Handling additional leading string packet in AD2CP files

[leewujung]

Currently the parser/set_grouper assumed having 1 leading string packet to parse the config parameters. However, for deployed files like those from glider, the first packet is often written (optionally) with an identifier of the mission/dive/etc. The current operation to parse config params therefore operates on the wrong string packet in this situation (should operate on the second one, which is the default AD2CP config string packet).

It seems that the config param string packet always start with "GETCLOCKSTR", so checking this can allow finding the correct string packet to parse params.

A bug related to this is that currently the Echosounder mode pulse compression setting (on which echogram) relies on parsing the config params. When the wrong string packet is used, the pulse compressed channel is set to the wrong one.

Related code sections:

echopype/echopype/convert/parse_ad2cp.py

Lines 292 to 296 in b81ffef

	def get_pulse_compressed(self) -> int:
	for i in range(1, 3 + 1):
	if "GETECHO" in self.config and self.config["GETECHO"][f"PULSECOMP{i}"] > 0: # type: ignore # noqa
	return i
	return 0

echopype/echopype/convert/set_groups_ad2cp.py

Line 34 in b81ffef

self.pulse_compressed = self.parser_obj.get_pulse_compressed()

echopype/echopype/convert/set_groups_ad2cp.py

Lines 360 to 362 in b81ffef

	pulse_compressed = np.zeros(3)
	pulse_compressed[self.pulse_compressed - 1] = 1
	ds["pulse_compressed"] = (("echogram",), pulse_compressed)