A Map of the Indiana HARN

This bulletin contains some interesting articles covering the history of the NGS High Accuracy Reference Network project, and the Indiana HARN. Indiana was the last state to have a HARN measured.

HARN points throughout the United States: Although the Indiana HARN is not as dense as the Minnesota HARN, our distribution is not bad as compared to West Virginia (taken from the September/October ACSM bulletin).

A national map of the HARN projects. The survey date and GPS project number are given for each state (taken from the September/October ACSM bulletin).

A train passes Q 94 (Tippecanoe County/Purdue Airport) while being occupied during the first phase of the Indiana HARN (Summer 1997).

The same Q 94 at Purdue Airport: here one can see the antenna, reciever, and the four VCR camera batteries that provide power.

It was a NGS crew who occupied Q 94 (Purdue Airport). On the left, the NGS observation campaign manager.

The NGS/GPS truck.

Now where did we put that 5-pin Lemo to DB9 cable?

GPS antenna on a 2 meter fixed height tripod.

Again a NGS/GPS receiver at Q 94 with their truck in the background.

The GPS base stations at Purdue University: The left antenna is for single and dual frequency survey work, while the right antenna is C/A-Code only is for support of GIS projects.

Although the GPS base stations at Purdue University are not part of the Indiana HARN, observations were made during the HARN observing sessions to verify the position of these antennae.

In the second phase of the HARN the contributions of INDOT personnel were as crucial as in the first phase. Here, an INDOT GPS observer (re)occupies Q 94, which is located in front of the terminal building at Purdue Airport.

To get a balanced network, many proposed HARN sites were dropped from the first phase. Here, an INDOT observer occupies one of the two new points in Tippecanoe county, Z125, just north of Battle Ground.