A CL65 FLT CREW DEVIATED FROM THE CHARTED DEP PROC WHEN THEIR FMS DROPPED THE GPS SIGNAL.

Narrative

DURING A DEP PROC OFF OF RWY 26R; WE WERE FLYING THE NEW PROC; A HDG OF 255 DEGS TO INTERCEPT THE 143 DEG RADIAL INBOUND TO THE POMONA VOR. BECAUSE OUR ACFT HAS THE DEP PROC IN THE FMS WE ARE ABLE TO NAV IN FMS MODE INFLT. WE VERIFIED BEFORE DEP IT WAS IN THE COMPUTER DATABASE PROPERLY AND CURRENT WHICH IT WAS. WE DEPARTED OFF OF RWY 26R AROUND XA15 LCL AND HAD THE AUTOPLT ON AFTER TKOF. THERE WAS A DIRECT XWIND THAT WAS FROM THE S ABOUT 15 KTS. I WOULD SAY THAT ABOUT 1 MIN AFTER WE HAD THE AUTOPLT ON WE HAD A MESSAGE THAT OUR GPS HAD LOST POS AND WAS TRYING TO GET IT BACK; SO WE CONTINUED TO FLY THE DEP HDG TO TRY TO INTERCEPT THE 143 DEG INBOUND TO POM VOR BUT ATC CONTACTED US DURING MY TURN INBOUND TO THE VOR AND ASKED US WHERE WE WERE GOING. WE TOLD THEM WE WERE ON THE POMONA 7 DEP AND WERE TRYING TO INTERCEPT THE 143 DEG INBOUND AND TOLD HIM WE HAD A GPS FAILURE AND DUE TO THE WIND REQUESTED A HDG THAT WOULD HAVE A BETTER INTERCEPT. HE THEN GAVE US A HDG OF 290 DEGS WHICH WAS THE SAME HDG THAT WE WERE ON. ATC TOLD US THAT WE WERE 2 MI N OFF COURSE AND THAT WE HAD TO CALL A NUMBER ON THE GND. AFTER WE HIT THE POM VOR WE FLEW THE DEP PROC IN FMS NAV AGAIN BECAUSE WE GOT OUR GPS BACK. ON THE GND WE EXPLAINED THE SITUATION TO ATC AND TOLD THEM THAT WE DID NOT UNDERSTAND THE POSSIBLE PLTDEV BECAUSE ATC HAD GIVEN US THE SAME HDG THAT WE WERE FLYING AND DID NOT UNDERSTAND WHAT WENT WRONG. ATC TOLD US THAT IT WAS A NEW PROC AND THAT A LOT OF CRJ'S WERE HAVING PROBS WITH THE PROC DUE TO THE FMS FAILURES. ATC ALSO TOLD US THAT WE WERE ABOUT 2-3 MI N OFF COURSE BEFORE WE INTERCEPTED THE 143 DEG RADIAL TO POMONA. WE TOLD HIM THAT THE DIRECT WIND FROM THE S TO THE N ABOUT 15 KTS WOULD HAVE BLOWN US ABOUT THAT FAR N AND THAT THEY SHOULD LOOK INTO WIND DRIFT DURING THE PROC. THEY TOLD US NOT TO WORRY ABOUT IT. I STILL AM CONCERNED WHAT WE DID WRONG BESIDES BEING 2-3 MI N OFF COURSE DUE TO THE WINDS.