E Comparison Of RT-2 And RT-20

206 MiLLennium Command Descriptions Manual

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 measurem ents. Dual-frequency GPS
receivers have two main advantages over their single-frequency counterparts when running R TK software:
1. resolution of cycle ambiguity is possible due to the use of wide lane searching
2. longer baselines are possible due to the removal of ionospheric errors
The MiLLennium L1/L2 receivers are capable of transmitting RTK messages for both the GPSCard RT-20 and the
MiLLennium RT-2 systems. Depending on the receiving receiver, it is capable of various levels of accuracy. Please
refer to the particular accuracy as shown in Table E-2.
Not yet implemented in receiver firmware revision 3.34
RT-2 RT-20
GPS Frequencies Utilized L1 & L2 L1
Nominal Accuracy 2 cm (CEP) 20 cm (CEP)
Lane Searching Wide lane and narrow lane None

Table E-2 RTK Messages Vs. Accuracy

Transmitting (Reference) Receiving (Remote) Accuracy Expected
MiLLennium L1/L2 transmitting RTCA
(i.e. RTCAOBS and RTCAREF) MiLLennium L1/L2 receiver 100 metre 2DRMS
MiLLennium RT-2 receiver 2 centimetre CEP
GPSCard RT-20 receiver 20 centimetre CEP
MiLLennium L1/L2 transmitting RTCM type 3 and 59 MiLLennium L1/L2 receiver 100 meter 2DRMS
MiLLennium RT-2 receiver 20 centimetre CEP
GPSCard RT-20 receiver 20 centimetre CEP
GPSCard RT-20 transmitting RTCM type 3 and 59 MiLLennium L1/L2 receiver 100 meter 2DRMS
MiLLennium RT-2 receiver 20 centimetre CEP
GPSCard RT-20 receiver 20 centimetre CEP
GPSCard RT-20 or MiLLennium L1/L2 transmitting
RTCM or RTCA type 1 MiLLennium L1/L2 receiver 1 metre SEP
MiLLennium RT-2 receiver 1 metre SEP
GPSCard RT-20 receiver 1 metre SEP
ECOMPARISON OF RT-2 AND RT-20