StringIndexOutOfBoundsException

I have in my log some of this warnings:

2019-03-20 01:24:54  INFO: [a340e9d5: 5001 < 71.6.135.131] HEX: 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
2019-03-20 01:24:54  WARN: [a340e9d5] error - begin 21, end 23, length 20 - StringIndexOutOfBoundsException (... < Gps103ProtocolDecoder:411 < ExtendedObjectDecoder:51 < ... < WrapperContext:102 < ...)
2019-03-20 03:02:20  INFO: [ac4458ff: 5001 < 46.17.47.202] HEX: 474554202f7265636f7264696e67732f20485454502f312e310d0a486f73743a203138382e39332e3232372e3137353a353030310d0a436f6e6e656374696f6e3a206b6565702d616c6976650d0a4163636570742d456e636f64696e673a20677a69702c206465666c6174650d0a4163636570743a202a2f2a0d0a557365722d4167656e743a20707974686f6e2d72657175657374732f322e32302e310d0a0d0a
2019-03-20 03:02:20  WARN: [ac4458ff] error - begin 21, end 23, length 9 - StringIndexOutOfBoundsException (... < Gps103ProtocolDecoder:411 < ExtendedObjectDecoder:51 < ... < WrapperContext:102 < ...)
2019-03-20 03:02:20  WARN: [ac4458ff] error - begin 21, end 23, length 2 - StringIndexOutOfBoundsException (... < Gps103ProtocolDecoder:411 < ExtendedObjectDecoder:51 < ... < WrapperContext:102 < ...)
2019-03-20 03:02:20  WARN: [ac4458ff] error - begin 21, end 23, length 2 - StringIndexOutOfBoundsException (... < Gps103ProtocolDecoder:411 < ExtendedObjectDecoder:51 < ... < WrapperContext:102 < ...)
2019-03-20 03:02:20  WARN: [ac4458ff] error - begin 21, end 23, length 2 - StringIndexOutOfBoundsException (... < Gps103ProtocolDecoder:411 < ExtendedObjectDecoder:51 < ... < WrapperContext:102 < ...)

Seems wrong protocol. How I identify what devices is seding this pacages?

JB

Most likely those messages are not from a real GPS tracking device.