Log format of the MTK logger
Model Date and time Millisecond Latitude/Longitude Speed Altitude Data
code
Byte Type Unit Byte Type Unit Byte Type Unit Byte Type Unit Byte Type Unit
Standard 4 LongWord 1Sec. 2 Word 1mS 8 Double Degree 4 Single km/h 4 Single m Text
M-241 4 LongWord 1Sec. 2 Word 1mS 4 Single Degree 4 Single km/h 3 Single3 m Text
M-241 Plus 4 LongWord 1Sec. - - - 4 Single Degree 2 Word 0.1km/h 2 Int 1m Binary
M-1000C 4 LongWord 1Sec. 2 Word 1mS 4 Single Degree 4 Int 1cm/Sec. 3 Single3 m Text
GPSport245 4 LongWord 1Sec. 2 Word 1mS 4 Single Degree 3 Int3 1/256cm/Sec. 4 Single m Text


Distance resolution of the 4 bytes single format
East - West
Resolution Latitude
15° 30° 45° 60° 75°
Longitude 1° to 2° 0.013m 0.013m 0.012m 0.010m 0.007m 0.004m
2° to 4° 0.027m 0.026m 0.023m 0.019m 0.013m 0.007m
4° to 8° 0.053m 0.052m 0.046m 0.038m 0.027m 0.014m
8° to 16° 0.106m 0.102m 0.092m 0.075m 0.053m 0.028m
16° to 32° 0.212m 0.204m 0.183m 0.150m 0.106m 0.055m
32° to 64° 0.423m 0.409m 0.367m 0.300m 0.212m 0.110m
64° to 128° 0.846m 0.817m 0.733m 0.599m 0.424m 0.220m
128° to 180° 1.670m 1.613m 1.447m 1.183m 0.837m 0.434m
Note) It is almost proportional to Cos(Latitude).

North - South
Latitude Resolution
1° to 2° 0.013m
2° to 4° 0.027m
4° to 8° 0.053m
8° to 16° 0.105m
16° to 32° 0.210m
32° to 64° 0.421m
64° to 90° 0.847m










Log trace of 4 byte single (32N, 128E) Sample log trace of M-241 Plus (35.3357N, 139.4064E)

Solution
By converting latitude and longitude(d) to a 4-byte integer(n), resolution can be reduced to 1.33cm or less.
n = Int(d*2^23), d = n/2^23
or
n = Int(d*10^7), d = n/10^7


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