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

Chapter 1 / Introduction
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generally acceptable a balance is struck between capability and cost; sensor
technology, more than most, being prone to requirement creep. Recent
advances in digital processing capability means that powerful algorithms
can now be employed to improve sensor performance in an attempt to keep
their cost under control. Table 1-3 provides an indication as to the sensor
used in the various Theatres of Operation.
The work on sensors presented in §3 concentrates on the system integration
aspects of sensors, particularly those errors that may impact on data fusion
algorithms. For contractual reasons it has become the norm to embed
detailed manufacturer sensor development models in performance
simulations. These models tend to be overly complicated for assessing
overall system performance and often restrict such studies when time and
resources are limited. The ethos here is to replace high frequency functions
with approximate low frequency models retaining the characteristics that
affect the performance of the state observers. Perfect measurements derived
directly from the reference-state are corrupted by dominant error sources
before delivery to the state observer via a digital interface, or radio link.
Two status flags accompany each measurement; one indicates that a
particular measurement is available, the other that it is ready for processing,
i.e. it is valid and operating within the sensors operational limits. The
sensor models are self-contained entities so that they are transportable, and
can be cloned dependent on application. Their generic nature means they
can be characterised to represent a range of similar sensors, for example,
gimballed Infra-Red (IR) seekers representing FLIR and TIALD, similarly,
a rotating phased array radar becomes a strapped-down device, or a steered
electro-optical tracker.
Table 1-3 : Sensors and Theatres of Operation
SENSORS
Air
Launched
1-7
Ship
Launched
Ground
Launched
Launch Missile Launch Missile Launch Missile
IMU gyroscope triad ✔ ✔ ✔ ✔ ✔
IMU accelerometer triad ✔ ✔ ✔ ✔ ✔
Barometric altimeter ✔
Radar altimeter/DLMS ✔ ✔ ✔ ✔
RF/IR seekers ✔ ✔ ✔ ✔
NAVSTAR GPS ✔ ✔ ✔
RF radar ✔ ✔ ✔
Helmet Mounted Sight ✔
Air data sensors ✔
FLIR and TIALD ✔
§3.1 introduces the sensor simulator, control of the individual sensor
models, and their interaction with the simulation infrastructure. There are a
number of errors that are commonly found in many of the sensors. These
are described generically in §3.2 in the context of the simulator and a Matrix