The orbit period of GPS satellites is almost 24 hours, and the period of one's own satellite in the sun-synchronous orbit is about 1.5 hours, so that means that the sun-synchronous orbit has been around for several weeks, and the GPS satellite only spares one week. So when calculating the Doppler frequency shift, you only need to calculate the Doppler frequency shift within one cycle of GPS. In other words, if the Doppler frequency shift is counted for more than 24 hours, the Doppler shift will be repeated. I only need the Doppler shift within the 24 hour GPS orbit period.
| Prn |
Satellite number |
| iodine |
The validity period of the current reference epoch given in the message |
| Crs |
The correction term of the orbit radius and angular distance given in the message—sine amplitude |
| delta_n |
The correction value of the horizontal angle given in the message |
| M_zero |
Mean anomaly at the reference time given in the message |
| Cuc |
Correction term for ascension of ascending node given in the message—cosine amplitude |
| e1 |
The eccentricity of the orbital ellipse given in the message |
| Cus |
Correction term for ascension of ascending node given in the message—sine amplitude |
| sqrt_a |
The square root of the semimajor axis of the satellite orbit ellipse given in the message |
| toe |
Reference time given in the message |
| Cic |
The correction term of the inclination angle distance given in the message—cosine amplitude |
| OMEGA_zero |
Ascension of the ascending node at the reference time given in the message |
| Cis |
The correction term of the inclination angle distance given in the message-sine amplitude |
| i_zero |
Orbital inclination at the reference time given in the message |
| Crc |
The correction term of the orbit radius and angular distance given in the message—cosine amplitude |
| omega |
The angular distance of orbital perigee given in the message |
| OMEGA_dot |
Ascension rate of ascending node given in the message |
| i_dot |
The rate of change of orbital inclination given in the message |
When you need to pay attention here, since the height of GPS from the ground is generally 20000km, and the synchronous satellite here is only 350km, the effect will not seem obvious, so here we set the parameters here to be larger, so that the effect looks slightly more obvious point. Then when you write the thesis, if you use the data in it, just change it back to 350. In addition, the cycle is 1.5 hours, so when in the house, the speed is too fast and it is not easy to observe, here is a slightly larger setting, and the use cycle is 6 hours.
The three-dimensional renderings of the entire system are as follows:
