Several problems related to GPS

It seems that this, I made up my mind,

1:The speed limit of GPS is 5 15m/s, which was set by the United States to force GPS not to participate in military use. It has little to do with Paris, but China has broken through this limit from the technical level.

Height limit 18288, and some are also called 18287M. This is stipulated, but it can be cancelled.

2.CEP is the unit of positioning accuracy and probability of GPS. Take your 5M as an example, that is, draw a circle with a radius of 5M, and 50% of the points can be hit into the circle. In other words, the probability of GPS positioning at 5M accuracy is 50%. Correspondingly, there is RMS(66. 7%)2DRMS(90%) Of course, many businesses are willing to give CEP, because the unit is large and the number in front is small, which looks good.

This question is too general. I guess you want to ask how many GPS satellites are in use. If there is, tell you, no one knows! ! ! ! Why, because the GPS system in the United States can be completed as long as there are 24 satellites in use, and the service life of each satellite ranges from 5 years to 15 years. A star whose service life has expired will be added by the US government, but the replacement does not mean that it is broken. It will continue to work, but it will not stay in its original position until it is broken and becomes cosmic garbage. These have been replaced.

4. The so-called signal-to-noise ratio is S/N0. Friends who study information should be familiar with this concept, which is the ratio of useful information to other noises. The landlord asked the wrong question. High signal-to-interference ratio is not a problem, but a reflection of the current satellite situation. For example, if a star is close to the ground level or partially blocked, you will naturally encounter problems in tracking this star, and the ratio of signal to dryness will increase. Generally speaking, around 30-40 is ideal, and below 50 is acceptable.

The information in 5:$ GPGGA is in ddmm.mmmm format, and Chinese only has decimal format.

Is there anything wrong with the landlord? You wrote so much. Give it to me.