PDS_VERSION_ID = PDS3
DATA_SET_ID = {"GO-J-PWS-2-REDR-LPW-SA-FULL-V1.0",
"GO-J-PWS-2-REDR-RTS-SA-FULL-V1.0"}
RECORD_TYPE = STREAM
OBJECT = TEXT
INTERCHANGE_FORMAT = ASCII
PUBLICATION_DATE = 1998-02-20
NOTE = "This is a format description of Galileo
PWS reformatted full-resolution spectrum analyzer (lrs) archive files.
This information is reproduced in PDS structure in associated 'safull.fmt'
files."
END_OBJECT = TEXT
END
Notes on full-resolution Galileo PWS LRS archival format
The Galileo PWS full-resolution LRS data are organized into the following
archival format for ease of use. Each 600-byte fixed-length record contains
data from available minor frames in a 28-minor-frame instrument cycle. During
this cycle, all available frequencies are sampled and two snapshots of
waveform data are taken. Items named "validity flags" are derived from the
8-bit data quality (DQ) word in the PWS minor frame which contains even parity
bits corresponding to the associated data items.
All multi-byte binary items are "big-endian" or high-byte-first unless noted
otherwise. Bits are numbered starting with 0 as the least significant (lowest
order or rightmost) bit up to 7 as the most significant (highest order or
leftmost) bit for 8-bit bytes or, for example, up to 31 for 4-byte binary
items.
HEADER SECTION, 44 bytes
byte
offset description
------ ---------------------------------------------------------------------
0 32-character string like "GO PWS 1996-06-27T00:00:00.000Z\0"
where the numbers represent the SCET of the beginning of the interval
(28 minor frame cycle) in PDS time format and the last character is
ASCII null "\0" (binary zero).
SCLK marking the beginning of a 28-minor-frame interval of PWS data
32 3-byte binary SCLK RIM count (24-bit unsigned range: 0 - 16777215)
35 1-byte binary SCLK minor frame count (modulo 91 counter: 0 - 90)
36 2-byte spare
SCET corresponding to above SCLK
38 2-byte binary days since January 1, 1958
40 4-byte binary millisecond of day (0 - 86401999, for 2 leap seconds)
TIME-ORDERED STATUS SECTION, 52 bytes
byte
offset description
------ ----------------------------------------------------------------------
44 32-bit minor frame presence flags.
In general, minor frame presence is indicated by a 1 in the
corresponding bit position. hexadecimal value 00000001 indicates
only the first minor frame is present, while 08000000 indicates only
the 28th minor frame is present, and 0FFFFFFF indicates all 28 minor
frames are present.
48 32-bit spectrum analyzer antenna switch flags.
The antenna switch position is logged for each minor frame and stored
in a bit position corresponding to the minor frame modulo 28 counter,
as in the previous item. Normally this will be hexadecimal 00000000
for all electric field minor frames or 0FFFFFFF for all magnetic
field minor frames.
52 Array of 7 8-bit command words obtained during the 28-minor-frame
cycle. A complete 8-bit command word is obtained for each 4
consecutive minor frames: Bits 7 and 6 are obtained during the first
minor frame, bits 5 and 4 during the second minor frame, bits 3 and 2
during the third minor frame, and bits 1 and 0 during the fourth minor
frame. The bits are specified as follows:
+---+---+---+---+---+---+-------+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 0 | PWS 8-bit command word
+---+---+---+---+---+---+-------+
bit description bit = 0 bit = 1
--- --------------------------------- -------------- --------------
7 waveform command enable inhibit
6 sa antenna switch e/b electric magnetic
5 sa antenna switch cyc/inh cycle inhibit
4 calibration inhibit enable
3 waveform select electric magnetic
2 waveform power on off
1-0 2-bit waveform receiver mode (0 - 3)
00 = waveform survey (alternating 1kHz and 10kHz snapshots)
01 = 25200 4-bit samples per second (50Hz - 10kHz mode)
10 = 201600 4-bit samples per second (80kHz mode)
11 = 3150 4-bit samples per second ( 5Hz - 1kHz mode)
59 Array of 7 8-bit WBR automatic gain control (AGC)
Indicates gain of wideband receiver. Can be used to calibrate WBR
data.
Relative to the beginning of the record (28-minor-frame interval),
the individual AGC sample times occur at -0.467s (-7 RTI) and every
2.667s (40 RTI) thereafter (where an RTI is one tenth of the minor
frame interval).
66 Array of 7 8-bit power supply monitor (PS MON)
Indicates health of instrument. Nominal value is 204 +/- 2.
Relative to the beginning of the record (28-minor-frame interval),
the individual PS MON sample times occur at +2.0s (+3 RTI) and every
2.667s (40 RTI) thereafter (where an RTI is one tenth of the minor
frame interval).
73 Array of 7 8-bit "8-bit ADC REF"
Indicates health of 8-bit analog to digital converter.
Nominal value is 55 +/- 2.
Relative to the beginning of the record (28-minor-frame interval),
the individual "8-bit ADC REF" sample times occur at +0.867s (+13 RTI)
and every 2.667s (40 RTI) thereafter (where an RTI is one tenth of
the minor frame interval).
80 Array of 7 8-bit "4-bit ADC REF"
Indicates health of 4-bit analog to digital converter.
Nominal value is 102 +/- 2.
Relative to the beginning of the record (28-minor-frame interval),
the individual "4-bit ADC REF" sample times occur at +1.533s (+23 RTI)
and every 2.667s (40 RTI) thereafter (where an RTI is one tenth of
the minor frame interval).
87 Array of 7 8-bit analog engineering status validity flags.
Four flags are present in each byte:
+---+---+---+---+---+---+---+---+
| x x x x | 3 | 2 | 1 | 0 | Analog Eng validity flags
+---+---+---+---+---+---+---+---+
bit description bit = 0 bit = 1
--- --------------------------------- -------------- --------------
3 "4-bit ADC REF" flag invalid valid
2 "8-bit ADC REF" flag invalid valid
1 "PS MON" flag invalid valid
0 "AGC" flag invalid valid
94 An 8-bit value giving the post-compression data rate.
The targeted data rate determines a quantization factor
in the compression algorithm. Also indicated is whether
the packet is normal or continuation and whether or not
the data was compressed.
bit pattern description
------------ --------------------
xxxx0xxx Normal packet
xxxx1xxx Continuation packet
xxxxx000 3 bits per second
xxxxx001 5 bits per second
xxxxx010 10 bits per second
xxxxx011 15 bits per second
xxxxx100 20 bits per second
xxxxx101 30 bits per second
xxxxx110 40 bits per second
11111111 No compression
95 1-byte spare
FREQUENCY-ORDERED STATUS SECTION, 28 bytes
byte
offset description
------ ----------------------------------------------------------------------
96 Array of 4 8-bit spectrum analyzer (SA) validity flags.
Each of the 4 channels is sampled 7 times during the record. The
validity of the first sample is indicated by bit 0, the second by bit
1, and so on up to the seventh sample by bit 6. A one bit indicates
available data that passes the parity check. The four bytes contain
flags for the four channels in increasing frequency order from the
first channel at 5.62 Hz to the fourth channel at 31.1 Hz.
+---+---+---+---+---+---+---+---+
| x | 6 | 5 | 4 | 3 | 2 | 1 | 0 | flag bit position
+---+---+---+---+---+---+---+---+
1 1 1 1 1 1 1 SA channel 1
.
.
.
+---+---+---+---+---+---+---+---+
| x | 6 | 5 | 4 | 3 | 2 | 1 | 0 | flag bit position
+---+---+---+---+---+---+---+---+
4 4 4 4 4 4 4 SA channel 4
100 Array of 4 32-bit sweep frequency receiver (SFR) validity flags.
Each individual channel of the SFR is sampled only once during
the record. These flags are grouped by filter bank of which there
are four of 28 channels each, ordered by increasing frequency. The
first 32-bit group contains validity flags for the lowest frequency
bank and the fourth 32-bit group contains flags for the highest
frequencies. The flags are arranged in each 4-byte element
(32-bit group) such that the lowest frequency is represented by
bit 0 and the highest frequency by bit 27, hence the hexadecimal
value 0FFFFFFF in an element indicates valid values for all 28
associated frequency channels.
+---+---+---+---+---+ +---+
| x x x x | 27| . . . | 0 | validity flag bit position
+---+---+---+---+---+ +---+
28 . . . 1 SFR channels 1 - 28
.
.
.
+---+---+---+---+---+ +---+
| x x x x | 27| . . . | 0 |
+---+---+---+---+---+ +---+
112 . . . 85 SFR channels 85 - 112
116 Array of 2 32-bit high frequency receiver (HFR) validity flags.
The lowest 14 HFR channels are sampled twice each and the upper
28 HFR channels are sampled once each during the record interval.
The first 4-byte element contains pairs of flags for each of the
lower 14 HFR channels and the second 4-byte element contains
individual flags for each of the upper 28 HFR channels. A 1 bit
indicates available data which passes the parity check.
+---+---+---+---+---+---+ +---+---+
| x x x x | 27| 26| . . . | 1 | 0 | flag bit position
+---+---+---+---+---+---+ +---+---+
14 14 . . . 1 1 HFR channels 1 - 14
+---+---+---+---+---+---+ +---+---+
| x x x x | 27| 26| . . . | 1 | 0 | flag bit position
+---+---+---+---+---+---+ +---+---+
42 41 . . . 16 15 HFR channels 15 - 42
LRS DATA SECTION, 196 bytes
byte
offset description
------ ----------------------------------------------------------------------
124 Array of 28 8-bit spectrum analyzer (SA) uncalibrated samples.
These consist of 7 time-ordered samples for channel 1 followed
by 7 samples from channel 2, followed by 7 samples from channel 3,
and finally 7 samples from channel 4.
Relative to the beginning of the record (28-minor-frame interval),
the sample times of the individual channels are:
SA channel relative sample time (10 RTI per minor frame)
---------- ----------------------------------------------------------
1 +1.867s (+28 RTI), repeating every 2.667s (40 RTI)
2 +1.200s (+18 RTI), repeating every 2.667s (40 RTI)
3 +0.533s (+08 RTI), repeating every 2.667s (40 RTI)
4 -0.133s (-02 RTI), repeating every 2.667s (40 RTI)
152 Array of 112 8-bit sweep frequency receiver (SFR) uncalibrated
samples. These are arranged from lowest to highest frequency
channels.
Relative to the beginning of the record (28-minor-frame interval),
the sample times of the individual channels are:
SFR channel relative sample time (10 RTI per minor frame)
----------- ---------------------------------------------------------
1+n, 29+n -0.133s + n*0.667s (-02 RTI + n RTI), for n = 0 .. 27
57+n, 85+n -0.467s + n*0.667s (-07 RTI + n RTI), for n = 0 .. 27
264 Array of 56 8-bit high frequency receiver (HFR) uncalibrated samples.
The lowest 14 channels are repeated twice, followed by the upper
28 channels: 1, 1, 2, 2, . . ., 14, 14, 15, 16, . . ., 41, 42
Relative to the beginning of the record (28-minor-frame interval),
the sample times of the individual channels are:
HFR channel relative sample time (10 RTI per minor frame)
----------- ---------------------------------------------------------
1+n two samples at -0.133s + n*2.667s and +0.533s + n*2.667s
(-02 RTI + n*40 RTI and +08 RTI + n*40 RTI),
for n = 0 .. 6
8+n two samples at +1.200s + n*2.667s and +1.867s + n*2.667s
(+18 RTI + n*40 RTI and +28 RTI + n*40 RTI),
for n = 0 .. 6
15+n -0.467s + n*2.667s (-07 RTI + n*40 RTI), for n = 0 .. 6
22+n +0.200s + n*2.667s (+03 RTI + n*40 RTI), for n = 0 .. 6
29+n +0.867s + n*2.667s (+13 RTI + n*40 RTI), for n = 0 .. 6
36+n +1.533s + n*2.667s (+23 RTI + n*40 RTI), for n = 0 .. 6
WAVEFORM SAMPLE DATA SECTION, 280 bytes
byte
offset description
------ ----------------------------------------------------------------------
320 Array of 280 4-bit waveform samples collected from the first 14
minor frames of this record. This is a snapshot of contiguous
samples.
+---+---+---+---+---+---+---+---+ -+---+---+---+---+
| 3 | 2 | 1 | 0 | 3 | 2 | 1 | 0 | . . . | 3 | 2 | 1 | 0 |
+---+---+---+---+---+---+---+---+ -+---+---+---+---+
sample 1, sample 2, . . . sample 280
Relative to the beginning of the record (28-minor-frame interval),
this waveform sample begins at -0.333s (-05 RTI).
460 Array of 280 4-bit waveform samples collected from the last 14
minor frames of this record. This is a snapshot of contiguous
samples.
Relative to the beginning of the record (28-minor-frame interval),
this waveform sample begins at +9.000s (+135 RTI).
------
600 bytes total