96 lines
1.9 KiB
Markdown
96 lines
1.9 KiB
Markdown
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# GPS on CAN
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In this task you will need to receive Can-frames on the can-bus that contain the GPS location of the
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vehicle. The raw data has to be converted to arc-milliseconds
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1°2'5" == (1*3600+ 2*60 + 5)*1000
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**Beware that the system you are running your code on will not support floating point operations.
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Use only unsigned and signed integers!**
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Still the precision of your calculations has to be +-100 milli-arc-seconds
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Dynamic allocation is not supported on the system.
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You will have to complete the *GpsConverter.cpp* (and .h).
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## Conversion to Arc-Degree
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inDegree hex = 180/(2^31-1) * (hex) [°]
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#### HINT 1
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Try to use constants as much as possible, isntead of computing stuff on the go.
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#### HINT 2
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In order to aviod losing decimals first multiply with a large factor and then divide to get the result in ms.
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## GPS Datalayout in CAN Message
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Byte7 ST_LAT_NAVI
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Byte6 ST_LAT_NAVI
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Byte5 ST_LAT_NAVI
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Byte4 ST_LAT_NAVI
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Byte3 ST_LONG_NAVI
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Byte2 ST_LONG_NAVI
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Byte1 ST_LONG_NAVI
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Byte0 ST_LONG_NAVI
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## Byteorder
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Little Endian (Least Significant Byte is at lowest address)
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## Status Longitude Navigation
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ST_LONG_NAVI
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### Possible Values
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-180° ... +180°
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### Signal type
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32 Bit Signed Integer (Byte 0 ... Byte 3)
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### Invalid Data
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Invalid-Value: 80 00 00 00
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Signal not available value: 7F FF FF FF and FF FF FF FF
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**Do not forget to check for these values**
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## Status Latitude Navigation
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ST_LAT_NAVI
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### Possible Values
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-180° ... +180°
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### Signal type
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32 Bit Signed Integer (Byte 4 ... Byte 7)
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### Invalid Data
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Invalid-Value: 80 00 00 00h
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Signal not available value: 7F FF FF FF
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## Send the data over to the AC
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Use the *IGpsACPusher*.
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## Running the tests
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you will need a working ruby installation to execute the tests
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### run the tests
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execute `rake run` from this directory
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### Install the bake tool
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see https://esrlabs.com/gems/doc/bake-toolkit/
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