Thesis - Leigh Moody.pdf - Bad Request - Cranfield University

values of CN are not always a reliable indicator of accuracy, nor even
stability, Daum [D.2] . Noise of 1 m 2 /s 4 /Hz was finally selected. The actual
position and acceleration errors compared with filter expectations are shown
in Figure 9-40. The position error is reasonably matched to the expectation,
although the steady state acceleration error is lower than filter expectation
indicating some over damping.
[metres]
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TIME [seconds]
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9-23
TG_A_MET
TG_A_SIG
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TIME [seconds]
Figure 9-40 : Tuned Acceleration Filter
Position and Acceleration Errors ( PIP ) and ( PIA )
This performance was compared with that using the Joseph covariance
update, and serially processing combinations of radar range, range-rate and
angle measurements. There was very little improvement in performance at
the current 10 Hz measurement update rate. One concludes that using 64 bit
arithmetic and linearisation between serial measurement updates removes
any sensitivity that may have existed. These techniques, together with
iteration and 2 nd order filtering, are only expected to make a significant
impact if the radar update rate reduces significantly to say 1 Hz.