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Template:FMX640 Short Burst Data (view source)
Revision as of 14:17, 5 September 2022
, 14:17, 5 September 2022no edit summary
[[File:FMB640 iridium1.png]]
[[File:FMB640 iridium1.png]]
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In scenario shown in above picture when panic record is made (generated by Digital Input 1 or Digital Input 2) internal 90 seconds timer will start to tick and if in that timeout device will not send record through GPRS network it will be sent with Iridium satellites
In scenario shown in above picture when panic record is made (generated by ''Digital Input 1'' or ''Digital Input 2'') internal 90 seconds timer will start to tick and if in that timeout device will not send record through GPRS network it will be sent with Iridium satellites.
===SDB record structure===
SDB Record which will be sent through Iridium satellites network will be different than the regular record. It will contain: 4 bytes timestamp, 3 bytes longitude, 3 bytes latitude, 1 byte record generation info, 1 byte DIN,DOUT info, 1 byte Speed value.
{| class="wikitable" style="font-weight:bold;"
|-
! Timestamp
! Longitude
! Latitude
! SDB AVL ID and flags
! DIN/DOUT info
! Reserved
! Speed
|- style="font-weight:normal; text-align:center;"
| 4B
| 3B
| 3B
| 1B
| 1B
| 1B
| 1B
|}
''Longitude'' in this packet is encoded in 3 bytes data. Server which gets this data should divide result from 46603,375 and subtract 180 in order to get actual longitude value. This coefficient is got in following way: 16777215(maximum 3 bytes value) divided from 360 (maximum longitude value then 180 is added). This calculation is used to fit negative and positive values to 3 bytes width variable.
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''Latitude'' is calculated in same way as longitude but since latitude maximum value is two times smaller than longitude it can produce a bit more accurate data. Coefficient for latitude is 93206,75. This coefficient is got in following way: 16777215(maximum 3 bytes value) divided from 180 (maximum latitude value then 90 is added). This calculation is used to fit negative and positive values to 3 bytes width variable.