Description:
- Object ID: M-XII: ALSA 2022.02.03 and LD-XII: ALSA 2022.02.04
- Made by: Ashtech Corporation
- Model: M-XII, LD-XII
- Serial Number: M-XII: 700157A0526, LD:XII: 700226C0296
- Date Made: Circa 1990.
- Approximate size:
- Accessories:
M-XII: Antenna L1-L2, s/n 11083. Two 2 V rechargeable sealed lead-acid batteries. Cable for attaching battery to GPS Receiver. Two cables for attaching antenna to GPS Receiver. Measuring rod for measuring height of antenna.
In a blue packsack: Ashtech X11 GPS Receiver Operating Manual; Ashtech X11 GPS Post Processing System Manual and five other various manuals.
LD-XII: Antenna L1-L2, s/n 700138A0602. Cable for attaching a battery to the GPS Receiver. Cable for attaching the antenna to the GPS Receiver. - Condition: Good.
Commentary:
In the 1980’s the Ashtech XII GPS was introduced. It was groundbreaking as a high-precision, 12-channel GPS receiver. It used the Navstar Global Positioning System to provide accurate positions for surveying and navigation. It had an “All-In-View” tracking capability, meaning it could automatically track all visible satellites simultaneously using dedicated physical channels
This Ashtech system is comprised of two receivers. The M-XII (Base Unit) is set up over a high accuracy control point (the base station) where it tracks GPS satellites and computes its position from the GPS signals. A real-time differential correction (the difference between the control point’s known position and the GPS-derived position) is determined. The LD-XII (Rover Unit) is set up over a station the position of which is not known. The LD-XII also obtains a position based on the GPS signal. Applying the real -time differential correction an accurate position of the station (on which the rover is on) is obtained in relation to the base station. The LD-XII can be moved from station to station thus obtaining their positions in a relatively short time..
Source of Object: Donated by Jim Pinchas.
Notes:
References: Visit article More than a Technological Change – GPS for additional information.
Description by: Entered by Ed Titanich on December 12, 2024, Gordon Olsson on January 9, 2026.