• Intro
• Downloads
• Community
• Development
• News
• TALK

N900 GPS Reverse Engineering

Revision as of 15:02, 21 July 2010

| 00000  00 92 01 00 00 00 00 xx  05 00 00 00 09 03 00 10
         S------------------- DL  DL S-------------------
| 00010  07 da 07 15 00 xx xx 00  xx xx 00 00 09 02 00 1c
         S------------- TL TS --        S----------------
| 00020  xx xx xx xx xx xx xx xx  00 00 xx xx 00 00 08 8b
         DL---       DL--- TS     S----       S---- ^eph^
| 00030  xx 00 xx xx xx xx xx xx  09 04 00 14 62 7e xx xx
            S- DL TS---    DL MS  S---------- track SS---
| 00040  xx xx 00 xx xx xx 00 xx  00 xx 00 00 09 05 00 74
         DL--- S-    TL    S- DS  S- DS S------------- DL
| 00050  09 00 00 00 00 02 xx xx  00 xx xx xx xx xx 00 00
         DL S---------- DL DL MS  S- TS--- I  TS MI S----
| 00060  00 04 xx xx xx xx xx xx  xx xx 00 00 00 xx xx xx
         S- DL T3 TS S- TL TS MS  TS MD S------- DL TS---
| 00070  00 xx xx xx xx xx 00 00  00 xx xx xx 00 03 xx xx
         S- TS--- I  TS MS S-------- T3 MS MS S- DL TS MS
| 00080  xx xx 00 00 00 xx xx xx  00 xx xx xx xx xx 00 00
         TS MD S------- T3 TS MS  S- TS--- MS TS MI S----
| 00090  00 xx xx xx 00 03 xx xx  xx xx 00 00 00 xx xx xx
         S- TS------ S- DL TS MD  TS MS S------- TS SS+TS
| 000a0  00 xx xx xx xx xx 00 00  00 xx xx xx 00 xx xx xx
         S- TL TS MS TS MD S-------- TS------ S- TL TS MI
| 000b0  xx xx 00 00 00 xx xx xx  00 xx xx xx xx xx 00 00
         TS--- S------- TS--- MS  S- TS--- MI TS MS S----
| 000c0  09 08 00 0c xx xx xx xx  xx xx xx xx
         DL----------------------------------

• S = Static, unchanging normally
• MS = Mostly static, varying in value normally slightly
• SS = Sometimes static, completely different values sometimes
• I = Incrementing
• MI = Incrementing, but not every packet
• D = Decrementing
• MD = Decrementing, but not every packet
• TS = Time-sensitive; changes over (short) durations of time
• TL = Time-sensitive, longer duration
• T3 = "
• DS = Distance-sensitive; changes over at least 30m distance
• DL = Distance-sensitive, like across the world; TEMP; *or* T4

• 19,1a = 0000-e678 (hex)
• 20 =
• 22,23 =
• 28 =
• 2b,2c = 0590-12a9 (hex)
• 2e,2f = eph (cm)
• 30 =
• 35 =
• 3c,3d = track: Direction of motion in hundredths of a degree
• 3e,3f = epd: Track accuracy (in hundredths?)
• 43 =
• 45 =