Linq to sql unkown return types stored procedure

ALTER PROCEDURE [dbo].[uspGetBusesByDepature] 
	-- Add the parameters for the stored procedure here
	@vRouteNumber varchar(4),
	@dtDepartureTime datetime,
	@dtArrivalTime datetime,
	@InDate datetime
AS
BEGIN
	-- SET NOCOUNT ON added to prevent extra result sets from
	-- interfering with SELECT statements.
	SET NOCOUNT ON;

	DECLARE @DeparturePoint geography,
			@Latitude float,
			@Longitude float,
			@Radius float

    -- Insert statements for procedure here
	SET @Latitude = (SELECT fRouteWayPointLatitude 
					 FROM dbo.RouteWayPoint 
					 WHERE vRouteNumber = @vRouteNumber 
							AND iSequence = 1)

	SET @Longitude = (SELECT fRouteWayPointLongitude
					 FROM dbo.RouteWayPoint 
					 WHERE vRouteNumber = @vRouteNumber 
							AND iSequence = 1)

	SET @Radius = (SELECT fRouteWayPointRadius
					 FROM dbo.RouteWayPoint 
					 WHERE vRouteNumber = @vRouteNumber 
							AND iSequence = 1) * 1000

	SET @DeparturePoint = geography::Point(@Latitude, @Longitude, 4326)
	SET @dtDepartureTime = CONVERT(varchar, @InDate, 101) + ' ' + CONVERT(varchar(8), @dtDepartureTime, 108)

	SELECT gps.iVehicleID, sDesc AS vVehicleDescription, sRegNo AS [vVehicleRegNo], 
			 SUBSTRING(CONVERT(varchar(8), MIN(dtTime), 108), 1, 5) 
			 + ' | ' + SUBSTRING(sDesc, 1, 4) + ' - ' + 
			 SUBSTRING(sRegNo, 1, CHARINDEX('-',sRegNo,1)-1) 
			AS vVehicleText, MIN(dtTime) AS dtTime--, 
			--dbo.fnBusIsAssigned(gps.iVehicleID, @dtDepartureTime, @dtArrivalTime, @InDate) AS isAssigned
	FROM dbo.GPSDataDW gps INNER JOIN Vehicles v
	ON gps.iVehicleID = v.iVehicleID
	WHERE dtTime BETWEEN  DATEADD(MI, -30, @dtDepartureTime) AND DATEADD(MI, 30, @dtDepartureTime) 
		AND @Radius >  @DeparturePoint.STDistance(geography::Point(fLatitude, fLongitude, 4326))
	GROUP BY gps.iVehicleID, sDesc, sRegNo

	END