I want to improve the probable accuracy of waypoints that I collect during vegetation surveys on foot, where the canopy is overhead and continuous. My handheld receiver unit is a Garmin GPS 60 (consumer grade, position <15 metres 95% typical accuracy).
The unit accuracy is adequate for survey of open-sky areas. However, particularly in forest settings where canopy cover prevents satellite availability, will an external antenna mounted to a pole improve the accuracy? I am presuming the external antenna will see more satellites and improve accuracy that way. But is that true in practice?
The type of external antenna I have in mind are the small units that seem to be sold mainly for consumer automotive GPS use, like a Garmin GA25 MCX or Gilsson FME amplified antenna.