GOES-7

Most GOES-7 data after 24 March 1987 (Julian day 87083) is AAA. This section documents the mode AAA for the IR and VAS instruments. Word 52 of the area directory contains the source type AAA.

The VAS senses the atmosphere for a given spatial location in up to 12 different IR spectral bands and one visible band. All or some of the IR bands may be included in a single VAS type area. The visible, however, may be contained in a separate area of VISR type. As a result, it may require two areas to contain the total information transmitted by the satellite during a given time period.

Word	Value	Description
14		number of spectral bands
19		band filter map; a bit is set to one for each band appearing in the area
52	AAA	image source type; 4 bytes ASCII
53	RAW	calibration type; 4 bytes ASCII

GOES-7 AAA data block

The line prefix consists of a 4-byte validity code, 512 bytes of IR common documentation, and 116 bytes of VAS calibration information organized as follows.

Bytes	Description
4	day, yyddd
4	time of the scan, hhmmss
4	scan number (satellite coordinate line number)
104	13 eight-byte groups (1 per possible band) each containing: channel number - 2-byte binary integer (see the table on the next page) number of spins - 2-byte binary integer unused - 4 bytes

The line prefix also contains 4, 8, 12 or 16 bytes of band list information; one byte for each band plus up to three bytes to round to the nearest whole word.

The structure of a VAS area is complicated by two facts:

Every line may not contain all the spectral bands indicated in the band map (word 19 in the directory block).
The order of the bands may not be the same on every line.

What does appear on a given line is indicated in the band list section, which acts as an index for the line. Only the leftmost n bytes of the band list contain nonzero data, with n being the actual number of bands contained in each element of the line. The I th byte of the band list corresponds to the I th 16-bit pixel in each element of the line. Unused band list bytes are filled with binary zeros; the data in the unused pixel locations may not be zero, but in any case should be ignored.

The channel numbers range from 1 to 38; channel 39 exists but has never been put into service. Each is described in the table below.

Channel	Detector	Size	Location	Spectral band
1	HGCDTE	large	upper	1
2	HGCDTE	large	upper	2
3	HGCDTE	large	upper	3
4	HGCDTE	large	upper	4
5	HGCDTE	large	upper	5
6	INSB	large	upper	6
7	HGCDTE	large	upper	7
8	HGCDTE	large	upper	8
9	HGCDTE	large	upper	9
10	HGCDTE	large	upper	10
11	INSB	large	upper	11
12	INSB	large	upper	12
13	HGCDTE	large	lower	1
14	HGCDTE	large	lower	2
15	HGCDTE	large	lower	3
16	HGCDTE	large	lower	4
17	HGCDTE	large	lower	5
18	INSB	large	lower	6
19	HGCDTE	large	lower	7
20	HGCDTE	large	lower	8
21	HGCDTE	large	lower	9
22	HGCDTE	large	lower	10
23	INSB	large	lower	11
24	INSB	large	lower	12
25	HGCDTE	small	upper	3
26	HGCDTE	small	upper	4
27	HGCDTE	small	upper	5
28	HGCDTE	small	upper	7
29	HGCDTE	small	upper	8
30	HGCDTE	small	upper	9
31	HGCDTE	small	upper	10
32	HGCDTE	small	lower	3
33	HGCDTE	small	lower	4
34	HGCDTE	small	lower	5
35	HGCDTE	small	lower	7
36	HGCDTE	small	lower	8
37	HGCDTE	small	lower	9
38	HGCDTE	small	lower	10

For a given spectral band, only one detector size is used in an area. However, two channels representing different positions of the detector for a particular band may appear in a single area although they may not appear on the same line. For example, channels 8 and 20 may appear in the same area, but not channels 8 and 36.

GOES-7 AAA navigation block

Unless otherwise noted, the words in the GOES-7 navigation block are twos-complement binary integers.

Word	Value	Description
1	GOES	navigation type (ASCII characters)
2		satellite ID, year, and Julian day, ssyyddd
3		nominal start time of the image, hhmmss
4 - 12 4 5 6 7 8 9 10 11 12	1	orbit parameters orbit type epoch date (ETIMY), yymmdd epoch time (ETIMH), hhmmss semimajor axis (SEMIMA), km * 100 orbital eccentricity (ECCEN) * 1000000 (unitless) orbital inclination (ORBINC), deg * 1000 mean anomaly (MEANA), deg * 1000 argument of perigee (PERIGEE), deg * 1000 right ascension of ascending node (ASNODE), deg * 1000
13 - 15 13 14 15		attitude parameters declination of satellite axis (DECLIN), dddmmss (+=north) right ascension of satellite axis (RASCEN), dddmmss picture center line number (PICLIN)
16		spin period (SPINP); the satellite period, in microseconds, or the spin rate in revolutions/minute
17 - 20 17 18 19 20		frame geometry total sweep angle, line direction (DEGLIN), dddmmss number of scan lines (LINTOT), nnlllll where nn is the number of sensors and lllll is the number of scans; total number of lines is nn * lllll total sweep angle, element direction (DEGELE), dddmmss number of elements in a scan line (ELETOT)
21 - 30 21 22 23 24 25 26 27 28 29 30	0	camera geometry forward-leaning (PITCH), dddmmss sideways-leaning (YAW), dddmmss rotation (ROLL), dddmmss reserved east/west adjustment (IAJUST) in visible elements (+ or -) time computed by IAJUST from the first valid landmark of the day (IAJTIM), hhmmss reserved angle between VISSR and sun sensor (ISEANG), dddmmss reserved for later implementation of SKEW reserved
31 - 38 31 32 33 34 35 36 37 38		betas for this area scan line of the first beta time of the first beta scan line (beginning), hhmmss time of the first beta scan line (continued), milliseconds10 beta count 1 scan line of the second beta time of the second beta scan line (beginning), hhmmss time of the second beta scan line (cont.), milliseconds10 beta count 2
39-128 39 40 41-120 121-128		gammas for this area gamma, element offset * 100; this is the nominal offset at time zero of this day gamma-dot, element drift per hour * 100 reserved memo; up to 32 ASCII characters of comments

Word	Value	Description
1		sensor source number
2		date, yyddd
3		time, hhmmss
4 - 9		radiance equation coefficients, array IAB(2,38)
80 - 117		radiance equation coefficients scale factors, IFAB(38)
118-128	0

McIDAS Programmer's Manual

GOES-7

GOES-7 AAA directory block

GOES-7 AAA data block

GOES-7 AAA navigation block

GOES-7 AAA calibration block