The Army's 33rd Artillery Group is based south-west of Tehran in a range of hills that host a number of other military units, including the Army's 23rd Commando Division to the south/south-east, and a sprawling industrial complex to the north-east associated with the Sepah Aerospace Force's missile development program. The artillery group itself shares its garrison with the NEZAJA's 99th Air Defense Group. The garrison is divided roughly in half by a large parade ground, with the 99th Group occupying the western portion, and the 33rd the eastern portion.
Thanks to it proximity to the capital, Google Earth offers a range of imagery from 10/2003, 05/2010, 07/2010, 05/2011, 06/2011, 09/2011, 06/2012, 10/2012, 05/2013, much of high quality. Furthermore, Wikimapia includes a host of user annotations, detailing the identity of certain buildings. Although it is risky to trust entirely in the credibility of these annotations, they are invaluable in many cases.
Secondary features noted on Wikimapia include: a fire-station (1), a bakery and adjacent tailor/barber (2), a dining-area/movie-theater (3), two clinics (4), communications building (5), intelligence department (6), general-staff offices (7), political-ideology department (8), guest-residences (9), water treatment plant (10), and offices for military police (11).
These annotations also provide clues as to the group's force structure. It confirms that the multi-stored T-shaped buildings are unit-barracks, including the 388th [Artillery] Battalion (12), 325th Air Defense Battalion (13), a command and headquarters battery (14). Another three barracks (15) aren't labeled, likely corresponding to an additional two artillery battalions, and – possibly – a training battalion. Note the distinct construction style employed in these barracks; multi-story (4-5 stories) battalion housing rather than shorter (1-2 stories) company housing employed elsewhere.
This nominal organization is supported by the NEZAJA's ever-so thoughtful decision to park their equipment in uncovered, well-organized motor-pools. In fact, this group provides an excellent case study in small-unit organization. Three battalions of guns are visible. Two of these (16) are equipped with the 130mm M-46 / Type-59 towed-gun, organized into three batteries around six guns each, though sometimes this number varies up or down.
The third battalion (17) is equipped with the 155 mm GHN-45 gun, which can be identified by its characteristic appearance when locked in travel configuration; like the D-30, the GHN-45's barrel is reversed and locked backwards over its trails when it is towed, making it appear square on overhead imagery. Although this battalion also has three batteries, the average strength of each battery is four-five, rather than six, guns.
From time to time, guns are removed from their respective batteries are can be found in the large, unpaved parade yard bisecting the compound, likely for purposes of routine training / weapon-familiarization. The 05/2011 imagery in notable in that it shows a handful of guns obscured by camouflage netting (18)
The image quality is high enough to allow for a high-confidence assessment of each battalion's support equipment as well. Gun tractors are uniformly Kraz-6322 6x6 trucks, while battery support vehicles include the smaller Kraz-5233 4x4. At the battalion level, truck-variety expands and uniform identification is impossible, though they surely include, or are in a comparable series to, the Mercedes Benz L 911/1924 range, which have historically served as the platform for carrying command/communication-shelters, bakeries and workshop containers, or as prime-movers for trailers. A number of these trailers are visible, including POL tanks, and generators and/or field-kitchens. At least some of them are the more modern cab-over-engine variants. These same vehicle-types of vehicles are also found at the group-level.
There is no readily visible equipment that would belong to the air defense battalion, though this isn't surprising considering that they would be restricted to towed or truck-mounted Zu-23-2s, and MANPADs. However, the motor-pool belonging to the command and headquarters battery (19) is marked on Wikimapia, showing a handful (<5) of cab-over-engine and cab-after-engine medium trucks. Also present are a number of smaller in the ¼ - ¾ ton range. At least one bucket loader and one digger are visible over the range of available imagery.