RTK GNSS/INS Module UM982/UM980 Centimeter-level Positioning and Orientation

All our antennas are Active Antenna.

A Passive Antenna does not contain any active electronic components.

An Active Antenna integrates a signal amplifier behind the passive antenna to improve signal strength.

Passive Antenna does not require power feeding; Active Antenna requires power feeding.

PPP stands for Precise Point Positioning. It uses predicted or post-mission precise GPS satellite ephemeris as the known coordinate starting data. The basic principle is similar to standard GPS single-point positioning, but the difference lies in the precision.

To achieve high precision, PPP has the following characteristics:

a. PPP provides absolute positioning, unlike RTK GNSS which provides relative positions relative to a reference station.

b. PPP does not use differential technology. Instead, it constructs ionosphere-free pseudorange and carrier-phase combinations using dual-frequency or multi-frequency receivers to eliminate the first-order ionospheric effects.

c. PPP uses precise ephemeris and precise satellite clock data. PPP is also affected by satellite visibility. If the user cannot track the required satellites, even the most accurate orbit and clock data cannot be used. When satellites from one system are not visible, using satellites from other GNSS systems ensures the best possible service.

d. PPP Accuracy: 10cm horizontal, 20cm vertical. Longer observation times result in higher accuracy.

Note: Only WTRTK-980 and WTRTK-982 support PPP.

Single-Frequency means the GNSS receiver operates on a single frequency band, typically L1.

Dual-Frequency means the GNSS receiver operates on two frequency bands, typically L1/L2 or L1/L5. It can cancel the majority of the ionospheric error using observations from both frequencies.

Triple-Frequency means the GNSS receiver operates on three frequency bands, typically L1/L2/L5.

Multi-Frequency means the GNSS receiver operates on multiple frequency bands, such as L1/L2/L5/L6. Generally, multi-frequency GNSS receivers offer higher signal acquisition sensitivity, stronger anti-interference capabilities, and higher positioning accuracy compared to single-frequency receivers.

Cold Start: The receiver starts up with no known ephemeris, almanac, approximate time, or approximate position.

Warm Start: The receiver starts up with known almanac, approximate time, and approximate position, but unknown ephemeris.

Hot Start: The receiver starts up with known ephemeris, almanac, approximate time, and approximate position.

It refers to the baseline vector formed between the primary antenna and the secondary antenna of the dual-antenna receiver. The Heading is defined as the counterclockwise angle between this baseline vector and true north.

The product does not have an internal IMU. Both Positioning and Heading are calculated based on longitude and latitude.

If longitude and latitude are unavailable, the Heading function cannot be used.

However, you can refer to our RTK-4GA product, which integrates an IMU and can still function without longitude and latitude data.

The Base Station transmits differential data containing the Base Station ID. Each Rover can be distinguished by its module version information.

Example:

1. Query version: VERSIONA
2. The returned version information is as follows:
   #VERSIONA,98,GPS,UNKNOWN,1,100000,0,0
   18,54:"UM982""R4.10Build11826""HRPTO0-S10C-p""2310415000012-LR23A2233111486"ff3b65918f09978e"2023/11/24"*9ca48213
3. The string LR23A2233111486 is the unique module identifier.