gps-details

FIT Fields

Author: Michael George

Created: 14 Dec 2024

Overview

This document describes the useful metadata that is available in the FIT files from Garmin, COROS and some other watch manufacturers.

Records

file_id

FIT files from COROS use the same product number for the APEX 2 and APEX 2 Pro. A simple workaround is proposed using the product_name field, mapping the APEX 2 to product number 821. More details about the issue are on GitHub.

Name	Field / Value	Criteria	Garmin?	COROS?
manufacturer ¹	manufacturer	-	Y	Y
product ^{1 2}	product	-	Y	Y
	821	product = 822 and product_name == “COROS Wearables”	-	Y
product_name ¹	product_name	-	-	Y
	“APEX 2”	product = 822 and product_name == “COROS Wearables”	-	Y
serial_number ³	serial_number	-	Y	-

Notes:

Suunto and Timex also include manufacturer, product and product_name.
Garmin used to include garmin_product instead of product.
Timex also includes serial_number.

developer_data_id

The application details from the developer_data_id record can be used to identify the application downloaded from the Connect IQ Store, but not side-loaded betas.

n.b. The application_id in COROS files doesn’t provide any useful insights.

Name	Field	Criteria	Garmin?	COROS?
application_id	application_id	-	Y	Y
application_version	application_version	-	Y	-

session

The session record includes activity details that can be used to determine whether the Garmin settings meet the GP3S requirements.

Name	Field	Criteria	Garmin?	COROS?
sport	sport	-	Y	Y
sub_sport	sub_sport	-	Y	-
craft	craft	-	APPro	-
app_name	app_name	-	APPro	-
app_ver	app_ver	-	APPro	-
gnss_config	gnss_config	-	APPro	-

Criteria for approved Garmin devices to receive the green icon on GP3S:

sport is either 0 (SPORT_GENERIC), 43 (SPORT_WINDSURFING), or 44 (SPORT_KITESURFING)
gnss_config is either 5 (CONFIGURATION_GPS_GLONASS_GALILEO_BEIDOU_L1) or 6 (CONFIGURATION_GPS_GLONASS_GALILEO_BEIDOU_L1_L5)

n.b. There is an additional approval process for individual watch models.

field_description

The developer fields in a COROS file can be used to determine whether the session uses the speedsurfing mode.

Name	Value	Criteria (where exists)	Garmin?	COROS?
flag_hdop	True	lower(field_name) == ‘hdop’	-	speedsurfing
flag_cog	True	lower(field_name) == ‘cog’	-	speedsurfing
flag_sats	True	lower(field_name) == ‘sat’	-	speedsurfing
flag_fix	True	field_name == ‘fix_quality’	APPro	-

Criteria for approved COROS devices to receive the green icon:

One or more of flag_hdop, flag_cog, or flag_sats must be true
This confirms whether the speedsurfing mode has been used, or not

device_info

The firmware and GNSS version could prove to be extremely useful in the future, should any bad firmware be released.

n.b. Garmin watches back in early-mid 2022 experienced the issues that COROS have introduced to some of their Airoha-based watches during 2024.

Name	Field	Criteria	Garmin?	COROS?
firmware_version	software_version	device_type is empty, or device_index == creator	Y	-
gnss_version	software_version	device_type == 0	Y	-