systems of the K9 Thunder and the K9 upgrade plan. The development took three years between 2007 and 2010. The upgrade started in 2010. In November 2010, in the wake of the North Korean artillery attack, the South Korean government authorized a massive increase in military spending. South Korea allocated 11.5 billion KRW on K55A1 upgrades for FY2011, more than a 1500% increase from 700 million KRW for FY2010. The upgrade was performed by Samsung Techwin, and the first vehicle was fielded by the South Korean Army in early 2011. The K55A1 is fitted with the same electronics and fire control system as the K9. The self-propelled gun has significantly enhanced field operability and accuracy through the installation of Honeywell Aerospace's TALIN 5000 INS (inertial navigation system), a satellite navigation device (GPS), and a speed calibrator. As a result, the vehicle automatically lays the gun in the desired direction and delivers a first round within 45 seconds when stationary, or 75 seconds on the move after receiving the shooting specification, which required 2 minutes and 11 minutes, respectively, on the K55. With the help of a new semi-autoloader, while charges are still inserted manually, the howitzer can fire 4 rounds per minute, increased from 2 to 3 rounds per minute. The improved suspension, involving a strut-type hydropneumatic buffer from Mottrol Co, Ltd., along with an enhanced chamber, allowed the vehicle to shoot without laying spades at a maximum distance of 32 km using base bleed ammunition. An APU (auxiliary power unit) was installed to operate the howitzer without turning on the main engine. The Army Consolidated Maintenance Depot joined the K55A1 upgrade, releasing its first results in December 2013. The upgrade cost 20% of the K9 Thunder, 800 million KRW, as of 2021. M109A7 The newest M109 version for U.S. service is the M109A7, formerly known as the M109A6 Paladin Integrated Management (PIM). The M109A7 shares common chassis components with the Bradley Fighting Vehicle (BFV) such as the engine, transmission, and tracks. This creates commonality with other systems and maximizes cost savings in production, parts inventory, and maintenance personnel. The M109A7's onboard power systems harness technologies originally developed for the Non-Line-of-Sight Cannon. The electric drive is faster than the previous hydraulic system, and the automatic rammer more consistently rams the round into the gun for consistent velocities and better accuracy. It features a 600-volt onboard power system to accommodate additional