I am currently reading about Ultrawideband Localization and came across the statement, that the short pulse duration that is used in UWB (for example ~2ns with 500MHz Channelbandwidth) results in a high spatial resolution.

Quote:

"The large absolute bandwidth, in US from 3.1 to 10.6 GHz [1] and in Europe from 6 to 8.5 GHz [2], corresponds to a very fine time resolution in the order of hundreds of picoseconds which translates to spatial resolution in the order of centimeters. The very fine time resolution allows a direct path to be easily dis-  tinguished from the reflected paths" (From the paper "Ultra-wideband Technology-based Ranging Platform with Real-time Signal Processing")

Now I am wondering why this is the case.

What I can see is that the short pulse duration has benefits when it comes to multipath propagation. Since it is less likely that a direct and a reflected pulse overlap destructively or arrive at the same point (antenna) within <2ns of each other, so you can still differentiate them.

But why does the length of the pulse affect the ranging accuracy?

The short pulse travels from one antenna to another and will arrive after some time, depending on the distance. If I make the pulse longer, the bandwidth gets smaller, and depending on the shape the leading edge would be flatter.

Can someone explain this and maybe point to a booksource or chapter where I can find further information about it or what to search for?

I am currently reading about ultrawideband localization and came across the statement, that the short pulse duration that is used in UWB (for example ~2ns with 500MHz channel bandwidth) results in a high spatial resolution.

Quote:

"The large absolute bandwidth, in US from 3.1 to 10.6 GHz [1] and in Europe from 6 to 8.5 GHz [2], corresponds to a very fine time resolution in the order of hundreds of picoseconds which translates to spatial resolution in the order of centimeters. The very fine time resolution allows a direct path to be easily dis-tinguished from the reflected paths" (From the paper "Ultra-wideband Technology-based Ranging Platform with Real-time Signal Processing")

Why is this the case?

What I can see is that the short pulse duration has benefits when it comes to multipath propagation. Since it is less likely that a direct and a reflected pulse overlap destructively or arrive at the same point (antenna) within <2ns of each other, so you can still differentiate them.

Why does the length of the pulse affect the ranging accuracy?

The short pulse travels from one antenna to another and will arrive after some time, depending on the distance.

If I make the pulse longer, the bandwidth gets smaller, and depending on the shape the leading edge would be flatter.

Can someone explain this and maybe point to a booksource or chapter where I can find further information about it or what to search for?