Example for ETSI CAM-ASN1 to Json Command

[patrizianeubauer]

Hi,

could you please provide an example, how to run your project to generate json files from the asn-files for example with your cam_pdu_descriptions_1_3_2.asn file?

Thank you!

Kind regards,
Patrizia

[nemesis03]

@patrizianeubauer
I also had trouble getting this to work. I found the following solution:
Get the current asn-file for CAM: https://forge.etsi.org/rep/ITS/asn1/cam_en302637_2/-/blob/master/CAM-PDU-Descriptions.asn (saved as "CAM-PDU-Descriptions.asn")
Get the ITS-Container in version v1.3.1: https://forge.etsi.org/rep/ITS/asn1/cdd_ts102894_2/-/blob/v1.3.1/ITS-Container.asn (saved as "ITS-Container.asn")

import base64
import asn1tools
files = ['CAM-PDU-Descriptions.asn','ITS-Container.asn']
cam = asn1tools.compile_files(files, 'uper')
s_base64="AgINl1aLXpNAWrOG4g4oO3viNCMMSDOWUFh5cKJYfgKWilc3/un/6iA//5RZgQJeAMyAFdjOAATwOlwGSsZwAVOB2WAyljOACewO/QGbMZwAT+B6eA0FjOACfwOhQGLsgAAS2BzOAwdjOACTwPHwGMsZwAUOB1iAy5jOACewOlQGbsZwAT+B4qAzZjOACqA="
cam.decode('CAM',base64.b64decode(s_base64))

The string s_base64 contains the base64 encoded ITS data (in my case exported from wireshark). It will return a python struct:
{'header': {'protocolVersion': 2, 'messageID': 2, 'stationID': 228021899}, 'cam': {'generationDeltaTime': 24211, 'camParameters': {'basicContainer': {'stationType': 5, 'referencePosition': {'latitude': 536301072, 'longitude': 100141535, 'positionConfidenceEllipse': {'semiMajorConfidence': 282, 'semiMinorConfidence': 280, 'semiMajorOrientation': 1572}, 'altitude': {'altitudeValue': 5650, 'altitudeConfidence': 'alt-005-00'}}}, 'highFrequencyContainer': ('basicVehicleContainerHighFrequency', {'heading': {'headingValue': 1943, 'headingConfidence': 6}, 'speed': {'speedValue': 1200, 'speedConfidence': 127}, 'driveDirection': 'forward', 'vehicleLength': {'vehicleLengthValue': 42, 'vehicleLengthConfidenceIndication': 'trailerPresenceIsUnknown'}, 'vehicleWidth': 18, 'longitudinalAcceleration': {'longitudinalAccelerationValue': -11, 'longitudinalAccelerationConfidence': 102}, 'curvature': {'curvatureValue': 1023, 'curvatureConfidence': 'unavailable'}, 'curvatureCalculationMode': 'unavailable', 'yawRate': {'yawRateValue': -4, 'yawRateConfidence': 'unavailable'}, 'accelerationControl': (b'\x80', 7), 'steeringWheelAngle': {'steeringWheelAngleValue': 0, 'steeringWheelAngleConfidence': 127}, 'lateralAcceleration': {'lateralAccelerationValue': 2, 'lateralAccelerationConfidence': 102}}), 'lowFrequencyContainer': ('basicVehicleContainerLowFrequency', {'vehicleRole': 'default', 'exteriorLights': (b'\x81', 8), 'pathHistory': [{'pathPosition': {'deltaLatitude': 205, 'deltaLongitude': 88, 'deltaAltitude': 0}, 'pathDeltaTime': 20}, {'pathPosition': {'deltaLatitude': 1868, 'deltaLongitude': 806, 'deltaAltitude': 0}, 'pathDeltaTime': 170}, {'pathPosition': {'deltaLatitude': 1894, 'deltaLongitude': 810, 'deltaAltitude': 0}, 'pathDeltaTime': 159}, {'pathPosition': {'deltaLatitude': 1919, 'deltaLongitude': 823, 'deltaAltitude': 0}, 'pathDeltaTime': 160}, {'pathPosition': {'deltaLatitude': 1960, 'deltaLongitude': 834, 'deltaAltitude': 0}, 'pathDeltaTime': 160}, {'pathPosition': {'deltaLatitude': 1859, 'deltaLongitude': 792, 'deltaAltitude': 100}, 'pathDeltaTime': 151}, {'pathPosition': {'deltaLatitude': 1844, 'deltaLongitude': 776, 'deltaAltitude': 0}, 'pathDeltaTime': 148}, {'pathPosition': {'deltaLatitude': 1936, 'deltaLongitude': 794, 'deltaAltitude': 0}, 'pathDeltaTime': 162}, {'pathPosition': {'deltaLatitude': 1881, 'deltaLongitude': 815, 'deltaAltitude': 0}, 'pathDeltaTime': 159}, {'pathPosition': {'deltaLatitude': 1867, 'deltaLongitude': 824, 'deltaAltitude': 0}, 'pathDeltaTime': 160}, {'pathPosition': {'deltaLatitude': 1931, 'deltaLongitude': 823, 'deltaAltitude': 0}, 'pathDeltaTime': 171}]})}}}

to export as JSON i issued the following commands

jer = asn1tools.compile_files(files, 'jer')
jer.encode('CAM', cam.decode('CAM',base64.b64decode(s_base64)))

Unfortunately there is an issue with the conversin of "accelerationControl" and "exteriorLights". The hex value from the struct ("\x80") is converted to a decimal value "80". So you have to be careful to treat this value as a hex value.

It is also possible to decode MAPEM and SPATEM messages. You only need the corresponding files:
https://forge.etsi.org/rep/ITS/asn1/is_ts103301/-/blob/release2/MAPEM-PDU-Descriptions.asn
https://forge.etsi.org/rep/ITS/asn1/is_ts103301/-/blob/release2/SPATEM-PDU-Descriptions.asn
https://forge.etsi.org/rep/ITS/asn1/is_ts103301/-/blob/release2/DSRC.asn
https://forge.etsi.org/rep/ITS/asn1/cdd_ts102894_2/-/blob/release2/ETSI-ITS-CDD.asn

import base64
import asn1tools
files = ['MAPEM-PDU-Descriptions.asn','DSRC.asn','ETSI-ITS-CDD.asn']
mapem = asn1tools.compile_files(files, 'uper')
s_base64="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"
mapem.decode('MAPEM',base64.b64decode(s_base64))

import base64
import asn1tools
files = ['SPATEM-PDU-Descriptions.asn','DSRC.asn','ETSI-ITS-CDD.asn']
spatem = asn1tools.compile_files(files, 'uper')
s_base64="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"
spatem.decode('SPATEM',base64.b64decode(s_base64))

You have to figure out whether your data is CAM or MAPEM or SPATEM.

An alternative might be to use tshark (e.g. "tshark -r dump.pcap -T json"). The advantage is that some values are split into their meaning:

                  "cam.accelerationControl": "40",
                  "cam.accelerationControl_tree": {
                    "its.AccelerationControl.brakePedalEngaged": "0",
                    "its.AccelerationControl.gasPedalEngaged": "1",
                    "its.AccelerationControl.emergencyBrakeEngaged": "0",
                    "its.AccelerationControl.collisionWarningEngaged": "0",
                    "its.AccelerationControl.accEngaged": "0",
                    "its.AccelerationControl.cruiseControlEngaged": "0",
                    "its.AccelerationControl.speedLimiterEngaged": "0"
                  },