PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM INTERCHANGE_FORMAT = ASCII INSTRUMENT_HOST_NAME = "CASSINI ORBITER" INSTRUMENT_HOST_ID = "CO" INSTRUMENT_NAME = "MAGNETOSPHERIC IMAGING INSTRUMENT" INSTRUMENT_ID = "MIMI" OBJECT = ASCII_DOCUMENT DOCUMENT_NAME = "CHEMS ACCUMULATION ALGORITHM DESCRIPTION" DESCRIPTION = "(Title page information follows.) ---------------------------------------------------------------------- Cassini Mission Magnetospheric Imaging Instrument CHEMS Accumulation Algorithm Description Version 2.0 rev. February 28, 2005 J. W. Manweiler Fundamental Technologies, LLC Lawrence, KS 66046 ---------------------------------------------------------------------- " PUBLICATION_DATE = 2005-03-01 DOCUMENT_TOPIC_TYPE = "ALGORITHM SPECIFICATION" INTERCHANGE_FORMAT = ASCII DOCUMENT_FORMAT = TEXT END_OBJECT = ASCII_DOCUMENT END FILE CONTENTS: Calibration algorithm for PDS data products containing Cassini/MIMI/CHEMS accumulator rates AUTHOR: Jerry W. Manweiler, Ph.D., Fundamental Technologies, LLC DATE: 03/01/2005 INTRODUCTION: This file contains a text and pseudo code algorithm to provide a means to use the accumulator rates PDS data products for the determination of the health of the CHEMS instrument and underlying science rates algorithm performance. In high rate periods this data may be used to provide normalization of the science rates. ALGORITHM: For normalization: Compare the sum of the basic rates to the double or triple coincidence rates to develop proper ratios to correct the science rates CHEMS Accumulation rates data does not require any specific calibration information to verify and or validate science rates algorithm performance hence the each column in the associated calibration file CACC0_CALIB_0000.CSV have been intentionally left unpopulated. GENERAL Cassini/MIMI CALIBRATION: Each data product type in the PDS Cassini/MIMI Level 1A data set has two associated calibration files: a calibration algorithm file that is specific to each sensor and a calibration data file that is specific to the instrument. Each calibration algorithm file (this file) contains a text and pseudo code algorithm that describes how to calibrate the Level 1A data. The calibration data file is a CSV file that contains data values used in the algorithm described in the calibration algorithm file. All records for a data product type in the PDS level 1A files and the calibration data files have the same format. The first field in each record is the purpose field. The purpose field indicates the intended use of the record. For example records containing science data have a purpose field with the value "sci" and a record containing the geometrical factors of the detectors in a sensor would have "geom" in the purpose field. All MIMI calibration algorithm files use a short hand notation to refer to fields in the data products and calibration data files. This shorthand notation consists of an instrument/data type, a file type, a purpose field value, and a column description. This notation is used to specify types of fields, in types of records, in types of files. This notation allows the algorithm file to specify the relationship between types of fields in various files. The syntax and examples of this notation are given below. SHORTHAND NOTATION: ::::...: :[] where: = dp or cdp where dp = data product and cdp = calibration data product = CACC, CPHA, CSCI, IACC, IIMG, IPHA, IACC, LFRT. The cdp does not include a identifier. = a specification of a particular value of a row in order of left to right for those rows that apply. It is notec that not all rows apply for each value. Literal values of identifiers are placed in double quotation marks. Variable values are in parenthesis "( )". = a column identifier (label) to be used to select the final unique value based upon the combination of row identifiers and the specific column that has the data value. Literal values are placed in double quotation marks. Variable values are in parenthesis "( )". examples: dp:IACC:"sci":["Start_Ephemeris_s"] = The starting time of the record with a single row identifier of "sci" dp:IACC:"sci":("Start_Ephemeris_s"):[(datacolumntype)] = A field representing a specific column of counts for a record that includes "sci" and a starting time in the column that uses the literal for the start time in a column that identifies the source of the counts. geom_factor = cdf:"GEOM_FACTOR":"ACC":"INCA":"DETECTOR":("Particle"): ("Start_Year"):("Start_DDOY"):["midpoint_value"] = Select the value of the geometrical factor using the literal "GEOM_FACTOR", "ACC", "INCA", "DETECTOR" rows and the variable rows for start year and DDOY (decimal day of year) in the column of "midpoint_value".