14 
m, 7 mean root square error of one line spacing produced by a 
180? - turn 
S = length of flight lines in km 
Mao = standard (lateral) error of unit weight (flight line of 1 km 
length) 
The values m. and m Qo can be expected to be 
m, et 0.100 km 
Mao = * 0.015 km 
(b) The longitudinal error in navigation can be expressed by the formula 
s So 
where 
m. = standard (longitudinal navigation) error 
S = distance flown from last fix 
mg = standard (longitudinal) error of unit weight (distance from 
last fix 1 km); its value can be expected to be + 0.01 km 
(c) The combination of lateral and longitudinal navigation error leads to 
the position error of the system. This position error can be represented 
by means of ellipses of errors. 
4B. Integrated inertial systems 
4B.1 Inertial systems in general 
The performance of an invertial navigation system is basically dependant 
upon the following generalized factors: 
a. Alignment and “initialization” accuracy 
b. Quality of inertial components 
c. Trajectory, manoeuvres, and gravitation anomalies 
A number of parameters are constant during a given flight but vary 
between flights.