WASHINGTON – The Army is expected to spend an aggressive $1.8 billion to upgrade its key air-and-missile defense system – the Raytheon-made Patriot – over the next five years, but the agency that serves as Congress' watchdog finds that not enough oversight of the program has been put in place in advance of the effort.

Congress has consistently taken issue with what it sees as the Army's inability to estimate the cost of the system in future years and has regularly withheld funds to upgrade portions of the system, demanding the Army provide more clarity to its plans before shelling out all of the requested cash to fund it.

The Government Accountability Office (GAO) released a report Aug. 26 finding the Army's plans to improve the system, which is expected to remain in operation until at least 2050, lacks oversight mechanisms as the Army carries out its strategy in the coming years.

Congress requested the GAO report, asking the auditing agency to look at the status of the Patriot system and the Army's strategy to upgrade it.

The Army has spent $1.1 billion since 2013 and plans to spend another $1.8 billion between now and 2021 to upgrade Patriot, according to the GAO report. "These efforts are intended to improve the system's performance, reliability, and communications as well as address obsolescence and sustainment issues," the report states.

Crucial to Patriot's functionality in the future is a string of major software upgrades called Post Deployment Build-8 (PDB-8) and PDB-8.1. The software upgrades are intended to help the system keep pace with emerging and current threats.

The Army is testing the operational functionality of the first variant of the software in fiscal 2016 and the second in 2019. "These test results will reveal the extent to which the near- and mid-term upgrades work as intended," the report notes.

The GAO found that the Army incorporated the Patriot upgrade efforts into the existing Patriot program, making certain oversight mechanisms inapplicable, even though the estimated cost of the upgrades categorizes the upgrade itself as a major defense acquisition program. The Army also decided not to establish a way to track or report the upgrades' progress in relation to cost, schedule and performance estimates, which is normally required for major acquisition programs.

The service "would have put itself in a much better position to oversee its Patriot upgrade efforts had it made the decision in 2013 to manage Patriot upgrades as a separate major defense acquisition program," the GAO found.

The office is recommending the Defense Secretary direct the service to establish better oversight procedures in line with major acquisition programs "if additional development is required for upgrades operationally tested with PDB-8 and PDB-8.1."

And the office wants to see annual updates from the Army to Congress comparing the latest cost and schedule estimates against the original ones and provide "explanations for any major deviations until development is complete."

The Army is also planning to upgrade or replace the radar element of the Patriot system. The GAO report determined the current Patriot system doesn't meet all documented performance requirements and critical warfighter needs. A new or upgraded radar is one crucial avenue to improving the system to meet current needs such as a 360-degree range to detect and counter incoming threats.

While the Army is just beginning testing on the PDB-8 software, a version of Patriot that includes this upgrade is what Raytheon is preparing to provide to Poland in what has been a high-profile procurement for the country.

The deal was held up as the new Polish administration was concerned primarily over the cost of the system and conducted a review of the previous administration’s decision to buy Patriot. Poland is said to still be weighing its options, but is expected to mint a deal with the US government by the end of the year that will include an agreement to conduct over 50 percent of the work to build Patriot in Poland.