The World Health Organizaion (WHO) states that 15 percent of world population are with disabilities. Deafblindness is a combination of vision and hearing impairments. There are a few people who are completely deaf and blind. Our world is organised around hearing sighted people, and this can present many challenges to a deafblind person. If you have little or no sight and hearing, learning to co...

I.inc-of-sight ionosphere measurements derived from differcncing dual-frequency Global Positioning System (GPS) range data are corrupted by instrumental biases in both the receiver and GPS satellite transmitters due to hardware delays in the L1 and L2 signal paths, The lineof-sight differential delay can be modeled as the sum of a rccciver bias, a satellite transmitter bias, and the line-ofsigh...