Brief introduction to integrity

Integrity is a measure of the reliability of the positioning information provided by the navigation and positioning system , The integrity of the navigation system should also ensure that when the positioning information is abnormal and can not be used , Provide alarm information to the user within the specified time .

Integrity includes three indicators ：

1. Integrity risk ： The probability that the positioning error exceeds the limit without timely warning .[ Integrity risk is equal to the probability of missing alarm , To be verified .]
2. Alarm time ： The time delay from the time of overrun to the time of accurate notification to the user .
3. Alarm limit ： The threshold value determined according to different service application requirements , It is generally related to the security requirements of the application scenario .

And pure GNSS The positioning system itself is subject to ionospheric storms 、 Tropospheric anomaly 、 Reference station interference 、 Multipath effect of terminal receiver 、GNSS Deception, interference, etc Corner Case The interference of the triggering conditions , This leads to incorrect positioning output , All this is based on a variety of Corner Case The triggering conditions of all systems need to be judged by integrity monitoring system and algorithm , Ensure that it is outside the capability of the positioning algorithm , It can provide alarm information to the auto drive system in time , So as to ensure that the expected functional safety risks meet the pure requirements GNSS The integrity risk of the positioning system is $10^{-6}/h$.