TransmitterPDU data appears to be misinterpreted.

[HalRules]

I’ve been getting a “Malformed Packet" message from the TransmitterPdu Class that I believe is interpreting the data incorrectly.

The Modulation Parameter length field (as listed in the online DIS Data Dictionary) should represent the SIZE of parameter data and not the parameter COUNT.

Specifically, IEEE 1278.1 states that the field “shall specify the length in octets of the modulation parameters that follow this field”.

This aligns with data that I have been reviewing. While it’s true that modulation parameter fields are supposed to be 2 bytes, it appears as though the data is interpreted differently depending on the modulation type in practice.

I’ve seen no data that includes Antenna Parameters, but it appears to me as though the Antenna Pattern Length Field should also represent total data size instead of the number of antenna patterns.

"This field shall specify the length in octets of the Antenna Pattern Parameters field. "

I would suggest the following changes:
antennaPatternCount should be changed to antennaPatternSize
modulationParameterCount should be changed to modulationParameterSize
mod_bytes should always be 1 (or removed altogether)
I haven’t any data to confirm, but I think “range(0, self.antennaPatternCount)” should probably be changed to “range(0, self.antennaPatternCount//39)” as well.

I've made not specific changes myself other than to change mod_bytes to 1 when it has a value larger than 2 so that I can interpret the data.

[HalRules]

The code I'm referring to is in the Parse method of the TransmitterPdu class around line 5538 of dis7.py.
Please be patient with me since I'm not adept at git.

[ngjunsiang]

This issue would benefit from the work being done on handling boundary padding in #53. It documents the MP records that would be required.

To handle modulation parameters as records in their own right and not an array of values, it will require the work being done in #73