Detection and removal of buried, unexploded ordnance (UXO) from past military activities are necessary to protect human lives and the environment. A key objective of the munition response program within the ESTCP portfolio is to demonstrate the capabilities of various technologies related to UXO detection and classification. Electromagnetic Induction (EMI)-based detection of UXO has been successfully demonstrated in the recent past; for example, the US Naval Research Laboratory’s (NRL) TEMTADS 2x2. The quality of the modeling results from the post-processing of EMI observations is directly related to the quality of the position and attitude information used to merge these observations into one anomaly map. In open, clear environments, GPS-based geolocation meets all the needs of so-called Advanced Geophysical Classification but in GPS-restricted environments another solution is required. The objective of this project is to demonstrate a geolocation solution that can be used in difficult environments.
The ESTCP project, titled Demonstration of Advanced Geolocation Technology to Support Dynamic Classification of EMI Data Collect in Navstar GPS-challenged Areas has delivered consistent performance during the demonstration session at NRL - Blossom Point. The quadruple sensor integration based system was able to accurately geolocate the EMI platform in forested areas, where Global Navigation Satellite System (GNSS) reception was not available or of poor quality. In general, all relevant project objectives, such as detection and acquisition accuracies are achieved or are within a small margin. Furthermore, the reacquisition test, which aimed to assess the performance of the Advanced Geolocation Technology (AGT) system for finding and flagging detected anomalies in the field, has also shown excellent results.
The technology development achieved in SERDP MR-1564 project, titled Novel Geolocation Technology for Geophysical Sensors for Detection and Discrimination of Unexploded Ordnance, formed the basis for the prototype systems developed for the demonstrations. As technology has advanced, the original sensor integration concept was updated to reflect the state-of-the-art in sensing, and consequently, in the data processing workflow. In short, the pseudolight and laser sensor sensors originally proposed were replaced by Ultra-Wideband (UWB) and Software Defined Radio technologies. Furthermore, due to technological improvements, two AGT prototype ietrations were developed. The first one was based on a pushcart data acquisition system, while the second was based on a backpack configuration.
Two AGT prototype systems have been tested, and while even the second one was not fully optimized for normal operations, the system worked well and imposed very little extra effort and attention on the field crew; note that the AGT system was operated by the developers, so their understanding was significantly higher than that of a typical technician. It is important to mention that with a moderate effort engineering, the AGT system can be almost entirely integrated to the existing TEMTADS 2x2 system; GNSS, recording, power, sharing the tablet for user interface, etc., can be shared. The only extra element is the UWB network. The current configuration of the network consists of four surveying poles, placed at the four corners of the site. Each pole has two UWB transmitters mounted at different heights. Note that the vertical separation of the UWB units allows for increased observability of the rover’s vertical position (Z coordinate). Since these sensors are small, they can be easily integrated into a standard surveying pole. The use of these sensor poles increase the preparation time by about 30%. Since the AGT data processing is an additional step, there is a small increase in the processing time.