星历计算

广播星历文件格式（2）
GPS导航文件头格式
广播星历文件格式（3）
G P S 导 航 文 件 数 据 格 式
+-----------------------------------------------------------------------------------------------------------+ | TABLE A4 | | GPS NAVIGATION MESSAGE FILE - DATA RECORD DESCRIPTION | +------------------------------+---------------------------------------------+----------------------------+ | OBS. RECORD | DESCRIPTION | FORMAT | +------------------------------+---------------------------------------------+----------------------------+ |PRN / EPOCH / SV CLK | - Satellite PRN number | I2, | | | - Epoch: Toc - Time of Clock | | | | year (2 digits, padded with 0 | | | | if necessary) | 1X,I2.2, | | | month | 1X,I2, | | | day | 1X,I2, | | | hour | 1X,I2, | | | minute | 1X,I2, | | | second | F5.1, | | 1 | - SV clock bias (seconds) | 3D19.12 | | 2| - SV clock drift (sec/sec) | | | 3| - SV clock drift rate (sec/sec2) | *) || +--------------------+-------------------------------------------------------+--------------------------+ | BROADCAST ORBIT - 1| - 4IODE Issue of Data, Ephemeris | 3X,4D19.12 | | 5| - Crs (meters) | | | 6| - Delta n (radians/sec) | | | 7| - M0 (radians) | | +--------------------+-------------------------------------------------------+--------------------------+ | BROADCAST ORBIT - 2| - 8Cuc (radians) | 3X,4D19.12 | | 9| - e Eccentricity | | | 10| - Cus (radians) | | | 11| - sqrt(A) (sqrt(m)) | | +------------------------------+---------------------------------------------+--------------------------+
时间变换
• GPS week: • Week=INT[(JD-2444244.5)/7] GPS second • Tgps=(JD-2444244.5week*7)*86400
3 GPS星历计算
由广播星历计算GPS卫星在 地固系中的位置
提
• • • • 广播星历
wk.baidu.com
要
广播星历参数 卫星位置计算 精密星历文件
+--------------------------------+--------------------------------------------------------+----------------+
| BROADCAST ORBIT – 6 24| - SV accuracy (meters) | 3X,4D19.12 | | 25| - SV health (bits 17-22 w 3 sf 1) | | | 26| - TGD (seconds) | | | 27| - IODC Issue of Data, Clock | | +--------------------------------+-------------------------------------------------------+-----------------+ | BROADCAST ORBIT – 7 | - Transmission time of message **) | 3X,4D19.12 | | | (sec of GPS week, derived e.g. | | | | from Z-count in Hand Over Word (HOW) | | | | - Fit interval (hours) | | | | (see ICD-GPS-200, 20.3.4.4) | | | | Zero if not known | | | | - spare | | | | - spare | | +--------------------------------+-------------------------------------------------------+-----------------+
3.2、导航信息中的星历参数
M0 Δn e a1/2 Ω0 i0 ω 平近点角 平运动差 偏心率 半长轴的平方根 轨道平面升交点经度 倾角 近地点角距 升交点速率

3.2、导航信息中的星历参数（2）
iDot Cuc，Cus Crc，Crs Cic，Cis toe a0 a1 a2 倾角速率 升交角距的摄动改正项 地心距的摄动改正项 倾角的摄动改正项 参考历元 卫星钟偏差 卫星钟漂移 卫星钟频率漂移
3.1、广播星历
广播星历文件
广播星历文件格式
RINEX : The Receiver Independent Exchange Format GPS导航文件头格式
+-------------------------------------------------------------------------------------------------------------+ | TABLE A3 | | GPS NAVIGATION MESSAGE FILE - HEADER SECTION DESCRIPTION | +-------------------------------+-------------------------------------------------+--------------------------+ | HEADER LABEL | DESCRIPTION | FORMAT | | (Columns 61-80) | | | +-------------------------------+--------------------------------------------------+-------------------------+ |RINEX VERSION / TYPE| - Format version (2.10) | F9.2,11X, | | | - File type ('N' for Navigation data) | A1,19X | +-------------------------------+--------------------------------------------------+-------------------------+ |PGM / RUN BY / DATE | - Name of program creating current file | A20, | | | - Name of agency creating current file | A20, | | | - Date of file creation | A20 | +-------------------------------+--------------------------------------------------+--------------------------
广播星历文件格式（4）
+--------------------------------+--------------------------------------------------------+-----------------+
| BROADCAST ORBIT – 3 12 | - Toe Time of Ephemeris (sec of GPS week) | 3X,4D19.12 | | 13| - Cic (radians) | | | 14| - OMEGA (radians) | | | 15| - CIS (radians) | | +--------------------------------+--------------------------------------------------------+-----------------+ | BROADCAST ORBIT – 4 16| - i0 (radians) | 3X,4D19.12 | | 17| - Crc (meters) | | | 18| - omega (radians) | | | 19| - OMEGA DOT (radians/sec) | | +--------------------------------+--------------------------------------------------------+----------------+ | BROADCAST ORBIT – 5 20| - IDOT (radians/sec) | 3X,4D19.12 | | 21| - Codes on L2 channel | | | 22| - GPS Week # (to go with TOE) | | | 23| Continuous number, not mod(1024)! - L2 P data flag |
3.2、导航信息中的星历参数（3）
af0 卫星PRN号，年，月，日，时，分，秒，
C , e,C
ic
rc
， af1 af1 ，
a
is
aode , C rs , n , M 0
uc us
,
t oe , C
i0 , C
, 0,C , ,
iDot, cflgl2,weekno, pflgl2 svacc, svhlth, tgd, aodc ttm
3.3、星历计算
μ= 3.986004418*1014 m3/s2 7.292115 10 -5 rad/s
e
地球引力场常数 地球自转速度 地球长半轴 计算的平运动
a ( a )2
n0
a3
n n0 n
tk t toe
t s c[a0 a1 (t toe ) a2 (t toe ) 2 ]
卫星位置计算
根据广播星历
时间变换
1 民用年历变换为儒略日 将时分秒化为时作单位UT • 设民用的年,月,日,时为Y,M,D,UT,则 • JD=INT[365.25y]+INT[30.6001(m+1)]+D + UT/24+1720981.5 • If M≤2, y=Y-1, m=M+12 • If M＞2, y=Y, m=M