Antenna selection for GNSS receivers
Embodiments of the invention provide a system and method to improve the performance of a GNSS receiver using antenna switching. The system has a plurality of antennas and at least one radio frequency RF chain. There are fewer RF chain(s) than antennas. A receiver processes a plurality of signals sent by a plurality of transmitters. The system also includes antenna switches and switch controller. The method includes processing signals from a plurality of satellite vehicles SVs using an antenna selected from a plurality of antennas.
1. A method for switching antennas, said method comprising:
processing signals from a plurality of satellite vehicles SVs using a first antenna Ai selected from a plurality of antennas, where i is antenna index;
computing a signal quality metric for one or more of the signals;
selecting an antenna from the plurality of antennas using a decision metric; and
switching antennas to the selected antenna, wherein there are two receive antennas and wherein switching antennas comprising changing index i to 3−i.
2. The method of claim 1 , further comprising computing a C/No for each SV using Ai: Ci(j)=C/No for the jth SV while using the ith antenna.
3. The method of claim 2 , further comprising selecting a second antenna based on a decision metric.
4. The method of claim 3 , further comprising switching to said second antenna.
5. A method for switching antennas, said method comprising:
processing signals from a plurality of satellite vehicles SVs using a first antenna Ai selected from a plurality of antennas, where i is antenna index;
computing a signal quality metric for one or more of the signals;
selecting an antenna from the plurality of antennas using a decision metric; and
switching antennas to the selected antenna, wherein switching antennas comprising changing index i by adding 1 to the Modulus of i and Nrx (Nrx is the number of receive antennas being selected from).
6. The method of claim 5 , further comprising changing index i based on a decision metric considering C 1 to CNrx.