Posted on by wusel

GPS data from the 1993’s?

WTF?! I bought a “Navilock GPS NL-464US USB Stick” (off Amazon) as a lightweight GPS device to expand my AR.Drone. Why is that thing stuck in 1993?!

I hooked the Navilock to a MK-802+ running a recent Debian Wheezy install — all armhf, off course. After some struggeling, it finally worked (if I knew how, I would have posted how I did get it finally to work) — in a way at least.

Thing is: while the time is current, the date is 20 years in the past, as can be witnessed here with this snapshot from “cgps”: 

lqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqklqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqk
x    Time:       1993-09-07T22:04:26.000Z   xxPRN:   Elev:  Azim:  SNR:  Used: x
x    Latitude:    51.892843 N               xx   5    10    030    23      Y   x
x    Longitude:    8.383873 E               xx  16    56    295    18      Y   x
x    Altitude:   73.9 m                     xx  29    30    084    39      Y   x
x    Speed:      0.0 kph                    xx  31    14    207    23      Y   x
x    Heading:    0.0 deg (true)             xx  18    18    145    30      Y   x
x    Climb:      0.0 m/min                  xx                                 x
x    Status:     3D FIX (63 secs)           xx                                 x
x    Longitude Err:   +/- 13 m              xx                                 x
x    Latitude Err:    +/- 11 m              xx                                 x
x    Altitude Err:    +/- 48 m              xx                                 x
x    Course Err:      n/a                   xx                                 x
x    Speed Err:       +/- 97 kph            xx                                 x
x    Time offset:     619315200.535         xx                                 x
x    Grid Square:     JO41ev                xx                                 x
mqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqjmqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqj
{"class":"SUBFRAME","device":"/dev/ttyUSB0","tSV":29,"TOW17":42047,"frame":2,"sc
aled":false,"EPHEM2":{"IODE":28,"Crs":-160,"deltan":13867,"M0":-1256856721,"Cuc"
:-198,"e":16818181,"Cus":2156,"sqrtA":2701998147,"toe":16200,"FIT":0,"AODO":27}}
{"class":"TPV","tag":"MID2","device":"/dev/ttyUSB0","mode":3,"time":"1993-09-07T
22:04:26.000Z","ept":0.005,"lat":51.892843404,"lon":8.383873373,"alt":73.904,"ep
x":13.591,"epy":11.076,"epv":48.573,"track":0.0000,"speed":0.000,"climb":0.000,"
eps":27.18}

Well, 79m altitude +/- 48m isn’t that great of an resolution, but the thing here is: I want to use gpxlogger to log my flight positions — but timestamps like “”, as reported by gpsd/gpxlogger, are not very helpful at all.

I’m no GPS specialist, played around with GPS and gpsd 3 to 5 years in the past a bit — but my understanding always was that GPS comes with a rather precise time and date, so why I’m offset by roughly 20 years here?! It that GPS stick just broken?

4 Replies to “GPS data from the 1993’s?”

    1. Well, retried the setup just now before heading to bed, and, well, the stick seems to have found the right decade:

      ┌───────────────────────────────────────────┐┌─────────────────────────────────┐
│    Time:       2013-04-24T22:12:59.920Z   ││PRN:   Elev:  Azim:  SNR:  Used: │
│    Latitude:    51.892809 N               ││  18    23    142    43      Y   │
│    Longitude:    8.384260 E               ││  21    73    111    33      Y   │
│    Altitude:   98.4 m                     ││  29    24    087    39      Y   │
│    Speed:      0.6 kph                    ││  31    08    204    18      Y   │
│    Heading:    306.5 deg (true)           ││  16    61    288    23      N   │
│    Climb:      5.2 m/min                  ││   5    06    025    17      N   │
│    Status:     3D FIX (16 secs)           ││   3    23    279    21      N   │
│    Longitude Err:   +/- 22 m              ││ 126    28    157    28      N   │
│    Latitude Err:    +/- 34 m              ││                                 │
│    Altitude Err:    +/- 52 m              ││                                 │
│    Course Err:      n/a                   ││                                 │
│    Speed Err:       +/- 214 kph           ││                                 │
│    Time offset:     0.161                 ││                                 │
│    Grid Square:     JO41ev                ││                                 │
└───────────────────────────────────────────┘└─────────────────────────────────┘

      It’s maybe still the fastest stationary GPS receiver on this continent, but at least it’s now in the right century … Still puzzled what happened yesterday, though.

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