The HackRF doesn't have an onboard clock that is accurate enough to simulate/spoof GPS signals. However, this can be done by buying a cheap external clock that plugs into the HackRF board inputs. Ebay has tons of Chinese sellers who advertise these for very cheap(around $15).
You could buy an Ettus USRP B200 or B210 for around $1,216, A bladeRF x40 for $420, or a LimeSDR for $299. LimeSDR is full-duplex, MIMO, and superior to BladeRF. The LimeSDR even matches much of the USRP's B210 specs. The only (temporary) drawback to the LimeSDR is that it doesn't have the same level of software support as the USRP. However, LimeSDR is completely open source and software development is moving very fast.
Comparisons
HackRF One
Ettus B200
Ettus B210
BladeRF x40
RTL-SDR
LimeSDR
Frequency Range
1MHz-6GHz
70MHz-6GHz
70MHz-6GHz
300MHz-3.8GHz
22MHz-2.2GHz
100kHz-3.8GHz
RF Bandwidth
20MHz
61.44MHz
61.44MHz
40MHz
3.2MHz
61.44MHz
Sample Depth
8 bits
12 bits
12 bits
12 bits
8 bits
12 bits
Sample Rate
20MSPS
61.44MSPS
61.44MSPS
40MSPS
3.2MSPS
61.44MSPS (Limited by USB 3.0 data rate)
Transmitter Channels
1
1
2
1
0
2
Receivers
1
1
2
1
1
2
Duplex
Half
Full
Full
Full
N/A
Full
Interface
USB 2.0
USB 3.0
USB 3.0
USB 3.0
USB 2.0
USB 3.0
Programmable Logic Gates
64 macrocell CPLD
75k
100k
40k (115k avail)
N/A
40k
Chipset
MAX5864, MAX2837, RFFC5072
AD9364
AD9361
LMS6002M
RTL2832U
LMS7002M
Open Source
Full
Schematic, Firmware
Schematic, Firmware
Schematic, Firmware
No
Full
Oscillator Precision
+/-20ppm
+/-2ppm
+/-2ppm
+/-1ppm
?
+/-1ppm initial, +/-4ppm stable
Transmit Power
-10dBm+ (15dBm @ 2.4GHz)
10dBm+
10dBm+
6dBm
N/A
0 to 10dBm (depending on frequency)
Price
$299
$686
$1,119
$420 ($650)
~$10
$299 ($289 pre-order)