14.02.2013 Views

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

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

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

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

Chapter 5 / Missile State Observer<br />

_ _<br />

IMU<br />

ACCELS<br />

MISSILE FF<br />

ANGULAR<br />

STATE<br />

PARTITION<br />

MISSILE FF<br />

LINEAR<br />

STATE<br />

PARTITION<br />

MISSILE FF<br />

TARGET<br />

STATE<br />

PARTITION<br />

IMU<br />

GYROS<br />

5-5<br />

SEEKER<br />

GROUND BASED<br />

PHASED ARRAY RADAR<br />

FILTER<br />

1<br />

FILTER<br />

2<br />

FILTER<br />

"N"<br />

TARGET STATE AND<br />

COVARIANCE COMBINATION<br />

Figure 5-4 : Hybrid Fusion Architecture for Air-Defence<br />

The IMM state and covariance data is up-linked and fused into the target<br />

state partition using information fusion techniques. Figure 5-5 encapsulates<br />

the measurement and track fusion processes for the air-defence system. The<br />

observer states and variances are then used to derive the seeker pointing,<br />

guidance and autopilot stabilisation parameters. The hybrid architecture<br />

selected for this application is shown in Figure 5-6 combining both track<br />

and measurement fusion.<br />

GROUND<br />

RADAR 10 HZ<br />

MEASURES<br />

IMM FILTER 1<br />

IMM FILTER 2<br />

IMM FILTER 3<br />

IMM FILTER 4<br />

DISTRIBUTED<br />

IMM TRACK<br />

FUSION<br />

I/F 1553, 10 HZ<br />

TARGET<br />

MESSAGE<br />

ENCODING<br />

I/F 1553, 10 HZ<br />

MISSILE<br />

MESSAGE<br />

ENCODING<br />

TARGET TRACK<br />

FUSION ON UPLINK<br />

INTERRUPT<br />

MISSILE<br />

CENTRALISED<br />

MEASUREMENT<br />

FUSION FILTER<br />

MISSILE 400 HZ<br />

GYROSCOPE<br />

MEASURMENTS<br />

MISSILE 100 HZ<br />

ACCELEROMETER<br />

MEASURMENTS<br />

SEEKER<br />

100 HZ<br />

MEASURMENTS<br />

Figure 5-5 : Data flow Within the Air-Defence Architecture<br />

Producing tracks using one or more remote sensors means each sensor can<br />

be allocated a dedicated filtering centre with parallel processing. Whilst<br />

each tracker is designed and tuned to its sensor the tracks are devoid of<br />

sensor characteristics. So, if a sensor is lost system survivability is high<br />

with a graceful degradation in overall observer accuracy. It has already<br />

been stated that centralised measurement fusion is the only architecture that<br />

can provide optimal state estimates, and that this would require up-linking<br />

the radar plots directly. Improved observer accuracy leads to better target<br />

association as smaller acceptance gates can be employed.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!