Interesting question. I'm curios to know its application. In theory, I think it might be possible to extend a GPS Antenna with an external optic fiber/cable antenna as long as it maintains line of sight with GPS satellites. If you are looking for 'External GPS Antenna' you will find many results if you simply search for it. As you may also know that there are gps tracking systems for reptiles/mammals/animals out there but I'm not sure how efficiently the signals can be tracked if they venture underground. I've never come across any 'buried' gps system with external antennas yet. It would be good to experiment with it though.

Actually I was designing an Instrument that passes inside the underground pipelines.,with the GPS set inside with its antenna extended to touch the inner surface of the steel pipe. in pipelines we are having TLPs(i.e. a wire welded to the outer surface of the pipe extending out to the open atmosphere distant 2 km each, that I thought could act as antenna) :(

Sorry, antennas don't work that way.  You're basically putting your radio inside a shielded tube (the metal pipe).  It doesn't matter if it's under ground or in space right in front of a GPS satellite, it's not going to work!  You can always take a receiver and run an RF cable (coax) to an external antenna, and you generally just degrade performance by the path loss of the cable, but you have to carry both conductors outside your shield.

GPS/INS Navigation system may be good solution. GPS repeaters are available in market. GPS repeaters re re radiate the GPS signals. GPS and GSM relievers can not be connected to common antenna. GPS works at L band where GSM works at 900 and 1800 MHz frequency....

I am afraid you may not receive GPS signal with a mere wire. The antenna should be extended with RF coaxial cable to ensure matched impedance circuit.