are intended to clarify the use of certain terms as they apply to this module:
1. The term byte is used to refer to an eight-bit quantity.
2. The term packet refers to a formatted block of information. A packet consists of two elements: the first element is a header, which marks the beginning of the packet; the second element is the data, which contains the information to be carried in the packet.
3. The term ASCII refers to the American Standard Code for Information Interchange, a seven-bit code for representing letters, digits, and symbols that has been standardized by the American National Standards Institute. This code has been incorporated into the ISO (International Organization for Standardization) code, which includes other symbols and alphabets. Since the ISO code is an eight-bit code, the ASCII code is embedded in an eight-bit field in which the most significant bit is set to zero. In this module, ASCII always refers to the seven-bit ASCII code embedded, as described, in an eight- bit field.
4. The term restricted ASCII (RA) refers to the subset of ASCII consisting of the codes for the twenty-six upper-case letters ('A' 'Z') and the ten decimal digits ('0' '9'). When applied to a multi-byte field, it implies that each byte in the field contains a Restricted ASCII character.
5. The term Observable refers to the measurements provided by DSN. Types of Observables are VLBI, Doppler, Range, and Angle. A detailed description is in Appendix A.
6. The term group is used to distinguish between different types of information in the ODF. There are 7 groups in the ODF. Each group contains a header and data except End-of-File group (paragraph 3.1.7). A Header contains group identification, and data contains information. Formats of a header and data are described in tables in paragraph 3.1.
7. The term block is used to distinguish between information in the ODF. A block is either group header or group data. Each block in the ODF is 36 bytes long.
8. The term data type is used to distinguish between different types of data in the orbit data group (paragraph 3.1.3). 20 data types are currently assigned and available, and data types are described in Table 3-3b.
9. The term EME50 refers to the earth mean equator of epoch Besselian year of January 1, 1950.
The following conventions are used in this module.
1. All numbers are expressed in decimal
2. The ODF File Label Data (Table 3-2) specifies a 2-digit year in the File Creation Date (item number 18). This item has no application to processing any data in the file. However, it is constructed with the premise that values from 50 to 99 shall signify dates with respect to 1900, and values between 00 and 49 shall represent dates with respect 2000.
3. Times, except as noted, are given as seconds past zero hours UTC of January 1, 1950.
4. Most data parameters will be provided as binary integers; two's complement will be used for all fields that may have negative values.
5. Single-bit status parameters will be set to one (1) for no, bad, off, out of tolerance, etc.; and will be set to zero (0) for yes, good, on, in tolerance, etc.
6. Data structures are divided into fields, where a field is a sequence of bits. Fields are identified by specifying the starting and ending byte/bits of the field in Byte/Bit (s) column of tables in paragraph 3.2. For fields that cross byte boundaries, bit 8 of byte M is more significant than, and is immediately followed by, bit 1 of byte M+1. A field in the tables is divided into subfields in a similar manner.
7. In the data structure descriptions in this module, many fields are defined to contain a numerical value. Unsigned integer-m and Integer-m expressing numbers are used, as follows:
Unsigned integer-m. An integer number is expressed in binary, using all bits of the field as necessary. Negative quantities cannot be expressed. For an n-bit field, the range of values that can be represented is from 0 to 2n-1. The number of bits in the unsigned integer-m is represented by "-m".
Integer-m. An integer number is expressed in binary, using two's complement notation. For an n-bit field, the range of values that can be represented is from -2n-1 to 2n-1-1. The number of bits in the integer-m is represented by "-m".
Documents
DSN 810-005, DSN Telecommunications Link Design Handbook,
Module 107 Radio Source Catalog
DSN 810-047 DSN Antenna and Facility Identifiers, DSN
Standard Practice
(DSN Internal Use Only)
DSN 820-013, D-16765 DSN External Interface Specification
820-013, OPS-6-21 Standard Code Assignments
820-013, TRK-2-34 DSN Tracking System, Data Archival Format
D-7669, Part 2 PDS (Planetary Data System) Standards Reference
D-31224 PDS archive preparation guide
ISO/IEC 646-1991 Information Technology - ISO 7-bit Coded
Character Set for Information Interchange
Web Sites
None.
ASCII American Standard Code for Information Interchange
DCC Downlink Channel Controller
deg Degrees
DOM Distributed Object Manager Subsystem
DSCC Deep Space Communications Complex Ranging
DSN Deep Space Network
DSS Deep Space Station
GCN Ground Communication Network System
Hz Hertz
H/P High Part
ISO International Organization for Standardization
JPL Jet propulsion Laboratory
L/P Low part
MDAS Mission Control, Data Management, and S/C Analysis System
Element
MGSO Multi-Mission Ground Support Office
mHz milli-Hertz
MPA Metric Pointing Assembly
msec milli-seconds
nsec nano-seconds
ODF Orbit Data File
OTS OVLBI Tracking Subsystem
OVLBI Orbiting Very Long Baseline Interferometry
PDS Planetary Data System
PN Pseudo Noise
RE Ranging Equipment
RMDC Radio Metric Data Conditioning Subsystem
RS Radio Science
RU Range unit
sec Seconds
S/C Spacecraft
TDDS Tracking Data Delivery Software
TTC Telemetry, Tracking, and Command System Element Subsystem
UPL Uplink Tracking and Command Subsystem
UTC Universal Time Coordinated
VLBI Very Long Baseline Interferometry
Figure 2-1 shows the tracking data flow from the Deep Space Communications Complex (DSCC) through the Ground Communication Network (GCN) system and to the Telemetry, Tracking, and Command (TTC) system element to the end users (JPL project, RS, or non JPL navigation).
ODF's are delivered to the end users in a TRK-2-18 data format. Deliveries are made by RMDC according to delivery schedules received from the projects. Daily deliveries are made routinely and special deliveries are also made upon request.
Appendix A defines Observables described in this document.
Figure 2-1. Data Flow for Orbit Data File Interface
The physical layout is shown in Figure 3-1. The physical layout is divided into seven groups: the file label, the identifier, the orbit data, ramp, the clock offset, and the end-of-file.
1. Each ODF consists of radio metric data for one spacecraft, zero or more quasars, and one or more stations.
2. A complete ODF will consist of the following data in order listed below:
a) File Label group – one header and one data block (Tables 3-l and 3- 2); required
b) Identifier group - one header and one data block (Tables 3-1 and 3- 3); required
c) Orbit data group – multiple, time ordered header and data block pairs (Tables 3-1 and 3-4a through 3-4g); required
d) Ramp group - one group for each DSS, multiple, time ordered header and data block pairs, and (Tables 3-1 and 3-5); optional - VLBI data currently does not utilize this group
e) Clock Offsets group - time ordered, multiple header and data block pairs (Tables 3-1 and 3-6); optional – this group is currently utilized by VLBI data only.
f) End-of-File group - one header block (Table 3-1); required
g) Filler blocks (all bytes are set to zero)
3. The ODF contains an integer multiple of 8064 bytes. When the ODF contains less than an integer multiple of 224 packets, then the remaining will be filled with filler bytes (0).
Figure 3-1. ODF Physical Layout
Each ODF consists of following groups, and these groups are described in this section.
Each group consists of a header (Table 3-1). Note that if ramps are generated from more than one DSS station, then each station ID will have its own Ramps header followed by one or more Ramp Group Data blocks (i.e., Table 3-5). Item numbers 5 through 9 of all group headers are set to zero (0).
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-3 Primary Key. Signed N/A -1,
-1 => End-of-File header Integer-32 101,
101 => File Label Header 107,
107 => Identifier Header 109,
109 => Orbit Data Header 2030,
2030 => Ramps Header 2040
2040 => Clock Offset Header
2 4-7 Secondary Key. Unsigned N/A 0 to 99
For a Ramps Header this Integer-32
number is the station ID per
810-047, it is 0 otherwise.
3 8-11 Logical Record Length. Unsigned 288-bit 0 or 1
0 for an end-of-file header, Integer-32 packets
1 otherwise.
4 12-15 Group Start Packet Number. Unsigned 288-bit 0, 2, 4,
The sequential packet number Integer-32 packets 5, 6, 7
within the ODF for this block. thru
It is always 0 for the File 222
Label Header, 2 for the
Identifier Header, and 4 for
the Orbit Data Header.
5 16-19 Filler 1. Unsigned N/A 0
Integer-32
6 20-23 Filler 2. Unsigned N/A 0
Integer-32
7 24-27 Filler 3. Unsigned N/A 0
Integer-32
8 28-31 Filler 4. Unsigned N/A 0
Integer-32
9 32-35 Filler 5. Unsigned N/A 0
Integer-32
================================================================================
The file label group identifies the system that created the file and the time at which the file was created. It also defines the reference time for time values that are expressed as seconds past the reference time. The file label group consists of header (Table 3-1) and data (Table 3-2).
Table 3-2. File Label Group Data Format
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-7 System ID. Restricted N/A
Left-justified, with blank ASCII-8
fill to the right. e.g.
'TDDS'
2 8-15 Program ID. Restricted N/A
Left-justified, with blank ASCII-8
fill to the right. e.g.
'AMMOS'
3 16-19 Spacecraft ID Number per Unsigned N/A 0 to
820-013, OPS-6-21 Integer-32 255
4 20-23 File Creation Date. N/A year, 0000101
In the format YYMMDD. It is month, to
constructed with the premise day 9991231
that YY values from 50 to 99
shall signify dates with
respect to 1900, and values
between 00 and 49 shall
represent dates with respect
2000.
5 24-27 File Creation Time. N/A hour, 000000
In the format HHMMSS minute, to
second 235960
6 28-31 File Reference Date. Unsigned year, 0 or
In the format YYYYMMDD. Integer-32 month, 19500101
Currently the ODF data time day
tags are seconds past
zero hours UTC 1 January
1950. Hence, this item is
set to 19500101. Older ODFs
which have file reference
date equal to zero will be
assumed to refer to
01/01/1950 UTC.
7 32-35 File Reference Time. Unsigned hour, 000000
In the format HHMMSS Integer-32 minute, to
second 235960
================================================================================
The identifier group consists of a header (Table 3-3) having the primary key set to 107 followed by Table 3-3 below:
Table 3-3. Identifier Group Data Format
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-7 Identifier 1. Restricted N/A TIMETAG
Left-justified, with blank ASCII-8
fill to the right.
2 8-15 Identifier 2. Restricted N/A OBSRVBL
Left-justified, with blank ASCII-8
fill to the right.
3 16-35 Identifier 3. Restricted N/A FREQ,
Left-justified, with blank ASCII-20 ANCILLARY-DATA
fill to the right.
================================================================================
The data portion contains 22 items of information. Items #1 through #14 contain information that is common to all observables, and is defined in Table 3-4a. Items #15 through #22 contain information that is data type dependent. The data type dependent information is defined in Tables 3-4b through 3-4g for the following respective data types:
Note that there is no ODF generation for the pseudo-noise range data.
Table 3-4a. Orbit Data Group Data Format, Common portion
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-3 Record Time Tag, integer Unsigned sec
part. Integer-32
In seconds since the
reference time specified in
the header packet.
2 4/1-5/2 Record Time Tag, fractional . Unsigned msec 0 to 999
part Integer-10
3 5/3-7/8 Primary Receiving Station Unsigned nsec
Downlink Delay. Integer-22
This is the downlink delay
between the receiving antenna
and the receiving electronics.
It shall include the array
delay for arrayed operations.
Note that both this item and
item 22 only allow for a
maximum delay of about 4
msec.
4 8-11 Observable, Integer Part. Signed varies;
Integer-32 see
item 10
5 12-15 Observable, Fractional Part. Signed 10-9
Integer-32 of those
of item 4
6 16/1-16/3 Format ID. Unsigned N/A 2
Integer-3
7 16/4-17/2 Primary Receiving Station ID Unsigned N/A 1 to 127
Number per 810-47. Integer-7
8 17/3-18/1 Transmitting Station ID Unsigned N/A 0 to 127
Number per 810-47. Integer-7
Zero if the data type does
not require a transmitting
station.
9 18/2-18/3 Network ID for the Unsigned N/A 0 to 2
Transmitting Station. Integer-2
0 => DSN
1 => Other
3 => UPL
10 18/4-19/1 Data Type ID. Unsigned N/A 1, 2, 3,
1 => D-DOD, Doppler mode; Hz Integer-6 4, 5, 6,
2 => D-DOD, phase mode; cycles 11, 12,
3 => D-DOD, Doppler mode; Hz 13, 36,
4 => D-DOD, phase mode; cycles 37, 41,
5 => D-DOR; nsec 51, 52,
6 => D-DOR; nsec 53, 54,
11 => 1-Way Doppler; Hz 55, 56,
12 => 2-Way Doppler; Hz 57, 58
13 => 3-Way Doppler; Hz
37 => Sequential Range; RU
41 => RE (Tone) Range; nsec
51 => Azimuth Angle; deg
52 => Elevation Angle; deg
53 => Hour Angle; deg
54 => Declination Angle; deg
55 => X Angle (where +X is
East); deg
56 => Y Angle (where +X is
East); deg
57 => X Angle (where +X is
South); deg
58 => Y Angle (where +X is
South); deg
11 19/2-19/3 Downlink Band ID. Unsigned N/A
0 => Ku-Band or angle data Integer-2
1 => S-Band
2 => X-Band
3 => Ka-Band
12 19/4-19/5 Uplink Band ID. Unsigned N/A
0 => N/A or Ku-Band Integer-2
1 => S-Band
2 => X-Band
3 => Ka-Band
13 19/6-19/7 Reference Frequency Band ID. Unsigned N/A
0 => Ku-Band or angle data Integer-2
1 => S-Band
2 => X-Band
3 => Ka-Band
14 19/8 Data Validity Indicator. Unsigned N/A
0 => valid Integer-1
1 => invalid
================================================================================
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Second Receiving Station ID Unsigned N/A 1 to 127
per 810-047 Integer-7
16 20/8-22/1 Quasar ID per 810-005 Module Unsigned N/A
107 or Spacecraft ID per Integer-10
820-013, OPS-6-21.
17 22/2 Phase Point Indicator Unsigned N/A 0
Integer-1
18 22/3-24/8 Reference Frequency, H/P. Unsigned 224
Used for charged particle Integer-22 mHz
calibrations.
19 25-27 Reference Frequency L/P. Unsigned mHz
Used for charged particle Integer-24
calibrations.
20 28/1-30/4 Composite 1. Signed N/A
This parameter has the value: Integer-20
(Phase Calibration Flag
minus 1) times 100000,
plus Channel ID times 10000.
Where the phase calibration
flag may be one of the
following:
1 => no calibration
2 => default calibration
3 => quasar calibration only
4 => S/C calibration only
5 => quasar and S/C
calibration
21 30/5-33/2 Compression Time. Unsigned 0.01 sec
Integer-22
22 33/3-35/8 Second Receiving Station Unsigned nsec
Downlink Delay. Integer-22
================================================================================
Note: 1. Item #18 "Reference Frequency, H/P" is
trunc(1000*Variable/2^24), where Variable is Reference Frequency
in Hz
2. Item #19 "Reference Frequency, L/P" is
trunc((1000*Variable)modulo2^24), where Variable is Reference
Frequency in Hz
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Second Receiving Station ID Unsigned N/A 1 to 127
per 810-047 Integer-7
16 20/8-22/1 Quasar ID number per 810-005 Unsigned N/A
Module 107 or Spacecraft ID Integer-10
per 820-013, OPS-6-21.
17 22/2 Modulus Indicator. Unsigned N/A 0 or 1
0 => modded, Integer-1
1 => unmodded
18 22/3-24/8 Reference Frequency, H/P. Unsigned 224
Used for charged particle Integer-22 mHz
calibrations.
19 25-27 Reference Frequency L/P. Unsigned mHz
Used for charged particle Integer-24
calibrations.
20 28/1-30/4 Composite 1. Signed N/A,
This parameter has the value: Integer-20 N/A,
(Channel Sampling Flag minus 10-1
1) times 100000, plus Mode nsec
ID times 10000, plus
Modulus H/P.
Channel Sampling Flag:
1 => multiplexed
2 => parallel
Mode ID:
0 => 1-way
1 => 2-way
21 30/5-33/2 Modulus L/P. Unsigned 10-7
Integer-22 nsec
22 33/3-35/8 Second Receiving Station Unsigned nsec
Downlink Delay. Integer-22
================================================================================
Note: 1. Item #18 "Reference Frequency, H/P" is
trunc(1000*Variable/2^24), where Variable is Reference Frequency
in Hz
2. Item #19 "Reference Frequency, L/P" is
trunc((1000*Variable)modulo2^24), where Variable is Reference
Frequency in Hz
3. Item #20 "Modulus H/P" is trunc(Variable*10), where Variable is
modulus in nanosecond.
4. Item #21, "Modulus L/P" is trunc((10^7*Variable) modulo 10^6),
where Variable is modulus in nanosecond.
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Receiver Channel Number. Unsigned N/A 0 to 24
Integer-7
16 20/8-22/1 Spacecraft ID. Unsigned N/A 0 to 255
Per 820-013, OPS-6-21 Integer-10
17 22/2 Receiver/Exciter Independent Unsigned N/A 0 or 1
Flag. Integer-1
This flag indicates whether
ramps (if available) should
be used to replace the
receiver reference
frequency.
0 => Both the transmitter
and the receiver are ramped.
1=> The transmitter is
ramped, but not the receiver.
18 22/3-24/8 Reference Frequency, H/P. Unsigned 224
Integer-22 mHz
19 25-27 Reference Frequency L/P. Unsigned mHz
Integer-24
20 28/1-30/4 Reserved Signed N/A 0
Integer-20
21 30/5-33/2 Compression Time. Unsigned 10-2
Integer-22 sec
22 33/3-35/8 Transmitting Station Uplink Unsigned nsec
Delay. Integer-22
================================================================================
Note: 1. Item #18 "Reference Frequency, H/P" is
trunc(1000*Variable/2^24), where Variable is Reference Frequency
in Hz
2. Item #19 "Reference Frequency, L/P" is
trunc((1000*Variable)modulo2^24), where Variable is Reference
Frequency in Hz
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Lowest Ranging Component. Unsigned N/A 1 to 24
Component with the lowest Integer-7
frequency
16 20/8-22/1 Spacecraft ID. Unsigned N/A 0 to 255
Per 820-013, OPS-6-21 Integer-10
17 22/2 Reserved Unsigned N/A 1
Integer-1
18 22/3-24/8 Reference Frequency, H/P. Unsigned 224
Integer-22 mHz
19 25-27 Reference Frequency L/P. Unsigned mHz
Integer-24
20 28/1-30/4 Uplink Ranging Coder In-Phase Signed sec
Time Offset from Sample Time Integer-20
Tag.
21 30/5-33/2 Composite 2. Unsigned sec
Highest ranging component Integer-22
times 100000, plus downlink
ranging coder in-phase time
offset from sample time tag.
22 33/3-35/8 Transmitting Station Uplink Unsigned nsec
Delay. Integer-22
For 1-way this is always
zero.
================================================================================
Note: 1. Item #18 "Reference Frequency, H/P" is
trunc(1000*Variable/2^24), where Variable is Reference Frequency
in Hz
2. Item #19 "Reference Frequency, L/P" is
trunc((1000*Variable)modulo2^24), where Variable is Reference
Frequency in Hz
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Integer Seconds of Observable Unsigned sec
Integer-7
16 20/8-22/1 Spacecraft ID. Unsigned N/A 0 to 255
Per 820-013, OPS-6-21 Integer-10
17 22/2 Reserved Unsigned N/A 0
Integer-1
18 22/3-24/8 Reference Frequency, H/P. Unsigned 2 224
Integer-2 mHz
19 25-27 Reference Frequency L/P. Unsigned mHz
Integer-24
20 28/1-30/4 Reserved Unsigned N/A 0
Integer-1
21 30/5-33/2 Reserved Unsigned N/A 0
Integer-1
22 33/3-35/8 Transmitting Station Uplink Unsigned nsec
Delay. Integer-22
For 1-way this is always
zero.
================================================================================
Note: 1. Item #18 "Reference Frequency, H/P" is
trunc(1000*Variable/2^24), where Variable is Reference Frequency
in Hz
3. Item #19 "Reference Frequency, L/P" is
trunc((1000*Variable)modulo2^24), where Variable is Reference
Frequency in Hz
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
15 20/1-20/7 Reserved. Unsigned N/A 0
Integer-7
16 20/8-22/1 Spacecraft ID. Unsigned N/A 0 to 255
Per 820-013, OPS-6-21 Integer-10
17 22/2 Reserved. Unsigned N/A 0
Integer-1
18 22/3-24/8 Reserved. Unsigned N/A 0
Integer-22
19 25-27 Reserved. Unsigned N/A 0
Integer-24
20 28/1-30/4 Reserved. Signed N/A 0
Integer-20
21 30/5-33/2 Reserved. Unsigned N/A 0
Integer-22
22 33/3-35/8 Reserved. Unsigned N/A 0
Integer-22
================================================================================
Note: Item #20 was used for train axis angle data from OVLBI Tracking
Subsystem (OTS). OTS was decommissioned from spacecraft tracking
operations on 1 January 2001.
Ramp group contains uplink frequency information and consists of header (Table 3-1) and data (Table 3-5). Note that each DSS will generate a ramp group header. The frequency and frequency rate in a ramp group data are always sky level values.
Table 3-5. Ramp Group Data Format
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-3 Ramp Start Time, Integer Unsigned sec
Part. Integer-32
In seconds from the
reference time.
2 4-7 Ramp Start Time, Fractional Unsigned nsec 0 to 109-1
Part. Integer-32
3 8-11 Ramp Rate, Integer Part. Signed Hz/s
Integer-32
4 12-15 Ramp Rate, Fractional Part. Signed 10-9 0 to 109-1
Integer-32 Hz/s
5 16/1-18/6 Ramp Start Frequency, Unsigned GHz
Integer GHz. Integer-22
6 18/7-19/8 Transmitting Station ID Unsigned N/A 1 to 127
number per 810-047. Integer-10
7 20-23 Ramp Start Frequency, Integer Unsigned Hz 0 to 109-1
Part Modulo 109. Integer-32
8 24-27 Ramp Start Frequency, Unsigned 10-9 0 to 109-1
Fractional Part. Integer-32 Hz
9 28-31 Ramp End Time, Integer Part. Unsigned sec
In seconds from the Integer-32
reference time.
10 32-35 Ramp End Time, Fractional Unsigned nsec 0 to 109-1
Part. Integer-32
===========================================================================
The clock offsets group contains clock offset information for the observable and consists of a header (Table 3-1) and data as described in table 3-6. Currently clock offset information is generated for D-DOD and D-DOR data only
Table 3-6. Clock Offsets Group Data Format
================================================================================
Item Byte/ Item Name and Description Format Units Range
# Bit (s)
================================================================================
1 0-3 Start Time, Integer Part. Unsigned sec
In seconds from the Integer-32
reference time.
2 4-7 Start Time, Fractional Part. Unsigned nsec 0 to 109-1
Integer-32
3 8-11 Clock Offset, Integer Part Signed sec
(two's complement). The Integer-32
clock offset is (UTC minus
Station Time) at the primary
station minus the same
quantity at the secondary
station.
4 12-15 Clock Offset, Fractional Signed nsec 0 to 109-1
Part. Integer-32
5 16-19 Primary Station ID per Unsigned N/A
810-047. Integer-32
6 20-23 Secondary Station ID per Unsigned N/A
810-047. Integer-32
7 24-27 Reserved. Unsigned N/A
Integer-32
8 28-31 End Time, Integer Part. Unsigned sec
In seconds from the Integer-32
reference time.
9 32-35 End Time, Fractional Part. Unsigned nsec 0 to 109-1
Integer-32
================================================================================
End-of-file group indicates end of the file and consists of header (Table 3-1) only. There is no data portion for the end-of-file group.
None identified.
The ODF VLBI observable (Orbit Data item 10) is derived from receiving a signal simultaneously at two tracking stations and then differencing them. The quasar D-DOR observable is the time of signal arrival at station 2 minus the time of signal arrival at station 1. The spacecraft D-DOR observable is the range at station 2 minus the range at station 1. The D-DOR observables are group delay measurements and have units of nsec. They are derived from data recorded in two separated frequency channels. The D-DOD Doppler observables are phase delay rate measurements and have units of Hz. They are derived from data recorded in a single frequency channel.
For D-DOD Doppler observables, the reference frequency is used to convert between units of Hz and units of sec/sec, just as for ordinary Doppler. For quasar D-DOD observables the reference frequency is the centroid of the received channel frequency used for data recording. For spacecraft D-DOD observables the reference frequency is the spacecraft transmitter frequency for the spectral component, e.g. carrier or sidetone, which is recorded in the channel. For D-DOD observables, the reference frequency is the geometric mean of the reference frequencies associated with the two separated channels used for data recording.
The reference frequency is used for scaling the charged particle correction for all VLBI data types.
The ODF Doppler observable (Orbit Data item 10) represents the average received frequency during a given time interval. The midpoint of the interval is the time tag (Orbit Data items 1 and 2), the start of the interval is the time tag minus half of the compression time (Orbit Data item 21), and the end of the interval is the time tag plus half of the compression time.
Doppler observables are generated by RMDC from the TRK-2-34 data, which contains the actual measurements made at the Deep Space Stations (DSS), and provided in the ODF Orbit Data Group (see Table 3-3b).
Doppler Observable [Hz] = Observable + Fbias
Where
The ODF range observable (Orbit Data item 10) measures the round trip light time between a DSS reference location and a spacecraft reference location. A range unit (RU) is 2 cycles of an S-band transmitting frequency or (749x2)/221 of an X-band transmitting frequency. The time tag (Orbit Data items 1 and 2) is the reception time at the ranging equipment. The reference frequency (Orbit Data items 18 and 19) shall be the uplink frequency at the time of reception, if there are no ramps, but sometimes is the uplink range calibration frequency for the pass.
For range data, the observable is computed as follows:
Observable = R - C + Z - S
where:
R = range measurement
C = station delay calibration
Z = Z-height correction
S = spacecraft delay
The transmitter time tag delay and the receiver time tag delay are included in the range observable. The receiver time tag delay includes any additional delay created by downlink arraying equipment.
The conversion factor F to convert from seconds to range units depends on the uplink band and the transmitting frequency (fT). The current DSN standard values are:
S-Band: F = fT / 2 [RU/sec]
X-Band: F = 221 / 749 * fT / 2 [RU/sec]
The observable has an ambiguity (range modulo) of 2 6+Last_Comp RU, where Last_Comp is Orbit Data item 15.