The document specifies the requirements for a differential GPS system, including both a reference station unit and rover handheld unit. The system is intended to rapidly acquire reasonably accurate latitude, longitude, and elevation data. It must be compatible with international GPS networks as well as India's upcoming IRNSS system. The reference unit must provide horizontal accuracy within 1 meter and vertical accuracy within 2 cm when operating within 1 km. It must have features such as data logging, removable storage, and an 8 hour battery. The rover unit must have a color display, memory storage, electronic compass, and barometric altimeter. Comprehensive manuals and instruction must be provided.