We use
GARMIN handheld GPS receivers, GPSII+, GPSIII+, and mobile computers for
orienteering mapping survey in the field.
The horizontal accuracy is approximately 1m by on-line (D-GPS) and
better than 20cm by off-line with post processing
(Carrier phase process).
Fig. 1 GPS Position Marker is shown on OCAD7
We also use the GPS phase data, which are provided by Geographical
Survey Institute JAPAN (GSI), as position of reference when we analyze post
processing to know higher accurate positions. GSI provide everyone the data of 1,000
GPS stations without any cost.
All of these GPS equipments are on the open market and very cheaper than others land survey equipments. We can buy many sets of the equipments easily. So, we are planning every field surveyor will use the GPS survey system, it will help them remarkably. We will be able to provide the high accuracy map for competitors.
Very Small !
Japanese GPS markets have been
grown drastically. SONY corp. put
portable GPS unit, IPS-8000, on the Japanese market March 2000. The GPS receiver has strong advantages,
which are high reception for GPS radio wave by 16 channels, can calculate by
only 2 satellites continuously and has quickly reacquisition (~10 sec). Even if the competitor
runs into deep forest or steep hill, the receiver can catch GPS satellites and
send the position data. The error is only few meters.
The position data is sent by a cellular
phone to competition center. Japanese cellar phone business is also becoming
very big market. The service area
is very wide (e.g. 99.9% covered by NTT DoCoMo), and the cost is very cheap.
Cellular Company will soon release a mobile phone with GPS. We will use it for
tracking of competitors.