Data Set Overview  :   This data set contains Raw data taken by New Horizons  Radio Science Experiment  instrument during the JUPITER mission phase.  The REX instrument measures the amplitude and phase of radio signals captured by the New Horizons high-gain antenna. The main investigation is an occultation experiment which uses radio signals transmitted from Earth to probe the atmosphere and ionosphere of Pluto and Charon. Ancillary investigations include measurements of the 4 cm wavelength radiothermal emission from planets or other radio sources. Phase data may also be combinedwith Pluto encounter tracking data, derived from the Radio Science Subsystem separately from REX and to be archived in separate non-REX data set(s), to infer the influence of gravitational fields on the spacecraft as it moves through the Pluto system.  The main investigation requires coordinated use of the Earth-based transmitters and the spacecraft receiver as the two physical elements of the REX instrument. The 'Ground Element' comprises DSN (Deep Space Network) hardware and operations facilities on Earth, and the 'Flight Element' includessignal processing hardware and software onboard the spacecraft.  Unless inclusion of tuning profiles for one-way uplink transmissions is noted below, this data set includes only samples taken and measurements made by the REX system hardware on-board the New Horizons spacecraft -- either of one-way uplink signals or of 4cm-wavelength thermal emission.  ######################################################################## ######################################################################## REQUIRED UNDERSTANDING: THE REX AND THE NEW HORIZONS (NH) REGENERATIVE RANGING TRACKER [DEBOLTETAL2005] ARE   *****SEPARATE***** AND *****INDEPENDENT*****  SUBSYSTEMS THAT BOTH USE THE RADIO FREQUENCY (RF) AND TELECOMMUNICATIONS SUBSYSTEMS. TWO-WAY RANGING DATA WILL NOT BE ARCHIVED IN REX DATA SETS. ######################################################################## ########################################################################  The New Horizons Jupiter encounter afforded no occultation or bi-static scattering geometries for which REX had sufficient sensitivity. The main REX activity during Jupiter flyby was a pair of radiometric scans of the High GainAntenna (HGA), across the Jovian disk for the purpose of calibrating the REX radiometer experiment. The scans were conducted with New Horizons at ~100 Rj both in-bound and out-bound, when the angular size of Jupiter was closely matched to the beamwidth of the HGA. The Jovian radiometric profile downlinked from the first scan exhibits high precision, and has been used to calibrate the REX radiometric response.  Other activities during the mission phase, not associated with the proximity to Jupiter and with the main purpose of characterizing the instrument, were standard checkout operations, looking for weak tones in the REX band by using a large gain, mapping the HGA beam pattern, and an interference test with other instruments.  Although one-way uplink data signals were sent from the Ground Element to REX,the characteristics of those signals are not needed to analyze these REX observations comprising instrument checkout, characterization and calibration activities. So no uplink tuning profiles are included in this data set.   Every observation provided in this data set was taken as a part of a  particular sequence. A list of these sequences has been provided in  file DOCUMENT/SEQ_REX_JUPITER.TAB.  N.B. Some sequences provided may have no corresponding observations.   For a list of observations, refer to the data set index table; this  is typically INDEX.TAB initially in the INDEX/ area of the data set;  there is also a file SLIMINDX.TAB in INDEX/ that summarizes key  information relevant to each observation, including which sequence  was in effect and what target was likely intended for the  observation.    Known issues in REX data  :   The following item assumes familiarity with the REX, REX terminology  and the required reading and other documentation provided with this  data set.   Time tag anomalies in ROF sequences  -----------------------------------   REX places ten incrementing time tags in each REX Output Frame (ROF).  The time tags can be used both to identify any breaks in a sequence of ROFs, and to determine the time between any two ROFs within a  sequence.   The normal sequence for time tags is to start at zero in the first ROF and increment ten times per ROF, so the first time tag of the second  ROF is 10, that of the third ROF is 20, etc. In practice, the first  and last ROFs in a sequence do not always show simple zero starts and  clean finishes, respectively, indicating data corruption in just those ROFs. There is no indication of corruption elsewhere in ROF streams,  and REX commanding ensures there are always adequate ROFs before and  after any observation, so discarding starting and ending ROFs in a  sequence based on simple inspection of time tags is the way to handle  this issue.   Refer to the REX documentation for more detail.    Version  :   This is VERSION 1.0 of this data set.    Processing  :   The data in this data set were created by a software data  processing pipeline on the Science Operation Center (SOC) at  the Southwest Research Institute (SwRI), Department of Space Studies.  This SOC pipeline assembled data as FITS files from raw telemetry  packets sent down by the spacecraft and populated the data labels  with housekeeping and engineering values, and computed geometry  parameters using SPICE kernels. The pipeline did not resample  the data.    Data  :   The observations in this data set are stored in data files using  standard Flexible Image Transport System (FITS) format. Each FITS  file has a corresponding detached PDS label file, named according  to a common convention. The FITS files may have image and/or table  extensions; see the PDS label plus the DOCUMENT files for a  description of these extensions and their contents.   This Data section comprises the following sub-topics:   - Filename/Product IDs  - Instrument description  - Other sources of information useful in interpreting these Data  - Visit Description, Visit Number, and Target in the Data Labels    Filename/Product IDs  --------------------   The filenames and product IDs of observations adhere to a  common convention e.g.   ALI_0123456789_0X0AB_ENG_1.FIT  ^^^ ^^^^^^^^^^ ^^^^^ ^^^ ^\__/  | | | | | ^^  | | | | | |  | | | | | +--File type (includes dot)  | | | | | - .FIT for FITS file  | | | | | - .LBL for PDS label  | | | | | - not part of product ID  | | | | |  | | | | +-- Version number from the SOC  | | | | (Science Operations Center)  | | | |  | | | +--ENG for CODMAC Level 2 data *  | | | SCI for CODMAC Level 3 data *  | | |  | | +--Application ID (ApID) of the telemetry data  | | packet from which the data come  | |  | +--MET (Mission Event Time) i.e. Spacecraft Clock  |  +--Instrument designator   * For those datasets where the NH project is delivering  CODMAC Level 1 & 2 data (REX & PEPSSI), ENG and SCI apply  to CODMAC Level 1 & 2 data, respectively.    Instrument Instrument designators ApIDs  : : :  REX REX 0X7B0 - 0X7B3 *   * Not all values in this range are in this data set   There are other ApIDs that contain housekeeping values and  other values. See the documentation for more details.    Here is a summary of the types of files generated by each ApID  along with the instrument designator that go with each ApID:    ApIDs Data product description/Prefix(es)  : :  0x7b0 - REX Lossless Compressed Data (CDH 1)/REX  0x7b1 - REX Packetized Data (CDH 1)/REX  0x7b2 - REX Lossless Compressed Data (CDH 2)/REX  0x7b3 - REX Packetized Data (CDH 2)/REX    Instrument description  ----------------------   Refer to the following files for a description of this instrument.   CATALOG   REX.CAT   DOCUMENTS   REX_SSR.*  SOC_INST_ICD.*    Other sources of information useful in interpreting these Data  --------------------------------------------------------------   Refer to the following files for more information about these data   NH Trajectory tables:   /DOCUMENT/NH_MISSION_TRAJECTORY.* - Heliocentric  /DOCUMENT/NH_TRAJECTORY.* - Jupiter-centric     Visit Description, Visit Number, and Target in the Data Labels  ---------------------------------------------------------------   The observation sequences were defined in Science Activity  Planning (SAP) documents, and grouped by Visit Description and  Visit Number. The SAPs are spreadsheets with one Visit Description  & Number per row. A nominal target is also included on each row  and included in the data labels, but does not always match with the  TARGET_NAME field's value in the data labels. In some cases, the  target was designated as RA,DEC pointing values in the form  ``RADEC:123.45,-12.34'' indicating Right Ascension and Declination,  in degrees, of the target from the spacecraft in the Earth  Equatorial J2000 inertial reference frame. This indicates either  that the target was either a star, or that the target's ephemeris  was not loaded into the spacecraft's attitude and control system  which in turn meant the spacecraft could not be pointed at the  target by a body identifier and an inertial pointing value had to  be specified as Right Ascension and Declination values. The PDS  standards do not allow putting a value like RADEC:... in the PDS  TARGET_NAME keyword's value; in those cases the PDS TARGET_NAME  value is set to CALIBRATION.    Ancillary Data  :   The geometry items included in the data labels were computed  using the SPICE kernels archived in the New Horizons SPICE  data set, NH-X-SPICE-6-JUPITER-V1.0.   Every observation provided in this data set was taken as a part of a  particular sequence. A list of these sequences has been provided in  file DOCUMENT/SEQ_REX_JUPITER.TAB. In addition, the  sequence identifier (ID) and description are included in the PDS label  for every observation. N.B. While every observation has an associated  sequence, every sequence may not have associated observations; that is,  some sequences may have failed to execute due to spacecraft events  (e.g. safing) and there will be observations associated with those  sequences. No attempt has been made during the preparation of this  data set to identify if any, or how many, such empty sequences there  are, so it is up to the user to compare the times of the sequences  to the times of the available observations from the INDEX/INDEX.TAB  table to identify such sequences.    Time  :   There are several time systems, or units, in use in this dataset:  New Horizons spacecraft MET (Mission Event Time or Mission Elapsed  Time), UTC (Coordinated Universal Time), and TDB Barycentric  Dynamical Time.   This section will give a summary description of the relationship  between these time systems. For a complete explanation of these  time systems the reader is referred to the documentation  distributed with the Navigation and Ancillary Information  Facility (NAIF) SPICE toolkit from the PDS NAIF node, (see  http://naif.jpl.nasa.gov/).   The most common time unit associated with the data is the spacecraft  MET. MET is a 32-bit counter on the New Horizons spacecraft that  runs at a rate of about one increment per second starting from a  value of zero at   19.January, 2006 18:08:02 UTC   or   JD2453755.256337 TDB.   The leapsecond adjustment (DELTA_ET : ET - UTC) over this dataset  is 65.184s.   The data labels for any given product in this dataset usually  contain at least one pair of common UTC and MET representations  of the time at the middle of the observation. Other portions  of the products, for example tables of data taken over periods  of up to a day or more, will only have the MET time associated  with a given row of the table.   For the data user's use in interpreting these times, a reasonable  approximation (+/- 1s) of the conversion between Julian Day (TDB)  and MET is as follows:   JD TDB : 2453755.256337 + ( MET / 86399.9998693 )   For more accurate calculations the reader is referred to the  NAIF/SPICE documentation as mentioned above.    Reference Frame  :    Geometric Parameter Reference Frame  -----------------------------------  Earth Mean Equator and Vernal Equinox of J2000 (EMEJ2000) is the  inertial reference frame used to specify observational geometry  items provided in the data labels. Geometric parameters are based  on best available SPICE data at time of data creation.    Epoch of Geometric Parameters  -----------------------------  All geometric parameters provided in the data labels were  computed at the epoch midway between the START_TIME and  STOP_TIME label fields.     Software  :   The observations in this data set are in standard FITS format  with PDS labels, and can be viewed by a number of PDS-provided  and commercial programs. For this reason no special software is  provided with this data set.    Contact Information  :   For any questions regarding the data format of the archive,  contact   New Horizons REX Principal Investigator:   Len Tyler, Stanford University   Len Tyler   350 Serra Mall, David Packard #372  Stanford University  Stanford, CA 94305-9515  USA

Confidence Level Overview  :  During the processing of the data in preparation for  delivery with this volume, the packet data associated with each  observation were used only if they passed a rigorous verification  process including standard checksums.   In addition, raw (Level 2) observation data for which adequate  contemporary housekeeping and other ancillary data are not available  may not be reduced to calibrated (Level 3) data. This issue is raised  here to explain why some data products in the raw data set,   NH-J-REX-2-JUPITER-V1.0,   may not have corresponding data products in the calibrated data set,   NH-J-REX-3-JUPITER-V1.0.    Data coverage and quality  :   Every observation provided in this data set was taken as a part of a  particular sequence. A list of these sequences has been provided in  file DOCUMENT/SEQ_REX_JUPITER.TAB. N.B. Some sequences  provided may have zero corresponding observations.   Refer to the Confidence Level Overview section above for a summary  of steps taken to assure data quality.   The Time Tag counter values included with REX data normally increment  by one both ten times within each data file and from the last Time  Tag of one file to the first Time Tag of the next file in a sequence.  However, there are sometimes anomalous departures from this behavior at  the start and end of contiguous runs of data files (see REX.CAT for a  brief discussion of such an issue related to compression). Files with  such anomalies are few compared to the total number of data files, and  excluding those files with anomalous Time Tag data from data analysis  will not significantly affect the results of the REX investigation.  Refer to the Science Operations Center/instrument interface control  document for more detail about REX Time Tags; there is adequate  information there for users to identify anomalous files.  In addition, products with Time Tag anomalies are listed in file  ERRATA.TXT provided with this data set.    Caveat about TARGET_NAME in PDS labels and observational intent  :   The New Horizons project does not have the resources to rigorously  determine and check the accuracy of the TARGET_NAME assignments in  the PDS labels for the observations in this data set. Instead, an  automated process using heuristics to analyze simulated operation  products has been put in place to make a best effort attempt to  identify the target and intent of each observation.   The user of these PDS data needs to be cautious when using the  TARGET_NAME and other target-related parameters stored in this data  set.    Review  :  This dataset was peer reviewed and certified for scientific use on  TBD.