In order to improve the GLA's reconnaissance capability, improved observation scanners can be installed from the Black Market, which gives it the following capabilities:
The Observation Van becomes harder to destroy, and can now detect stealthed enemies around itself.
The Command Truck can perform radar scans to see enemy activity in large areas around the battlefield and becomes stealthed while deployed, forcing the enemy to bring detectors to seek and destroy it to cripple the GLA command and control network.
Behind the scenes
Prior to 1.87 this upgrade is named Command Expansion and only affects the Command Truck. It is also $500 cheaper and are researched from the Chemical Lab.