> 1. I can receive encoder information through odometry messages. My worry is
> now related to the range i have with URG-04. Is there any work around by
> which i can overcome the issues of large area?

I would suggest you try it with the laser you have to get a feel for things.

> 2. I will surely look into the package of laser tools though... but it is
> intended to be used without any odometry and in our system we can have
> encoder information.
> 3. Ivan: which model of angular rate sensor (Gyro) you are preferring?
> So like, as suggested by you Gyro + Laser Range + odometry will quite
> improve our Robot localization even i dont have IMU sensor.

I'm by no means an expert on this. I can point you to this sensor,
which is cheap and easy to use, and I've used it with good results
before:

http://www.analog.com/en/sensors/inertial-sensors/adxrs610/products/product.html