"vanguard unit" is correct and usable in written English.
The term generally refers to a group or unit that is at the forefront of an effort. For example, "The vanguard unit was sent out ahead of the rest of the troops to scout the area."
One vanguard unit of the new Iraqi Army, known as the Iraqi Intervention Force, is allowed to patrol the streets without Americans.
A battalion of 774 Nigerian troops, which had been part of a peacekeeping force in Sierra Leone, is expected to be the vanguard unit of troops on the ground.
The gap, which was initially an Indian footpath, was discovered in 1755 by a vanguard unit of British and colonial troops led by General Edward Braddock in an ill-fated attempt to move westward across the mountains and expel the French from the Ohio River valley.
Lauren Cerre is a producer for the award-winning "Vanguard" unit of Current TV journalists.
The afternoon of January 27th , 1945 a vanguard unit from the Red Army crossed over into Hell: Auschwitz.
In a report of October 15, Stahlecker wrote that they had succeeded in covering up their vanguard unit (Vorkommando) actions, and it was made to look like it was the initiative of the local population.
So successful has the project been that vanguard units of red squirrels have been crossing bridges to the mainland, where they have set up camp near Bangor.
The I SS Panzer Corps also included a number of ad hoc vanguard units, including Kampfgruppe Peiper (forming part of the 1st SS Panzer Division), which contained a panzer battalion (72 mixed Panzer IV and Panther tanks) from the 1st SS Panzer Regiment, the 501st SS Heavy Panzer Battalion (45 Tiger Is) and the 3rd SS Panzer Grenadier Battalion.
Current, which caters to an 18- to 34-year-old audience and has posted generally low ratings in its four years, tried to fill what it identified as a void in mainstream news coverage with the creation of "vanguard journalism," a unit assembled to cover "untold stories around the globe," as the network put it.
The French vanguard attacked a unit of English archers who had been placed to block the road.
Mr. Wren, 49, has been in the vanguard of adding specialized units, spurred by the increasing demands from marketers for ads beyond traditional forms.
