Novatel OM-20000041 ECOMPARISON OF RT-2 AND RT-20

E Comparison Of RT-2 And RT-20
MiLLennium GPSCard Software Version 4.50 Command Descriptions Manual Rev 1 225
E COMPARISON OF RT-2 AND RT-20
E.1 RT-2 & RT-20 PERFORMANCE
RT-2 and RT-20 are real-time kinematic software products developed by NovAtel. They can only be used in
conjunction with NovAtel GPS receivers. A quick comparison of RT-2 and RT-20 is shown in Table E-1:
Table E-1 Comparison of RT-2 and RT-20
NovAtel’s RTK software algorithms utilize both carrier and code phase measurements; thus, the solutions are
robust, reliable, accurate and rapid. While both RT-20 and RT-2 operate along similar principles, RT-2 achieves
its extra accuracy and precision due to its being able to utilize dual-frequency measurements. Dual-frequency GPS
receivers have two main advantages over their single-frequency counterparts when running RTK software:
1. resolution of cycle ambiguity is possible due to the use of wide lan e searching
2. longer baselines are possible due to the removal of ionospheric errors
Depending on the transmitting and receiving receivers, various levels of accuracy can be obtained. Please refer to
the particular accuracy as shown in Table E-2.
RT-2 RT-20
GPS Frequencies Utilized L1 & L2 L1
Nominal Accuracy 2 cm (CEP) 20 cm (CEP)
Lane Searching Wide lane and n arrow lane None
Table E-2 RTK Messages Vs. Accuracy
Transmitting (Reference) Receiving (Remote) Accura cy Expected
GPSCard transmitting RTCA
(i.e. RTCAOBS and RTCAREF) RT-2 receiver 2 centimetre CEP
RT-20 receiver 2 0 centimetre CEP
GPSCard transmitting RTCM type 3 and 59 RT-2 receiver 20 centimetre CEP
RT-20 receiver 2 0 centimetre CEP
GPSCard transmitting RTCM or RTCA type 1 RT-2 receiver 1 metre SEP
RT-20 receiver 1 metre SEP
GPSCard transmitting RTCM type 18 and 19 with type 31RT-2 receiver 20 centimetre CEP
RT-20 receiver 2 0 centimetre CEP
1 The RTCM1819 message can only be transmitted and received by MiLLennium GPSCards
ECOMPARISON OF RT-2 AND RT-20