Sensor model and Likelihood Function

• The probabiloty density function (pdf) p(z|x) serves as the sensor model.
• This can be thought of in two ways:
• to build the sensor model: we can fix x = x and ask what pdf in z results. Then, p(z|x) is a function of z. An exmaple would be, say we know the true location of a target then p(z|x) is the distribution of the observation.
• when the sensor model is established observatione are made and z = z will be fixed. From this then we want to infer the state x. Thus, p(z|x) will then be a distribution of x. This distribution is called the likelihood function. L(x) = p(z|x)
• In the case of likelihood function we know the observation z = z. But, that does not mean we are going to calculate p(x|z); we are still dealing with p(z|x).