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AOC Slow Tape Format

AOC slow tapes record aircraft flight level data a 1 Hz frequency. The data are recorded as 16 bit HP words. Most of the data is recorded as integer counts and must be converted to volts and then to meaningful units. All of the navigation data is stored in a special format, and can only be read by performing special bit shifting operations. If examination of the raw navigation data is desired, ask AOC for a copy of the bit shifting subroutine called PACK.

Beginning with the 2000 Hurricane Season, locations 32-38 contain GPS data from the ASHTECH BR2G system (BR2G prefix).

This element table is for the NOAA42- N42RF-Aircraft during the 2003 Hurricane season, the Tamdar project, and a wind calibration flight.

LocationDescription
1Type of record (4)
2Number of words in record (222)
3MS byte: Slow tape ID
LS byte: Aircraft #
4Size of slow tape logical record = 220
5-10Micro 29 time - yr,mo,da,hr,mn,sc
11-13 Time based generator 1 - hr,mn,sc; binary (not BCD)
14-16 Time based generator 2 - same as TBG 1
17-19 GPS time of fix - hr, min,sec; same as TBG's
20-21 GPS altitude - MS bit = -102400*32 ft
22-23 GPS latitude - MS bit = -PI*4 radians
24-25 GPS longitude - MS bit = -PI*4 radians
26-27 GPS north vel. - MS bit = -1638.4*2 knots
28-29 GPS east vel. - MS bit = -1638.4*2 knots
30-31 GPS vert. vel. - MS bit = -2048*2 ft/s
32 BR2G GPS data Time; 0 - 3600, lsb = 1/100 sec
33 BR2G GPS Altitude; +/- 32767, lsb = 1 ft
34-35 BR2G GPS Latitude; msb = -PI*4 radians
36-37 BR2G GPS Longitude; msb = -PI*4 radians
38 BR2G GPS Status and Horiz Dilution of Precision
bits 15,14: 00 - no position, 01 - uncorrected,
10 - diff corrected, 11 - almanac used
bits 13 - 8: number of satellites used,
ls byte - HDOP 00 - 99
39 Spare
40 Astech GPS north accel. - MS bit = -128 m/s**2
41 Astech GPS east accel. - MS bit = -128 m/s**2
42 Astech GPS vert. accel. - MS bit = -128 m/s**2
43 Astech GPS Chan 1 status 1 (see rcvr 3M specs for bit assignments
44 Astech GPS Chan 1 status 2 (same as status 1)
45-52 Astech GPS Chan 2-5 status (same as chan 1 status 1&2)
53 Astech GPS Figure of Merit word - see rcvr 3M spec.
Note: Time FOM from word 64 is in reserved bits
(12,11,5,4 in HP notation; 3,4,10,11 in Astech
notation)
54 Astech GPS expected horiz error - lS bit = 1 meter
55 Astech GPS expected vert error - lS bit = 1 meter
56 Spare
57-58 INE 1 Altitude - MS bit = -102400*32 ft
59-60 INE 1 Latitude - MS bit = -PI*4 radians
61-62 INE 1 Longitude - MS bit =-PI*4 radians
63-64 INE 1 North Vel. - MS bit = -1638.4*2 knots
65-66 INE 1 East Vel. - MS bit = -1638.4*2 knots
67-68 INE 1 Vert speed - MS bit = -2048*2 ft/s
69-70 INE 1 Drift Angle - MS bit = -PI*4 radians
71-72 INE 1 Heading - MS bit = -PI*4 radians
73-74 INE 1 Pitch Angle - MS bit = -PI*4 radians
75-76 INE 1 Roll Angle - MS bit = -PI*4 radians
77-96 INE 2 Data - Same as INE 1
97 APN 232 RA data in meters; 1 sec avg
98 Spare; 1 sec avg
99 Spare; 1 sec avg
100 RA - APN159 Synchro data in meters; 1 sec avg
101 RA - APN159 digital encoder in meters
102 # of INE bursts av'd this sec; MS byte:INE 1
LS byte:INE 2
103 GPS RA burst count;
ms nybble - GPS lat/lon/alt burst count
2ND nyble - GPS velocity east/north/vert burst count
LS byte - RA number of words averaged this second.
104 # of ISEC word 98 and 99 samples avg this second;
ms byte- ISEC(98)
ls byte- ISEC(99)
105 Dig_Err: Error flags for Dig. Avg; bit 0
106 Spare
107 ADC unit status - from ADC slow data burst
108 IAU unit status - from IAU burst
109 Operator selections:
MS nybble - temp probe
nybble 2 - nav. unit
nybble 3 - alt. source
ls nybl - dewpoint unit
110 Status from Wing Wiring Junction Box
111 Status from Cloud Physics Station
112 Status from Flight Director Station
113 Spare
114 Event switch data - Nav, Sta1, Sta2, Sta3
115 Event switch data - Nrack, Sta5, C3X, Sta7
116 Event switch data - F/D, Pilot
117 Spare
118 Spare
119 Spare
120 Spare
121-129 Spare
130-140 Spare
141 M99 10 msec tic when time was read
- use for clock drift tracking
142 J-W Liquid water
143 RMST TOTAL TEMP #1 (TT1)
144 RMST TOTAL TEMP #2 (TT2)
145 GENERAL EASTERN DewPointer (DW1)
146 AP Differential Alpha (attack) Pressure
147 DAP Dynamic Alpha Pressure
148 BP Differential Beta (slip) Pressure
149 DBP Dynamic Beta (slip) pressure
150 PSW Rosemount static pressure from wingtip(#1281)
151 PQW Rosemount dynamic pressure from wingtip(#1281)
152 RD Radiometer Down measures SST (PRT-5)
153 Spare
154 RS Side Radiometer (CO2)
155 Spare
156 Vertical Acceleration 2
157 Vertical Acceleration 1
158 RADOME ATTACK PRESSURE
159 RADOME SIDESLIP PRESSURE
160 RADOME DIFF. PRESSURE (RPQ)
161 RADOME IMPACT PRESSURE
162 RMST TOTAL TEMP #3 (Radome)
163 Spare
164 Spare
165 Spare
166 Dewpoint #2 EdgeTech
167 Spare
168 Spare
169 Dewpoint #3 (DW3) MayCom Laser Hygro
170 TMPQ
171 TNDS
172 TW1PS
173 King Liquid water
174 PSF - Static Pressure COPILOT ROSEMOUNT #1281 (FUSELAGE)
175 PQF1 - COPILOT ROSEMOUNT #1281 (FUSELAGE)
176 PQF2 - COPILOT ROSEMOUNT #1221F(FUSELAGE)
177 AFT FIELDMILL SENSITIVE
178 AFT FIELDMILL INSENSITIVE
179 AFT FIELDMILL SUPER INSENSITIVE
180 FIELDMILL HVPS CURRENT
181 FIELDMILL HVPS VOLTAGE
182 RIGHT FIELDMILL SENSITIVE
183 RIGHT FIELDMILL INSENSITIVE
184 RIGHT FIELDMILL SUPER INSENSITIVE
185 UP FIELDMILL SENSITIVE
186 UP FIELDMILL INSENSITIVE
187 UP FIELDMILL SUPER INSENSITIVE
188 Spare
189 Cabin Pressure (RSMT 1201F)
190 AXBT CHANNEL #1
191 AXBT CHANNEL #2
192 AXBT CHANNEL #3
193 OZONE TECO CARSEY
194 Spare
195 Spare
196 Spare
197 Spare
198 Spare
199 Spare
200 Spare
201 Spare
202 Spare
203 Spare
204 Spare
205 Up PRT-5 Radiometer
206-214 Spare
215 DOWN FIELDMILL SENSITIVE
216 DOWN FIELDMILL INSENSITIVE
217 DOWN FIELDMILL SUPER INSENSITIVE
218 LEFT FIELDMILL SENSITIVE
219 LEFT FIELDMILL INSENSITIVE
220 LEFT FIELDMILL SUPER INSENSITIVE
221 Spare
222 Checksum for this second
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