gps - 解码SMS报告肯尼亚狮子的GPS位置

Question

Mara-Naboisho Lion Project具有asked for our help解码功能，可以绘制出装有GPS项圈的狮子的位置。

他们从衣领收到短信:

Collar07854_100806210058.SMS

074952494449554d0000000000000000000000000000000000000000000000040f33303030333430313232393738393000000000000000000000000000000000f10a0806100028008c13ef348a0039d0fe000de871004cc92b5ca92d6213ef26640039d108000de86b004cc92d5ca92d5d13ef18620039d101000de865004cc92c5ca92d5813ef0a930039d0fc000de864004cc9311c682d5413eefc170039d045000de7d4004cc95b7c692c5013eeee280039d0ff000de85f004cc92a7c692d6fffffffffffffffffffffffffffffffffffffffffff

Collar07854_100807060011.SMS

074952494449554d0000000000000000000000000000000000000000000000040f33303030333430313232393738393000000000000000000000000000000000f10a0807020038008c13efb2eb0039d0ed000de853004cc92e3cea2d8813efa5060039d0fb000de860004cc9291c6a2d8413ef96fd0039d0fc000de85e004cc92d5c6a2d7f13ef88e00039d0f6000de85a004cc92b5c6a2d7b13ef7ad80039d0fa000de85a004cc9327c6a2d77ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff

这些大概是SMS PDU，尽管简单的在线解码器似乎对其意义不大。其中有ASCII文本“IRIDIUM”，大概是SMSC或发送者或某种字符串，因为IRIDIUM是卫星电话系统，并且大概是项圈发出位置时的承载者。

更新:它们具有一些与这些项圈相对应的KML文件。我已经上传了KML here和 here。领子可能是由Vectronic-Aerospace制造的。

它是什么格式，我们如何解码？

(这是一个 giving code项目；也许您想 help them，或者看看那里的其他问题？)

Answer 1

我已经能够翻译纬度/经度位置!从领子开发人员浏览网站后，我发现他们正在使用x / y / z ECEF坐标。

第一条消息的第一行:

13ef 348a 0039 d0fe 000d e871 004c c92b 5ca9 2d62

Is translated as:

0039 d0fe = X = 3789054000d e871 = Y = 911473004c c92b = Z = 5032235

This translates into:

Lat: 52.43067054630929Lon: 13.525755535406619Height: 88.99500464554876

This results into a location in Germany... which sounds wrong for a Kenya reserve, but in fact it is the street of the company which makes these collars:check their website

The code to translate the coordinates has been found online:

public static double[] xyz2LLH(double x, double y, double z)
{
    double[] llh = new double[3];
    double da = 0.0; // datum parameter
    double df = 0.0; // datum parameter
    double a = 6378137 - da;
    double f = 1 / 298.2572235630 - df;
    double b = (1 - f) * a;
    double e2 = 2 * f - f * f;
    double E2 = (a * a - b * b) / (b * b);
    double p = Math.sqrt(x * x + y * y);
    llh[0] = Math.atan2(y, x);
    double theta = Math.atan((z * a) / (p * b));
    llh[1] = Math.atan((z + E2 * b * Math.pow(Math.sin(theta), 3)) / (p - e2 * a * Math.pow(Math.cos(theta), 3)));
    double N = a / Math.sqrt(1 - e2 * Math.sin(llh[1]) * Math.sin(llh[1]));
    llh[2] = p / Math.cos(llh[1]) - N;
    llh[0] = Math.toDegrees(llh[0]);
    llh[1] = Math.toDegrees(llh[1]);
    return llh;
}

因此，留给解密者的唯一代码是最后一位: 5ca9 2d62 。

该网站的另一个线索表明这些字节保存着主电压/备用电压和温度。