e 2 cos u03c6 an initial value for r can now be calculated using equation 20 equ24 the aircraft then executes another turn until it is flying in a straight path along leg k3 the angle u03c6 2 between legs k2 and k3 is determined using the navigation system while the aircraft is flying in a straight line along the leg k3 at the same velocity v b another sample is taken by measuring a train of pulses 1 to n inclusive to determine a new time interval t 39 n t 39 1 the value of e 3 is calculated as equ25 the value of u03b8 3 is then calculated using equation 19 the value of u03c6 2 for u03c6 equ26 where p e 2 e 3 cos u03c6 another value for r can now be calculated using equation 20 equ27 the iteration then continues repeating the above steps along successive legs k4 etc until the value of r is refined to the point that it remains substantially constant from leg to leg the value of the angle of arrival u03b8 k can then be calculated each time a sample of n pulses is measured note that a plurality of samples may be measured on each leg and averaged for the time interval of the received pulses error affects fig6 up to this point the affects of transmission and measurement errors have been ignored the following discussion addresses two types of potential errors 1 transmission jitter and 2 measurement quantization the basic time of transmission error commonly called jitter can primarily be traced back to the.