******************************************************************************** PVMOV ******************************************************************************** Not accessible thru the PDS catalog system-Contact Node. This program is run at the University of California, Los Angeles. It reads the EDR tape and makes a set of disk files containing the OMAG and OEFD data. It also reads the SEDR tape and makes a disk file containing the ephemeris data, the pulse time data, and the selected roll reference (SRR or SR14) data. The software is no accessible through the PDS catalog system - contact Node. ******************************************************************************** PVO ******************************************************************************** Not accessible thru the PDS catalog system-Contact Node. PVO is a C-shell script which calls a series of Fortran programs in which process the OMAG, OEFD and Ephemeris data files. It reads a set of input files created by the program PVMOV, and generates a set of output files. For the Magnetometer, the process of converting the raw sensor data to orthogonal vector components includes the following steps: 1. Remove the average of the T sensor, computed over an integral number of spin periods. The spacecraft spin period information is contained in the PVO Supplemental Experimenter Data Record. 2. Convert the sensor data to orthogonal components using a coupling matrix, whose elements are calculated, to first order, from the physical orientation of the sensors. 3. The coupling matrix and spacecraft interference parameters are adjusted by monitoring any DC amplitude and the relative phase and amplitude of the spin plane components, and any spin period modulation of the spin-aligned component. 4. The amplitude of the transverse waves in the interplanetary medium is much greater than that of compressional waves, and so the amplitude of the magnetic field remains roughly constant when the field direction changes. This behavior was used to determine the zero level of the magnetometer, which was found to be Zoff = (.13 nT - .005 nT / year) for the years 1979-1984. Approximate values and ranges of the magnetometer parameters: T sensor offset: 2.5 nT +- 1 nT Spacecraft field contribution to G sensor: 3 nT +- 1 nT G sensor offset: -10nT +- 2 nT after orbit 2205, Dec 18, 1984 P sensor offset: .13nT - .005 nT/year T and G sensors have not been functioning after orbit 3602, Oct 16, 1988. We have attempted to determine the spin plane components of the magnetic field from this data, at one hour resolution, using an observed tilt of .14 degrees of the P sensor away from the spin axis. However, this technique has possible problems such as errors from a wondering spin axis relative to the geometric axis. For the Electron Field Detector (OEFD), the data processing steps are: 1. Convert the eight bit digitized output from the Automatic Gain Controllers (range 0 to 255) to an AGC voltage (range 0 to 5V) for each channel. 2. Convert the AGC voltage to a wave amplitude in V/m/root(Hz) using preflight calibration data for each channel. 3. Convert the wave amplitude to a power (amplitude squared) if it's required. 4. Use the spacecraft orientation information to calculate the antenna phase for each channel. The phase is corrected for difference in sampling times. For the Ephemeris data the processing steps are: 1. Read in the raw ephemeris file created by PVMOV which contains the entire ephemeris data portion of the SEDR and extract the following components: (8) is the distance from the sun to the spacecraft. (11) is the celestial lat. of the spacecraft, in degrees. (12) is the celestial long. of the spacecraft, in degrees. (13) is the celestial lat. of earth. (14) is the celestial long. of earth. (32-34) are Venus-spacecraft radius vector (63-65) are the spin axis X Y Z in spacecraft centered non-rotating coordinates (92-94) are the solar position wrt Venus. (95-97) are the solar velocity wrt Venus. 2. Convert Venus-spacecraft range to altitude by subtracting 6050 and the Sun-spacecraft rage to A.U. by dividing by 149,674,000 3. Construct a VSO rotation matrix from the solar position and velocity of Venus 4. Rotate the Venus-Spacecraft and spin axis vectors into VSO coordinates"